markdown.rs

   1pub mod parser;
   2mod path_range;
   3
   4use base64::Engine as _;
   5use futures::FutureExt as _;
   6use gpui::HitboxBehavior;
   7use language::LanguageName;
   8use log::Level;
   9pub use path_range::{LineCol, PathWithRange};
  10use ui::Checkbox;
  11use ui::CopyButton;
  12
  13use std::borrow::Cow;
  14use std::iter;
  15use std::mem;
  16use std::ops::Range;
  17use std::path::Path;
  18use std::rc::Rc;
  19use std::sync::Arc;
  20use std::time::Duration;
  21
  22use collections::{HashMap, HashSet};
  23use gpui::{
  24    AnyElement, App, BorderStyle, Bounds, ClipboardItem, CursorStyle, DispatchPhase, Edges, Entity,
  25    FocusHandle, Focusable, FontStyle, FontWeight, GlobalElementId, Hitbox, Hsla, Image,
  26    ImageFormat, KeyContext, Length, MouseButton, MouseDownEvent, MouseEvent, MouseMoveEvent,
  27    MouseUpEvent, Point, ScrollHandle, Stateful, StrikethroughStyle, StyleRefinement, StyledText,
  28    Task, TextLayout, TextRun, TextStyle, TextStyleRefinement, actions, img, point, quad,
  29};
  30use language::{Language, LanguageRegistry, Rope};
  31use parser::CodeBlockMetadata;
  32use parser::{MarkdownEvent, MarkdownTag, MarkdownTagEnd, parse_links_only, parse_markdown};
  33use pulldown_cmark::Alignment;
  34use sum_tree::TreeMap;
  35use theme::SyntaxTheme;
  36use ui::{ScrollAxes, Scrollbars, WithScrollbar, prelude::*};
  37use util::ResultExt;
  38
  39use crate::parser::CodeBlockKind;
  40
  41/// A callback function that can be used to customize the style of links based on the destination URL.
  42/// If the callback returns `None`, the default link style will be used.
  43type LinkStyleCallback = Rc<dyn Fn(&str, &App) -> Option<TextStyleRefinement>>;
  44
  45/// Defines custom style refinements for each heading level (H1-H6)
  46#[derive(Clone, Default)]
  47pub struct HeadingLevelStyles {
  48    pub h1: Option<TextStyleRefinement>,
  49    pub h2: Option<TextStyleRefinement>,
  50    pub h3: Option<TextStyleRefinement>,
  51    pub h4: Option<TextStyleRefinement>,
  52    pub h5: Option<TextStyleRefinement>,
  53    pub h6: Option<TextStyleRefinement>,
  54}
  55
  56#[derive(Clone)]
  57pub struct MarkdownStyle {
  58    pub base_text_style: TextStyle,
  59    pub container_style: StyleRefinement,
  60    pub code_block: StyleRefinement,
  61    pub code_block_overflow_x_scroll: bool,
  62    pub inline_code: TextStyleRefinement,
  63    pub block_quote: TextStyleRefinement,
  64    pub link: TextStyleRefinement,
  65    pub link_callback: Option<LinkStyleCallback>,
  66    pub rule_color: Hsla,
  67    pub block_quote_border_color: Hsla,
  68    pub syntax: Arc<SyntaxTheme>,
  69    pub selection_background_color: Hsla,
  70    pub heading: StyleRefinement,
  71    pub heading_level_styles: Option<HeadingLevelStyles>,
  72    pub height_is_multiple_of_line_height: bool,
  73    pub prevent_mouse_interaction: bool,
  74    pub table_columns_min_size: bool,
  75}
  76
  77impl Default for MarkdownStyle {
  78    fn default() -> Self {
  79        Self {
  80            base_text_style: Default::default(),
  81            container_style: Default::default(),
  82            code_block: Default::default(),
  83            code_block_overflow_x_scroll: false,
  84            inline_code: Default::default(),
  85            block_quote: Default::default(),
  86            link: Default::default(),
  87            link_callback: None,
  88            rule_color: Default::default(),
  89            block_quote_border_color: Default::default(),
  90            syntax: Arc::new(SyntaxTheme::default()),
  91            selection_background_color: Default::default(),
  92            heading: Default::default(),
  93            heading_level_styles: None,
  94            height_is_multiple_of_line_height: false,
  95            prevent_mouse_interaction: false,
  96            table_columns_min_size: false,
  97        }
  98    }
  99}
 100
 101pub struct Markdown {
 102    source: SharedString,
 103    selection: Selection,
 104    pressed_link: Option<RenderedLink>,
 105    autoscroll_request: Option<usize>,
 106    parsed_markdown: ParsedMarkdown,
 107    images_by_source_offset: HashMap<usize, Arc<Image>>,
 108    should_reparse: bool,
 109    pending_parse: Option<Task<()>>,
 110    focus_handle: FocusHandle,
 111    language_registry: Option<Arc<LanguageRegistry>>,
 112    fallback_code_block_language: Option<LanguageName>,
 113    options: Options,
 114    copied_code_blocks: HashSet<ElementId>,
 115    code_block_scroll_handles: HashMap<usize, ScrollHandle>,
 116    context_menu_selected_text: Option<String>,
 117}
 118
 119struct Options {
 120    parse_links_only: bool,
 121}
 122
 123pub enum CodeBlockRenderer {
 124    Default {
 125        copy_button: bool,
 126        copy_button_on_hover: bool,
 127        border: bool,
 128    },
 129    Custom {
 130        render: CodeBlockRenderFn,
 131        /// A function that can modify the parent container after the code block
 132        /// content has been appended as a child element.
 133        transform: Option<CodeBlockTransformFn>,
 134    },
 135}
 136
 137pub type CodeBlockRenderFn = Arc<
 138    dyn Fn(
 139        &CodeBlockKind,
 140        &ParsedMarkdown,
 141        Range<usize>,
 142        CodeBlockMetadata,
 143        &mut Window,
 144        &App,
 145    ) -> Div,
 146>;
 147
 148pub type CodeBlockTransformFn =
 149    Arc<dyn Fn(AnyDiv, Range<usize>, CodeBlockMetadata, &mut Window, &App) -> AnyDiv>;
 150
 151actions!(
 152    markdown,
 153    [
 154        /// Copies the selected text to the clipboard.
 155        Copy,
 156        /// Copies the selected text as markdown to the clipboard.
 157        CopyAsMarkdown
 158    ]
 159);
 160
 161impl Markdown {
 162    pub fn new(
 163        source: SharedString,
 164        language_registry: Option<Arc<LanguageRegistry>>,
 165        fallback_code_block_language: Option<LanguageName>,
 166        cx: &mut Context<Self>,
 167    ) -> Self {
 168        let focus_handle = cx.focus_handle();
 169        let mut this = Self {
 170            source,
 171            selection: Selection::default(),
 172            pressed_link: None,
 173            autoscroll_request: None,
 174            should_reparse: false,
 175            images_by_source_offset: Default::default(),
 176            parsed_markdown: ParsedMarkdown::default(),
 177            pending_parse: None,
 178            focus_handle,
 179            language_registry,
 180            fallback_code_block_language,
 181            options: Options {
 182                parse_links_only: false,
 183            },
 184            copied_code_blocks: HashSet::default(),
 185            code_block_scroll_handles: HashMap::default(),
 186            context_menu_selected_text: None,
 187        };
 188        this.parse(cx);
 189        this
 190    }
 191
 192    pub fn new_text(source: SharedString, cx: &mut Context<Self>) -> Self {
 193        let focus_handle = cx.focus_handle();
 194        let mut this = Self {
 195            source,
 196            selection: Selection::default(),
 197            pressed_link: None,
 198            autoscroll_request: None,
 199            should_reparse: false,
 200            parsed_markdown: ParsedMarkdown::default(),
 201            images_by_source_offset: Default::default(),
 202            pending_parse: None,
 203            focus_handle,
 204            language_registry: None,
 205            fallback_code_block_language: None,
 206            options: Options {
 207                parse_links_only: true,
 208            },
 209            copied_code_blocks: HashSet::default(),
 210            code_block_scroll_handles: HashMap::default(),
 211            context_menu_selected_text: None,
 212        };
 213        this.parse(cx);
 214        this
 215    }
 216
 217    fn code_block_scroll_handle(&mut self, id: usize) -> ScrollHandle {
 218        self.code_block_scroll_handles
 219            .entry(id)
 220            .or_insert_with(ScrollHandle::new)
 221            .clone()
 222    }
 223
 224    fn retain_code_block_scroll_handles(&mut self, ids: &HashSet<usize>) {
 225        self.code_block_scroll_handles
 226            .retain(|id, _| ids.contains(id));
 227    }
 228
 229    fn clear_code_block_scroll_handles(&mut self) {
 230        self.code_block_scroll_handles.clear();
 231    }
 232
 233    pub fn is_parsing(&self) -> bool {
 234        self.pending_parse.is_some()
 235    }
 236
 237    pub fn source(&self) -> &str {
 238        &self.source
 239    }
 240
 241    pub fn append(&mut self, text: &str, cx: &mut Context<Self>) {
 242        self.source = SharedString::new(self.source.to_string() + text);
 243        self.parse(cx);
 244    }
 245
 246    pub fn replace(&mut self, source: impl Into<SharedString>, cx: &mut Context<Self>) {
 247        self.source = source.into();
 248        self.parse(cx);
 249    }
 250
 251    pub fn reset(&mut self, source: SharedString, cx: &mut Context<Self>) {
 252        if source == self.source() {
 253            return;
 254        }
 255        self.source = source;
 256        self.selection = Selection::default();
 257        self.autoscroll_request = None;
 258        self.pending_parse = None;
 259        self.should_reparse = false;
 260        // Don't clear parsed_markdown here - keep existing content visible until new parse completes
 261        self.parse(cx);
 262    }
 263
 264    #[cfg(any(test, feature = "test-support"))]
 265    pub fn parsed_markdown(&self) -> &ParsedMarkdown {
 266        &self.parsed_markdown
 267    }
 268
 269    pub fn escape(s: &str) -> Cow<'_, str> {
 270        // Valid to use bytes since multi-byte UTF-8 doesn't use ASCII chars.
