//! This module defines where the text should be displayed in an [`Editor`][Editor].
//!
//! Not literally though - rendering, layout and all that jazz is a responsibility of [`EditorElement`][EditorElement].
//! Instead, [`DisplayMap`] decides where Inlays/Inlay hints are displayed, when
//! to apply a soft wrap, where to add fold indicators, whether there are any tabs in the buffer that
//! we display as spaces and where to display custom blocks (like diagnostics).
//! Seems like a lot? That's because it is. [`DisplayMap`] is conceptually made up
//! of several smaller structures that form a hierarchy (starting at the bottom):
//! - [`InlayMap`] that decides where the [`Inlay`]s should be displayed.
//! - [`FoldMap`] that decides where the fold indicators should be; it also tracks parts of a source file that are currently folded.
//! - [`TabMap`] that keeps track of hard tabs in a buffer.
//! - [`WrapMap`] that handles soft wrapping.
//! - [`BlockMap`] that tracks custom blocks such as diagnostics that should be displayed within buffer.
//! - [`DisplayMap`] that adds background highlights to the regions of text.
//!   Each one of those builds on top of preceding map.
//!
//! ## Structure of the display map layers
//!
//! Each layer in the map (and the multibuffer itself to some extent) has a few
//! structures that are used to implement the public API available to the layer
//! above:
//! - a `Transform` type - this represents a region of text that the layer in
//!   question is "managing", that it transforms into a more "processed" text
//!   for the layer above. For example, the inlay map has an `enum Transform`
//!   that has two variants:
//!     - `Isomorphic`, representing a region of text that has no inlay hints (i.e.
//!       is passed through the map transparently)
//!     - `Inlay`, representing a location where an inlay hint is to be inserted.
//! - a `TransformSummary` type, which is usually a struct with two fields:
//!   [`input: TextSummary`][`TextSummary`] and [`output: TextSummary`][`TextSummary`]. Here,
//!   `input` corresponds to "text in the layer below", and `output` corresponds to the text
//!   exposed to the layer above. So in the inlay map case, a `Transform::Isomorphic`'s summary is
//!   just `input = output = summary`, where `summary` is the [`TextSummary`] stored in that
//!   variant. Conversely, a `Transform::Inlay` always has an empty `input` summary, because it's
//!   not "replacing" any text that exists on disk. The `output` is the summary of the inlay text
//!   to be injected. - Various newtype wrappers for co-ordinate spaces (e.g. [`WrapRow`]
//!   represents a row index, after soft-wrapping (and all lower layers)).
//! - A `Snapshot` type (e.g. [`InlaySnapshot`]) that captures the state of a layer at a specific
//!   point in time.
//! - various APIs which drill through the layers below to work with the underlying text. Notably:
//!   - `fn text_summary_for_offset()` returns a [`TextSummary`] for the range in the co-ordinate
//!     space that the map in question is responsible for.
//!   - `fn <A>_point_to_<B>_point()` converts a point in co-ordinate space `A` into co-ordinate
//!     space `B`.
//!   - A [`RowInfo`] iterator (e.g. [`InlayBufferRows`]) and a [`Chunk`] iterator
//!     (e.g. [`InlayChunks`])
//!   - A `sync` function (e.g. [`InlayMap::sync`]) that takes a snapshot and list of [`Edit<T>`]s,
//!     and returns a new snapshot and a list of transformed [`Edit<S>`]s. Note that the generic
//!     parameter on `Edit` changes, since these methods take in edits in the co-ordinate space of
//!     the lower layer, and return edits in their own co-ordinate space. The term "edit" is
//!     slightly misleading, since an [`Edit<T>`] doesn't tell you what changed - rather it can be
//!     thought of as a "region to invalidate". In theory, it would be correct to always use a
//!     single edit that covers the entire range. However, this would lead to lots of unnecessary
//!     recalculation.
//!
//! See the docs for the [`inlay_map`] module for a more in-depth explanation of how a single layer
//! works.
//!
//! [Editor]: crate::Editor
//! [EditorElement]: crate::element::EditorElement
//! [`TextSummary`]: multi_buffer::MBTextSummary
//! [`WrapRow`]: wrap_map::WrapRow
//! [`InlayBufferRows`]: inlay_map::InlayBufferRows
//! [`InlayChunks`]: inlay_map::InlayChunks
//! [`Edit<T>`]: text::Edit
//! [`Edit<S>`]: text::Edit
//! [`Chunk`]: language::Chunk

#[macro_use]
mod dimensions;

mod block_map;
mod crease_map;
mod custom_highlights;
mod fold_map;
mod inlay_map;
mod invisibles;
mod tab_map;
mod wrap_map;

pub use crate::display_map::{fold_map::FoldMap, inlay_map::InlayMap, tab_map::TabMap};
pub use block_map::{
    Block, BlockChunks as DisplayChunks, BlockContext, BlockId, BlockMap, BlockPlacement,
    BlockPoint, BlockProperties, BlockRows, BlockStyle, CompanionView, CustomBlockId,
    EditorMargins, RenderBlock, StickyHeaderExcerpt,
};
pub use crease_map::*;
pub use fold_map::{
    ChunkRenderer, ChunkRendererContext, ChunkRendererId, Fold, FoldId, FoldPlaceholder, FoldPoint,
};
pub use inlay_map::{InlayOffset, InlayPoint};
pub use invisibles::{is_invisible, replacement};
pub use wrap_map::{WrapPoint, WrapRow, WrapSnapshot};

use collections::{HashMap, HashSet};
use gpui::{
    App, Context, Entity, EntityId, Font, HighlightStyle, LineLayout, Pixels, UnderlineStyle,
    WeakEntity,
};
use language::{Point, Subscription as BufferSubscription, language_settings::language_settings};
use multi_buffer::{
    Anchor, AnchorRangeExt, ExcerptId, MultiBuffer, MultiBufferOffset, MultiBufferOffsetUtf16,
    MultiBufferPoint, MultiBufferRow, MultiBufferSnapshot, RowInfo, ToOffset, ToPoint,
};
use project::InlayId;
use project::project_settings::DiagnosticSeverity;
use serde::Deserialize;
use sum_tree::{Bias, TreeMap};
use text::{BufferId, LineIndent, Patch};
use ui::{SharedString, px};
use unicode_segmentation::UnicodeSegmentation;
use ztracing::instrument;

use std::{
    any::TypeId,
    borrow::Cow,
    fmt::Debug,
    iter,
    num::NonZeroU32,
    ops::{Add, Bound, Range, Sub},
    sync::Arc,
};

use crate::{
    EditorStyle, RowExt, hover_links::InlayHighlight, inlays::Inlay, movement::TextLayoutDetails,
};
use block_map::{BlockRow, BlockSnapshot};
use fold_map::FoldSnapshot;
use inlay_map::InlaySnapshot;
use tab_map::TabSnapshot;
use wrap_map::{WrapMap, WrapPatch};

#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub enum FoldStatus {
    Folded,
    Foldable,
}

#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub enum HighlightKey {
    Type(TypeId),
    TypePlus(TypeId, usize),
}

pub trait ToDisplayPoint {
    fn to_display_point(&self, map: &DisplaySnapshot) -> DisplayPoint;
}

type TextHighlights = TreeMap<HighlightKey, Arc<(HighlightStyle, Vec<Range<Anchor>>)>>;
type InlayHighlights = TreeMap<TypeId, TreeMap<InlayId, (HighlightStyle, InlayHighlight)>>;

#[derive(Debug)]
pub struct CompanionExcerptPatch {
    pub patch: Patch<MultiBufferPoint>,
    pub edited_range: Range<MultiBufferPoint>,
    pub source_excerpt_range: Range<MultiBufferPoint>,
    pub target_excerpt_range: Range<MultiBufferPoint>,
}

pub type ConvertMultiBufferRows = fn(
    &HashMap<ExcerptId, ExcerptId>,
    &MultiBufferSnapshot,
    &MultiBufferSnapshot,
    (Bound<MultiBufferPoint>, Bound<MultiBufferPoint>),
) -> Vec<CompanionExcerptPatch>;

/// Decides how text in a [`MultiBuffer`] should be displayed in a buffer, handling inlay hints,
/// folding, hard tabs, soft wrapping, custom blocks (like diagnostics), and highlighting.
///
/// See the [module level documentation](self) for more information.
pub struct DisplayMap {
    entity_id: EntityId,
    /// The buffer that we are displaying.
    buffer: Entity<MultiBuffer>,
    buffer_subscription: BufferSubscription<MultiBufferOffset>,
    /// Decides where the [`Inlay`]s should be displayed.
    inlay_map: InlayMap,
    /// Decides where the fold indicators should be and tracks parts of a source file that are currently folded.
    fold_map: FoldMap,
    /// Keeps track of hard tabs in a buffer.
    tab_map: TabMap,
    /// Handles soft wrapping.
    wrap_map: Entity<WrapMap>,
    /// Tracks custom blocks such as diagnostics that should be displayed within buffer.
    block_map: BlockMap,
    /// Regions of text that should be highlighted.
    text_highlights: TextHighlights,
    /// Regions of inlays that should be highlighted.
    inlay_highlights: InlayHighlights,
    /// A container for explicitly foldable ranges, which supersede indentation based fold range suggestions.
    crease_map: CreaseMap,
    pub(crate) fold_placeholder: FoldPlaceholder,
    pub clip_at_line_ends: bool,
    pub(crate) masked: bool,
    pub(crate) diagnostics_max_severity: DiagnosticSeverity,
    pub(crate) companion: Option<(WeakEntity<DisplayMap>, Entity<Companion>)>,
}

pub(crate) struct Companion {
    rhs_display_map_id: EntityId,
    rhs_folded_buffers: HashSet<BufferId>,
    rhs_buffer_to_lhs_buffer: HashMap<BufferId, BufferId>,
    lhs_buffer_to_rhs_buffer: HashMap<BufferId, BufferId>,
    rhs_excerpt_to_lhs_excerpt: HashMap<ExcerptId, ExcerptId>,
    lhs_excerpt_to_rhs_excerpt: HashMap<ExcerptId, ExcerptId>,
    rhs_rows_to_lhs_rows: ConvertMultiBufferRows,
    lhs_rows_to_rhs_rows: ConvertMultiBufferRows,
}

impl Companion {
    pub(crate) fn new(
        rhs_display_map_id: EntityId,
        rhs_folded_buffers: HashSet<BufferId>,
        rhs_rows_to_lhs_rows: ConvertMultiBufferRows,
        lhs_rows_to_rhs_rows: ConvertMultiBufferRows,
    ) -> Self {
        Self {
            rhs_display_map_id,
            rhs_folded_buffers,
            rhs_buffer_to_lhs_buffer: Default::default(),
            lhs_buffer_to_rhs_buffer: Default::default(),
            rhs_excerpt_to_lhs_excerpt: Default::default(),
            lhs_excerpt_to_rhs_excerpt: Default::default(),
            rhs_rows_to_lhs_rows,
            lhs_rows_to_rhs_rows,
        }
    }

    pub(crate) fn convert_rows_to_companion(
        &self,
        display_map_id: EntityId,
        companion_snapshot: &MultiBufferSnapshot,
        our_snapshot: &MultiBufferSnapshot,
        bounds: (Bound<MultiBufferPoint>, Bound<MultiBufferPoint>),
    ) -> Vec<CompanionExcerptPatch> {
        let (excerpt_map, convert_fn) = if display_map_id == self.rhs_display_map_id {
            (&self.rhs_excerpt_to_lhs_excerpt, self.rhs_rows_to_lhs_rows)
        } else {
            (&self.lhs_excerpt_to_rhs_excerpt, self.lhs_rows_to_rhs_rows)
        };
        convert_fn(excerpt_map, companion_snapshot, our_snapshot, bounds)
    }

    pub(crate) fn convert_point_from_companion(
        &self,
        display_map_id: EntityId,
        our_snapshot: &MultiBufferSnapshot,
        companion_snapshot: &MultiBufferSnapshot,
        point: MultiBufferPoint,
    ) -> Range<MultiBufferPoint> {
        let (excerpt_map, convert_fn) = if display_map_id == self.rhs_display_map_id {
            (&self.lhs_excerpt_to_rhs_excerpt, self.lhs_rows_to_rhs_rows)
        } else {
            (&self.rhs_excerpt_to_lhs_excerpt, self.rhs_rows_to_lhs_rows)
        };

        let excerpt = convert_fn(
            excerpt_map,
            our_snapshot,
            companion_snapshot,
            (Bound::Included(point), Bound::Included(point)),
        )
        .into_iter()
        .next();

        let Some(excerpt) = excerpt else {
            return Point::zero()..our_snapshot.max_point();
        };
        excerpt.patch.edit_for_old_position(point).new
    }

    pub(crate) fn companion_excerpt_to_excerpt(
        &self,
        display_map_id: EntityId,
    ) -> &HashMap<ExcerptId, ExcerptId> {
        if display_map_id == self.rhs_display_map_id {
            &self.lhs_excerpt_to_rhs_excerpt
        } else {
            &self.rhs_excerpt_to_lhs_excerpt
        }
    }

    fn buffer_to_companion_buffer(&self, display_map_id: EntityId) -> &HashMap<BufferId, BufferId> {
        if display_map_id == self.rhs_display_map_id {
            &self.rhs_buffer_to_lhs_buffer
        } else {
            &self.lhs_buffer_to_rhs_buffer
        }
    }

    pub(crate) fn add_excerpt_mapping(&mut self, lhs_id: ExcerptId, rhs_id: ExcerptId) {
        self.lhs_excerpt_to_rhs_excerpt.insert(lhs_id, rhs_id);
        self.rhs_excerpt_to_lhs_excerpt.insert(rhs_id, lhs_id);
    }

    pub(crate) fn remove_excerpt_mappings(
        &mut self,
        lhs_ids: impl IntoIterator<Item = ExcerptId>,
        rhs_ids: impl IntoIterator<Item = ExcerptId>,
    ) {
        for id in lhs_ids {
            self.lhs_excerpt_to_rhs_excerpt.remove(&id);
        }
        for id in rhs_ids {
            self.rhs_excerpt_to_lhs_excerpt.remove(&id);
        }
    }

    pub(crate) fn lhs_to_rhs_buffer(&self, lhs_buffer_id: BufferId) -> Option<BufferId> {
        self.lhs_buffer_to_rhs_buffer.get(&lhs_buffer_id).copied()
    }

    pub(crate) fn add_buffer_mapping(&mut self, lhs_buffer: BufferId, rhs_buffer: BufferId) {
        self.lhs_buffer_to_rhs_buffer.insert(lhs_buffer, rhs_buffer);
        self.rhs_buffer_to_lhs_buffer.insert(rhs_buffer, lhs_buffer);
    }
}

impl DisplayMap {
    pub fn new(
        buffer: Entity<MultiBuffer>,
        font: Font,
        font_size: Pixels,
        wrap_width: Option<Pixels>,
        buffer_header_height: u32,
        excerpt_header_height: u32,
        fold_placeholder: FoldPlaceholder,
        diagnostics_max_severity: DiagnosticSeverity,
        cx: &mut Context<Self>,
    ) -> Self {
        let buffer_subscription = buffer.update(cx, |buffer, _| buffer.subscribe());

        let tab_size = Self::tab_size(&buffer, cx);
        let buffer_snapshot = buffer.read(cx).snapshot(cx);
        let crease_map = CreaseMap::new(&buffer_snapshot);
        let (inlay_map, snapshot) = InlayMap::new(buffer_snapshot);
        let (fold_map, snapshot) = FoldMap::new(snapshot);
        let (tab_map, snapshot) = TabMap::new(snapshot, tab_size);
        let (wrap_map, snapshot) = WrapMap::new(snapshot, font, font_size, wrap_width, cx);
        let block_map = BlockMap::new(snapshot, buffer_header_height, excerpt_header_height);

        cx.observe(&wrap_map, |_, _, cx| cx.notify()).detach();