 271        let count = s
 272            .bytes()
 273            .filter(|c| *c == b'\n' || c.is_ascii_punctuation())
 274            .count();
 275        if count > 0 {
 276            let mut output = String::with_capacity(s.len() + count);
 277            let mut is_newline = false;
 278            for c in s.chars() {
 279                if is_newline && c == ' ' {
 280                    continue;
 281                }
 282                is_newline = c == '\n';
 283                if c == '\n' {
 284                    output.push('\n')
 285                } else if c.is_ascii_punctuation() {
 286                    output.push('\\')
 287                }
 288                output.push(c)
 289            }
 290            output.into()
 291        } else {
 292            s.into()
 293        }
 294    }
 295
 296    pub fn selected_text(&self) -> Option<String> {
 297        if self.selection.end <= self.selection.start {
 298            None
 299        } else {
 300            Some(self.source[self.selection.start..self.selection.end].to_string())
 301        }
 302    }
 303
 304    fn copy(&self, text: &RenderedText, _: &mut Window, cx: &mut Context<Self>) {
 305        if self.selection.end <= self.selection.start {
 306            return;
 307        }
 308        let text = text.text_for_range(self.selection.start..self.selection.end);
 309        cx.write_to_clipboard(ClipboardItem::new_string(text));
 310    }
 311
 312    fn copy_as_markdown(&mut self, _: &mut Window, cx: &mut Context<Self>) {
 313        if let Some(text) = self.context_menu_selected_text.take() {
 314            cx.write_to_clipboard(ClipboardItem::new_string(text));
 315            return;
 316        }
 317        if self.selection.end <= self.selection.start {
 318            return;
 319        }
 320        let text = self.source[self.selection.start..self.selection.end].to_string();
 321        cx.write_to_clipboard(ClipboardItem::new_string(text));
 322    }
 323
 324    fn capture_selection_for_context_menu(&mut self) {
 325        self.context_menu_selected_text = self.selected_text();
 326    }
 327
 328    fn parse(&mut self, cx: &mut Context<Self>) {
 329        if self.source.is_empty() {
 330            return;
 331        }
 332
 333        if self.pending_parse.is_some() {
 334            self.should_reparse = true;
 335            return;
 336        }
 337        self.should_reparse = false;
 338        self.pending_parse = Some(self.start_background_parse(cx));
 339    }
 340
 341    fn start_background_parse(&self, cx: &Context<Self>) -> Task<()> {
 342        let source = self.source.clone();
 343        let should_parse_links_only = self.options.parse_links_only;
 344        let language_registry = self.language_registry.clone();
 345        let fallback = self.fallback_code_block_language.clone();
 346
 347        let parsed = cx.background_spawn(async move {
 348            if should_parse_links_only {
 349                return (
 350                    ParsedMarkdown {
 351                        events: Arc::from(parse_links_only(source.as_ref())),
 352                        source,
 353                        languages_by_name: TreeMap::default(),
 354                        languages_by_path: TreeMap::default(),
 355                    },
 356                    Default::default(),
 357                );
 358            }
 359
 360            let (events, language_names, paths) = parse_markdown(&source);
 361            let mut images_by_source_offset = HashMap::default();
 362            let mut languages_by_name = TreeMap::default();
 363            let mut languages_by_path = TreeMap::default();
 364            if let Some(registry) = language_registry.as_ref() {
 365                for name in language_names {
 366                    let language = if !name.is_empty() {
 367                        registry.language_for_name_or_extension(&name).left_future()
 368                    } else if let Some(fallback) = &fallback {
 369                        registry.language_for_name(fallback.as_ref()).right_future()
 370                    } else {
 371                        continue;
 372                    };
 373                    if let Ok(language) = language.await {
 374                        languages_by_name.insert(name, language);
 375                    }
 376                }
 377
 378                for path in paths {
 379                    if let Ok(language) = registry
 380                        .load_language_for_file_path(Path::new(path.as_ref()))
 381                        .await
 382                    {
 383                        languages_by_path.insert(path, language);
 384                    }
 385                }
 386            }
 387
 388            for (range, event) in &events {
 389                if let MarkdownEvent::Start(MarkdownTag::Image { dest_url, .. }) = event
 390                    && let Some(data_url) = dest_url.strip_prefix("data:")
 391                {
 392                    let Some((mime_info, data)) = data_url.split_once(',') else {
 393                        continue;
 394                    };
 395                    let Some((mime_type, encoding)) = mime_info.split_once(';') else {
 396                        continue;
 397                    };
 398                    let Some(format) = ImageFormat::from_mime_type(mime_type) else {
 399                        continue;
 400                    };
 401                    let is_base64 = encoding == "base64";
 402                    if is_base64
 403                        && let Some(bytes) = base64::prelude::BASE64_STANDARD
 404                            .decode(data)
 405                            .log_with_level(Level::Debug)
 406                    {
 407                        let image = Arc::new(Image::from_bytes(format, bytes));
 408                        images_by_source_offset.insert(range.start, image);
 409                    }
 410                }
 411            }
 412
 413            (
 414                ParsedMarkdown {
 415                    source,
 416                    events: Arc::from(events),
 417                    languages_by_name,
 418                    languages_by_path,
 419                },
 420                images_by_source_offset,
 421            )
 422        });
 423
 424        cx.spawn(async move |this, cx| {
 425            let (parsed, images_by_source_offset) = parsed.await;
 426
 427            this.update(cx, |this, cx| {
 428                this.parsed_markdown = parsed;
 429                this.images_by_source_offset = images_by_source_offset;
 430                this.pending_parse.take();
 431                if this.should_reparse {
 432                    this.parse(cx);
 433                }
 434                cx.refresh_windows();
 435            })
 436            .ok();
 437        })
 438    }
 439}
 440
 441impl Focusable for Markdown {
 442    fn focus_handle(&self, _cx: &App) -> FocusHandle {
 443        self.focus_handle.clone()
 444    }
 445}
 446
 447#[derive(Debug, Default, Clone)]
 448enum SelectMode {
 449    #[default]
 450    Character,
 451    Word(Range<usize>),
 452    Line(Range<usize>),
 453    All,
 454}
 455
 456#[derive(Clone, Default)]
 457struct Selection {
 458    start: usize,
 459    end: usize,
 460    reversed: bool,
 461    pending: bool,
 462    mode: SelectMode,
 463}
 464
 465impl Selection {
 466    fn set_head(&mut self, head: usize, rendered_text: &RenderedText) {
 467        match &self.mode {
 468            SelectMode::Character => {
 469                if head < self.tail() {
 470                    if !self.reversed {
 471                        self.end = self.start;
 472                        self.reversed = true;
 473                    }
 474                    self.start = head;
 475                } else {
 476                    if self.reversed {
 477                        self.start = self.end;
 478                        self.reversed = false;
 479                    }
 480                    self.end = head;
 481                }
 482            }
 483            SelectMode::Word(original_range) | SelectMode::Line(original_range) => {
 484                let head_range = if matches!(self.mode, SelectMode::Word(_)) {
 485                    rendered_text.surrounding_word_range(head)
 486                } else {
 487                    rendered_text.surrounding_line_range(head)
 488                };
 489
 490                if head < original_range.start {
 491                    self.start = head_range.start;
 492                    self.end = original_range.end;
 493                    self.reversed = true;
 494                } else if head >= original_range.end {
 495                    self.start = original_range.start;
 496                    self.end = head_range.end;
 497                    self.reversed = false;
 498                } else {
 499                    self.start = original_range.start;
 500                    self.end = original_range.end;
 501                    self.reversed = false;
 502                }
 503            }
 504            SelectMode::All => {
 505                self.start = 0;
 506                self.end = rendered_text
 507                    .lines
 508                    .last()
 509                    .map(|line| line.source_end)
 510                    .unwrap_or(0);
 511                self.reversed = false;
 512            }
 513        }
 514    }
 515
 516    fn tail(&self) -> usize {
 517        if self.reversed { self.end } else { self.start }
 518    }
 519}
 520
 521#[derive(Debug, Clone, Default)]
 522pub struct ParsedMarkdown {
 523    pub source: SharedString,
 524    pub events: Arc<[(Range<usize>, MarkdownEvent)]>,
 525    pub languages_by_name: TreeMap<SharedString, Arc<Language>>,
 526    pub languages_by_path: TreeMap<Arc<str>, Arc<Language>>,
 527}
 528
 529impl ParsedMarkdown {
 530    pub fn source(&self) -> &SharedString {
 531        &self.source
 532    }
 533
 534    pub fn events(&self) -> &Arc<[(Range<usize>, MarkdownEvent)]> {
 535        &self.events
 536    }
 537}
 538
 539pub struct MarkdownElement {
 540    markdown: Entity<Markdown>,
 541    style: MarkdownStyle,
 542    code_block_renderer: CodeBlockRenderer,
 543    on_url_click: Option<Box<dyn Fn(SharedString, &mut Window, &mut App)>>,
 544}
 545
 546impl MarkdownElement {
 547    pub fn new(markdown: Entity<Markdown>, style: MarkdownStyle) -> Self {
 548        Self {
 549            markdown,
 550            style,
 551            code_block_renderer: CodeBlockRenderer::Default {
 552                copy_button: true,
 553                copy_button_on_hover: false,
 554                border: false,
 555            },
 556            on_url_click: None,
 557        }
 558    }
 559
 560    #[cfg(any(test, feature = "test-support"))]
 561    pub fn rendered_text(
 562        markdown: Entity<Markdown>,
 563        cx: &mut gpui::VisualTestContext,
 564        style: impl FnOnce(&Window, &App) -> MarkdownStyle,
 565    ) -> String {
 566        use gpui::size;
 567
 568        let (text, _) = cx.draw(
 569            Default::default(),
 570            size(px(600.0), px(600.0)),
 571            |window, cx| Self::new(markdown, style(window, cx)),
 572        );
 573        text.text
 574            .lines
 575            .iter()
 576            .map(|line| line.layout.wrapped_text())
 577            .collect::<Vec<_>>()
 578            .join("\n")
 579    }
 580
 581    pub fn code_block_renderer(mut self, variant: CodeBlockRenderer) -> Self {
 582        self.code_block_renderer = variant;
 583        self
 584    }
 585
 586    pub fn on_url_click(
 587        mut self,
 588        handler: impl Fn(SharedString, &mut Window, &mut App) + 'static,
 589    ) -> Self {
 590        self.on_url_click = Some(Box::new(handler));
 591        self
 592    }
 593
 594    fn paint_selection(
 595        &self,
 596        bounds: Bounds<Pixels>,
 597        rendered_text: &RenderedText,
 598        window: &mut Window,
 599        cx: &mut App,
 600    ) {
 601        let selection = self.markdown.read(cx).selection.clone();
 602        let selection_start = rendered_text.position_for_source_index(selection.start);
 603        let selection_end = rendered_text.position_for_source_index(selection.end);
 604        if let Some(((start_position, start_line_height), (end_position, end_line_height))) =
 605            selection_start.zip(selection_end)
 606        {
 607            if start_position.y == end_position.y {
 608                window.paint_quad(quad(
 609                    Bounds::from_corners(
 610                        start_position,
 611                        point(end_position.x, end_position.y + end_line_height),
 612                    ),
 613                    Pixels::ZERO,
 614                    self.style.selection_background_color,
 615                    Edges::default(),
 616                    Hsla::transparent_black(),
 617                    BorderStyle::default(),
 618                ));
 619            } else {
 620                window.paint_quad(quad(
 621                    Bounds::from_corners(
 622                        start_position,
 623                        point(bounds.right(), start_position.y + start_line_height),
 624                    ),
 625                    Pixels::ZERO,
 626                    self.style.selection_background_color,
 627                    Edges::default(),
 628                    Hsla::transparent_black(),
 629                    BorderStyle::default(),
 630                ));
 631
 632                if end_position.y > start_position.y + start_line_height {
 633                    window.paint_quad(quad(
 634                        Bounds::from_corners(
 635                            point(bounds.left(), start_position.y + start_line_height),
 636                            point(bounds.right(), end_position.y),
 637                        ),
 638                        Pixels::ZERO,