        DisplayMap {
            entity_id: cx.entity_id(),
            buffer,
            buffer_subscription,
            fold_map,
            inlay_map,
            tab_map,
            wrap_map,
            block_map,
            crease_map,
            fold_placeholder,
            diagnostics_max_severity,
            text_highlights: Default::default(),
            inlay_highlights: Default::default(),
            clip_at_line_ends: false,
            masked: false,
            companion: None,
        }
    }

    pub(crate) fn set_companion(
        &mut self,
        companion: Option<(WeakEntity<DisplayMap>, Entity<Companion>)>,
        cx: &mut Context<Self>,
    ) {
        let Some((companion_display_map, companion)) = companion else {
            self.companion = None;
            let (snapshot, edits) = self.sync_through_wrap(cx);
            let edits = edits.compose([text::Edit {
                old: WrapRow(0)..snapshot.max_point().row(),
                new: WrapRow(0)..snapshot.max_point().row(),
            }]);
            self.block_map.read(snapshot, edits, None);
            return;
        };

        let rhs_display_map_id = companion.read(cx).rhs_display_map_id;
        if self.entity_id != rhs_display_map_id {
            let buffer_mapping = companion
                .read(cx)
                .buffer_to_companion_buffer(rhs_display_map_id);
            self.block_map.folded_buffers = companion
                .read(cx)
                .rhs_folded_buffers
                .iter()
                .filter_map(|id| buffer_mapping.get(id).copied())
                .collect();
        }

        let snapshot = self.unfold_intersecting([Anchor::min()..Anchor::max()], true, cx);

        self.companion = Some((companion_display_map.clone(), companion));

        let companion_wrap_data = companion_display_map
            .update(cx, |dm, cx| dm.sync_through_wrap(cx))
            .ok();
        let companion = self.companion.as_ref().map(|(_, c)| c.read(cx));
        let companion_view =
            companion_wrap_data
                .as_ref()
                .zip(companion)
                .map(|((snapshot, edits), companion)| {
                    CompanionView::new(self.entity_id, snapshot, edits, companion)
                });

        let edits = Patch::new(
            [text::Edit {
                old: WrapRow(0)..snapshot.max_point().row(),
                new: WrapRow(0)..snapshot.max_point().row(),
            }]
            .into_iter()
            .collect(),
        );
        self.block_map
            .read(snapshot.clone(), edits.clone(), companion_view);

        if let Some((companion_dm, _)) = &self.companion {
            let _ = companion_dm.update(cx, |dm, _cx| {
                if let Some((companion_snapshot, companion_edits)) = companion_wrap_data {
                    let their_companion_ref = dm.companion.as_ref().map(|(_, c)| c.read(_cx));
                    dm.block_map.read(
                        companion_snapshot,
                        companion_edits,
                        their_companion_ref
                            .map(|c| CompanionView::new(dm.entity_id, &snapshot, &edits, c)),
                    );
                }
            });
        }
    }

    pub(crate) fn companion(&self) -> Option<&Entity<Companion>> {
        self.companion.as_ref().map(|(_, c)| c)
    }

    pub(crate) fn companion_excerpt_to_my_excerpt(
        &self,
        their_id: ExcerptId,
        cx: &App,
    ) -> Option<ExcerptId> {
        let (_, companion) = self.companion.as_ref()?;
        let c = companion.read(cx);
        c.companion_excerpt_to_excerpt(self.entity_id)
            .get(&their_id)
            .copied()
    }

    fn sync_through_wrap(&mut self, cx: &mut App) -> (WrapSnapshot, WrapPatch) {
        let tab_size = Self::tab_size(&self.buffer, cx);
        let buffer_snapshot = self.buffer.read(cx).snapshot(cx);
        let edits = self.buffer_subscription.consume().into_inner();

        let (snapshot, edits) = self.inlay_map.sync(buffer_snapshot, edits);
        let (snapshot, edits) = self.fold_map.read(snapshot, edits);
        let (snapshot, edits) = self.tab_map.sync(snapshot, edits, tab_size);
        self.wrap_map
            .update(cx, |map, cx| map.sync(snapshot, edits, cx))
    }

    #[instrument(skip_all)]
    pub fn snapshot(&mut self, cx: &mut Context<Self>) -> DisplaySnapshot {
        let (self_wrap_snapshot, self_wrap_edits) = self.sync_through_wrap(cx);
        let companion_wrap_data = self.companion.as_ref().and_then(|(companion_dm, _)| {
            companion_dm
                .update(cx, |dm, cx| dm.sync_through_wrap(cx))
                .ok()
        });
        let companion_ref = self.companion.as_ref().map(|(_, c)| c.read(cx));
        let companion_view = companion_wrap_data.as_ref().zip(companion_ref).map(
            |((snapshot, edits), companion)| {
                CompanionView::new(self.entity_id, snapshot, edits, companion)
            },
        );

        let block_snapshot = self
            .block_map
            .read(
                self_wrap_snapshot.clone(),
                self_wrap_edits.clone(),
                companion_view,
            )
            .snapshot;

        if let Some((companion_dm, _)) = &self.companion {
            let _ = companion_dm.update(cx, |dm, _cx| {
                if let Some((companion_snapshot, companion_edits)) = companion_wrap_data {
                    let their_companion_ref = dm.companion.as_ref().map(|(_, c)| c.read(_cx));
                    dm.block_map.read(
                        companion_snapshot,
                        companion_edits,
                        their_companion_ref.map(|c| {
                            CompanionView::new(
                                dm.entity_id,
                                &self_wrap_snapshot,
                                &self_wrap_edits,
                                c,
                            )
                        }),
                    );
                }
            });
        }

        let companion_display_snapshot = self.companion.as_ref().and_then(|(companion_dm, _)| {
            companion_dm
                .update(cx, |dm, cx| Arc::new(dm.snapshot_simple(cx)))
                .ok()
        });

        DisplaySnapshot {
            display_map_id: self.entity_id,
            companion_display_snapshot,
            block_snapshot,
            diagnostics_max_severity: self.diagnostics_max_severity,
            crease_snapshot: self.crease_map.snapshot(),
            text_highlights: self.text_highlights.clone(),
            inlay_highlights: self.inlay_highlights.clone(),
            clip_at_line_ends: self.clip_at_line_ends,
            masked: self.masked,
            fold_placeholder: self.fold_placeholder.clone(),
        }
    }

    fn snapshot_simple(&mut self, cx: &mut Context<Self>) -> DisplaySnapshot {
        let (wrap_snapshot, wrap_edits) = self.sync_through_wrap(cx);

        let block_snapshot = self
            .block_map
            .read(wrap_snapshot, wrap_edits, None)
            .snapshot;

        DisplaySnapshot {
            display_map_id: self.entity_id,
            companion_display_snapshot: None,
            block_snapshot,
            diagnostics_max_severity: self.diagnostics_max_severity,
            crease_snapshot: self.crease_map.snapshot(),
            text_highlights: self.text_highlights.clone(),
            inlay_highlights: self.inlay_highlights.clone(),
            clip_at_line_ends: self.clip_at_line_ends,
            masked: self.masked,
            fold_placeholder: self.fold_placeholder.clone(),
        }
    }

    #[instrument(skip_all)]
    pub fn set_state(&mut self, other: &DisplaySnapshot, cx: &mut Context<Self>) {
        self.fold(
            other
                .folds_in_range(MultiBufferOffset(0)..other.buffer_snapshot().len())
                .map(|fold| {
                    Crease::simple(
                        fold.range.to_offset(other.buffer_snapshot()),
                        fold.placeholder.clone(),
                    )
                })
                .collect(),
            cx,
        );
    }

    /// Creates folds for the given creases.
    #[instrument(skip_all)]
    pub fn fold<T: Clone + ToOffset>(&mut self, creases: Vec<Crease<T>>, cx: &mut Context<Self>) {
        if self.companion().is_some() {
            return;
        }

        let buffer_snapshot = self.buffer.read(cx).snapshot(cx);
        let edits = self.buffer_subscription.consume().into_inner();
        let tab_size = Self::tab_size(&self.buffer, cx);

        let companion_wrap_data = self.companion.as_ref().and_then(|(companion_dm, _)| {
            companion_dm
                .update(cx, |dm, cx| dm.sync_through_wrap(cx))
                .ok()
        });

        let (snapshot, edits) = self.inlay_map.sync(buffer_snapshot.clone(), edits);
        let (mut fold_map, snapshot, edits) = self.fold_map.write(snapshot, edits);
        let (snapshot, edits) = self.tab_map.sync(snapshot, edits, tab_size);
        let (snapshot, edits) = self
            .wrap_map
            .update(cx, |map, cx| map.sync(snapshot, edits, cx));

        {
            let companion_ref = self.companion.as_ref().map(|(_, c)| c.read(cx));
            let companion_view = companion_wrap_data.as_ref().zip(companion_ref).map(
                |((snapshot, edits), companion)| {
                    CompanionView::new(self.entity_id, snapshot, edits, companion)
                },
            );
            self.block_map.read(snapshot, edits, companion_view);
        }

        let inline = creases.iter().filter_map(|crease| {
            if let Crease::Inline {
                range, placeholder, ..
            } = crease
            {
                Some((range.clone(), placeholder.clone()))
            } else {
                None
            }
        });
        let (snapshot, edits) = fold_map.fold(inline);

        let (snapshot, edits) = self.tab_map.sync(snapshot, edits, tab_size);
        let (self_new_wrap_snapshot, self_new_wrap_edits) = self
            .wrap_map
            .update(cx, |map, cx| map.sync(snapshot, edits, cx));

        let (self_wrap_snapshot, self_wrap_edits) =
            (self_new_wrap_snapshot.clone(), self_new_wrap_edits.clone());

        let mut block_map = {
            let companion_ref = self.companion.as_ref().map(|(_, c)| c.read(cx));
            let companion_view = companion_wrap_data.as_ref().zip(companion_ref).map(
                |((snapshot, edits), companion)| {
                    CompanionView::new(self.entity_id, snapshot, edits, companion)
                },
            );
            self.block_map
                .write(self_new_wrap_snapshot, self_new_wrap_edits, companion_view)
        };
        let blocks = creases.into_iter().filter_map(|crease| {
            if let Crease::Block {
                range,
                block_height,
                render_block,
                block_style,
                block_priority,
                ..
            } = crease
            {
                Some((
                    range,
                    render_block,
                    block_height,
                    block_style,
                    block_priority,
                ))
            } else {
                None
            }
        });
        block_map.insert(
            blocks
                .into_iter()
                .map(|(range, render, height, style, priority)| {
                    let start = buffer_snapshot.anchor_before(range.start);
                    let end = buffer_snapshot.anchor_after(range.end);
                    BlockProperties {
                        placement: BlockPlacement::Replace(start..=end),
                        render,
                        height: Some(height),
                        style,
                        priority,
                    }
                }),
        );

        if let Some((companion_dm, _)) = &self.companion {
            let _ = companion_dm.update(cx, |dm, cx| {
                if let Some((companion_snapshot, companion_edits)) = companion_wrap_data {
                    let their_companion_ref = dm.companion.as_ref().map(|(_, c)| c.read(cx));
                    dm.block_map.read(
                        companion_snapshot,
                        companion_edits,
                        their_companion_ref.map(|c| {
                            CompanionView::new(
                                dm.entity_id,
                                &self_wrap_snapshot,
                                &self_wrap_edits,
                                c,
                            )
                        }),
                    );
                }
            });
        }
    }

    /// Removes any folds with the given ranges.
    #[instrument(skip_all)]
    pub fn remove_folds_with_type<T: ToOffset>(
        &mut self,
        ranges: impl IntoIterator<Item = Range<T>>,
        type_id: TypeId,
        cx: &mut Context<Self>,
    ) {
        let snapshot = self.buffer.read(cx).snapshot(cx);
        let edits = self.buffer_subscription.consume().into_inner();
        let tab_size = Self::tab_size(&self.buffer, cx);

        let companion_wrap_data = self.companion.as_ref().and_then(|(companion_dm, _)| {
            companion_dm
                .update(cx, |dm, cx| dm.sync_through_wrap(cx))
                .ok()
        });

        let (snapshot, edits) = self.inlay_map.sync(snapshot, edits);
        let (mut fold_map, snapshot, edits) = self.fold_map.write(snapshot, edits);
        let (snapshot, edits) = self.tab_map.sync(snapshot, edits, tab_size);
        let (snapshot, edits) = self
            .wrap_map
            .update(cx, |map, cx| map.sync(snapshot, edits, cx));

        {
            let companion_ref = self.companion.as_ref().map(|(_, c)| c.read(cx));
            let companion_view = companion_wrap_data.as_ref().zip(companion_ref).map(
                |((snapshot, edits), companion)| {
                    CompanionView::new(self.entity_id, snapshot, edits, companion)
                },
            );
            self.block_map.read(snapshot, edits, companion_view);
        }

        let (snapshot, edits) = fold_map.remove_folds(ranges, type_id);
        let (snapshot, edits) = self.tab_map.sync(snapshot, edits, tab_size);
        let (self_new_wrap_snapshot, self_new_wrap_edits) = self
            .wrap_map
            .update(cx, |map, cx| map.sync(snapshot, edits, cx));

        let (self_wrap_snapshot, self_wrap_edits) =
            (self_new_wrap_snapshot.clone(), self_new_wrap_edits.clone());

        {
            let companion_ref = self.companion.as_ref().map(|(_, c)| c.read(cx));
            let companion_view = companion_wrap_data.as_ref().zip(companion_ref).map(
                |((snapshot, edits), companion)| {
                    CompanionView::new(self.entity_id, snapshot, edits, companion)
                },
            );
            self.block_map
                .write(self_new_wrap_snapshot, self_new_wrap_edits, companion_view);
        }

        if let Some((companion_dm, _)) = &self.companion {
            let _ = companion_dm.update(cx, |dm, cx| {
                if let Some((companion_snapshot, companion_edits)) = companion_wrap_data {
                    let their_companion_ref = dm.companion.as_ref().map(|(_, c)| c.read(cx));
                    dm.block_map.read(
                        companion_snapshot,
                        companion_edits,
                        their_companion_ref.map(|c| {
                            CompanionView::new(
                                dm.entity_id,
                                &self_wrap_snapshot,
                                &self_wrap_edits,
                                c,
                            )
                        }),
                    );
                }
            });
        }
    }

    /// Removes any folds whose ranges intersect any of the given ranges.
    #[instrument(skip_all)]
    pub fn unfold_intersecting<T: ToOffset>(
        &mut self,
        ranges: impl IntoIterator<Item = Range<T>>,
        inclusive: bool,
        cx: &mut Context<Self>,
    ) -> WrapSnapshot {
        let snapshot = self.buffer.read(cx).snapshot(cx);
        let offset_ranges = ranges
            .into_iter()
            .map(|range| range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot))
            .collect::<Vec<_>>();
        let edits = self.buffer_subscription.consume().into_inner();
        let tab_size = Self::tab_size(&self.buffer, cx);

        let companion_wrap_data = self.companion.as_ref().and_then(|(companion_dm, _)| {
            companion_dm
                .update(cx, |dm, cx| dm.sync_through_wrap(cx))
                .ok()
        });

        let (snapshot, edits) = self.inlay_map.sync(snapshot, edits);
        let (mut fold_map, snapshot, edits) = self.fold_map.write(snapshot, edits);
        let (snapshot, edits) = self.tab_map.sync(snapshot, edits, tab_size);
        let (snapshot, edits) = self
            .wrap_map
            .update(cx, |map, cx| map.sync(snapshot, edits, cx));

        {
            let companion_ref = self.companion.as_ref().map(|(_, c)| c.read(cx));
            let companion_view = companion_wrap_data.as_ref().zip(companion_ref).map(
                |((snapshot, edits), companion)| {
                    CompanionView::new(self.entity_id, snapshot, edits, companion)
                },
            );
            self.block_map.read(snapshot, edits, companion_view);
        }

        let (snapshot, edits) =
            fold_map.unfold_intersecting(offset_ranges.iter().cloned(), inclusive);
        let (snapshot, edits) = self.tab_map.sync(snapshot, edits, tab_size);
        let (self_new_wrap_snapshot, self_new_wrap_edits) = self
            .wrap_map
            .update(cx, |map, cx| map.sync(snapshot, edits, cx));

        let (self_wrap_snapshot, self_wrap_edits) =
            (self_new_wrap_snapshot.clone(), self_new_wrap_edits.clone());

        let mut block_map = {
            let companion_ref = self.companion.as_ref().map(|(_, c)| c.read(cx));
            let companion_view = companion_wrap_data.as_ref().zip(companion_ref).map(
                |((snapshot, edits), companion)| {
                    CompanionView::new(self.entity_id, snapshot, edits, companion)
                },
            );
            self.block_map.write(
                self_new_wrap_snapshot.clone(),
                self_new_wrap_edits,
                companion_view,
            )
        };
        block_map.remove_intersecting_replace_blocks(offset_ranges, inclusive);

        if let Some((companion_dm, _)) = &self.companion {
            let _ = companion_dm.update(cx, |dm, cx| {
                if let Some((companion_snapshot, companion_edits)) = companion_wrap_data {
                    let their_companion_ref = dm.companion.as_ref().map(|(_, c)| c.read(cx));
                    dm.block_map.read(
                        companion_snapshot,
                        companion_edits,
                        their_companion_ref.map(|c| {
                            CompanionView::new(
                                dm.entity_id,
                                &self_wrap_snapshot,
                                &self_wrap_edits,
                                c,
                            )
                        }),
                    );
                }
            });
        }

        self_new_wrap_snapshot
    }

    #[instrument(skip_all)]
    pub fn disable_header_for_buffer(&mut self, buffer_id: BufferId, cx: &mut Context<Self>) {
        let (self_wrap_snapshot, self_wrap_edits) = self.sync_through_wrap(cx);

        let companion_wrap_data = self.companion.as_ref().and_then(|(companion_dm, _)| {
            companion_dm
                .update(cx, |dm, cx| dm.sync_through_wrap(cx))
                .ok()
        });

        let companion_ref = self.companion.as_ref().map(|(_, c)| c.read(cx));
        let companion_view = companion_wrap_data.as_ref().zip(companion_ref).map(
            |((snapshot, edits), companion)| {
                CompanionView::new(self.entity_id, snapshot, edits, companion)
            },
        );

        let mut block_map = self.block_map.write(
            self_wrap_snapshot.clone(),
            self_wrap_edits.clone(),
            companion_view,
        );
        block_map.disable_header_for_buffer(buffer_id);

        if let Some((companion_dm, _)) = &self.companion {
            let _ = companion_dm.update(cx, |dm, cx| {
                if let Some((companion_snapshot, companion_edits)) = companion_wrap_data {
                    let their_companion_ref = dm.companion.as_ref().map(|(_, c)| c.read(cx));
                    dm.block_map.read(
                        companion_snapshot,
                        companion_edits,
                        their_companion_ref.map(|c| {
                            CompanionView::new(
                                dm.entity_id,
                                &self_wrap_snapshot,
                                &self_wrap_edits,
                                c,
                            )
                        }),
                    );
                }
            });
        }
    }