 639                        self.style.selection_background_color,
 640                        Edges::default(),
 641                        Hsla::transparent_black(),
 642                        BorderStyle::default(),
 643                    ));
 644                }
 645
 646                window.paint_quad(quad(
 647                    Bounds::from_corners(
 648                        point(bounds.left(), end_position.y),
 649                        point(end_position.x, end_position.y + end_line_height),
 650                    ),
 651                    Pixels::ZERO,
 652                    self.style.selection_background_color,
 653                    Edges::default(),
 654                    Hsla::transparent_black(),
 655                    BorderStyle::default(),
 656                ));
 657            }
 658        }
 659    }
 660
 661    fn paint_mouse_listeners(
 662        &mut self,
 663        hitbox: &Hitbox,
 664        rendered_text: &RenderedText,
 665        window: &mut Window,
 666        cx: &mut App,
 667    ) {
 668        if self.style.prevent_mouse_interaction {
 669            return;
 670        }
 671
 672        let is_hovering_link = hitbox.is_hovered(window)
 673            && !self.markdown.read(cx).selection.pending
 674            && rendered_text
 675                .link_for_position(window.mouse_position())
 676                .is_some();
 677
 678        if !self.style.prevent_mouse_interaction {
 679            if is_hovering_link {
 680                window.set_cursor_style(CursorStyle::PointingHand, hitbox);
 681            } else {
 682                window.set_cursor_style(CursorStyle::IBeam, hitbox);
 683            }
 684        }
 685
 686        let on_open_url = self.on_url_click.take();
 687
 688        self.on_mouse_event(window, cx, {
 689            let hitbox = hitbox.clone();
 690            move |markdown, event: &MouseDownEvent, phase, window, _| {
 691                if phase.capture()
 692                    && event.button == MouseButton::Right
 693                    && hitbox.is_hovered(window)
 694                {
 695                    // Capture selected text so it survives until menu item is clicked
 696                    markdown.capture_selection_for_context_menu();
 697                }
 698            }
 699        });
 700
 701        self.on_mouse_event(window, cx, {
 702            let rendered_text = rendered_text.clone();
 703            let hitbox = hitbox.clone();
 704            move |markdown, event: &MouseDownEvent, phase, window, cx| {
 705                if hitbox.is_hovered(window) {
 706                    if phase.bubble() {
 707                        if let Some(link) = rendered_text.link_for_position(event.position) {
 708                            markdown.pressed_link = Some(link.clone());
 709                        } else {
 710                            let source_index =
 711                                match rendered_text.source_index_for_position(event.position) {
 712                                    Ok(ix) | Err(ix) => ix,
 713                                };
 714                            let (range, mode) = match event.click_count {
 715                                1 => {
 716                                    let range = source_index..source_index;
 717                                    (range, SelectMode::Character)
 718                                }
 719                                2 => {
 720                                    let range = rendered_text.surrounding_word_range(source_index);
 721                                    (range.clone(), SelectMode::Word(range))
 722                                }
 723                                3 => {
 724                                    let range = rendered_text.surrounding_line_range(source_index);
 725                                    (range.clone(), SelectMode::Line(range))
 726                                }
 727                                _ => {
 728                                    let range = 0..rendered_text
 729                                        .lines
 730                                        .last()
 731                                        .map(|line| line.source_end)
 732                                        .unwrap_or(0);
 733                                    (range, SelectMode::All)
 734                                }
 735                            };
 736                            markdown.selection = Selection {
 737                                start: range.start,
 738                                end: range.end,
 739                                reversed: false,
 740                                pending: true,
 741                                mode,
 742                            };
 743                            window.focus(&markdown.focus_handle, cx);
 744                        }
 745
 746                        window.prevent_default();
 747                        cx.notify();
 748                    }
 749                } else if phase.capture() && event.button == MouseButton::Left {
 750                    markdown.selection = Selection::default();
 751                    markdown.pressed_link = None;
 752                    cx.notify();
 753                }
 754            }
 755        });
 756        self.on_mouse_event(window, cx, {
 757            let rendered_text = rendered_text.clone();
 758            let hitbox = hitbox.clone();
 759            let was_hovering_link = is_hovering_link;
 760            move |markdown, event: &MouseMoveEvent, phase, window, cx| {
 761                if phase.capture() {
 762                    return;
 763                }
 764
 765                if markdown.selection.pending {
 766                    let source_index = match rendered_text.source_index_for_position(event.position)
 767                    {
 768                        Ok(ix) | Err(ix) => ix,
 769                    };
 770                    markdown.selection.set_head(source_index, &rendered_text);
 771                    markdown.autoscroll_request = Some(source_index);
 772                    cx.notify();
 773                } else {
 774                    let is_hovering_link = hitbox.is_hovered(window)
 775                        && rendered_text.link_for_position(event.position).is_some();
 776                    if is_hovering_link != was_hovering_link {
 777                        cx.notify();
 778                    }
 779                }
 780            }
 781        });
 782        self.on_mouse_event(window, cx, {
 783            let rendered_text = rendered_text.clone();
 784            move |markdown, event: &MouseUpEvent, phase, window, cx| {
 785                if phase.bubble() {
 786                    if let Some(pressed_link) = markdown.pressed_link.take()
 787                        && Some(&pressed_link) == rendered_text.link_for_position(event.position)
 788                    {
 789                        if let Some(open_url) = on_open_url.as_ref() {
 790                            open_url(pressed_link.destination_url, window, cx);
 791                        } else {
 792                            cx.open_url(&pressed_link.destination_url);
 793                        }
 794                    }
 795                } else if markdown.selection.pending {
 796                    markdown.selection.pending = false;
 797                    #[cfg(any(target_os = "linux", target_os = "freebsd"))]
 798                    {
 799                        let text = rendered_text
 800                            .text_for_range(markdown.selection.start..markdown.selection.end);
 801                        cx.write_to_primary(ClipboardItem::new_string(text))
 802                    }
 803                    cx.notify();
 804                }
 805            }
 806        });
 807    }
 808
 809    fn autoscroll(
 810        &self,
 811        rendered_text: &RenderedText,
 812        window: &mut Window,
 813        cx: &mut App,
 814    ) -> Option<()> {
 815        let autoscroll_index = self
 816            .markdown
 817            .update(cx, |markdown, _| markdown.autoscroll_request.take())?;
 818        let (position, line_height) = rendered_text.position_for_source_index(autoscroll_index)?;
 819
 820        let text_style = self.style.base_text_style.clone();
 821        let font_id = window.text_system().resolve_font(&text_style.font());
 822        let font_size = text_style.font_size.to_pixels(window.rem_size());
 823        let em_width = window.text_system().em_width(font_id, font_size).unwrap();
 824        window.request_autoscroll(Bounds::from_corners(
 825            point(position.x - 3. * em_width, position.y - 3. * line_height),
 826            point(position.x + 3. * em_width, position.y + 3. * line_height),
 827        ));
 828        Some(())
 829    }
 830
 831    fn on_mouse_event<T: MouseEvent>(
 832        &self,
 833        window: &mut Window,
 834        _cx: &mut App,
 835        mut f: impl 'static
 836        + FnMut(&mut Markdown, &T, DispatchPhase, &mut Window, &mut Context<Markdown>),
 837    ) {
 838        window.on_mouse_event({
 839            let markdown = self.markdown.downgrade();
 840            move |event, phase, window, cx| {
 841                markdown
 842                    .update(cx, |markdown, cx| f(markdown, event, phase, window, cx))
 843                    .log_err();
 844            }
 845        });
 846    }
 847}
 848
 849impl Styled for MarkdownElement {
 850    fn style(&mut self) -> &mut StyleRefinement {
 851        &mut self.style.container_style
 852    }
 853}
 854
 855impl Element for MarkdownElement {
 856    type RequestLayoutState = RenderedMarkdown;
 857    type PrepaintState = Hitbox;
 858
 859    fn id(&self) -> Option<ElementId> {
 860        None
 861    }
 862
 863    fn source_location(&self) -> Option<&'static core::panic::Location<'static>> {
 864        None
 865    }
 866
 867    fn request_layout(
 868        &mut self,
 869        _id: Option<&GlobalElementId>,
 870        _inspector_id: Option<&gpui::InspectorElementId>,
 871        window: &mut Window,
 872        cx: &mut App,
 873    ) -> (gpui::LayoutId, Self::RequestLayoutState) {
 874        let mut builder = MarkdownElementBuilder::new(
 875            &self.style.container_style,
 876            self.style.base_text_style.clone(),
 877            self.style.syntax.clone(),
 878        );
 879        let (parsed_markdown, images) = {
 880            let markdown = self.markdown.read(cx);
 881            (
 882                markdown.parsed_markdown.clone(),
 883                markdown.images_by_source_offset.clone(),
 884            )
 885        };
 886        let markdown_end = if let Some(last) = parsed_markdown.events.last() {
 887            last.0.end
 888        } else {
 889            0
 890        };
 891        let mut code_block_ids = HashSet::default();
 892
 893        let mut current_img_block_range: Option<Range<usize>> = None;
 894        for (index, (range, event)) in parsed_markdown.events.iter().enumerate() {
 895            // Skip alt text for images that rendered
 896            if let Some(current_img_block_range) = &current_img_block_range
 897                && current_img_block_range.end > range.end
 898            {
 899                continue;
 900            }
 901
 902            match event {
 903                MarkdownEvent::Start(tag) => {
 904                    match tag {
 905                        MarkdownTag::Image { .. } => {
 906                            if let Some(image) = images.get(&range.start) {
 907                                current_img_block_range = Some(range.clone());
 908                                builder.modify_current_div(|el| {
 909                                    el.items_center()
 910                                        .flex()
 911                                        .flex_row()
 912                                        .child(img(image.clone()))
 913                                });
 914                            }
 915                        }
 916                        MarkdownTag::Paragraph => {
 917                            builder.push_div(
 918                                div().when(!self.style.height_is_multiple_of_line_height, |el| {
 919                                    el.mb_2().line_height(rems(1.3))
 920                                }),
 921                                range,
 922                                markdown_end,
 923                            );
 924                        }
 925                        MarkdownTag::Heading { level, .. } => {
 926                            let mut heading = div().mb_2();
 927
 928                            heading = apply_heading_style(
 929                                heading,
 930                                *level,
 931                                self.style.heading_level_styles.as_ref(),
 932                            );
 933
 934                            heading.style().refine(&self.style.heading);
 935
 936                            let text_style = self.style.heading.text_style().clone();
 937
 938                            builder.push_text_style(text_style);
 939                            builder.push_div(heading, range, markdown_end);
 940                        }
 941                        MarkdownTag::BlockQuote => {
 942                            builder.push_text_style(self.style.block_quote.clone());
 943                            builder.push_div(
 944                                div()
 945                                    .pl_4()
 946                                    .mb_2()
 947                                    .border_l_4()
 948                                    .border_color(self.style.block_quote_border_color),
 949                                range,
 950                                markdown_end,
 951                            );
 952                        }
 953                        MarkdownTag::CodeBlock { kind, .. } => {