    #[instrument(skip_all)]
    pub fn fold_buffers(
        &mut self,
        buffer_ids: impl IntoIterator<Item = language::BufferId>,
        cx: &mut App,
    ) {
        let buffer_ids: Vec<_> = buffer_ids.into_iter().collect();

        if let Some((_, companion_entity)) = &self.companion {
            companion_entity.update(cx, |companion, _| {
                if self.entity_id == companion.rhs_display_map_id {
                    companion
                        .rhs_folded_buffers
                        .extend(buffer_ids.iter().copied());
                } else {
                    let rhs_ids = buffer_ids
                        .iter()
                        .filter_map(|id| companion.lhs_buffer_to_rhs_buffer.get(id).copied());
                    companion.rhs_folded_buffers.extend(rhs_ids);
                }
            });
        }

        let (self_wrap_snapshot, self_wrap_edits) = self.sync_through_wrap(cx);

        let companion_wrap_data = self.companion.as_ref().and_then(|(companion_dm, _)| {
            companion_dm
                .update(cx, |dm, cx| dm.sync_through_wrap(cx))
                .ok()
        });

        let companion_ref = self.companion.as_ref().map(|(_, c)| c.read(cx));
        let companion_view = companion_wrap_data.as_ref().zip(companion_ref).map(
            |((snapshot, edits), companion)| {
                CompanionView::new(self.entity_id, snapshot, edits, companion)
            },
        );

        let mut block_map = self.block_map.write(
            self_wrap_snapshot.clone(),
            self_wrap_edits.clone(),
            companion_view,
        );
        block_map.fold_buffers(buffer_ids.iter().copied(), self.buffer.read(cx), cx);

        if let Some((companion_dm, companion_entity)) = &self.companion {
            let buffer_mapping = companion_entity
                .read(cx)
                .buffer_to_companion_buffer(self.entity_id);
            let their_buffer_ids: Vec<_> = buffer_ids
                .iter()
                .filter_map(|id| buffer_mapping.get(id).copied())
                .collect();

            let _ = companion_dm.update(cx, |dm, cx| {
                if let Some((companion_snapshot, companion_edits)) = companion_wrap_data {
                    let their_companion_ref = dm.companion.as_ref().map(|(_, c)| c.read(cx));
                    let mut block_map = dm.block_map.write(
                        companion_snapshot,
                        companion_edits,
                        their_companion_ref.map(|c| {
                            CompanionView::new(
                                dm.entity_id,
                                &self_wrap_snapshot,
                                &self_wrap_edits,
                                c,
                            )
                        }),
                    );
                    if !their_buffer_ids.is_empty() {
                        block_map.fold_buffers(their_buffer_ids, dm.buffer.read(cx), cx);
                    }
                }
            });
        }
    }

    #[instrument(skip_all)]
    pub fn unfold_buffers(
        &mut self,
        buffer_ids: impl IntoIterator<Item = language::BufferId>,
        cx: &mut Context<Self>,
    ) {
        let buffer_ids: Vec<_> = buffer_ids.into_iter().collect();

        if let Some((_, companion_entity)) = &self.companion {
            companion_entity.update(cx, |companion, _| {
                if self.entity_id == companion.rhs_display_map_id {
                    for id in &buffer_ids {
                        companion.rhs_folded_buffers.remove(id);
                    }
                } else {
                    for id in &buffer_ids {
                        if let Some(rhs_id) = companion.lhs_buffer_to_rhs_buffer.get(id) {
                            companion.rhs_folded_buffers.remove(rhs_id);
                        }
                    }
                }
            });
        }

        let (self_wrap_snapshot, self_wrap_edits) = self.sync_through_wrap(cx);

        let companion_wrap_data = self.companion.as_ref().and_then(|(companion_dm, _)| {
            companion_dm
                .update(cx, |dm, cx| dm.sync_through_wrap(cx))
                .ok()
        });

        let companion_ref = self.companion.as_ref().map(|(_, c)| c.read(cx));
        let companion_view = companion_wrap_data.as_ref().zip(companion_ref).map(
            |((snapshot, edits), companion)| {
                CompanionView::new(self.entity_id, snapshot, edits, companion)
            },
        );

        let mut block_map = self.block_map.write(
            self_wrap_snapshot.clone(),
            self_wrap_edits.clone(),
            companion_view,
        );
        block_map.unfold_buffers(buffer_ids.iter().copied(), self.buffer.read(cx), cx);

        if let Some((companion_dm, companion_entity)) = &self.companion {
            let buffer_mapping = companion_entity
                .read(cx)
                .buffer_to_companion_buffer(self.entity_id);
            let their_buffer_ids: Vec<_> = buffer_ids
                .iter()
                .filter_map(|id| buffer_mapping.get(id).copied())
                .collect();

            let _ = companion_dm.update(cx, |dm, cx| {
                if let Some((companion_snapshot, companion_edits)) = companion_wrap_data {
                    let their_companion_ref = dm.companion.as_ref().map(|(_, c)| c.read(cx));
                    let mut block_map = dm.block_map.write(
                        companion_snapshot,
                        companion_edits,
                        their_companion_ref.map(|c| {
                            CompanionView::new(
                                dm.entity_id,
                                &self_wrap_snapshot,
                                &self_wrap_edits,
                                c,
                            )
                        }),
                    );
                    if !their_buffer_ids.is_empty() {
                        block_map.unfold_buffers(their_buffer_ids, dm.buffer.read(cx), cx);
                    }
                }
            });
        }
    }

    #[instrument(skip_all)]
    pub(crate) fn is_buffer_folded(&self, buffer_id: language::BufferId) -> bool {
        self.block_map.folded_buffers.contains(&buffer_id)
    }

    #[instrument(skip_all)]
    pub(crate) fn folded_buffers(&self) -> &HashSet<BufferId> {
        &self.block_map.folded_buffers
    }

    #[instrument(skip_all)]
    pub fn insert_creases(
        &mut self,
        creases: impl IntoIterator<Item = Crease<Anchor>>,
        cx: &mut Context<Self>,
    ) -> Vec<CreaseId> {
        let snapshot = self.buffer.read(cx).snapshot(cx);
        self.crease_map.insert(creases, &snapshot)
    }

    #[instrument(skip_all)]
    pub fn remove_creases(
        &mut self,
        crease_ids: impl IntoIterator<Item = CreaseId>,
        cx: &mut Context<Self>,
    ) -> Vec<(CreaseId, Range<Anchor>)> {
        let snapshot = self.buffer.read(cx).snapshot(cx);
        self.crease_map.remove(crease_ids, &snapshot)
    }

    #[instrument(skip_all)]
    pub fn insert_blocks(
        &mut self,
        blocks: impl IntoIterator<Item = BlockProperties<Anchor>>,
        cx: &mut Context<Self>,
    ) -> Vec<CustomBlockId> {
        let (self_wrap_snapshot, self_wrap_edits) = self.sync_through_wrap(cx);

        let companion_wrap_data = self.companion.as_ref().and_then(|(companion_dm, _)| {
            companion_dm
                .update(cx, |dm, cx| dm.sync_through_wrap(cx))
                .ok()
        });

        let companion_ref = self.companion.as_ref().map(|(_, c)| c.read(cx));
        let companion_view = companion_wrap_data.as_ref().zip(companion_ref).map(
            |((snapshot, edits), companion)| {
                CompanionView::new(self.entity_id, snapshot, edits, companion)
            },
        );

        let mut block_map = self.block_map.write(
            self_wrap_snapshot.clone(),
            self_wrap_edits.clone(),
            companion_view,
        );
        let result = block_map.insert(blocks);

        if let Some((companion_dm, _)) = &self.companion {
            let _ = companion_dm.update(cx, |dm, cx| {
                if let Some((companion_snapshot, companion_edits)) = companion_wrap_data {
                    let their_companion_ref = dm.companion.as_ref().map(|(_, c)| c.read(cx));
                    dm.block_map.read(
                        companion_snapshot,
                        companion_edits,
                        their_companion_ref.map(|c| {
                            CompanionView::new(
                                dm.entity_id,
                                &self_wrap_snapshot,
                                &self_wrap_edits,
                                c,
                            )
                        }),
                    );
                }
            });
        }

        result
    }

    #[instrument(skip_all)]
    pub fn resize_blocks(&mut self, heights: HashMap<CustomBlockId, u32>, cx: &mut Context<Self>) {
        let (self_wrap_snapshot, self_wrap_edits) = self.sync_through_wrap(cx);

        let companion_wrap_data = self.companion.as_ref().and_then(|(companion_dm, _)| {
            companion_dm
                .update(cx, |dm, cx| dm.sync_through_wrap(cx))
                .ok()
        });

        let companion_ref = self.companion.as_ref().map(|(_, c)| c.read(cx));
        let companion_view = companion_wrap_data.as_ref().zip(companion_ref).map(
            |((snapshot, edits), companion)| {
                CompanionView::new(self.entity_id, snapshot, edits, companion)
            },
        );

        let mut block_map = self.block_map.write(
            self_wrap_snapshot.clone(),
            self_wrap_edits.clone(),
            companion_view,
        );
        block_map.resize(heights);

        if let Some((companion_dm, _)) = &self.companion {
            let _ = companion_dm.update(cx, |dm, cx| {
                if let Some((companion_snapshot, companion_edits)) = companion_wrap_data {
                    let their_companion_ref = dm.companion.as_ref().map(|(_, c)| c.read(cx));
                    dm.block_map.read(
                        companion_snapshot,
                        companion_edits,
                        their_companion_ref.map(|c| {
                            CompanionView::new(
                                dm.entity_id,
                                &self_wrap_snapshot,
                                &self_wrap_edits,
                                c,
                            )
                        }),
                    );
                }
            });
        }
    }

    #[instrument(skip_all)]
    pub fn replace_blocks(&mut self, renderers: HashMap<CustomBlockId, RenderBlock>) {
        self.block_map.replace_blocks(renderers);
    }

    #[instrument(skip_all)]
    pub fn remove_blocks(&mut self, ids: HashSet<CustomBlockId>, cx: &mut Context<Self>) {
        let (self_wrap_snapshot, self_wrap_edits) = self.sync_through_wrap(cx);

        let companion_wrap_data = self.companion.as_ref().and_then(|(companion_dm, _)| {
            companion_dm
                .update(cx, |dm, cx| dm.sync_through_wrap(cx))
                .ok()
        });

        let companion_ref = self.companion.as_ref().map(|(_, c)| c.read(cx));
        let companion_view = companion_wrap_data.as_ref().zip(companion_ref).map(
            |((snapshot, edits), companion)| {
                CompanionView::new(self.entity_id, snapshot, edits, companion)
            },
        );

        let mut block_map = self.block_map.write(
            self_wrap_snapshot.clone(),
            self_wrap_edits.clone(),
            companion_view,
        );
        block_map.remove(ids);

        if let Some((companion_dm, _)) = &self.companion {
            let _ = companion_dm.update(cx, |dm, cx| {
                if let Some((companion_snapshot, companion_edits)) = companion_wrap_data {
                    let their_companion_ref = dm.companion.as_ref().map(|(_, c)| c.read(cx));
                    dm.block_map.read(
                        companion_snapshot,
                        companion_edits,
                        their_companion_ref.map(|c| {
                            CompanionView::new(
                                dm.entity_id,
                                &self_wrap_snapshot,
                                &self_wrap_edits,
                                c,
                            )
                        }),
                    );
                }
            });
        }
    }

    #[instrument(skip_all)]
    pub fn row_for_block(
        &mut self,
        block_id: CustomBlockId,
        cx: &mut Context<Self>,
    ) -> Option<DisplayRow> {
        let (self_wrap_snapshot, self_wrap_edits) = self.sync_through_wrap(cx);

        let companion_wrap_data = self.companion.as_ref().and_then(|(companion_dm, _)| {
            companion_dm
                .update(cx, |dm, cx| dm.sync_through_wrap(cx))
                .ok()
        });

        let companion_ref = self.companion.as_ref().map(|(_, c)| c.read(cx));
        let companion_view = companion_wrap_data.as_ref().zip(companion_ref).map(
            |((snapshot, edits), companion)| {
                CompanionView::new(self.entity_id, snapshot, edits, companion)
            },
        );

        let block_map = self.block_map.read(
            self_wrap_snapshot.clone(),
            self_wrap_edits.clone(),
            companion_view,
        );
        let block_row = block_map.row_for_block(block_id)?;

        if let Some((companion_dm, _)) = &self.companion {
            let _ = companion_dm.update(cx, |dm, cx| {
                if let Some((companion_snapshot, companion_edits)) = companion_wrap_data {
                    let their_companion_ref = dm.companion.as_ref().map(|(_, c)| c.read(cx));
                    dm.block_map.read(
                        companion_snapshot,
                        companion_edits,
                        their_companion_ref.map(|c| {
                            CompanionView::new(
                                dm.entity_id,
                                &self_wrap_snapshot,
                                &self_wrap_edits,
                                c,
                            )
                        }),
                    );
                }
            });
        }

        Some(DisplayRow(block_row.0))
    }

    #[instrument(skip_all)]
    pub fn highlight_text(
        &mut self,
        key: HighlightKey,
        ranges: Vec<Range<Anchor>>,
        style: HighlightStyle,
        merge: bool,
        cx: &App,
    ) {
        let multi_buffer_snapshot = self.buffer.read(cx).snapshot(cx);
        let to_insert = match self.text_highlights.remove(&key).filter(|_| merge) {
            Some(previous) => {
                let mut merged_ranges = previous.1.clone();
                for new_range in ranges {
                    let i = merged_ranges
                        .binary_search_by(|probe| {
                            probe.start.cmp(&new_range.start, &multi_buffer_snapshot)
                        })
                        .unwrap_or_else(|i| i);
                    merged_ranges.insert(i, new_range);
                }
                Arc::new((style, merged_ranges))
            }
            None => Arc::new((style, ranges)),
        };
        self.text_highlights.insert(key, to_insert);
    }

    #[instrument(skip_all)]
    pub(crate) fn highlight_inlays(
        &mut self,
        type_id: TypeId,
        highlights: Vec<InlayHighlight>,
        style: HighlightStyle,
    ) {
        for highlight in highlights {
            let update = self.inlay_highlights.update(&type_id, |highlights| {
                highlights.insert(highlight.inlay, (style, highlight.clone()))
            });
            if update.is_none() {
                self.inlay_highlights.insert(
                    type_id,
                    TreeMap::from_ordered_entries([(highlight.inlay, (style, highlight))]),
                );
            }
        }
    }

    #[instrument(skip_all)]
    pub fn text_highlights(&self, type_id: TypeId) -> Option<(HighlightStyle, &[Range<Anchor>])> {
        let highlights = self.text_highlights.get(&HighlightKey::Type(type_id))?;
        Some((highlights.0, &highlights.1))
    }

    #[cfg(feature = "test-support")]
    pub fn all_text_highlights(
        &self,
    ) -> impl Iterator<Item = &Arc<(HighlightStyle, Vec<Range<Anchor>>)>> {
        self.text_highlights.values()
    }

    #[instrument(skip_all)]
    pub fn clear_highlights(&mut self, type_id: TypeId) -> bool {
        let mut cleared = self
            .text_highlights
            .remove(&HighlightKey::Type(type_id))
            .is_some();
        self.text_highlights.retain(|key, _| {
            let retain = if let HighlightKey::TypePlus(key_type_id, _) = key {
                key_type_id != &type_id
            } else {
                true
            };
            cleared |= !retain;
            retain
        });
        cleared |= self.inlay_highlights.remove(&type_id).is_some();
        cleared
    }

    pub fn set_font(&self, font: Font, font_size: Pixels, cx: &mut Context<Self>) -> bool {
        self.wrap_map
            .update(cx, |map, cx| map.set_font_with_size(font, font_size, cx))
    }

    pub fn set_wrap_width(&self, width: Option<Pixels>, cx: &mut Context<Self>) -> bool {
        self.wrap_map
            .update(cx, |map, cx| map.set_wrap_width(width, cx))
    }

    #[instrument(skip_all)]
    pub fn update_fold_widths(
        &mut self,
        widths: impl IntoIterator<Item = (ChunkRendererId, Pixels)>,
        cx: &mut Context<Self>,
    ) -> bool {
        let snapshot = self.buffer.read(cx).snapshot(cx);
        let edits = self.buffer_subscription.consume().into_inner();
        let tab_size = Self::tab_size(&self.buffer, cx);

        let companion_wrap_data = self.companion.as_ref().and_then(|(companion_dm, _)| {
            companion_dm
                .update(cx, |dm, cx| dm.sync_through_wrap(cx))
                .ok()
        });

        let (snapshot, edits) = self.inlay_map.sync(snapshot, edits);
        let (mut fold_map, snapshot, edits) = self.fold_map.write(snapshot, edits);
        let (snapshot, edits) = self.tab_map.sync(snapshot, edits, tab_size);
        let (snapshot, edits) = self
            .wrap_map
            .update(cx, |map, cx| map.sync(snapshot, edits, cx));

        {
            let companion_ref = self.companion.as_ref().map(|(_, c)| c.read(cx));
            let companion_view = companion_wrap_data.as_ref().zip(companion_ref).map(
                |((snapshot, edits), companion)| {
                    CompanionView::new(self.entity_id, snapshot, edits, companion)
                },
            );
            self.block_map.read(snapshot, edits, companion_view);
        }

        let (snapshot, edits) = fold_map.update_fold_widths(widths);
        let widths_changed = !edits.is_empty();
        let (snapshot, edits) = self.tab_map.sync(snapshot, edits, tab_size);
        let (self_new_wrap_snapshot, self_new_wrap_edits) = self
            .wrap_map
            .update(cx, |map, cx| map.sync(snapshot, edits, cx));

        let (self_wrap_snapshot, self_wrap_edits) =
            (self_new_wrap_snapshot.clone(), self_new_wrap_edits.clone());

        {
            let companion_ref = self.companion.as_ref().map(|(_, c)| c.read(cx));
            let companion_view = companion_wrap_data.as_ref().zip(companion_ref).map(
                |((snapshot, edits), companion)| {
                    CompanionView::new(self.entity_id, snapshot, edits, companion)
                },
            );
            self.block_map
                .read(self_new_wrap_snapshot, self_new_wrap_edits, companion_view);
        }

        if let Some((companion_dm, _)) = &self.companion {
            let _ = companion_dm.update(cx, |dm, cx| {
                if let Some((companion_snapshot, companion_edits)) = companion_wrap_data {
                    let their_companion_ref = dm.companion.as_ref().map(|(_, c)| c.read(cx));
                    dm.block_map.read(
                        companion_snapshot,
                        companion_edits,
                        their_companion_ref.map(|c| {
                            CompanionView::new(
                                dm.entity_id,
                                &self_wrap_snapshot,
                                &self_wrap_edits,
                                c,
                            )
                        }),
                    );
                }
            });
        }

        widths_changed
    }

    pub(crate) fn current_inlays(&self) -> impl Iterator<Item = &Inlay> {
        self.inlay_map.current_inlays()
    }

    #[instrument(skip_all)]
    pub(crate) fn splice_inlays(
        &mut self,
        to_remove: &[InlayId],
        to_insert: Vec<Inlay>,
        cx: &mut Context<Self>,
    ) {
        if to_remove.is_empty() && to_insert.is_empty() {
            return;
        }
        let buffer_snapshot = self.buffer.read(cx).snapshot(cx);
        let edits = self.buffer_subscription.consume().into_inner();
        let tab_size = Self::tab_size(&self.buffer, cx);

        let companion_wrap_data = self.companion.as_ref().and_then(|(companion_dm, _)| {
            companion_dm
                .update(cx, |dm, cx| dm.sync_through_wrap(cx))
                .ok()
        });

        let (snapshot, edits) = self.inlay_map.sync(buffer_snapshot, edits);
        let (snapshot, edits) = self.fold_map.read(snapshot, edits);
        let (snapshot, edits) = self.tab_map.sync(snapshot, edits, tab_size);
        let (snapshot, edits) = self
            .wrap_map
            .update(cx, |map, cx| map.sync(snapshot, edits, cx));

        {
            let companion_ref = self.companion.as_ref().map(|(_, c)| c.read(cx));
            let companion_view = companion_wrap_data.as_ref().zip(companion_ref).map(
                |((snapshot, edits), companion)| {
                    CompanionView::new(self.entity_id, snapshot, edits, companion)
                },
            );
            self.block_map.read(snapshot, edits, companion_view);
        }

        let (snapshot, edits) = self.inlay_map.splice(to_remove, to_insert);
        let (snapshot, edits) = self.fold_map.read(snapshot, edits);
        let (snapshot, edits) = self.tab_map.sync(snapshot, edits, tab_size);
        let (self_new_wrap_snapshot, self_new_wrap_edits) = self
            .wrap_map
            .update(cx, |map, cx| map.sync(snapshot, edits, cx));

        let (self_wrap_snapshot, self_wrap_edits) =
            (self_new_wrap_snapshot.clone(), self_new_wrap_edits.clone());

        {
            let companion_ref = self.companion.as_ref().map(|(_, c)| c.read(cx));
            let companion_view = companion_wrap_data.as_ref().zip(companion_ref).map(
                |((snapshot, edits), companion)| {
                    CompanionView::new(self.entity_id, snapshot, edits, companion)
                },
            );
            self.block_map
                .read(self_new_wrap_snapshot, self_new_wrap_edits, companion_view);
        }

        if let Some((companion_dm, _)) = &self.companion {
            let _ = companion_dm.update(cx, |dm, cx| {
                if let Some((companion_snapshot, companion_edits)) = companion_wrap_data {
                    let their_companion_ref = dm.companion.as_ref().map(|(_, c)| c.read(cx));
                    dm.block_map.read(
                        companion_snapshot,
                        companion_edits,
                        their_companion_ref.map(|c| {
                            CompanionView::new(
                                dm.entity_id,
                                &self_wrap_snapshot,
                                &self_wrap_edits,
                                c,
                            )
                        }),
                    );
                }
            });
        }
    }

    #[instrument(skip_all)]
    fn tab_size(buffer: &Entity<MultiBuffer>, cx: &App) -> NonZeroU32 {
        let buffer = buffer.read(cx).as_singleton().map(|buffer| buffer.read(cx));
        let language = buffer
            .and_then(|buffer| buffer.language())
            .map(|l| l.name());
        let file = buffer.and_then(|buffer| buffer.file());
        language_settings(language, file, cx).tab_size
    }

    #[cfg(test)]
    pub fn is_rewrapping(&self, cx: &gpui::App) -> bool {
        self.wrap_map.read(cx).is_rewrapping()
    }
}

#[derive(Debug, Default)]
pub(crate) struct Highlights<'a> {
    pub text_highlights: Option<&'a TextHighlights>,
    pub inlay_highlights: Option<&'a InlayHighlights>,
    pub styles: HighlightStyles,
}

#[derive(Clone, Copy, Debug)]
pub struct EditPredictionStyles {
    pub insertion: HighlightStyle,
    pub whitespace: HighlightStyle,
}

#[derive(Default, Debug, Clone, Copy)]
pub struct HighlightStyles {
    pub inlay_hint: Option<HighlightStyle>,
    pub edit_prediction: Option<EditPredictionStyles>,
}

#[derive(Clone)]
pub enum ChunkReplacement {
    Renderer(ChunkRenderer),
    Str(SharedString),
}

pub struct HighlightedChunk<'a> {
    pub text: &'a str,
    pub style: Option<HighlightStyle>,
    pub is_tab: bool,
    pub is_inlay: bool,
    pub replacement: Option<ChunkReplacement>,
}

impl<'a> HighlightedChunk<'a> {
    #[instrument(skip_all)]
    fn highlight_invisibles(
        self,
        editor_style: &'a EditorStyle,
    ) -> impl Iterator<Item = Self> + 'a {
        let mut chars = self.text.chars().peekable();
        let mut text = self.text;
        let style = self.style;
        let is_tab = self.is_tab;
        let renderer = self.replacement;
        let is_inlay = self.is_inlay;
        iter::from_fn(move || {
            let mut prefix_len = 0;
            while let Some(&ch) = chars.peek() {
                if !is_invisible(ch) {
                    prefix_len += ch.len_utf8();
                    chars.next();
                    continue;
                }
                if prefix_len > 0 {
                    let (prefix, suffix) = text.split_at(prefix_len);
                    text = suffix;
                    return Some(HighlightedChunk {
                        text: prefix,
                        style,
                        is_tab,
                        is_inlay,
                        replacement: renderer.clone(),
                    });
                }
                chars.next();
                let (prefix, suffix) = text.split_at(ch.len_utf8());
                text = suffix;
                if let Some(replacement) = replacement(ch) {
                    let invisible_highlight = HighlightStyle {
                        background_color: Some(editor_style.status.hint_background),
                        underline: Some(UnderlineStyle {
                            color: Some(editor_style.status.hint),
                            thickness: px(1.),
                            wavy: false,
                        }),
                        ..Default::default()
                    };
                    let invisible_style = if let Some(style) = style {
                        style.highlight(invisible_highlight)
                    } else {
                        invisible_highlight
                    };
                    return Some(HighlightedChunk {
                        text: prefix,
                        style: Some(invisible_style),
                        is_tab: false,
                        is_inlay,
                        replacement: Some(ChunkReplacement::Str(replacement.into())),
                    });
                } else {
                    let invisible_highlight = HighlightStyle {
                        background_color: Some(editor_style.status.hint_background),
                        underline: Some(UnderlineStyle {
                            color: Some(editor_style.status.hint),
                            thickness: px(1.),
                            wavy: false,
                        }),
                        ..Default::default()
                    };
                    let invisible_style = if let Some(style) = style {
                        style.highlight(invisible_highlight)
                    } else {
                        invisible_highlight
                    };

                    return Some(HighlightedChunk {
                        text: prefix,
                        style: Some(invisible_style),
                        is_tab: false,
                        is_inlay,
                        replacement: renderer.clone(),
                    });
                }
            }

            if !text.is_empty() {
                let remainder = text;
                text = "";
                Some(HighlightedChunk {
                    text: remainder,
                    style,
                    is_tab,
                    is_inlay,
                    replacement: renderer.clone(),
                })
            } else {
                None
            }
        })
    }
}

#[derive(Clone)]
pub struct DisplaySnapshot {
    pub display_map_id: EntityId,
    pub companion_display_snapshot: Option<Arc<DisplaySnapshot>>,
    pub crease_snapshot: CreaseSnapshot,
    block_snapshot: BlockSnapshot,
    text_highlights: TextHighlights,
    inlay_highlights: InlayHighlights,
    clip_at_line_ends: bool,
    masked: bool,
    diagnostics_max_severity: DiagnosticSeverity,
    pub(crate) fold_placeholder: FoldPlaceholder,
}

impl DisplaySnapshot {
    pub fn companion_snapshot(&self) -> Option<&DisplaySnapshot> {
        self.companion_display_snapshot.as_deref()
    }

    pub fn wrap_snapshot(&self) -> &WrapSnapshot {
        &self.block_snapshot.wrap_snapshot
    }
    pub fn tab_snapshot(&self) -> &TabSnapshot {
        &self.block_snapshot.wrap_snapshot.tab_snapshot
    }

    pub fn fold_snapshot(&self) -> &FoldSnapshot {
        &self.block_snapshot.wrap_snapshot.tab_snapshot.fold_snapshot
    }

    pub fn inlay_snapshot(&self) -> &InlaySnapshot {
        &self
            .block_snapshot
            .wrap_snapshot
            .tab_snapshot
            .fold_snapshot
            .inlay_snapshot
    }

    pub fn buffer_snapshot(&self) -> &MultiBufferSnapshot {
        &self
            .block_snapshot
            .wrap_snapshot
            .tab_snapshot
            .fold_snapshot
            .inlay_snapshot
            .buffer
    }

    #[cfg(test)]
    pub fn fold_count(&self) -> usize {
        self.fold_snapshot().fold_count()
    }

    pub fn is_empty(&self) -> bool {
        self.buffer_snapshot().len() == MultiBufferOffset(0)
    }

    pub fn row_infos(&self, start_row: DisplayRow) -> impl Iterator<Item = RowInfo> + '_ {
        self.block_snapshot.row_infos(BlockRow(start_row.0))
    }

    pub fn widest_line_number(&self) -> u32 {
        self.buffer_snapshot().widest_line_number()
    }

    #[instrument(skip_all)]
    pub fn prev_line_boundary(&self, mut point: MultiBufferPoint) -> (Point, DisplayPoint) {
        loop {
            let mut inlay_point = self.inlay_snapshot().to_inlay_point(point);
            let mut fold_point = self.fold_snapshot().to_fold_point(inlay_point, Bias::Left);
            fold_point.0.column = 0;
            inlay_point = fold_point.to_inlay_point(self.fold_snapshot());
            point = self.inlay_snapshot().to_buffer_point(inlay_point);

            let mut display_point = self.point_to_display_point(point, Bias::Left);
            *display_point.column_mut() = 0;
            let next_point = self.display_point_to_point(display_point, Bias::Left);
            if next_point == point {
                return (point, display_point);
            }
            point = next_point;
        }
    }

    #[instrument(skip_all)]
    pub fn next_line_boundary(
        &self,
        mut point: MultiBufferPoint,
    ) -> (MultiBufferPoint, DisplayPoint) {
        let original_point = point;
        loop {
            let mut inlay_point = self.inlay_snapshot().to_inlay_point(point);
            let mut fold_point = self.fold_snapshot().to_fold_point(inlay_point, Bias::Right);
            fold_point.0.column = self.fold_snapshot().line_len(fold_point.row());
            inlay_point = fold_point.to_inlay_point(self.fold_snapshot());
            point = self.inlay_snapshot().to_buffer_point(inlay_point);

            let mut display_point = self.point_to_display_point(point, Bias::Right);
            *display_point.column_mut() = self.line_len(display_point.row());
            let next_point = self.display_point_to_point(display_point, Bias::Right);
            if next_point == point || original_point == point || original_point == next_point {
                return (point, display_point);
            }
            point = next_point;
        }
    }

    // used by line_mode selections and tries to match vim behavior
    pub fn expand_to_line(&self, range: Range<Point>) -> Range<Point> {
        let new_start = MultiBufferPoint::new(range.start.row, 0);
        let new_end = if range.end.column > 0 {
            MultiBufferPoint::new(
                range.end.row,
                self.buffer_snapshot()
                    .line_len(MultiBufferRow(range.end.row)),
            )
        } else {
            range.end
        };

        new_start..new_end
    }

    #[instrument(skip_all)]
    pub fn point_to_display_point(&self, point: MultiBufferPoint, bias: Bias) -> DisplayPoint {
        let inlay_point = self.inlay_snapshot().to_inlay_point(point);
        let fold_point = self.fold_snapshot().to_fold_point(inlay_point, bias);
        let tab_point = self.tab_snapshot().fold_point_to_tab_point(fold_point);
        let wrap_point = self.wrap_snapshot().tab_point_to_wrap_point(tab_point);
        let block_point = self.block_snapshot.to_block_point(wrap_point);
        DisplayPoint(block_point)
    }

    pub fn display_point_to_point(&self, point: DisplayPoint, bias: Bias) -> Point {
        self.inlay_snapshot()
            .to_buffer_point(self.display_point_to_inlay_point(point, bias))
    }

    pub fn display_point_to_inlay_offset(&self, point: DisplayPoint, bias: Bias) -> InlayOffset {
        self.inlay_snapshot()
            .to_offset(self.display_point_to_inlay_point(point, bias))
    }

    pub fn anchor_to_inlay_offset(&self, anchor: Anchor) -> InlayOffset {
        self.inlay_snapshot()
            .to_inlay_offset(anchor.to_offset(self.buffer_snapshot()))
    }

    pub fn display_point_to_anchor(&self, point: DisplayPoint, bias: Bias) -> Anchor {
        self.buffer_snapshot()
            .anchor_at(point.to_offset(self, bias), bias)
    }

    #[instrument(skip_all)]
    fn display_point_to_inlay_point(&self, point: DisplayPoint, bias: Bias) -> InlayPoint {
        let block_point = point.0;
        let wrap_point = self.block_snapshot.to_wrap_point(block_point, bias);
        let tab_point = self.wrap_snapshot().to_tab_point(wrap_point);
        let fold_point = self
            .tab_snapshot()
            .tab_point_to_fold_point(tab_point, bias)
            .0;
        fold_point.to_inlay_point(self.fold_snapshot())
    }

    #[instrument(skip_all)]
    pub fn display_point_to_fold_point(&self, point: DisplayPoint, bias: Bias) -> FoldPoint {
        let block_point = point.0;
        let wrap_point = self.block_snapshot.to_wrap_point(block_point, bias);
        let tab_point = self.wrap_snapshot().to_tab_point(wrap_point);
        self.tab_snapshot()
            .tab_point_to_fold_point(tab_point, bias)
            .0
    }

    #[instrument(skip_all)]
    pub fn fold_point_to_display_point(&self, fold_point: FoldPoint) -> DisplayPoint {
        let tab_point = self.tab_snapshot().fold_point_to_tab_point(fold_point);
        let wrap_point = self.wrap_snapshot().tab_point_to_wrap_point(tab_point);
        let block_point = self.block_snapshot.to_block_point(wrap_point);
        DisplayPoint(block_point)
    }

    pub fn max_point(&self) -> DisplayPoint {
        DisplayPoint(self.block_snapshot.max_point())
    }