 954                            let language = match kind {
 955                                CodeBlockKind::Fenced => None,
 956                                CodeBlockKind::FencedLang(language) => {
 957                                    parsed_markdown.languages_by_name.get(language).cloned()
 958                                }
 959                                CodeBlockKind::FencedSrc(path_range) => parsed_markdown
 960                                    .languages_by_path
 961                                    .get(&path_range.path)
 962                                    .cloned(),
 963                                _ => None,
 964                            };
 965
 966                            let is_indented = matches!(kind, CodeBlockKind::Indented);
 967                            let scroll_handle = if self.style.code_block_overflow_x_scroll {
 968                                code_block_ids.insert(range.start);
 969                                Some(self.markdown.update(cx, |markdown, _| {
 970                                    markdown.code_block_scroll_handle(range.start)
 971                                }))
 972                            } else {
 973                                None
 974                            };
 975
 976                            match (&self.code_block_renderer, is_indented) {
 977                                (CodeBlockRenderer::Default { .. }, _) | (_, true) => {
 978                                    // This is a parent container that we can position the copy button inside.
 979                                    let parent_container =
 980                                        div().group("code_block").relative().w_full();
 981
 982                                    let mut parent_container: AnyDiv = if let Some(scroll_handle) =
 983                                        scroll_handle.as_ref()
 984                                    {
 985                                        let scrollbars = Scrollbars::new(ScrollAxes::Horizontal)
 986                                            .id(("markdown-code-block-scrollbar", range.start))
 987                                            .tracked_scroll_handle(scroll_handle)
 988                                            .with_track_along(
 989                                                ScrollAxes::Horizontal,
 990                                                cx.theme().colors().editor_background,
 991                                            )
 992                                            .notify_content();
 993
 994                                        parent_container
 995                                            .rounded_lg()
 996                                            .custom_scrollbars(scrollbars, window, cx)
 997                                            .into()
 998                                    } else {
 999                                        parent_container.into()
1000                                    };
1001
1002                                    if let CodeBlockRenderer::Default { border: true, .. } =
1003                                        &self.code_block_renderer
1004                                    {
1005                                        parent_container = parent_container
1006                                            .rounded_md()
1007                                            .border_1()
1008                                            .border_color(cx.theme().colors().border_variant);
1009                                    }
1010
1011                                    parent_container.style().refine(&self.style.code_block);
1012                                    builder.push_div(parent_container, range, markdown_end);
1013
1014                                    let code_block = div()
1015                                        .id(("code-block", range.start))
1016                                        .rounded_lg()
1017                                        .map(|mut code_block| {
1018                                            if let Some(scroll_handle) = scroll_handle.as_ref() {
1019                                                code_block.style().restrict_scroll_to_axis =
1020                                                    Some(true);
1021                                                code_block
1022                                                    .flex()
1023                                                    .overflow_x_scroll()
1024                                                    .track_scroll(scroll_handle)
1025                                            } else {
1026                                                code_block.w_full()
1027                                            }
1028                                        });
1029
1030                                    builder.push_text_style(self.style.code_block.text.to_owned());
1031                                    builder.push_code_block(language);
1032                                    builder.push_div(code_block, range, markdown_end);
1033                                }
1034                                (CodeBlockRenderer::Custom { .. }, _) => {}
1035                            }
1036                        }
1037                        MarkdownTag::HtmlBlock => builder.push_div(div(), range, markdown_end),
1038                        MarkdownTag::List(bullet_index) => {
1039                            builder.push_list(*bullet_index);
1040                            builder.push_div(div().pl_2p5(), range, markdown_end);
1041                        }
1042                        MarkdownTag::Item => {
1043                            let bullet = if let Some((_, MarkdownEvent::TaskListMarker(checked))) =
1044                                parsed_markdown.events.get(index.saturating_add(1))
1045                            {
1046                                let source = &parsed_markdown.source()[range.clone()];
1047
1048                                Checkbox::new(
1049                                    ElementId::Name(source.to_string().into()),
1050                                    if *checked {
1051                                        ToggleState::Selected
1052                                    } else {
1053                                        ToggleState::Unselected
1054                                    },
1055                                )
1056                                .fill()
1057                                .visualization_only(true)
1058                                .into_any_element()
1059                            } else if let Some(bullet_index) = builder.next_bullet_index() {
1060                                div().child(format!("{}.", bullet_index)).into_any_element()
1061                            } else {
1062                                div().child("").into_any_element()
1063                            };
1064                            builder.push_div(
1065                                div()
1066                                    .when(!self.style.height_is_multiple_of_line_height, |el| {
1067                                        el.mb_1().gap_1().line_height(rems(1.3))
1068                                    })
1069                                    .h_flex()
1070                                    .items_start()
1071                                    .child(bullet),
1072                                range,
1073                                markdown_end,
1074                            );
1075                            // Without `w_0`, text doesn't wrap to the width of the container.
1076                            builder.push_div(div().flex_1().w_0(), range, markdown_end);
1077                        }
1078                        MarkdownTag::Emphasis => builder.push_text_style(TextStyleRefinement {
1079                            font_style: Some(FontStyle::Italic),
1080                            ..Default::default()
1081                        }),
1082                        MarkdownTag::Strong => builder.push_text_style(TextStyleRefinement {
1083                            font_weight: Some(FontWeight::BOLD),
1084                            ..Default::default()
1085                        }),
1086                        MarkdownTag::Strikethrough => {
1087                            builder.push_text_style(TextStyleRefinement {
1088                                strikethrough: Some(StrikethroughStyle {
1089                                    thickness: px(1.),
1090                                    color: None,
1091                                }),
1092                                ..Default::default()
1093                            })
1094                        }
1095                        MarkdownTag::Link { dest_url, .. } => {
1096                            if builder.code_block_stack.is_empty() {
1097                                builder.push_link(dest_url.clone(), range.clone());
1098                                let style = self
1099                                    .style
1100                                    .link_callback
1101                                    .as_ref()
1102                                    .and_then(|callback| callback(dest_url, cx))
1103                                    .unwrap_or_else(|| self.style.link.clone());
1104                                builder.push_text_style(style)
1105                            }
1106                        }
1107                        MarkdownTag::MetadataBlock(_) => {}
1108                        MarkdownTag::Table(alignments) => {
1109                            builder.table.start(alignments.clone());
1110
1111                            let column_count = alignments.len();
1112                            builder.push_div(
1113                                div()
1114                                    .id(("table", range.start))
1115                                    .grid()
1116                                    .grid_cols(column_count as u16)
1117                                    .when(self.style.table_columns_min_size, |this| {
1118                                        this.grid_cols_min_content(column_count as u16)
1119                                    })
1120                                    .when(!self.style.table_columns_min_size, |this| {
1121                                        this.grid_cols(column_count as u16)
1122                                    })
1123                                    .size_full()
1124                                    .mb_2()
1125                                    .border(px(1.5))
1126                                    .border_color(cx.theme().colors().border)
1127                                    .rounded_sm()
1128                                    .overflow_hidden(),
1129                                range,
1130                                markdown_end,
1131                            );
1132                        }
1133                        MarkdownTag::TableHead => {
1134                            builder.table.start_head();
1135                            builder.push_text_style(TextStyleRefinement {
1136                                font_weight: Some(FontWeight::SEMIBOLD),
1137                                ..Default::default()
1138                            });
1139                        }
1140                        MarkdownTag::TableRow => {
1141                            builder.table.start_row();
1142                        }
1143                        MarkdownTag::TableCell => {
1144                            let is_header = builder.table.in_head;
1145                            let row_index = builder.table.row_index;
1146                            let col_index = builder.table.col_index;
1147
1148                            builder.push_div(
1149                                div()
1150                                    .when(col_index > 0, |this| this.border_l_1())
1151                                    .when(row_index > 0, |this| this.border_t_1())
1152                                    .border_color(cx.theme().colors().border)
1153                                    .px_1()
1154                                    .py_0p5()
1155                                    .when(is_header, |this| {
1156                                        this.bg(cx.theme().colors().title_bar_background)
1157                                    })
1158                                    .when(!is_header && row_index % 2 == 1, |this| {
1159                                        this.bg(cx.theme().colors().panel_background)
1160                                    }),
1161                                range,
1162                                markdown_end,
1163                            );
1164                        }
1165                        _ => log::debug!("unsupported markdown tag {:?}", tag),
1166                    }
1167                }
1168                MarkdownEvent::End(tag) => match tag {
1169                    MarkdownTagEnd::Image => {
1170                        current_img_block_range.take();
1171                    }
1172                    MarkdownTagEnd::Paragraph => {
1173                        builder.pop_div();
1174                    }
1175                    MarkdownTagEnd::Heading(_) => {
1176                        builder.pop_div();
1177                        builder.pop_text_style()
1178                    }
1179                    MarkdownTagEnd::BlockQuote(_kind) => {
1180                        builder.pop_text_style();
1181                        builder.pop_div()
1182                    }
1183                    MarkdownTagEnd::CodeBlock => {
1184                        builder.trim_trailing_newline();
1185
1186                        builder.pop_div();
1187                        builder.pop_code_block();
1188                        builder.pop_text_style();
1189
1190                        if let CodeBlockRenderer::Default {
1191                            copy_button: true, ..