    /// Returns text chunks starting at the given display row until the end of the file
    #[instrument(skip_all)]
    pub fn text_chunks(&self, display_row: DisplayRow) -> impl Iterator<Item = &str> {
        self.block_snapshot
            .chunks(
                BlockRow(display_row.0)..BlockRow(self.max_point().row().next_row().0),
                false,
                self.masked,
                Highlights::default(),
            )
            .map(|h| h.text)
    }

    /// Returns text chunks starting at the end of the given display row in reverse until the start of the file
    #[instrument(skip_all)]
    pub fn reverse_text_chunks(&self, display_row: DisplayRow) -> impl Iterator<Item = &str> {
        (0..=display_row.0).rev().flat_map(move |row| {
            self.block_snapshot
                .chunks(
                    BlockRow(row)..BlockRow(row + 1),
                    false,
                    self.masked,
                    Highlights::default(),
                )
                .map(|h| h.text)
                .collect::<Vec<_>>()
                .into_iter()
                .rev()
        })
    }

    #[instrument(skip_all)]
    pub fn chunks(
        &self,
        display_rows: Range<DisplayRow>,
        language_aware: bool,
        highlight_styles: HighlightStyles,
    ) -> DisplayChunks<'_> {
        self.block_snapshot.chunks(
            BlockRow(display_rows.start.0)..BlockRow(display_rows.end.0),
            language_aware,
            self.masked,
            Highlights {
                text_highlights: Some(&self.text_highlights),
                inlay_highlights: Some(&self.inlay_highlights),
                styles: highlight_styles,
            },
        )
    }

    #[instrument(skip_all)]
    pub fn highlighted_chunks<'a>(
        &'a self,
        display_rows: Range<DisplayRow>,
        language_aware: bool,
        editor_style: &'a EditorStyle,
    ) -> impl Iterator<Item = HighlightedChunk<'a>> {
        self.chunks(
            display_rows,
            language_aware,
            HighlightStyles {
                inlay_hint: Some(editor_style.inlay_hints_style),
                edit_prediction: Some(editor_style.edit_prediction_styles),
            },
        )
        .flat_map(|chunk| {
            let highlight_style = chunk
                .syntax_highlight_id
                .and_then(|id| id.style(&editor_style.syntax));

            let chunk_highlight = chunk.highlight_style.map(|chunk_highlight| {
                HighlightStyle {
                    // For color inlays, blend the color with the editor background
                    // if the color has transparency (alpha < 1.0)
                    color: chunk_highlight.color.map(|color| {
                        if chunk.is_inlay && !color.is_opaque() {
                            editor_style.background.blend(color)
                        } else {
                            color
                        }
                    }),
                    ..chunk_highlight
                }
            });

            let diagnostic_highlight = chunk
                .diagnostic_severity
                .filter(|severity| {
                    self.diagnostics_max_severity
                        .into_lsp()
                        .is_some_and(|max_severity| severity <= &max_severity)
                })
                .map(|severity| HighlightStyle {
                    fade_out: chunk
                        .is_unnecessary
                        .then_some(editor_style.unnecessary_code_fade),
                    underline: (chunk.underline
                        && editor_style.show_underlines
                        && !(chunk.is_unnecessary && severity > lsp::DiagnosticSeverity::WARNING))
                        .then(|| {
                            let diagnostic_color =
                                super::diagnostic_style(severity, &editor_style.status);
                            UnderlineStyle {
                                color: Some(diagnostic_color),
                                thickness: 1.0.into(),
                                wavy: true,
                            }
                        }),
                    ..Default::default()
                });

            let style = [highlight_style, chunk_highlight, diagnostic_highlight]
                .into_iter()
                .flatten()
                .reduce(|acc, highlight| acc.highlight(highlight));

            HighlightedChunk {
                text: chunk.text,
                style,
                is_tab: chunk.is_tab,
                is_inlay: chunk.is_inlay,
                replacement: chunk.renderer.map(ChunkReplacement::Renderer),
            }
            .highlight_invisibles(editor_style)
        })
    }

    #[instrument(skip_all)]
    pub fn layout_row(
        &self,
        display_row: DisplayRow,
        TextLayoutDetails {
            text_system,
            editor_style,
            rem_size,
            scroll_anchor: _,
            visible_rows: _,
            vertical_scroll_margin: _,
        }: &TextLayoutDetails,
    ) -> Arc<LineLayout> {
        let mut runs = Vec::new();
        let mut line = String::new();

        let range = display_row..display_row.next_row();
        for chunk in self.highlighted_chunks(range, false, editor_style) {
            line.push_str(chunk.text);

            let text_style = if let Some(style) = chunk.style {
                Cow::Owned(editor_style.text.clone().highlight(style))
            } else {
                Cow::Borrowed(&editor_style.text)
            };

            runs.push(text_style.to_run(chunk.text.len()))
        }

        if line.ends_with('\n') {
            line.pop();
            if let Some(last_run) = runs.last_mut() {
                last_run.len -= 1;
                if last_run.len == 0 {
                    runs.pop();
                }
            }
        }

        let font_size = editor_style.text.font_size.to_pixels(*rem_size);
        text_system.layout_line(&line, font_size, &runs, None)
    }

    pub fn x_for_display_point(
        &self,
        display_point: DisplayPoint,
        text_layout_details: &TextLayoutDetails,
    ) -> Pixels {
        let line = self.layout_row(display_point.row(), text_layout_details);
        line.x_for_index(display_point.column() as usize)
    }

    pub fn display_column_for_x(
        &self,
        display_row: DisplayRow,
        x: Pixels,
        details: &TextLayoutDetails,
    ) -> u32 {
        let layout_line = self.layout_row(display_row, details);
        layout_line.closest_index_for_x(x) as u32
    }

    #[instrument(skip_all)]
    pub fn grapheme_at(&self, mut point: DisplayPoint) -> Option<SharedString> {
        point = DisplayPoint(self.block_snapshot.clip_point(point.0, Bias::Left));
        let chars = self
            .text_chunks(point.row())
            .flat_map(str::chars)
            .skip_while({
                let mut column = 0;
                move |char| {
                    let at_point = column >= point.column();
                    column += char.len_utf8() as u32;
                    !at_point
                }
            })
            .take_while({
                let mut prev = false;
                move |char| {
                    let now = char.is_ascii();
                    let end = char.is_ascii() && (char.is_ascii_whitespace() || prev);
                    prev = now;
                    !end
                }
            });
        chars.collect::<String>().graphemes(true).next().map(|s| {
            if let Some(invisible) = s.chars().next().filter(|&c| is_invisible(c)) {
                replacement(invisible).unwrap_or(s).to_owned().into()
            } else if s == "\n" {
                " ".into()
            } else {
                s.to_owned().into()
            }
        })
    }

    pub fn buffer_chars_at(
        &self,
        mut offset: MultiBufferOffset,
    ) -> impl Iterator<Item = (char, MultiBufferOffset)> + '_ {
        self.buffer_snapshot().chars_at(offset).map(move |ch| {
            let ret = (ch, offset);
            offset += ch.len_utf8();
            ret
        })
    }

    pub fn reverse_buffer_chars_at(
        &self,
        mut offset: MultiBufferOffset,
    ) -> impl Iterator<Item = (char, MultiBufferOffset)> + '_ {
        self.buffer_snapshot()
            .reversed_chars_at(offset)
            .map(move |ch| {
                offset -= ch.len_utf8();
                (ch, offset)
            })
    }

    pub fn clip_point(&self, point: DisplayPoint, bias: Bias) -> DisplayPoint {
        let mut clipped = self.block_snapshot.clip_point(point.0, bias);
        if self.clip_at_line_ends {
            clipped = self.clip_at_line_end(DisplayPoint(clipped)).0
        }
        DisplayPoint(clipped)
    }

    pub fn clip_ignoring_line_ends(&self, point: DisplayPoint, bias: Bias) -> DisplayPoint {
        DisplayPoint(self.block_snapshot.clip_point(point.0, bias))
    }

    pub fn clip_at_line_end(&self, display_point: DisplayPoint) -> DisplayPoint {
        let mut point = self.display_point_to_point(display_point, Bias::Left);

        if point.column != self.buffer_snapshot().line_len(MultiBufferRow(point.row)) {
            return display_point;
        }
        point.column = point.column.saturating_sub(1);
        point = self.buffer_snapshot().clip_point(point, Bias::Left);
        self.point_to_display_point(point, Bias::Left)
    }

    pub fn folds_in_range<T>(&self, range: Range<T>) -> impl Iterator<Item = &Fold>
    where
        T: ToOffset,
    {
        self.fold_snapshot().folds_in_range(range)
    }

    pub fn blocks_in_range(
        &self,
        rows: Range<DisplayRow>,
    ) -> impl Iterator<Item = (DisplayRow, &Block)> {
        self.block_snapshot
            .blocks_in_range(BlockRow(rows.start.0)..BlockRow(rows.end.0))
            .map(|(row, block)| (DisplayRow(row.0), block))
    }

    pub fn sticky_header_excerpt(&self, row: f64) -> Option<StickyHeaderExcerpt<'_>> {
        self.block_snapshot.sticky_header_excerpt(row)
    }

    pub fn block_for_id(&self, id: BlockId) -> Option<Block> {
        self.block_snapshot.block_for_id(id)
    }

    pub fn intersects_fold<T: ToOffset>(&self, offset: T) -> bool {
        self.fold_snapshot().intersects_fold(offset)
    }

    pub fn is_line_folded(&self, buffer_row: MultiBufferRow) -> bool {
        self.block_snapshot.is_line_replaced(buffer_row)
            || self.fold_snapshot().is_line_folded(buffer_row)
    }

    pub fn is_block_line(&self, display_row: DisplayRow) -> bool {
        self.block_snapshot.is_block_line(BlockRow(display_row.0))
    }

    pub fn is_folded_buffer_header(&self, display_row: DisplayRow) -> bool {
        self.block_snapshot
            .is_folded_buffer_header(BlockRow(display_row.0))
    }

    pub fn soft_wrap_indent(&self, display_row: DisplayRow) -> Option<u32> {
        let wrap_row = self
            .block_snapshot
            .to_wrap_point(BlockPoint::new(BlockRow(display_row.0), 0), Bias::Left)
            .row();
        self.wrap_snapshot().soft_wrap_indent(wrap_row)
    }

    pub fn text(&self) -> String {
        self.text_chunks(DisplayRow(0)).collect()
    }

    pub fn line(&self, display_row: DisplayRow) -> String {
        let mut result = String::new();
        for chunk in self.text_chunks(display_row) {
            if let Some(ix) = chunk.find('\n') {
                result.push_str(&chunk[0..ix]);
                break;
            } else {
                result.push_str(chunk);
            }
        }
        result
    }

    pub fn line_indent_for_buffer_row(&self, buffer_row: MultiBufferRow) -> LineIndent {
        self.buffer_snapshot().line_indent_for_row(buffer_row)
    }

    pub fn line_len(&self, row: DisplayRow) -> u32 {
        self.block_snapshot.line_len(BlockRow(row.0))
    }

    pub fn longest_row(&self) -> DisplayRow {
        DisplayRow(self.block_snapshot.longest_row().0)
    }

    pub fn longest_row_in_range(&self, range: Range<DisplayRow>) -> DisplayRow {
        let block_range = BlockRow(range.start.0)..BlockRow(range.end.0);
        let longest_row = self.block_snapshot.longest_row_in_range(block_range);
        DisplayRow(longest_row.0)
    }

    pub fn starts_indent(&self, buffer_row: MultiBufferRow) -> bool {
        let max_row = self.buffer_snapshot().max_row();
        if buffer_row >= max_row {
            return false;
        }

        let line_indent = self.line_indent_for_buffer_row(buffer_row);
        if line_indent.is_line_blank() {
            return false;
        }

        (buffer_row.0 + 1..=max_row.0)
            .find_map(|next_row| {
                let next_line_indent = self.line_indent_for_buffer_row(MultiBufferRow(next_row));
                if next_line_indent.raw_len() > line_indent.raw_len() {
                    Some(true)
                } else if !next_line_indent.is_line_blank() {
                    Some(false)
                } else {
                    None
                }
            })
            .unwrap_or(false)
    }

    #[instrument(skip_all)]
    pub fn crease_for_buffer_row(&self, buffer_row: MultiBufferRow) -> Option<Crease<Point>> {
        let start =
            MultiBufferPoint::new(buffer_row.0, self.buffer_snapshot().line_len(buffer_row));
        if let Some(crease) = self
            .crease_snapshot
            .query_row(buffer_row, self.buffer_snapshot())
        {
            match crease {
                Crease::Inline {
                    range,
                    placeholder,
                    render_toggle,
                    render_trailer,
                    metadata,
                } => Some(Crease::Inline {
                    range: range.to_point(self.buffer_snapshot()),
                    placeholder: placeholder.clone(),
                    render_toggle: render_toggle.clone(),
                    render_trailer: render_trailer.clone(),
                    metadata: metadata.clone(),
                }),
                Crease::Block {
                    range,
                    block_height,
                    block_style,
                    render_block,
                    block_priority,
                    render_toggle,
                } => Some(Crease::Block {
                    range: range.to_point(self.buffer_snapshot()),
                    block_height: *block_height,
                    block_style: *block_style,
                    render_block: render_block.clone(),
                    block_priority: *block_priority,
                    render_toggle: render_toggle.clone(),
                }),
            }
        } else if self.starts_indent(MultiBufferRow(start.row))
            && !self.is_line_folded(MultiBufferRow(start.row))
        {
            let start_line_indent = self.line_indent_for_buffer_row(buffer_row);
            let max_point = self.buffer_snapshot().max_point();
            let mut end = None;

            for row in (buffer_row.0 + 1)..=max_point.row {
                let line_indent = self.line_indent_for_buffer_row(MultiBufferRow(row));
                if !line_indent.is_line_blank()
                    && line_indent.raw_len() <= start_line_indent.raw_len()
                {
                    let prev_row = row - 1;
                    end = Some(Point::new(
                        prev_row,
                        self.buffer_snapshot().line_len(MultiBufferRow(prev_row)),
                    ));
                    break;
                }
            }

            let mut row_before_line_breaks = end.unwrap_or(max_point);
            while row_before_line_breaks.row > start.row
                && self
                    .buffer_snapshot()
                    .is_line_blank(MultiBufferRow(row_before_line_breaks.row))
            {
                row_before_line_breaks.row -= 1;
            }

            row_before_line_breaks = Point::new(
                row_before_line_breaks.row,
                self.buffer_snapshot()
                    .line_len(MultiBufferRow(row_before_line_breaks.row)),
            );

            Some(Crease::Inline {
                range: start..row_before_line_breaks,
                placeholder: self.fold_placeholder.clone(),
                render_toggle: None,
                render_trailer: None,
                metadata: None,
            })
        } else {
            None
        }
    }

    #[cfg(any(test, feature = "test-support"))]
    #[instrument(skip_all)]
    pub fn text_highlight_ranges<Tag: ?Sized + 'static>(
        &self,
    ) -> Option<Arc<(HighlightStyle, Vec<Range<Anchor>>)>> {
        let type_id = TypeId::of::<Tag>();
        self.text_highlights
            .get(&HighlightKey::Type(type_id))
            .cloned()
    }

    #[cfg(any(test, feature = "test-support"))]
    #[instrument(skip_all)]
    pub fn all_text_highlight_ranges<Tag: ?Sized + 'static>(
        &self,
    ) -> Vec<(gpui::Hsla, Range<Point>)> {
        use itertools::Itertools;

        let required_type_id = TypeId::of::<Tag>();
        self.text_highlights
            .iter()
            .filter(|(key, _)| match key {
                HighlightKey::Type(type_id) => type_id == &required_type_id,
                HighlightKey::TypePlus(type_id, _) => type_id == &required_type_id,
            })
            .map(|(_, value)| value.clone())
            .flat_map(|ranges| {
                ranges
                    .1
                    .iter()
                    .flat_map(|range| {
                        Some((ranges.0.color?, range.to_point(self.buffer_snapshot())))
                    })
                    .collect::<Vec<_>>()
            })
            .sorted_by_key(|(_, range)| range.start)
            .collect()
    }

    #[allow(unused)]
    #[cfg(any(test, feature = "test-support"))]
    pub(crate) fn inlay_highlights<Tag: ?Sized + 'static>(
        &self,
    ) -> Option<&TreeMap<InlayId, (HighlightStyle, InlayHighlight)>> {
        let type_id = TypeId::of::<Tag>();
        self.inlay_highlights.get(&type_id)
    }

    pub fn buffer_header_height(&self) -> u32 {
        self.block_snapshot.buffer_header_height
    }

    pub fn excerpt_header_height(&self) -> u32 {
        self.block_snapshot.excerpt_header_height
    }