1192                        } = &self.code_block_renderer
1193                        {
1194                            builder.modify_current_div(|el| {
1195                                let content_range = parser::extract_code_block_content_range(
1196                                    &parsed_markdown.source()[range.clone()],
1197                                );
1198                                let content_range = content_range.start + range.start
1199                                    ..content_range.end + range.start;
1200
1201                                let code = parsed_markdown.source()[content_range].to_string();
1202                                let codeblock = render_copy_code_block_button(
1203                                    range.end,
1204                                    code,
1205                                    self.markdown.clone(),
1206                                );
1207                                el.child(
1208                                    h_flex()
1209                                        .w_4()
1210                                        .absolute()
1211                                        .top_1p5()
1212                                        .right_1p5()
1213                                        .justify_end()
1214                                        .child(codeblock),
1215                                )
1216                            });
1217                        }
1218
1219                        if let CodeBlockRenderer::Default {
1220                            copy_button_on_hover: true,
1221                            ..
1222                        } = &self.code_block_renderer
1223                        {
1224                            builder.modify_current_div(|el| {
1225                                let content_range = parser::extract_code_block_content_range(
1226                                    &parsed_markdown.source()[range.clone()],
1227                                );
1228                                let content_range = content_range.start + range.start
1229                                    ..content_range.end + range.start;
1230
1231                                let code = parsed_markdown.source()[content_range].to_string();
1232                                let codeblock = render_copy_code_block_button(
1233                                    range.end,
1234                                    code,
1235                                    self.markdown.clone(),
1236                                );
1237                                el.child(
1238                                    h_flex()
1239                                        .w_4()
1240                                        .absolute()
1241                                        .top_0()
1242                                        .right_0()
1243                                        .justify_end()
1244                                        .visible_on_hover("code_block")
1245                                        .child(codeblock),
1246                                )
1247                            });
1248                        }
1249
1250                        // Pop the parent container.
1251                        builder.pop_div();
1252                    }
1253                    MarkdownTagEnd::HtmlBlock => builder.pop_div(),
1254                    MarkdownTagEnd::List(_) => {
1255                        builder.pop_list();
1256                        builder.pop_div();
1257                    }
1258                    MarkdownTagEnd::Item => {
1259                        builder.pop_div();
1260                        builder.pop_div();
1261                    }
1262                    MarkdownTagEnd::Emphasis => builder.pop_text_style(),
1263                    MarkdownTagEnd::Strong => builder.pop_text_style(),
1264                    MarkdownTagEnd::Strikethrough => builder.pop_text_style(),
1265                    MarkdownTagEnd::Link => {
1266                        if builder.code_block_stack.is_empty() {
1267                            builder.pop_text_style()
1268                        }
1269                    }
1270                    MarkdownTagEnd::Table => {
1271                        builder.pop_div();
1272                        builder.table.end();
1273                    }
1274                    MarkdownTagEnd::TableHead => {
1275                        builder.pop_text_style();
1276                        builder.table.end_head();
1277                    }
1278                    MarkdownTagEnd::TableRow => {
1279                        builder.table.end_row();
1280                    }
1281                    MarkdownTagEnd::TableCell => {
1282                        builder.pop_div();
1283                        builder.table.end_cell();
1284                    }
1285                    _ => log::debug!("unsupported markdown tag end: {:?}", tag),
1286                },
1287                MarkdownEvent::Text => {
1288                    builder.push_text(&parsed_markdown.source[range.clone()], range.clone());
1289                }
1290                MarkdownEvent::SubstitutedText(text) => {
1291                    builder.push_text(text, range.clone());
1292                }
1293                MarkdownEvent::Code => {
1294                    builder.push_text_style(self.style.inline_code.clone());
1295                    builder.push_text(&parsed_markdown.source[range.clone()], range.clone());
1296                    builder.pop_text_style();
1297                }
1298                MarkdownEvent::Html => {
1299                    let html = &parsed_markdown.source[range.clone()];
1300                    if html.starts_with("<!--") {
1301                        builder.html_comment = true;
1302                    }
1303                    if html.trim_end().ends_with("-->") {
1304                        builder.html_comment = false;
1305                        continue;
1306                    }
1307                    if builder.html_comment {
1308                        continue;
1309                    }
1310                    builder.push_text(html, range.clone());
1311                }
1312                MarkdownEvent::InlineHtml => {
1313                    let html = &parsed_markdown.source[range.clone()];
1314                    if html.starts_with("<code>") {
1315                        builder.push_text_style(self.style.inline_code.clone());
1316                        continue;
1317                    }
1318                    if html.trim_end().starts_with("</code>") {
1319                        builder.pop_text_style();
1320                        continue;
1321                    }
1322                    builder.push_text(&parsed_markdown.source[range.clone()], range.clone());
1323                }
1324                MarkdownEvent::Rule => {
1325                    builder.push_div(
1326                        div()
1327                            .border_b_1()
1328                            .my_2()
1329                            .border_color(self.style.rule_color),
1330                        range,
1331                        markdown_end,
1332                    );
1333                    builder.pop_div()
1334                }
1335                MarkdownEvent::SoftBreak => builder.push_text(" ", range.clone()),
1336                MarkdownEvent::HardBreak => builder.push_text("\n", range.clone()),
1337                MarkdownEvent::TaskListMarker(_) => {
1338                    // handled inside the `MarkdownTag::Item` case
1339                }
1340                _ => log::debug!("unsupported markdown event {:?}", event),
1341            }
1342        }
1343        if self.style.code_block_overflow_x_scroll {
1344            let code_block_ids = code_block_ids;
1345            self.markdown.update(cx, move |markdown, _| {
1346                markdown.retain_code_block_scroll_handles(&code_block_ids);
1347            });
1348        } else {
1349            self.markdown
1350                .update(cx, |markdown, _| markdown.clear_code_block_scroll_handles());
1351        }
1352        let mut rendered_markdown = builder.build();
1353        let child_layout_id = rendered_markdown.element.request_layout(window, cx);
1354        let layout_id = window.request_layout(gpui::Style::default(), [child_layout_id], cx);
1355        (layout_id, rendered_markdown)
1356    }
1357
1358    fn prepaint(
1359        &mut self,
1360        _id: Option<&GlobalElementId>,
1361        _inspector_id: Option<&gpui::InspectorElementId>,
1362        bounds: Bounds<Pixels>,
1363        rendered_markdown: &mut Self::RequestLayoutState,
1364        window: &mut Window,
1365        cx: &mut App,
1366    ) -> Self::PrepaintState {
1367        let focus_handle = self.markdown.read(cx).focus_handle.clone();
1368        window.set_focus_handle(&focus_handle, cx);
1369        window.set_view_id(self.markdown.entity_id());