    /// Given a `DisplayPoint`, returns another `DisplayPoint` corresponding to
    /// the start of the buffer row that is a given number of buffer rows away
    /// from the provided point.
    ///
    /// This moves by buffer rows instead of display rows, a distinction that is
    /// important when soft wrapping is enabled.
    #[instrument(skip_all)]
    pub fn start_of_relative_buffer_row(&self, point: DisplayPoint, times: isize) -> DisplayPoint {
        let start = self.display_point_to_fold_point(point, Bias::Left);
        let target = start.row() as isize + times;
        let new_row = (target.max(0) as u32).min(self.fold_snapshot().max_point().row());

        self.clip_point(
            self.fold_point_to_display_point(
                self.fold_snapshot()
                    .clip_point(FoldPoint::new(new_row, 0), Bias::Right),
            ),
            Bias::Right,
        )
    }
}

impl std::ops::Deref for DisplaySnapshot {
    type Target = BlockSnapshot;

    fn deref(&self) -> &Self::Target {
        &self.block_snapshot
    }
}

/// A zero-indexed point in a text buffer consisting of a row and column adjusted for inserted blocks.
#[derive(Copy, Clone, Default, Eq, Ord, PartialOrd, PartialEq)]
pub struct DisplayPoint(BlockPoint);

impl Debug for DisplayPoint {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.write_fmt(format_args!(
            "DisplayPoint({}, {})",
            self.row().0,
            self.column()
        ))
    }
}

impl Add for DisplayPoint {
    type Output = Self;

    fn add(self, other: Self) -> Self::Output {
        DisplayPoint(BlockPoint(self.0.0 + other.0.0))
    }
}

impl Sub for DisplayPoint {
    type Output = Self;

    fn sub(self, other: Self) -> Self::Output {
        DisplayPoint(BlockPoint(self.0.0 - other.0.0))
    }
}

#[derive(Debug, Copy, Clone, Default, Eq, Ord, PartialOrd, PartialEq, Deserialize, Hash)]
#[serde(transparent)]
pub struct DisplayRow(pub u32);

impl DisplayRow {
    pub(crate) fn as_display_point(&self) -> DisplayPoint {
        DisplayPoint::new(*self, 0)
    }
}

impl Add<DisplayRow> for DisplayRow {
    type Output = Self;

    fn add(self, other: Self) -> Self::Output {
        DisplayRow(self.0 + other.0)
    }
}

impl Add<u32> for DisplayRow {
    type Output = Self;

    fn add(self, other: u32) -> Self::Output {
        DisplayRow(self.0 + other)
    }
}

impl Sub<DisplayRow> for DisplayRow {
    type Output = Self;

    fn sub(self, other: Self) -> Self::Output {
        DisplayRow(self.0 - other.0)
    }
}

impl Sub<u32> for DisplayRow {
    type Output = Self;

    fn sub(self, other: u32) -> Self::Output {
        DisplayRow(self.0 - other)
    }
}

impl DisplayPoint {
    pub fn new(row: DisplayRow, column: u32) -> Self {
        Self(BlockPoint(Point::new(row.0, column)))
    }

    pub fn zero() -> Self {
        Self::new(DisplayRow(0), 0)
    }

    pub fn is_zero(&self) -> bool {
        self.0.is_zero()
    }

    pub fn row(self) -> DisplayRow {
        DisplayRow(self.0.row)
    }

    pub fn column(self) -> u32 {
        self.0.column
    }

    pub fn row_mut(&mut self) -> &mut u32 {
        &mut self.0.row
    }

    pub fn column_mut(&mut self) -> &mut u32 {
        &mut self.0.column
    }

    pub fn to_point(self, map: &DisplaySnapshot) -> Point {
        map.display_point_to_point(self, Bias::Left)
    }

    pub fn to_offset(self, map: &DisplaySnapshot, bias: Bias) -> MultiBufferOffset {
        let wrap_point = map.block_snapshot.to_wrap_point(self.0, bias);
        let tab_point = map.wrap_snapshot().to_tab_point(wrap_point);
        let fold_point = map
            .tab_snapshot()
            .tab_point_to_fold_point(tab_point, bias)
            .0;
        let inlay_point = fold_point.to_inlay_point(map.fold_snapshot());
        map.inlay_snapshot()
            .to_buffer_offset(map.inlay_snapshot().to_offset(inlay_point))
    }
}

impl ToDisplayPoint for MultiBufferOffset {
    fn to_display_point(&self, map: &DisplaySnapshot) -> DisplayPoint {
        map.point_to_display_point(self.to_point(map.buffer_snapshot()), Bias::Left)
    }
}

impl ToDisplayPoint for MultiBufferOffsetUtf16 {
    fn to_display_point(&self, map: &DisplaySnapshot) -> DisplayPoint {
        self.to_offset(map.buffer_snapshot()).to_display_point(map)
    }
}

impl ToDisplayPoint for Point {
    fn to_display_point(&self, map: &DisplaySnapshot) -> DisplayPoint {
        map.point_to_display_point(*self, Bias::Left)
    }
}

impl ToDisplayPoint for Anchor {
    fn to_display_point(&self, map: &DisplaySnapshot) -> DisplayPoint {
        self.to_point(map.buffer_snapshot()).to_display_point(map)
    }
}

#[cfg(test)]
pub mod tests {
    use super::*;
    use crate::{
        movement,
        test::{marked_display_snapshot, test_font},
    };
    use Bias::*;
    use block_map::BlockPlacement;
    use gpui::{
        App, AppContext as _, BorrowAppContext, Element, Hsla, Rgba, div, font, observe, px,
    };
    use language::{
        Buffer, Diagnostic, DiagnosticEntry, DiagnosticSet, Language, LanguageConfig,
        LanguageMatcher,
    };
    use lsp::LanguageServerId;

    use rand::{Rng, prelude::*};
    use settings::{SettingsContent, SettingsStore};
    use smol::stream::StreamExt;
    use std::{env, sync::Arc};
    use text::PointUtf16;
    use theme::{LoadThemes, SyntaxTheme};
    use unindent::Unindent as _;
    use util::test::{marked_text_ranges, sample_text};

    #[gpui::test(iterations = 100)]
    async fn test_random_display_map(cx: &mut gpui::TestAppContext, mut rng: StdRng) {
        cx.background_executor.set_block_on_ticks(0..=50);
        let operations = env::var("OPERATIONS")
            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
            .unwrap_or(10);

        let mut tab_size = rng.random_range(1..=4);
        let buffer_start_excerpt_header_height = rng.random_range(1..=5);
        let excerpt_header_height = rng.random_range(1..=5);
        let font_size = px(14.0);
        let max_wrap_width = 300.0;
        let mut wrap_width = if rng.random_bool(0.1) {
            None
        } else {
            Some(px(rng.random_range(0.0..=max_wrap_width)))
        };

        log::info!("tab size: {}", tab_size);
        log::info!("wrap width: {:?}", wrap_width);

        cx.update(|cx| {
            init_test(cx, |s| {
                s.project.all_languages.defaults.tab_size = NonZeroU32::new(tab_size)
            });
        });

        let buffer = cx.update(|cx| {
            if rng.random() {
                let len = rng.random_range(0..10);
                let text = util::RandomCharIter::new(&mut rng)
                    .take(len)
                    .collect::<String>();
                MultiBuffer::build_simple(&text, cx)
            } else {
                MultiBuffer::build_random(&mut rng, cx)
            }
        });

        let font = test_font();
        let map = cx.new(|cx| {
            DisplayMap::new(
                buffer.clone(),
                font,
                font_size,
                wrap_width,
                buffer_start_excerpt_header_height,
                excerpt_header_height,
                FoldPlaceholder::test(),
                DiagnosticSeverity::Warning,
                cx,
            )
        });
        let mut notifications = observe(&map, cx);
        let mut fold_count = 0;
        let mut blocks = Vec::new();

        let snapshot = map.update(cx, |map, cx| map.snapshot(cx));
        log::info!("buffer text: {:?}", snapshot.buffer_snapshot().text());
        log::info!("fold text: {:?}", snapshot.fold_snapshot().text());
        log::info!("tab text: {:?}", snapshot.tab_snapshot().text());
        log::info!("wrap text: {:?}", snapshot.wrap_snapshot().text());
        log::info!("block text: {:?}", snapshot.block_snapshot.text());
        log::info!("display text: {:?}", snapshot.text());

        for _i in 0..operations {
            match rng.random_range(0..100) {
                0..=19 => {
                    wrap_width = if rng.random_bool(0.2) {
                        None
                    } else {
                        Some(px(rng.random_range(0.0..=max_wrap_width)))
                    };
                    log::info!("setting wrap width to {:?}", wrap_width);
                    map.update(cx, |map, cx| map.set_wrap_width(wrap_width, cx));
                }
                20..=29 => {
                    let mut tab_sizes = vec![1, 2, 3, 4];
                    tab_sizes.remove((tab_size - 1) as usize);
                    tab_size = *tab_sizes.choose(&mut rng).unwrap();
                    log::info!("setting tab size to {:?}", tab_size);
                    cx.update(|cx| {
                        cx.update_global::<SettingsStore, _>(|store, cx| {
                            store.update_user_settings(cx, |s| {
                                s.project.all_languages.defaults.tab_size =
                                    NonZeroU32::new(tab_size);
                            });
                        });
                    });
                }
                30..=44 => {
                    map.update(cx, |map, cx| {
                        if rng.random() || blocks.is_empty() {
                            let snapshot = map.snapshot(cx);
                            let buffer = snapshot.buffer_snapshot();
                            let block_properties = (0..rng.random_range(1..=1))
                                .map(|_| {
                                    let position = buffer.anchor_after(buffer.clip_offset(
                                        rng.random_range(MultiBufferOffset(0)..=buffer.len()),
                                        Bias::Left,
                                    ));

                                    let placement = if rng.random() {
                                        BlockPlacement::Above(position)
                                    } else {
                                        BlockPlacement::Below(position)
                                    };
                                    let height = rng.random_range(1..5);
                                    log::info!(
                                        "inserting block {:?} with height {}",
                                        placement.as_ref().map(|p| p.to_point(&buffer)),
                                        height
                                    );
                                    let priority = rng.random_range(1..100);
                                    BlockProperties {
                                        placement,
                                        style: BlockStyle::Fixed,
                                        height: Some(height),
                                        render: Arc::new(|_| div().into_any()),
                                        priority,
                                    }
                                })
                                .collect::<Vec<_>>();
                            blocks.extend(map.insert_blocks(block_properties, cx));
                        } else {
                            blocks.shuffle(&mut rng);
                            let remove_count = rng.random_range(1..=4.min(blocks.len()));
                            let block_ids_to_remove = (0..remove_count)
                                .map(|_| blocks.remove(rng.random_range(0..blocks.len())))
                                .collect();
                            log::info!("removing block ids {:?}", block_ids_to_remove);
                            map.remove_blocks(block_ids_to_remove, cx);
                        }
                    });
                }
                45..=79 => {
                    let mut ranges = Vec::new();
                    for _ in 0..rng.random_range(1..=3) {
                        buffer.read_with(cx, |buffer, cx| {
                            let buffer = buffer.read(cx);
                            let end = buffer.clip_offset(
                                rng.random_range(MultiBufferOffset(0)..=buffer.len()),
                                Right,
                            );
                            let start = buffer
                                .clip_offset(rng.random_range(MultiBufferOffset(0)..=end), Left);
                            ranges.push(start..end);
                        });
                    }

                    if rng.random() && fold_count > 0 {
                        log::info!("unfolding ranges: {:?}", ranges);
                        map.update(cx, |map, cx| {
                            map.unfold_intersecting(ranges, true, cx);
                        });
                    } else {
                        log::info!("folding ranges: {:?}", ranges);
                        map.update(cx, |map, cx| {
                            map.fold(
                                ranges
                                    .into_iter()
                                    .map(|range| Crease::simple(range, FoldPlaceholder::test()))
                                    .collect(),
                                cx,
                            );
                        });
                    }
                }
                _ => {
                    buffer.update(cx, |buffer, cx| buffer.randomly_mutate(&mut rng, 5, cx));
                }
            }

            if map.read_with(cx, |map, cx| map.is_rewrapping(cx)) {
                notifications.next().await.unwrap();
            }

            let snapshot = map.update(cx, |map, cx| map.snapshot(cx));
            fold_count = snapshot.fold_count();
            log::info!("buffer text: {:?}", snapshot.buffer_snapshot().text());
            log::info!("fold text: {:?}", snapshot.fold_snapshot().text());
            log::info!("tab text: {:?}", snapshot.tab_snapshot().text());
            log::info!("wrap text: {:?}", snapshot.wrap_snapshot().text());
            log::info!("block text: {:?}", snapshot.block_snapshot.text());
            log::info!("display text: {:?}", snapshot.text());

            // Line boundaries
            let buffer = snapshot.buffer_snapshot();
            for _ in 0..5 {
                let row = rng.random_range(0..=buffer.max_point().row);
                let column = rng.random_range(0..=buffer.line_len(MultiBufferRow(row)));
                let point = buffer.clip_point(Point::new(row, column), Left);

                let (prev_buffer_bound, prev_display_bound) = snapshot.prev_line_boundary(point);
                let (next_buffer_bound, next_display_bound) = snapshot.next_line_boundary(point);

                assert!(prev_buffer_bound <= point);
                assert!(next_buffer_bound >= point);
                assert_eq!(prev_buffer_bound.column, 0);
                assert_eq!(prev_display_bound.column(), 0);
                if next_buffer_bound < buffer.max_point() {
                    assert_eq!(buffer.chars_at(next_buffer_bound).next(), Some('\n'));
                }

                assert_eq!(
                    prev_display_bound,
                    prev_buffer_bound.to_display_point(&snapshot),
                    "row boundary before {:?}. reported buffer row boundary: {:?}",
                    point,
                    prev_buffer_bound
                );
                assert_eq!(
                    next_display_bound,
                    next_buffer_bound.to_display_point(&snapshot),
                    "display row boundary after {:?}. reported buffer row boundary: {:?}",
                    point,
                    next_buffer_bound
                );
                assert_eq!(
                    prev_buffer_bound,
                    prev_display_bound.to_point(&snapshot),
                    "row boundary before {:?}. reported display row boundary: {:?}",
                    point,
                    prev_display_bound
                );
                assert_eq!(
                    next_buffer_bound,
                    next_display_bound.to_point(&snapshot),
                    "row boundary after {:?}. reported display row boundary: {:?}",
                    point,
                    next_display_bound
                );
            }

            // Movement
            let min_point = snapshot.clip_point(DisplayPoint::new(DisplayRow(0), 0), Left);
            let max_point = snapshot.clip_point(snapshot.max_point(), Right);
            for _ in 0..5 {
                let row = rng.random_range(0..=snapshot.max_point().row().0);
                let column = rng.random_range(0..=snapshot.line_len(DisplayRow(row)));
                let point = snapshot.clip_point(DisplayPoint::new(DisplayRow(row), column), Left);

                log::info!("Moving from point {:?}", point);

                let moved_right = movement::right(&snapshot, point);
                log::info!("Right {:?}", moved_right);
                if point < max_point {
                    assert!(moved_right > point);
                    if point.column() == snapshot.line_len(point.row())
                        || snapshot.soft_wrap_indent(point.row()).is_some()
                            && point.column() == snapshot.line_len(point.row()) - 1
                    {
                        assert!(moved_right.row() > point.row());
                    }
                } else {
                    assert_eq!(moved_right, point);
                }

                let moved_left = movement::left(&snapshot, point);
                log::info!("Left {:?}", moved_left);
                if point > min_point {
                    assert!(moved_left < point);
                    if point.column() == 0 {
                        assert!(moved_left.row() < point.row());
                    }
                } else {
                    assert_eq!(moved_left, point);
                }
            }
        }
    }

    #[gpui::test(retries = 5)]
    async fn test_soft_wraps(cx: &mut gpui::TestAppContext) {
        cx.background_executor
            .set_block_on_ticks(usize::MAX..=usize::MAX);
        cx.update(|cx| {
            init_test(cx, |_| {});
        });

        let mut cx = crate::test::editor_test_context::EditorTestContext::new(cx).await;
        let editor = cx.editor.clone();
        let window = cx.window;

        _ = cx.update_window(window, |_, window, cx| {
            let text_layout_details =
                editor.update(cx, |editor, cx| editor.text_layout_details(window, cx));

            let font_size = px(12.0);
            let wrap_width = Some(px(96.));

            let text = "one two three four five\nsix seven eight";
            let buffer = MultiBuffer::build_simple(text, cx);
            let map = cx.new(|cx| {
                DisplayMap::new(
                    buffer.clone(),
                    font("Helvetica"),
                    font_size,
                    wrap_width,
                    1,
                    1,
                    FoldPlaceholder::test(),
                    DiagnosticSeverity::Warning,
                    cx,
                )
            });

            let snapshot = map.update(cx, |map, cx| map.snapshot(cx));
            assert_eq!(
                snapshot.text_chunks(DisplayRow(0)).collect::<String>(),
                "one two \nthree four \nfive\nsix seven \neight"
            );
            assert_eq!(
                snapshot.clip_point(DisplayPoint::new(DisplayRow(0), 8), Bias::Left),
                DisplayPoint::new(DisplayRow(0), 7)
            );
            assert_eq!(
                snapshot.clip_point(DisplayPoint::new(DisplayRow(0), 8), Bias::Right),
                DisplayPoint::new(DisplayRow(1), 0)
            );
            assert_eq!(
                movement::right(&snapshot, DisplayPoint::new(DisplayRow(0), 7)),
                DisplayPoint::new(DisplayRow(1), 0)
            );
            assert_eq!(
                movement::left(&snapshot, DisplayPoint::new(DisplayRow(1), 0)),
                DisplayPoint::new(DisplayRow(0), 7)
            );

            let x = snapshot
                .x_for_display_point(DisplayPoint::new(DisplayRow(1), 10), &text_layout_details);
            assert_eq!(
                movement::up(
                    &snapshot,
                    DisplayPoint::new(DisplayRow(1), 10),
                    language::SelectionGoal::None,
                    false,
                    &text_layout_details,
                ),
                (
                    DisplayPoint::new(DisplayRow(0), 7),
                    language::SelectionGoal::HorizontalPosition(f64::from(x))
                )
            );
            assert_eq!(
                movement::down(
                    &snapshot,
                    DisplayPoint::new(DisplayRow(0), 7),
                    language::SelectionGoal::HorizontalPosition(f64::from(x)),
                    false,
                    &text_layout_details
                ),
                (
                    DisplayPoint::new(DisplayRow(1), 10),
                    language::SelectionGoal::HorizontalPosition(f64::from(x))
                )
            );
            assert_eq!(
                movement::down(
                    &snapshot,
                    DisplayPoint::new(DisplayRow(1), 10),
                    language::SelectionGoal::HorizontalPosition(f64::from(x)),
                    false,
                    &text_layout_details
                ),
                (
                    DisplayPoint::new(DisplayRow(2), 4),
                    language::SelectionGoal::HorizontalPosition(f64::from(x))
                )
            );

            let ix = MultiBufferOffset(snapshot.buffer_snapshot().text().find("seven").unwrap());
            buffer.update(cx, |buffer, cx| {
                buffer.edit([(ix..ix, "and ")], None, cx);
            });

            let snapshot = map.update(cx, |map, cx| map.snapshot(cx));
            assert_eq!(
                snapshot.text_chunks(DisplayRow(1)).collect::<String>(),
                "three four \nfive\nsix and \nseven eight"
            );

            // Re-wrap on font size changes
            map.update(cx, |map, cx| {
                map.set_font(font("Helvetica"), font_size + Pixels::from(3.), cx)
            });

            let snapshot = map.update(cx, |map, cx| map.snapshot(cx));
            assert_eq!(
                snapshot.text_chunks(DisplayRow(1)).collect::<String>(),
                "three \nfour five\nsix and \nseven \neight"
            )
        });
    }

    #[gpui::test]
    fn test_text_chunks(cx: &mut gpui::App) {
        init_test(cx, |_| {});

        let text = sample_text(6, 6, 'a');
        let buffer = MultiBuffer::build_simple(&text, cx);

        let font_size = px(14.0);
        let map = cx.new(|cx| {
            DisplayMap::new(
                buffer.clone(),
                font("Helvetica"),
                font_size,
                None,
                1,
                1,
                FoldPlaceholder::test(),
                DiagnosticSeverity::Warning,
                cx,
            )
        });

        buffer.update(cx, |buffer, cx| {
            buffer.edit(
                vec![
                    (
                        MultiBufferPoint::new(1, 0)..MultiBufferPoint::new(1, 0),
                        "\t",
                    ),
                    (
                        MultiBufferPoint::new(1, 1)..MultiBufferPoint::new(1, 1),
                        "\t",
                    ),
                    (
                        MultiBufferPoint::new(2, 1)..MultiBufferPoint::new(2, 1),
                        "\t",
                    ),
                ],
                None,
                cx,
            )
        });

        assert_eq!(
            map.update(cx, |map, cx| map.snapshot(cx))
                .text_chunks(DisplayRow(1))
                .collect::<String>()
                .lines()
                .next(),
            Some("    b   bbbbb")
        );
        assert_eq!(
            map.update(cx, |map, cx| map.snapshot(cx))
                .text_chunks(DisplayRow(2))
                .collect::<String>()
                .lines()
                .next(),
            Some("c   ccccc")
        );
    }

    #[gpui::test]
    fn test_inlays_with_newlines_after_blocks(cx: &mut gpui::TestAppContext) {
        cx.update(|cx| init_test(cx, |_| {}));

        let buffer = cx.new(|cx| Buffer::local("a", cx));
        let buffer = cx.new(|cx| MultiBuffer::singleton(buffer, cx));
        let buffer_snapshot = buffer.read_with(cx, |buffer, cx| buffer.snapshot(cx));

        let font_size = px(14.0);
        let map = cx.new(|cx| {
            DisplayMap::new(
                buffer.clone(),
                font("Helvetica"),
                font_size,
                None,
                1,
                1,
                FoldPlaceholder::test(),
                DiagnosticSeverity::Warning,
                cx,
            )
        });

        map.update(cx, |map, cx| {
            map.insert_blocks(
                [BlockProperties {
                    placement: BlockPlacement::Above(
                        buffer_snapshot.anchor_before(Point::new(0, 0)),
                    ),
                    height: Some(2),
                    style: BlockStyle::Sticky,
                    render: Arc::new(|_| div().into_any()),
                    priority: 0,
                }],
                cx,
            );
        });
        map.update(cx, |m, cx| assert_eq!(m.snapshot(cx).text(), "\n\na"));

        map.update(cx, |map, cx| {
            map.splice_inlays(
                &[],
                vec![Inlay::edit_prediction(
                    0,
                    buffer_snapshot.anchor_after(MultiBufferOffset(0)),
                    "\n",
                )],
                cx,
            );
        });
        map.update(cx, |m, cx| assert_eq!(m.snapshot(cx).text(), "\n\n\na"));

        // Regression test: updating the display map does not crash when a
        // block is immediately followed by a multi-line inlay.
        buffer.update(cx, |buffer, cx| {
            buffer.edit(
                [(MultiBufferOffset(1)..MultiBufferOffset(1), "b")],
                None,
                cx,
            );
        });
        map.update(cx, |m, cx| assert_eq!(m.snapshot(cx).text(), "\n\n\nab"));
    }

    #[gpui::test]
    async fn test_chunks(cx: &mut gpui::TestAppContext) {
        let text = r#"
            fn outer() {}

            mod module {
                fn inner() {}
            }"#
        .unindent();

        let theme =
            SyntaxTheme::new_test(vec![("mod.body", Hsla::red()), ("fn.name", Hsla::blue())]);
        let language = Arc::new(
            Language::new(
                LanguageConfig {
                    name: "Test".into(),
                    matcher: LanguageMatcher {
                        path_suffixes: vec![".test".to_string()],
                        ..Default::default()
                    },
                    ..Default::default()
                },
                Some(tree_sitter_rust::LANGUAGE.into()),
            )
            .with_highlights_query(
                r#"
                (mod_item name: (identifier) body: _ @mod.body)
                (function_item name: (identifier) @fn.name)
                "#,
            )
            .unwrap(),
        );
        language.set_theme(&theme);

        cx.update(|cx| {
            init_test(cx, |s| {
                s.project.all_languages.defaults.tab_size = Some(2.try_into().unwrap())
            })
        });

        let buffer = cx.new(|cx| Buffer::local(text, cx).with_language(language, cx));
        cx.condition(&buffer, |buf, _| !buf.is_parsing()).await;
        let buffer = cx.new(|cx| MultiBuffer::singleton(buffer, cx));

        let font_size = px(14.0);

        let map = cx.new(|cx| {
            DisplayMap::new(
                buffer,
                font("Helvetica"),
                font_size,
                None,
                1,
                1,
                FoldPlaceholder::test(),
                DiagnosticSeverity::Warning,
                cx,
            )
        });
        assert_eq!(
            cx.update(|cx| syntax_chunks(DisplayRow(0)..DisplayRow(5), &map, &theme, cx)),
            vec![
                ("fn ".to_string(), None),
                ("outer".to_string(), Some(Hsla::blue())),
                ("() {}\n\nmod module ".to_string(), None),
                ("{\n    fn ".to_string(), Some(Hsla::red())),
                ("inner".to_string(), Some(Hsla::blue())),
                ("() {}\n}".to_string(), Some(Hsla::red())),
            ]
        );
        assert_eq!(
            cx.update(|cx| syntax_chunks(DisplayRow(3)..DisplayRow(5), &map, &theme, cx)),
            vec![
                ("    fn ".to_string(), Some(Hsla::red())),
                ("inner".to_string(), Some(Hsla::blue())),
                ("() {}\n}".to_string(), Some(Hsla::red())),
            ]
        );

        map.update(cx, |map, cx| {
            map.fold(
                vec![Crease::simple(
                    MultiBufferPoint::new(0, 6)..MultiBufferPoint::new(3, 2),
                    FoldPlaceholder::test(),
                )],
                cx,
            )
        });
        assert_eq!(
            cx.update(|cx| syntax_chunks(DisplayRow(0)..DisplayRow(2), &map, &theme, cx)),
            vec![
                ("fn ".to_string(), None),
                ("out".to_string(), Some(Hsla::blue())),
                ("⋯".to_string(), None),
                ("  fn ".to_string(), Some(Hsla::red())),
                ("inner".to_string(), Some(Hsla::blue())),
                ("() {}\n}".to_string(), Some(Hsla::red())),
            ]
        );
    }

    #[gpui::test]
    async fn test_chunks_with_syntax_highlighting_across_blocks(cx: &mut gpui::TestAppContext) {
        cx.background_executor
            .set_block_on_ticks(usize::MAX..=usize::MAX);

        let text = r#"
            const A: &str = "
                one
                two
                three
            ";
            const B: &str = "four";
        "#
        .unindent();

        let theme = SyntaxTheme::new_test(vec![
            ("string", Hsla::red()),
            ("punctuation", Hsla::blue()),
            ("keyword", Hsla::green()),
        ]);
        let language = Arc::new(
            Language::new(
                LanguageConfig {
                    name: "Rust".into(),
                    ..Default::default()
                },
                Some(tree_sitter_rust::LANGUAGE.into()),
            )
            .with_highlights_query(
                r#"
                (string_literal) @string
                "const" @keyword
                [":" ";"] @punctuation
                "#,
            )
            .unwrap(),
        );
        language.set_theme(&theme);

        cx.update(|cx| init_test(cx, |_| {}));

        let buffer = cx.new(|cx| Buffer::local(text, cx).with_language(language, cx));
        cx.condition(&buffer, |buf, _| !buf.is_parsing()).await;
        let buffer = cx.new(|cx| MultiBuffer::singleton(buffer, cx));
        let buffer_snapshot = buffer.read_with(cx, |buffer, cx| buffer.snapshot(cx));

        let map = cx.new(|cx| {
            DisplayMap::new(
                buffer,
                font("Courier"),
                px(16.0),
                None,
                1,
                1,
                FoldPlaceholder::test(),
                DiagnosticSeverity::Warning,
                cx,
            )
        });

        // Insert two blocks in the middle of a multi-line string literal.
        // The second block has zero height.
        map.update(cx, |map, cx| {
            map.insert_blocks(
                [
                    BlockProperties {
                        placement: BlockPlacement::Below(
                            buffer_snapshot.anchor_before(Point::new(1, 0)),
                        ),
                        height: Some(1),
                        style: BlockStyle::Sticky,
                        render: Arc::new(|_| div().into_any()),
                        priority: 0,
                    },
                    BlockProperties {
                        placement: BlockPlacement::Below(
                            buffer_snapshot.anchor_before(Point::new(2, 0)),
                        ),
                        height: None,
                        style: BlockStyle::Sticky,
                        render: Arc::new(|_| div().into_any()),
                        priority: 0,
                    },
                ],
                cx,
            )
        });

        pretty_assertions::assert_eq!(
            cx.update(|cx| syntax_chunks(DisplayRow(0)..DisplayRow(7), &map, &theme, cx)),
            [
                ("const".into(), Some(Hsla::green())),
                (" A".into(), None),
                (":".into(), Some(Hsla::blue())),
                (" &str = ".into(), None),
                ("\"\n    one\n".into(), Some(Hsla::red())),
                ("\n".into(), None),
                ("    two\n    three\n\"".into(), Some(Hsla::red())),
                (";".into(), Some(Hsla::blue())),
                ("\n".into(), None),
                ("const".into(), Some(Hsla::green())),
                (" B".into(), None),
                (":".into(), Some(Hsla::blue())),
                (" &str = ".into(), None),
                ("\"four\"".into(), Some(Hsla::red())),
                (";".into(), Some(Hsla::blue())),
                ("\n".into(), None),
            ]
        );
    }

    #[gpui::test]
    async fn test_chunks_with_diagnostics_across_blocks(cx: &mut gpui::TestAppContext) {
        cx.background_executor
            .set_block_on_ticks(usize::MAX..=usize::MAX);

        let text = r#"
            struct A {
                b: usize;
            }
            const c: usize = 1;
        "#
        .unindent();

        cx.update(|cx| init_test(cx, |_| {}));

        let buffer = cx.new(|cx| Buffer::local(text, cx));

        buffer.update(cx, |buffer, cx| {
            buffer.update_diagnostics(
                LanguageServerId(0),
                DiagnosticSet::new(
                    [DiagnosticEntry {
                        range: PointUtf16::new(0, 0)..PointUtf16::new(2, 1),
                        diagnostic: Diagnostic {
                            severity: lsp::DiagnosticSeverity::ERROR,
                            group_id: 1,
                            message: "hi".into(),
                            ..Default::default()
                        },
                    }],
                    buffer,
                ),
                cx,
            )
        });

        let buffer = cx.new(|cx| MultiBuffer::singleton(buffer, cx));
        let buffer_snapshot = buffer.read_with(cx, |buffer, cx| buffer.snapshot(cx));

        let map = cx.new(|cx| {
            DisplayMap::new(
                buffer,
                font("Courier"),
                px(16.0),
                None,
                1,
                1,
                FoldPlaceholder::test(),
                DiagnosticSeverity::Warning,
                cx,
            )
        });

        let black = gpui::black().to_rgb();
        let red = gpui::red().to_rgb();

        // Insert a block in the middle of a multi-line diagnostic.
        map.update(cx, |map, cx| {
            map.highlight_text(
                HighlightKey::Type(TypeId::of::<usize>()),
                vec![
                    buffer_snapshot.anchor_before(Point::new(3, 9))
                        ..buffer_snapshot.anchor_after(Point::new(3, 14)),
                    buffer_snapshot.anchor_before(Point::new(3, 17))
                        ..buffer_snapshot.anchor_after(Point::new(3, 18)),
                ],
                red.into(),
                false,
                cx,
            );
            map.insert_blocks(
                [BlockProperties {
                    placement: BlockPlacement::Below(
                        buffer_snapshot.anchor_before(Point::new(1, 0)),
                    ),
                    height: Some(1),
                    style: BlockStyle::Sticky,
                    render: Arc::new(|_| div().into_any()),
                    priority: 0,
                }],
                cx,
            )
        });

        let snapshot = map.update(cx, |map, cx| map.snapshot(cx));
        let mut chunks = Vec::<(String, Option<lsp::DiagnosticSeverity>, Rgba)>::new();
        for chunk in snapshot.chunks(DisplayRow(0)..DisplayRow(5), true, Default::default()) {
            let color = chunk
                .highlight_style
                .and_then(|style| style.color)
                .map_or(black, |color| color.to_rgb());
            if let Some((last_chunk, last_severity, last_color)) = chunks.last_mut()
                && *last_severity == chunk.diagnostic_severity
                && *last_color == color
            {
                last_chunk.push_str(chunk.text);
                continue;
            }

            chunks.push((chunk.text.to_string(), chunk.diagnostic_severity, color));
        }

        assert_eq!(
            chunks,
            [
                (
                    "struct A {\n    b: usize;\n".into(),
                    Some(lsp::DiagnosticSeverity::ERROR),
                    black
                ),
                ("\n".into(), None, black),
                ("}".into(), Some(lsp::DiagnosticSeverity::ERROR), black),
                ("\nconst c: ".into(), None, black),
                ("usize".into(), None, red),
                (" = ".into(), None, black),
                ("1".into(), None, red),
                (";\n".into(), None, black),
            ]
        );
    }