1370
1371        let hitbox = window.insert_hitbox(bounds, HitboxBehavior::Normal);
1372        rendered_markdown.element.prepaint(window, cx);
1373        self.autoscroll(&rendered_markdown.text, window, cx);
1374        hitbox
1375    }
1376
1377    fn paint(
1378        &mut self,
1379        _id: Option<&GlobalElementId>,
1380        _inspector_id: Option<&gpui::InspectorElementId>,
1381        bounds: Bounds<Pixels>,
1382        rendered_markdown: &mut Self::RequestLayoutState,
1383        hitbox: &mut Self::PrepaintState,
1384        window: &mut Window,
1385        cx: &mut App,
1386    ) {
1387        let mut context = KeyContext::default();
1388        context.add("Markdown");
1389        window.set_key_context(context);
1390        window.on_action(std::any::TypeId::of::<crate::Copy>(), {
1391            let entity = self.markdown.clone();
1392            let text = rendered_markdown.text.clone();
1393            move |_, phase, window, cx| {
1394                let text = text.clone();
1395                if phase == DispatchPhase::Bubble {
1396                    entity.update(cx, move |this, cx| this.copy(&text, window, cx))
1397                }
1398            }
1399        });
1400        window.on_action(std::any::TypeId::of::<crate::CopyAsMarkdown>(), {
1401            let entity = self.markdown.clone();
1402            move |_, phase, window, cx| {
1403                if phase == DispatchPhase::Bubble {
1404                    entity.update(cx, move |this, cx| this.copy_as_markdown(window, cx))
1405                }
1406            }
1407        });
1408
1409        self.paint_mouse_listeners(hitbox, &rendered_markdown.text, window, cx);
1410        rendered_markdown.element.paint(window, cx);
1411        self.paint_selection(bounds, &rendered_markdown.text, window, cx);
1412    }
1413}
1414
1415fn apply_heading_style(
1416    mut heading: Div,
1417    level: pulldown_cmark::HeadingLevel,
1418    custom_styles: Option<&HeadingLevelStyles>,
1419) -> Div {
1420    heading = match level {
1421        pulldown_cmark::HeadingLevel::H1 => heading.text_3xl(),
1422        pulldown_cmark::HeadingLevel::H2 => heading.text_2xl(),
1423        pulldown_cmark::HeadingLevel::H3 => heading.text_xl(),
1424        pulldown_cmark::HeadingLevel::H4 => heading.text_lg(),
1425        pulldown_cmark::HeadingLevel::H5 => heading.text_base(),
1426        pulldown_cmark::HeadingLevel::H6 => heading.text_sm(),
1427    };
1428
1429    if let Some(styles) = custom_styles {
1430        let style_opt = match level {
1431            pulldown_cmark::HeadingLevel::H1 => &styles.h1,
1432            pulldown_cmark::HeadingLevel::H2 => &styles.h2,
1433            pulldown_cmark::HeadingLevel::H3 => &styles.h3,
1434            pulldown_cmark::HeadingLevel::H4 => &styles.h4,
1435            pulldown_cmark::HeadingLevel::H5 => &styles.h5,
1436            pulldown_cmark::HeadingLevel::H6 => &styles.h6,
1437        };
1438
1439        if let Some(style) = style_opt {
1440            heading.style().text = style.clone();
1441        }
1442    }
1443
1444    heading
1445}
1446
1447fn render_copy_code_block_button(
1448    id: usize,
1449    code: String,
1450    markdown: Entity<Markdown>,
1451) -> impl IntoElement {
1452    let id = ElementId::named_usize("copy-markdown-code", id);
1453
1454    CopyButton::new(code.clone()).custom_on_click({
1455        let markdown = markdown;
1456        move |_window, cx| {
1457            let id = id.clone();
1458            markdown.update(cx, |this, cx| {
1459                this.copied_code_blocks.insert(id.clone());
1460
1461                cx.write_to_clipboard(ClipboardItem::new_string(code.clone()));
1462
1463                cx.spawn(async move |this, cx| {
1464                    cx.background_executor().timer(Duration::from_secs(2)).await;
1465
1466                    cx.update(|cx| {
1467                        this.update(cx, |this, cx| {
1468                            this.copied_code_blocks.remove(&id);
1469                            cx.notify();
1470                        })
1471                    })
1472                    .ok();
1473                })
1474                .detach();
1475            });
1476        }
1477    })
1478}
1479
1480impl IntoElement for MarkdownElement {
1481    type Element = Self;
1482
1483    fn into_element(self) -> Self::Element {
1484        self
1485    }
1486}
1487
1488pub enum AnyDiv {
1489    Div(Div),
1490    Stateful(Stateful<Div>),
1491}
1492
1493impl AnyDiv {
1494    fn into_any_element(self) -> AnyElement {
1495        match self {
1496            Self::Div(div) => div.into_any_element(),
1497            Self::Stateful(div) => div.into_any_element(),
1498        }
1499    }
1500}
1501
1502impl From<Div> for AnyDiv {
1503    fn from(value: Div) -> Self {
1504        Self::Div(value)
1505    }
1506}
1507
1508impl From<Stateful<Div>> for AnyDiv {
1509    fn from(value: Stateful<Div>) -> Self {
1510        Self::Stateful(value)
1511    }
1512}
1513
1514impl Styled for AnyDiv {
1515    fn style(&mut self) -> &mut StyleRefinement {
1516        match self {
1517            Self::Div(div) => div.style(),
1518            Self::Stateful(div) => div.style(),
1519        }
1520    }
1521}
1522
1523impl ParentElement for AnyDiv {
1524    fn extend(&mut self, elements: impl IntoIterator<Item = AnyElement>) {
1525        match self {
1526            Self::Div(div) => div.extend(elements),
1527            Self::Stateful(div) => div.extend(elements),
1528        }
1529    }
1530}
1531
1532#[derive(Default)]
1533struct TableState {
1534    alignments: Vec<Alignment>,
1535    in_head: bool,
1536    row_index: usize,
1537    col_index: usize,
1538}
1539
1540impl TableState {
1541    fn start(&mut self, alignments: Vec<Alignment>) {
1542        self.alignments = alignments;
1543        self.in_head = false;
1544        self.row_index = 0;
1545        self.col_index = 0;
1546    }
1547
1548    fn end(&mut self) {
1549        self.alignments.clear();
1550        self.in_head = false;
1551        self.row_index = 0;
1552        self.col_index = 0;
1553    }
1554
1555    fn start_head(&mut self) {
1556        self.in_head = true;
1557    }
1558
1559    fn end_head(&mut self) {
1560        self.in_head = false;
1561    }
1562
1563    fn start_row(&mut self) {
1564        self.col_index = 0;
1565    }
1566
1567    fn end_row(&mut self) {
1568        self.row_index += 1;
1569    }
1570
1571    fn end_cell(&mut self) {
1572        self.col_index += 1;
1573    }
1574}
1575
1576struct MarkdownElementBuilder {
1577    div_stack: Vec<AnyDiv>,
1578    rendered_lines: Vec<RenderedLine>,
1579    pending_line: PendingLine,
1580    rendered_links: Vec<RenderedLink>,
1581    current_source_index: usize,
1582    html_comment: bool,
1583    base_text_style: TextStyle,
1584    text_style_stack: Vec<TextStyleRefinement>,
1585    code_block_stack: Vec<Option<Arc<Language>>>,
1586    list_stack: Vec<ListStackEntry>,
1587    table: TableState,
1588    syntax_theme: Arc<SyntaxTheme>,
1589}
1590
1591#[derive(Default)]
1592struct PendingLine {
1593    text: String,
1594    runs: Vec<TextRun>,
1595    source_mappings: Vec<SourceMapping>,
1596}
1597
1598struct ListStackEntry {
1599    bullet_index: Option<u64>,
1600}
1601
1602impl MarkdownElementBuilder {
1603    fn new(
1604        container_style: &StyleRefinement,
1605        base_text_style: TextStyle,
1606        syntax_theme: Arc<SyntaxTheme>,
1607    ) -> Self {
1608        Self {
1609            div_stack: vec![{
1610                let mut base_div = div();
1611                base_div.style().refine(container_style);
1612                base_div.debug_selector(|| "inner".into()).into()
1613            }],
1614            rendered_lines: Vec::new(),
1615            pending_line: PendingLine::default(),
1616            rendered_links: Vec::new(),
1617            current_source_index: 0,
1618            html_comment: false,
1619            base_text_style,
1620            text_style_stack: Vec::new(),
1621            code_block_stack: Vec::new(),
1622            list_stack: Vec::new(),
1623            table: TableState::default(),
1624            syntax_theme,
1625        }
1626    }
1627
1628    fn push_text_style(&mut self, style: TextStyleRefinement) {
1629        self.text_style_stack.push(style);
1630    }
1631
1632    fn text_style(&self) -> TextStyle {
1633        let mut style = self.base_text_style.clone();
1634        for refinement in &self.text_style_stack {
1635            style.refine(refinement);
1636        }
1637        style
1638    }
1639
1640    fn pop_text_style(&mut self) {
1641        self.text_style_stack.pop();
1642    }
1643
1644    fn push_div(&mut self, div: impl Into<AnyDiv>, range: &Range<usize>, markdown_end: usize) {
1645        let mut div = div.into();
1646        self.flush_text();
1647
1648        if range.start == 0 {
1649            // Remove the top margin on the first element.
1650            div.style().refine(&StyleRefinement {
1651                margin: gpui::EdgesRefinement {
1652                    top: Some(Length::Definite(px(0.).into())),
1653                    left: None,
1654                    right: None,
1655                    bottom: None,
1656                },
1657                ..Default::default()
1658            });
1659        }
1660
1661        if range.end == markdown_end {
1662            div.style().refine(&StyleRefinement {
1663                margin: gpui::EdgesRefinement {
1664                    top: None,
1665                    left: None,
1666                    right: None,
1667                    bottom: Some(Length::Definite(rems(0.).into())),
1668                },
1669                ..Default::default()
1670            });
1671        }
1672
1673        self.div_stack.push(div);
1674    }
1675
1676    fn modify_current_div(&mut self, f: impl FnOnce(AnyDiv) -> AnyDiv) {
1677        self.flush_text();
1678        if let Some(div) = self.div_stack.pop() {
1679            self.div_stack.push(f(div));
1680        }
1681    }
1682
1683    fn pop_div(&mut self) {
1684        self.flush_text();
1685        let div = self.div_stack.pop().unwrap().into_any_element();
1686        self.div_stack.last_mut().unwrap().extend(iter::once(div));
1687    }
1688
1689    fn push_list(&mut self, bullet_index: Option<u64>) {
1690        self.list_stack.push(ListStackEntry { bullet_index });
1691    }
1692
1693    fn next_bullet_index(&mut self) -> Option<u64> {
1694        self.list_stack.last_mut().and_then(|entry| {
1695            let item_index = entry.bullet_index.as_mut()?;
1696            *item_index += 1;
1697            Some(*item_index - 1)
1698        })
1699    }
1700
1701    fn pop_list(&mut self) {
1702        self.list_stack.pop();
1703    }
1704
1705    fn push_code_block(&mut self, language: Option<Arc<Language>>) {
1706        self.code_block_stack.push(language);
1707    }
1708
1709    fn pop_code_block(&mut self) {
1710        self.code_block_stack.pop();
1711    }
1712
1713    fn push_link(&mut self, destination_url: SharedString, source_range: Range<usize>) {
1714        self.rendered_links.push(RenderedLink {
1715            source_range,
1716            destination_url,
1717        });
1718    }
1719
1720    fn push_text(&mut self, text: &str, source_range: Range<usize>) {
1721        self.pending_line.source_mappings.push(SourceMapping {
1722            rendered_index: self.pending_line.text.len(),
1723            source_index: source_range.start,
1724        });
1725        self.pending_line.text.push_str(text);
1726        self.current_source_index = source_range.end;
1727
1728        if let Some(Some(language)) = self.code_block_stack.last() {
1729            let mut offset = 0;
1730            for (range, highlight_id) in language.highlight_text(&Rope::from(text), 0..text.len()) {
1731                if range.start > offset {
1732                    self.pending_line
1733                        .runs
1734                        .push(self.text_style().to_run(range.start - offset));
1735                }
1736
1737                let mut run_style = self.text_style();
1738                if let Some(highlight) = highlight_id.style(&self.syntax_theme) {
1739                    run_style = run_style.highlight(highlight);
1740                }
1741                self.pending_line.runs.push(run_style.to_run(range.len()));
1742                offset = range.end;
1743            }
1744
1745            if offset < text.len() {
1746                self.pending_line
1747                    .runs
1748                    .push(self.text_style().to_run(text.len() - offset));
1749            }
1750        } else {
1751            self.pending_line
1752                .runs
1753                .push(self.text_style().to_run(text.len()));
1754        }
1755    }
1756
1757    fn trim_trailing_newline(&mut self) {
1758        if self.pending_line.text.ends_with('\n') {
1759            self.pending_line
1760                .text
1761                .truncate(self.pending_line.text.len() - 1);
1762            self.pending_line.runs.last_mut().unwrap().len -= 1;
1763            self.current_source_index -= 1;
1764        }
1765    }
1766
1767    fn flush_text(&mut self) {
1768        let line = mem::take(&mut self.pending_line);
1769        if line.text.is_empty() {
1770            return;
1771        }
1772
1773        let text = StyledText::new(line.text).with_runs(line.runs);
1774        self.rendered_lines.push(RenderedLine {
1775            layout: text.layout().clone(),
1776            source_mappings: line.source_mappings,
1777            source_end: self.current_source_index,
1778        });
1779        self.div_stack.last_mut().unwrap().extend([text.into_any()]);
1780    }
1781
1782    fn build(mut self) -> RenderedMarkdown {
1783        debug_assert_eq!(self.div_stack.len(), 1);
1784        self.flush_text();
1785        RenderedMarkdown {
1786            element: self.div_stack.pop().unwrap().into_any_element(),
1787            text: RenderedText {
1788                lines: self.rendered_lines.into(),
1789                links: self.rendered_links.into(),
1790            },
1791        }
1792    }
1793}
1794
1795struct RenderedLine {
1796    layout: TextLayout,
1797    source_mappings: Vec<SourceMapping>,
1798    source_end: usize,
1799}
1800
1801impl RenderedLine {
1802    fn rendered_index_for_source_index(&self, source_index: usize) -> usize {
1803        if source_index >= self.source_end {
1804            return self.layout.len();
1805        }
1806
1807        let mapping = match self
1808            .source_mappings
1809            .binary_search_by_key(&source_index, |probe| probe.source_index)
1810        {
1811            Ok(ix) => &self.source_mappings[ix],
1812            Err(ix) => &self.source_mappings[ix - 1],
1813        };
1814        mapping.rendered_index + (source_index - mapping.source_index)
1815    }
1816
1817    fn source_index_for_rendered_index(&self, rendered_index: usize) -> usize {
1818        if rendered_index >= self.layout.len() {
1819            return self.source_end;
1820        }
1821
1822        let mapping = match self
1823            .source_mappings
1824            .binary_search_by_key(&rendered_index, |probe| probe.rendered_index)
1825        {
1826            Ok(ix) => &self.source_mappings[ix],
1827            Err(ix) => &self.source_mappings[ix - 1],
1828        };
1829        mapping.source_index + (rendered_index - mapping.rendered_index)
1830    }
1831
1832    fn source_index_for_position(&self, position: Point<Pixels>) -> Result<usize, usize> {
1833        let line_rendered_index;
1834        let out_of_bounds;
1835        match self.layout.index_for_position(position) {
1836            Ok(ix) => {
1837                line_rendered_index = ix;
1838                out_of_bounds = false;
1839            }
1840            Err(ix) => {
1841                line_rendered_index = ix;
1842                out_of_bounds = true;
1843            }
1844        };
1845        let source_index = self.source_index_for_rendered_index(line_rendered_index);
1846        if out_of_bounds {
1847            Err(source_index)
1848        } else {
1849            Ok(source_index)
1850        }
1851    }
1852}
1853
1854#[derive(Copy, Clone, Debug, Default)]
1855struct SourceMapping {
1856    rendered_index: usize,
1857    source_index: usize,
1858}
1859
1860pub struct RenderedMarkdown {
1861    element: AnyElement,
1862    text: RenderedText,
1863}
1864
1865#[derive(Clone)]
1866struct RenderedText {
1867    lines: Rc<[RenderedLine]>,
1868    links: Rc<[RenderedLink]>,
1869}
1870
1871#[derive(Debug, Clone, Eq, PartialEq)]
1872struct RenderedLink {
1873    source_range: Range<usize>,
1874    destination_url: SharedString,
1875}
1876
1877impl RenderedText {
1878    fn source_index_for_position(&self, position: Point<Pixels>) -> Result<usize, usize> {
1879        let mut lines = self.lines.iter().peekable();
1880
1881        while let Some(line) = lines.next() {
1882            let line_bounds = line.layout.bounds();
1883            if position.y > line_bounds.bottom() {
1884                if let Some(next_line) = lines.peek()
1885                    && position.y < next_line.layout.bounds().top()
1886                {
1887                    return Err(line.source_end);
1888                }
1889
1890                continue;
1891            }
1892
1893            return line.source_index_for_position(position);
1894        }
1895
1896        Err(self.lines.last().map_or(0, |line| line.source_end))
1897    }
1898
1899    fn position_for_source_index(&self, source_index: usize) -> Option<(Point<Pixels>, Pixels)> {
1900        for line in self.lines.iter() {
1901            let line_source_start = line.source_mappings.first().unwrap().source_index;
1902            if source_index < line_source_start {
1903                break;
1904            } else if source_index > line.source_end {
1905                continue;
1906            } else {
1907                let line_height = line.layout.line_height();
1908                let rendered_index_within_line = line.rendered_index_for_source_index(source_index);
1909                let position = line.layout.position_for_index(rendered_index_within_line)?;
1910                return Some((position, line_height));
1911            }
1912        }
1913        None
1914    }
1915
1916    fn surrounding_word_range(&self, source_index: usize) -> Range<usize> {
1917        for line in self.lines.iter() {
1918            if source_index > line.source_end {
1919                continue;
1920            }
1921
1922            let line_rendered_start = line.source_mappings.first().unwrap().rendered_index;
1923            let rendered_index_in_line =
1924                line.rendered_index_for_source_index(source_index) - line_rendered_start;
1925            let text = line.layout.text();
1926            let previous_space = if let Some(idx) = text[0..rendered_index_in_line].rfind(' ') {
1927                idx + ' '.len_utf8()
1928            } else {
1929                0
1930            };
1931            let next_space = if let Some(idx) = text[rendered_index_in_line..].find(' ') {
1932                rendered_index_in_line + idx
1933            } else {
1934                text.len()
1935            };
1936
1937            return line.source_index_for_rendered_index(line_rendered_start + previous_space)
1938                ..line.source_index_for_rendered_index(line_rendered_start + next_space);
1939        }
1940
1941        source_index..source_index
1942    }
1943
1944    fn surrounding_line_range(&self, source_index: usize) -> Range<usize> {
1945        for line in self.lines.iter() {
1946            if source_index > line.source_end {
1947                continue;
1948            }
1949            let line_source_start = line.source_mappings.first().unwrap().source_index;
1950            return line_source_start..line.source_end;
1951        }
1952
1953        source_index..source_index
1954    }
1955
1956    fn text_for_range(&self, range: Range<usize>) -> String {
1957        let mut accumulator = String::new();
1958
1959        for line in self.lines.iter() {
1960            if range.start > line.source_end {
1961                continue;
1962            }
1963            let line_source_start = line.source_mappings.first().unwrap().source_index;
1964            if range.end < line_source_start {
1965                break;
1966            }
1967
1968            let text = line.layout.text();
1969
1970            let start = if range.start < line_source_start {
1971                0
1972            } else {
1973                line.rendered_index_for_source_index(range.start)
1974            };
1975            let end = if range.end > line.source_end {
1976                line.rendered_index_for_source_index(line.source_end)
1977            } else {
1978                line.rendered_index_for_source_index(range.end)
1979            }
1980            .min(text.len());
1981
1982            accumulator.push_str(&text[start..end]);
1983            accumulator.push('\n');
1984        }
1985        // Remove trailing newline
1986        accumulator.pop();
1987        accumulator
1988    }
1989
1990    fn link_for_position(&self, position: Point<Pixels>) -> Option<&RenderedLink> {
1991        let source_index = self.source_index_for_position(position).ok()?;
1992        self.links
1993            .iter()
1994            .find(|link| link.source_range.contains(&source_index))
1995    }
1996}
1997
1998#[cfg(test)]
1999mod tests {
2000    use super::*;
2001    use gpui::{TestAppContext, size};
2002
2003    #[gpui::test]
2004    fn test_mappings(cx: &mut TestAppContext) {
2005        // Formatting.
2006        assert_mappings(
2007            &render_markdown("He*l*lo", cx),
2008            vec![vec![(0, 0), (1, 1), (2, 3), (3, 5), (4, 6), (5, 7)]],
2009        );
2010
2011        // Multiple lines.
2012        assert_mappings(
2013            &render_markdown("Hello\n\nWorld", cx),
2014            vec![
2015                vec![(0, 0), (1, 1), (2, 2), (3, 3), (4, 4), (5, 5)],
2016                vec![(0, 7), (1, 8), (2, 9), (3, 10), (4, 11), (5, 12)],
2017            ],
2018        );
2019
2020        // Multi-byte characters.
2021        assert_mappings(
2022            &render_markdown("αβγ\n\nδεζ", cx),
2023            vec![
2024                vec![(0, 0), (2, 2), (4, 4), (6, 6)],
2025                vec![(0, 8), (2, 10), (4, 12), (6, 14)],
2026            ],
2027        );
2028
2029        // Smart quotes.