    #[gpui::test]
    async fn test_point_translation_with_replace_blocks(cx: &mut gpui::TestAppContext) {
        cx.background_executor
            .set_block_on_ticks(usize::MAX..=usize::MAX);

        cx.update(|cx| init_test(cx, |_| {}));

        let buffer = cx.update(|cx| MultiBuffer::build_simple("abcde\nfghij\nklmno\npqrst", cx));
        let buffer_snapshot = buffer.read_with(cx, |buffer, cx| buffer.snapshot(cx));
        let map = cx.new(|cx| {
            DisplayMap::new(
                buffer.clone(),
                font("Courier"),
                px(16.0),
                None,
                1,
                1,
                FoldPlaceholder::test(),
                DiagnosticSeverity::Warning,
                cx,
            )
        });

        let snapshot = map.update(cx, |map, cx| {
            map.insert_blocks(
                [BlockProperties {
                    placement: BlockPlacement::Replace(
                        buffer_snapshot.anchor_before(Point::new(1, 2))
                            ..=buffer_snapshot.anchor_after(Point::new(2, 3)),
                    ),
                    height: Some(4),
                    style: BlockStyle::Fixed,
                    render: Arc::new(|_| div().into_any()),
                    priority: 0,
                }],
                cx,
            );
            map.snapshot(cx)
        });

        assert_eq!(snapshot.text(), "abcde\n\n\n\n\npqrst");

        let point_to_display_points = [
            (Point::new(1, 0), DisplayPoint::new(DisplayRow(1), 0)),
            (Point::new(2, 0), DisplayPoint::new(DisplayRow(1), 0)),
            (Point::new(3, 0), DisplayPoint::new(DisplayRow(5), 0)),
        ];
        for (buffer_point, display_point) in point_to_display_points {
            assert_eq!(
                snapshot.point_to_display_point(buffer_point, Bias::Left),
                display_point,
                "point_to_display_point({:?}, Bias::Left)",
                buffer_point
            );
            assert_eq!(
                snapshot.point_to_display_point(buffer_point, Bias::Right),
                display_point,
                "point_to_display_point({:?}, Bias::Right)",
                buffer_point
            );
        }

        let display_points_to_points = [
            (
                DisplayPoint::new(DisplayRow(1), 0),
                Point::new(1, 0),
                Point::new(2, 5),
            ),
            (
                DisplayPoint::new(DisplayRow(2), 0),
                Point::new(1, 0),
                Point::new(2, 5),
            ),
            (
                DisplayPoint::new(DisplayRow(3), 0),
                Point::new(1, 0),
                Point::new(2, 5),
            ),
            (
                DisplayPoint::new(DisplayRow(4), 0),
                Point::new(1, 0),
                Point::new(2, 5),
            ),
            (
                DisplayPoint::new(DisplayRow(5), 0),
                Point::new(3, 0),
                Point::new(3, 0),
            ),
        ];
        for (display_point, left_buffer_point, right_buffer_point) in display_points_to_points {
            assert_eq!(
                snapshot.display_point_to_point(display_point, Bias::Left),
                left_buffer_point,
                "display_point_to_point({:?}, Bias::Left)",
                display_point
            );
            assert_eq!(
                snapshot.display_point_to_point(display_point, Bias::Right),
                right_buffer_point,
                "display_point_to_point({:?}, Bias::Right)",
                display_point
            );
        }
    }

    #[gpui::test]
    async fn test_chunks_with_soft_wrapping(cx: &mut gpui::TestAppContext) {
        cx.background_executor
            .set_block_on_ticks(usize::MAX..=usize::MAX);

        let text = r#"
            fn outer() {}

            mod module {
                fn inner() {}
            }"#
        .unindent();

        let theme =
            SyntaxTheme::new_test(vec![("mod.body", Hsla::red()), ("fn.name", Hsla::blue())]);
        let language = Arc::new(
            Language::new(
                LanguageConfig {
                    name: "Test".into(),
                    matcher: LanguageMatcher {
                        path_suffixes: vec![".test".to_string()],
                        ..Default::default()
                    },
                    ..Default::default()
                },
                Some(tree_sitter_rust::LANGUAGE.into()),
            )
            .with_highlights_query(
                r#"
                (mod_item name: (identifier) body: _ @mod.body)
                (function_item name: (identifier) @fn.name)
                "#,
            )
            .unwrap(),
        );
        language.set_theme(&theme);

        cx.update(|cx| init_test(cx, |_| {}));

        let buffer = cx.new(|cx| Buffer::local(text, cx).with_language(language, cx));
        cx.condition(&buffer, |buf, _| !buf.is_parsing()).await;
        let buffer = cx.new(|cx| MultiBuffer::singleton(buffer, cx));

        let font_size = px(16.0);

        let map = cx.new(|cx| {
            DisplayMap::new(
                buffer,
                font("Courier"),
                font_size,
                Some(px(40.0)),
                1,
                1,
                FoldPlaceholder::test(),
                DiagnosticSeverity::Warning,
                cx,
            )
        });
        assert_eq!(
            cx.update(|cx| syntax_chunks(DisplayRow(0)..DisplayRow(5), &map, &theme, cx)),
            [
                ("fn \n".to_string(), None),
                ("oute".to_string(), Some(Hsla::blue())),
                ("\n".to_string(), None),
                ("r".to_string(), Some(Hsla::blue())),
                ("() \n{}\n\n".to_string(), None),
            ]
        );
        assert_eq!(
            cx.update(|cx| syntax_chunks(DisplayRow(3)..DisplayRow(5), &map, &theme, cx)),
            [("{}\n\n".to_string(), None)]
        );

        map.update(cx, |map, cx| {
            map.fold(
                vec![Crease::simple(
                    MultiBufferPoint::new(0, 6)..MultiBufferPoint::new(3, 2),
                    FoldPlaceholder::test(),
                )],
                cx,
            )
        });
        assert_eq!(
            cx.update(|cx| syntax_chunks(DisplayRow(1)..DisplayRow(4), &map, &theme, cx)),
            [
                ("out".to_string(), Some(Hsla::blue())),
                ("⋯\n".to_string(), None),
                ("  ".to_string(), Some(Hsla::red())),
                ("\n".to_string(), None),
                ("fn ".to_string(), Some(Hsla::red())),
                ("i".to_string(), Some(Hsla::blue())),
                ("\n".to_string(), None)
            ]
        );
    }

    #[gpui::test]
    async fn test_chunks_with_text_highlights(cx: &mut gpui::TestAppContext) {
        cx.update(|cx| init_test(cx, |_| {}));

        let theme =
            SyntaxTheme::new_test(vec![("operator", Hsla::red()), ("string", Hsla::green())]);
        let language = Arc::new(
            Language::new(
                LanguageConfig {
                    name: "Test".into(),
                    matcher: LanguageMatcher {
                        path_suffixes: vec![".test".to_string()],
                        ..Default::default()
                    },
                    ..Default::default()
                },
                Some(tree_sitter_rust::LANGUAGE.into()),
            )
            .with_highlights_query(
                r#"
                ":" @operator
                (string_literal) @string
                "#,
            )
            .unwrap(),
        );
        language.set_theme(&theme);

        let (text, highlighted_ranges) = marked_text_ranges(r#"constˇ «a»«:» B = "c «d»""#, false);

        let buffer = cx.new(|cx| Buffer::local(text, cx).with_language(language, cx));
        cx.condition(&buffer, |buf, _| !buf.is_parsing()).await;

        let buffer = cx.new(|cx| MultiBuffer::singleton(buffer, cx));
        let buffer_snapshot = buffer.read_with(cx, |buffer, cx| buffer.snapshot(cx));

        let font_size = px(16.0);
        let map = cx.new(|cx| {
            DisplayMap::new(
                buffer,
                font("Courier"),
                font_size,
                None,
                1,
                1,
                FoldPlaceholder::test(),
                DiagnosticSeverity::Warning,
                cx,
            )
        });

        enum MyType {}

        let style = HighlightStyle {
            color: Some(Hsla::blue()),
            ..Default::default()
        };

        map.update(cx, |map, cx| {
            map.highlight_text(
                HighlightKey::Type(TypeId::of::<MyType>()),
                highlighted_ranges
                    .into_iter()
                    .map(|range| MultiBufferOffset(range.start)..MultiBufferOffset(range.end))
                    .map(|range| {
                        buffer_snapshot.anchor_before(range.start)
                            ..buffer_snapshot.anchor_before(range.end)
                    })
                    .collect(),
                style,
                false,
                cx,
            );
        });

        assert_eq!(
            cx.update(|cx| chunks(DisplayRow(0)..DisplayRow(10), &map, &theme, cx)),
            [
                ("const ".to_string(), None, None),
                ("a".to_string(), None, Some(Hsla::blue())),
                (":".to_string(), Some(Hsla::red()), Some(Hsla::blue())),
                (" B = ".to_string(), None, None),
                ("\"c ".to_string(), Some(Hsla::green()), None),
                ("d".to_string(), Some(Hsla::green()), Some(Hsla::blue())),
                ("\"".to_string(), Some(Hsla::green()), None),
            ]
        );
    }

    #[gpui::test]
    fn test_clip_point(cx: &mut gpui::App) {
        init_test(cx, |_| {});

        fn assert(text: &str, shift_right: bool, bias: Bias, cx: &mut gpui::App) {
            let (unmarked_snapshot, mut markers) = marked_display_snapshot(text, cx);

            match bias {
                Bias::Left => {
                    if shift_right {
                        *markers[1].column_mut() += 1;
                    }

                    assert_eq!(unmarked_snapshot.clip_point(markers[1], bias), markers[0])
                }
                Bias::Right => {
                    if shift_right {
                        *markers[0].column_mut() += 1;
                    }

                    assert_eq!(unmarked_snapshot.clip_point(markers[0], bias), markers[1])
                }
            };
        }

        use Bias::{Left, Right};
        assert("ˇˇα", false, Left, cx);
        assert("ˇˇα", true, Left, cx);
        assert("ˇˇα", false, Right, cx);
        assert("ˇαˇ", true, Right, cx);
        assert("ˇˇ✋", false, Left, cx);
        assert("ˇˇ✋", true, Left, cx);
        assert("ˇˇ✋", false, Right, cx);
        assert("ˇ✋ˇ", true, Right, cx);
        assert("ˇˇ🍐", false, Left, cx);
        assert("ˇˇ🍐", true, Left, cx);
        assert("ˇˇ🍐", false, Right, cx);
        assert("ˇ🍐ˇ", true, Right, cx);
        assert("ˇˇ\t", false, Left, cx);
        assert("ˇˇ\t", true, Left, cx);
        assert("ˇˇ\t", false, Right, cx);
        assert("ˇ\tˇ", true, Right, cx);
        assert(" ˇˇ\t", false, Left, cx);
        assert(" ˇˇ\t", true, Left, cx);
        assert(" ˇˇ\t", false, Right, cx);
        assert(" ˇ\tˇ", true, Right, cx);
        assert("   ˇˇ\t", false, Left, cx);
        assert("   ˇˇ\t", false, Right, cx);
    }

    #[gpui::test]
    fn test_clip_at_line_ends(cx: &mut gpui::App) {
        init_test(cx, |_| {});

        fn assert(text: &str, cx: &mut gpui::App) {
            let (mut unmarked_snapshot, markers) = marked_display_snapshot(text, cx);
            unmarked_snapshot.clip_at_line_ends = true;
            assert_eq!(
                unmarked_snapshot.clip_point(markers[1], Bias::Left),
                markers[0]
            );
        }

        assert("ˇˇ", cx);
        assert("ˇaˇ", cx);
        assert("aˇbˇ", cx);
        assert("aˇαˇ", cx);
    }

    #[gpui::test]
    fn test_creases(cx: &mut gpui::App) {
        init_test(cx, |_| {});

        let text = "aaa\nbbb\nccc\nddd\neee\nfff\nggg\nhhh\niii\njjj\nkkk\nlll";
        let buffer = MultiBuffer::build_simple(text, cx);
        let font_size = px(14.0);
        cx.new(|cx| {
            let mut map = DisplayMap::new(
                buffer.clone(),
                font("Helvetica"),
                font_size,
                None,
                1,
                1,
                FoldPlaceholder::test(),
                DiagnosticSeverity::Warning,
                cx,
            );
            let snapshot = map.buffer.read(cx).snapshot(cx);
            let range =
                snapshot.anchor_before(Point::new(2, 0))..snapshot.anchor_after(Point::new(3, 3));

            map.crease_map.insert(
                [Crease::inline(
                    range,
                    FoldPlaceholder::test(),
                    |_row, _status, _toggle, _window, _cx| div(),
                    |_row, _status, _window, _cx| div(),
                )],
                &map.buffer.read(cx).snapshot(cx),
            );

            map
        });
    }

    #[gpui::test]
    fn test_tabs_with_multibyte_chars(cx: &mut gpui::App) {
        init_test(cx, |_| {});

        let text = "✅\t\tα\nβ\t\n🏀β\t\tγ";
        let buffer = MultiBuffer::build_simple(text, cx);
        let font_size = px(14.0);

        let map = cx.new(|cx| {
            DisplayMap::new(
                buffer.clone(),
                font("Helvetica"),
                font_size,
                None,
                1,
                1,
                FoldPlaceholder::test(),
                DiagnosticSeverity::Warning,
                cx,
            )
        });
        let map = map.update(cx, |map, cx| map.snapshot(cx));
        assert_eq!(map.text(), "✅       α\nβ   \n🏀β      γ");
        assert_eq!(
            map.text_chunks(DisplayRow(0)).collect::<String>(),
            "✅       α\nβ   \n🏀β      γ"
        );
        assert_eq!(
            map.text_chunks(DisplayRow(1)).collect::<String>(),
            "β   \n🏀β      γ"
        );
        assert_eq!(
            map.text_chunks(DisplayRow(2)).collect::<String>(),
            "🏀β      γ"
        );

        let point = MultiBufferPoint::new(0, "✅\t\t".len() as u32);
        let display_point = DisplayPoint::new(DisplayRow(0), "✅       ".len() as u32);
        assert_eq!(point.to_display_point(&map), display_point);
        assert_eq!(display_point.to_point(&map), point);

        let point = MultiBufferPoint::new(1, "β\t".len() as u32);
        let display_point = DisplayPoint::new(DisplayRow(1), "β   ".len() as u32);
        assert_eq!(point.to_display_point(&map), display_point);
        assert_eq!(display_point.to_point(&map), point,);

        let point = MultiBufferPoint::new(2, "🏀β\t\t".len() as u32);
        let display_point = DisplayPoint::new(DisplayRow(2), "🏀β      ".len() as u32);
        assert_eq!(point.to_display_point(&map), display_point);
        assert_eq!(display_point.to_point(&map), point,);

        // Display points inside of expanded tabs
        assert_eq!(
            DisplayPoint::new(DisplayRow(0), "✅      ".len() as u32).to_point(&map),
            MultiBufferPoint::new(0, "✅\t".len() as u32),
        );
        assert_eq!(
            DisplayPoint::new(DisplayRow(0), "✅ ".len() as u32).to_point(&map),
            MultiBufferPoint::new(0, "✅".len() as u32),
        );

        // Clipping display points inside of multi-byte characters
        assert_eq!(
            map.clip_point(
                DisplayPoint::new(DisplayRow(0), "✅".len() as u32 - 1),
                Left
            ),
            DisplayPoint::new(DisplayRow(0), 0)
        );
        assert_eq!(
            map.clip_point(
                DisplayPoint::new(DisplayRow(0), "✅".len() as u32 - 1),
                Bias::Right
            ),
            DisplayPoint::new(DisplayRow(0), "✅".len() as u32)
        );
    }

    #[gpui::test]
    fn test_max_point(cx: &mut gpui::App) {
        init_test(cx, |_| {});

        let buffer = MultiBuffer::build_simple("aaa\n\t\tbbb", cx);
        let font_size = px(14.0);
        let map = cx.new(|cx| {
            DisplayMap::new(
                buffer.clone(),
                font("Helvetica"),
                font_size,
                None,
                1,
                1,
                FoldPlaceholder::test(),
                DiagnosticSeverity::Warning,
                cx,
            )
        });
        assert_eq!(
            map.update(cx, |map, cx| map.snapshot(cx)).max_point(),
            DisplayPoint::new(DisplayRow(1), 11)
        )
    }

    fn syntax_chunks(
        rows: Range<DisplayRow>,
        map: &Entity<DisplayMap>,
        theme: &SyntaxTheme,
        cx: &mut App,
    ) -> Vec<(String, Option<Hsla>)> {
        chunks(rows, map, theme, cx)
            .into_iter()
            .map(|(text, color, _)| (text, color))
            .collect()
    }

    fn chunks(
        rows: Range<DisplayRow>,
        map: &Entity<DisplayMap>,
        theme: &SyntaxTheme,
        cx: &mut App,
    ) -> Vec<(String, Option<Hsla>, Option<Hsla>)> {
        let snapshot = map.update(cx, |map, cx| map.snapshot(cx));
        let mut chunks: Vec<(String, Option<Hsla>, Option<Hsla>)> = Vec::new();
        for chunk in snapshot.chunks(rows, true, HighlightStyles::default()) {
            let syntax_color = chunk
                .syntax_highlight_id
                .and_then(|id| id.style(theme)?.color);
            let highlight_color = chunk.highlight_style.and_then(|style| style.color);
            if let Some((last_chunk, last_syntax_color, last_highlight_color)) = chunks.last_mut()
                && syntax_color == *last_syntax_color
                && highlight_color == *last_highlight_color
            {
                last_chunk.push_str(chunk.text);
                continue;
            }
            chunks.push((chunk.text.to_string(), syntax_color, highlight_color));
        }
        chunks
    }

    fn init_test(cx: &mut App, f: impl Fn(&mut SettingsContent)) {
        let settings = SettingsStore::test(cx);
        cx.set_global(settings);
        crate::init(cx);
        theme::init(LoadThemes::JustBase, cx);
        cx.update_global::<SettingsStore, _>(|store, cx| {
            store.update_user_settings(cx, f);
        });
    }
}