2030        assert_mappings(&render_markdown("\"", cx), vec![vec![(0, 0), (3, 1)]]);
2031        assert_mappings(
2032            &render_markdown("\"hey\"", cx),
2033            vec![vec![(0, 0), (3, 1), (4, 2), (5, 3), (6, 4), (9, 5)]],
2034        );
2035
2036        // HTML Comments are ignored
2037        assert_mappings(
2038            &render_markdown(
2039                "<!--\nrdoc-file=string.c\n- str.intern   -> symbol\n- str.to_sym   -> symbol\n-->\nReturns",
2040                cx,
2041            ),
2042            vec![vec![
2043                (0, 78),
2044                (1, 79),
2045                (2, 80),
2046                (3, 81),
2047                (4, 82),
2048                (5, 83),
2049                (6, 84),
2050            ]],
2051        );
2052    }
2053
2054    fn render_markdown(markdown: &str, cx: &mut TestAppContext) -> RenderedText {
2055        struct TestWindow;
2056
2057        impl Render for TestWindow {
2058            fn render(&mut self, _: &mut Window, _: &mut Context<Self>) -> impl IntoElement {
2059                div()
2060            }
2061        }
2062
2063        let (_, cx) = cx.add_window_view(|_, _| TestWindow);
2064        let markdown = cx.new(|cx| Markdown::new(markdown.to_string().into(), None, None, cx));
2065        cx.run_until_parked();
2066        let (rendered, _) = cx.draw(
2067            Default::default(),
2068            size(px(600.0), px(600.0)),
2069            |_window, _cx| MarkdownElement::new(markdown, MarkdownStyle::default()),
2070        );
2071        rendered.text
2072    }
2073
2074    #[gpui::test]
2075    fn test_surrounding_word_range(cx: &mut TestAppContext) {
2076        let rendered = render_markdown("Hello world tesεζ", cx);
2077
2078        // Test word selection for "Hello"
2079        let word_range = rendered.surrounding_word_range(2); // Simulate click on 'l' in "Hello"
2080        let selected_text = rendered.text_for_range(word_range);
2081        assert_eq!(selected_text, "Hello");
2082
2083        // Test word selection for "world"
2084        let word_range = rendered.surrounding_word_range(7); // Simulate click on 'o' in "world"
2085        let selected_text = rendered.text_for_range(word_range);
2086        assert_eq!(selected_text, "world");
2087
2088        // Test word selection for "tesεζ"
2089        let word_range = rendered.surrounding_word_range(14); // Simulate click on 's' in "tesεζ"
2090        let selected_text = rendered.text_for_range(word_range);
2091        assert_eq!(selected_text, "tesεζ");
2092
2093        // Test word selection at word boundary (space)
2094        let word_range = rendered.surrounding_word_range(5); // Simulate click on space between "Hello" and "world", expect highlighting word to the left
2095        let selected_text = rendered.text_for_range(word_range);
2096        assert_eq!(selected_text, "Hello");
2097    }
2098
2099    #[gpui::test]
2100    fn test_surrounding_line_range(cx: &mut TestAppContext) {
2101        let rendered = render_markdown("First line\n\nSecond line\n\nThird lineεζ", cx);
2102
2103        // Test getting line range for first line
2104        let line_range = rendered.surrounding_line_range(5); // Simulate click somewhere in first line
2105        let selected_text = rendered.text_for_range(line_range);
2106        assert_eq!(selected_text, "First line");
2107
2108        // Test getting line range for second line
2109        let line_range = rendered.surrounding_line_range(13); // Simulate click at beginning in second line
2110        let selected_text = rendered.text_for_range(line_range);
2111        assert_eq!(selected_text, "Second line");
2112
2113        // Test getting line range for third line
2114        let line_range = rendered.surrounding_line_range(37); // Simulate click at end of third line with multi-byte chars
2115        let selected_text = rendered.text_for_range(line_range);
2116        assert_eq!(selected_text, "Third lineεζ");
2117    }
2118
2119    #[gpui::test]
2120    fn test_selection_head_movement(cx: &mut TestAppContext) {
2121        let rendered = render_markdown("Hello world test", cx);
2122
2123        let mut selection = Selection {
2124            start: 5,
2125            end: 5,
2126            reversed: false,
2127            pending: false,
2128            mode: SelectMode::Character,
2129        };
2130
2131        // Test forward selection
2132        selection.set_head(10, &rendered);
2133        assert_eq!(selection.start, 5);
2134        assert_eq!(selection.end, 10);
2135        assert!(!selection.reversed);
2136        assert_eq!(selection.tail(), 5);
2137
2138        // Test backward selection
2139        selection.set_head(2, &rendered);
2140        assert_eq!(selection.start, 2);
2141        assert_eq!(selection.end, 5);
2142        assert!(selection.reversed);
2143        assert_eq!(selection.tail(), 5);
2144
2145        // Test forward selection again from reversed state
2146        selection.set_head(15, &rendered);
2147        assert_eq!(selection.start, 5);
2148        assert_eq!(selection.end, 15);
2149        assert!(!selection.reversed);
2150        assert_eq!(selection.tail(), 5);
2151    }
2152
2153    #[gpui::test]
2154    fn test_word_selection_drag(cx: &mut TestAppContext) {
2155        let rendered = render_markdown("Hello world test", cx);
2156
2157        // Start with a simulated double-click on "world" (index 6-10)
2158        let word_range = rendered.surrounding_word_range(7); // Click on 'o' in "world"
2159        let mut selection = Selection {
2160            start: word_range.start,
2161            end: word_range.end,
2162            reversed: false,
2163            pending: true,
2164            mode: SelectMode::Word(word_range),
2165        };
2166
2167        // Drag forward to "test" - should expand selection to include "test"
2168        selection.set_head(13, &rendered); // Index in "test"
2169        assert_eq!(selection.start, 6); // Start of "world"
2170        assert_eq!(selection.end, 16); // End of "test"
2171        assert!(!selection.reversed);
2172        let selected_text = rendered.text_for_range(selection.start..selection.end);
2173        assert_eq!(selected_text, "world test");
2174
2175        // Drag backward to "Hello" - should expand selection to include "Hello"
2176        selection.set_head(2, &rendered); // Index in "Hello"
2177        assert_eq!(selection.start, 0); // Start of "Hello"
2178        assert_eq!(selection.end, 11); // End of "world" (original selection)
2179        assert!(selection.reversed);
2180        let selected_text = rendered.text_for_range(selection.start..selection.end);
2181        assert_eq!(selected_text, "Hello world");
2182
2183        // Drag back within original word - should revert to original selection
2184        selection.set_head(8, &rendered); // Back within "world"
2185        assert_eq!(selection.start, 6); // Start of "world"
2186        assert_eq!(selection.end, 11); // End of "world"
2187        assert!(!selection.reversed);
2188        let selected_text = rendered.text_for_range(selection.start..selection.end);
2189        assert_eq!(selected_text, "world");
2190    }
2191
2192    #[gpui::test]
2193    fn test_selection_with_markdown_formatting(cx: &mut TestAppContext) {
2194        let rendered = render_markdown(
2195            "This is **bold** text, this is *italic* text, use `code` here",
2196            cx,
2197        );
2198        let word_range = rendered.surrounding_word_range(10); // Inside "bold"
2199        let selected_text = rendered.text_for_range(word_range);
2200        assert_eq!(selected_text, "bold");
2201
2202        let word_range = rendered.surrounding_word_range(32); // Inside "italic"
2203        let selected_text = rendered.text_for_range(word_range);
2204        assert_eq!(selected_text, "italic");
2205
2206        let word_range = rendered.surrounding_word_range(51); // Inside "code"
2207        let selected_text = rendered.text_for_range(word_range);
2208        assert_eq!(selected_text, "code");
2209    }
2210
2211    #[gpui::test]
2212    fn test_all_selection(cx: &mut TestAppContext) {
2213        let rendered = render_markdown("Hello world\n\nThis is a test\n\nwith multiple lines", cx);
2214
2215        let total_length = rendered
2216            .lines
2217            .last()
2218            .map(|line| line.source_end)
2219            .unwrap_or(0);
2220
2221        let mut selection = Selection {
2222            start: 0,
2223            end: total_length,
2224            reversed: false,
2225            pending: true,
2226            mode: SelectMode::All,
2227        };
2228
2229        selection.set_head(5, &rendered); // Try to set head in middle
2230        assert_eq!(selection.start, 0);
2231        assert_eq!(selection.end, total_length);
2232        assert!(!selection.reversed);
2233
2234        selection.set_head(25, &rendered); // Try to set head near end
2235        assert_eq!(selection.start, 0);
2236        assert_eq!(selection.end, total_length);
2237        assert!(!selection.reversed);
2238
2239        let selected_text = rendered.text_for_range(selection.start..selection.end);
2240        assert_eq!(
2241            selected_text,
2242            "Hello world\nThis is a test\nwith multiple lines"
2243        );
2244    }
2245
2246    #[test]
2247    fn test_escape() {
2248        assert_eq!(Markdown::escape("hello `world`"), "hello \\`world\\`");
2249        assert_eq!(
2250            Markdown::escape("hello\n    cool world"),
2251            "hello\n\ncool world"
2252        );
2253    }
2254
2255    #[track_caller]
2256    fn assert_mappings(rendered: &RenderedText, expected: Vec<Vec<(usize, usize)>>) {
2257        assert_eq!(rendered.lines.len(), expected.len(), "line count mismatch");
2258        for (line_ix, line_mappings) in expected.into_iter().enumerate() {
2259            let line = &rendered.lines[line_ix];
2260
2261            assert!(
2262                line.source_mappings.windows(2).all(|mappings| {
2263                    mappings[0].source_index < mappings[1].source_index
2264                        && mappings[0].rendered_index < mappings[1].rendered_index
2265                }),
2266                "line {} has duplicate mappings: {:?}",
2267                line_ix,
2268                line.source_mappings
2269            );
2270
2271            for (rendered_ix, source_ix) in line_mappings {
2272                assert_eq!(
2273                    line.source_index_for_rendered_index(rendered_ix),
2274                    source_ix,
2275                    "line {}, rendered_ix {}",
2276                    line_ix,
2277                    rendered_ix
2278                );
2279
2280                assert_eq!(
2281                    line.rendered_index_for_source_index(source_ix),
2282                    rendered_ix,
2283                    "line {}, source_ix {}",
2284                    line_ix,
2285                    source_ix
2286                );
2287            }
2288        }
2289    }
2290}