use crate::{
    item::{Item, ItemHandle, ItemSettings, WeakItemHandle},
    toolbar::Toolbar,
    workspace_settings::{AutosaveSetting, WorkspaceSettings},
    SplitDirection, Workspace,
};
use anyhow::Result;
use collections::{HashMap, HashSet, VecDeque};
use gpui::{
    actions, prelude::*, register_action, AppContext, AsyncWindowContext, Component, Div, EntityId,
    EventEmitter, FocusHandle, Model, PromptLevel, Render, Task, View, ViewContext, VisualContext,
    WeakView, WindowContext,
};
use parking_lot::Mutex;
use project2::{Project, ProjectEntryId, ProjectPath};
use serde::Deserialize;
use settings2::Settings;
use std::{
    any::Any,
    cmp, fmt, mem,
    path::{Path, PathBuf},
    sync::{
        atomic::{AtomicUsize, Ordering},
        Arc,
    },
};
use ui::v_stack;
use ui::{prelude::*, Icon, IconButton, IconElement, TextColor, TextTooltip};
use util::truncate_and_remove_front;

#[derive(PartialEq, Clone, Copy, Deserialize, Debug)]
#[serde(rename_all = "camelCase")]
pub enum SaveIntent {
    /// write all files (even if unchanged)
    /// prompt before overwriting on-disk changes
    Save,
    /// write any files that have local changes
    /// prompt before overwriting on-disk changes
    SaveAll,
    /// always prompt for a new path
    SaveAs,
    /// prompt "you have unsaved changes" before writing
    Close,
    /// write all dirty files, don't prompt on conflict
    Overwrite,
    /// skip all save-related behavior
    Skip,
}

//todo!("Do we need the default bound on actions? Decide soon")
// #[register_action]
#[derive(Clone, Deserialize, PartialEq, Debug)]
pub struct ActivateItem(pub usize);

// #[derive(Clone, PartialEq)]
// pub struct CloseItemById {
//     pub item_id: usize,
//     pub pane: WeakView<Pane>,
// }

// #[derive(Clone, PartialEq)]
// pub struct CloseItemsToTheLeftById {
//     pub item_id: usize,
//     pub pane: WeakView<Pane>,
// }

// #[derive(Clone, PartialEq)]
// pub struct CloseItemsToTheRightById {
//     pub item_id: usize,
//     pub pane: WeakView<Pane>,
// }

#[register_action]
#[derive(Clone, PartialEq, Debug, Deserialize, Default)]
#[serde(rename_all = "camelCase")]
pub struct CloseActiveItem {
    pub save_intent: Option<SaveIntent>,
}

#[register_action]
#[derive(Clone, PartialEq, Debug, Deserialize, Default)]
#[serde(rename_all = "camelCase")]
pub struct CloseAllItems {
    pub save_intent: Option<SaveIntent>,
}

// todo!(These used to be under pane::{Action}. Are they now workspace::pane::{Action}?)
actions!(
    ActivatePrevItem,
    ActivateNextItem,
    ActivateLastItem,
    CloseInactiveItems,
    CloseCleanItems,
    CloseItemsToTheLeft,
    CloseItemsToTheRight,
    GoBack,
    GoForward,
    ReopenClosedItem,
    SplitLeft,
    SplitUp,
    SplitRight,
    SplitDown,
);

const MAX_NAVIGATION_HISTORY_LEN: usize = 1024;

pub fn init(cx: &mut AppContext) {
    // todo!()
    //     cx.add_action(Pane::toggle_zoom);
    //     cx.add_action(|pane: &mut Pane, action: &ActivateItem, cx| {
    //         pane.activate_item(action.0, true, true, cx);
    //     });
    //     cx.add_action(|pane: &mut Pane, _: &ActivateLastItem, cx| {
    //         pane.activate_item(pane.items.len() - 1, true, true, cx);
    //     });
    //     cx.add_action(|pane: &mut Pane, _: &ActivatePrevItem, cx| {
    //         pane.activate_prev_item(true, cx);
    //     });
    //     cx.add_action(|pane: &mut Pane, _: &ActivateNextItem, cx| {
    //         pane.activate_next_item(true, cx);
    //     });
    //     cx.add_async_action(Pane::close_active_item);
    //     cx.add_async_action(Pane::close_inactive_items);
    //     cx.add_async_action(Pane::close_clean_items);
    //     cx.add_async_action(Pane::close_items_to_the_left);
    //     cx.add_async_action(Pane::close_items_to_the_right);
    //     cx.add_async_action(Pane::close_all_items);
    //     cx.add_action(|pane: &mut Pane, _: &SplitLeft, cx| pane.split(SplitDirection::Left, cx));
    //     cx.add_action(|pane: &mut Pane, _: &SplitUp, cx| pane.split(SplitDirection::Up, cx));
    //     cx.add_action(|pane: &mut Pane, _: &SplitRight, cx| pane.split(SplitDirection::Right, cx));
    //     cx.add_action(|pane: &mut Pane, _: &SplitDown, cx| pane.split(SplitDirection::Down, cx));
}

pub enum Event {
    AddItem { item: Box<dyn ItemHandle> },
    ActivateItem { local: bool },
    Remove,
    RemoveItem { item_id: EntityId },
    Split(SplitDirection),
    ChangeItemTitle,
    Focus,
    ZoomIn,
    ZoomOut,
}

impl fmt::Debug for Event {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Event::AddItem { item } => f.debug_struct("AddItem").field("item", &item.id()).finish(),
            Event::ActivateItem { local } => f
                .debug_struct("ActivateItem")
                .field("local", local)
                .finish(),
            Event::Remove => f.write_str("Remove"),
            Event::RemoveItem { item_id } => f
                .debug_struct("RemoveItem")
                .field("item_id", item_id)
                .finish(),
            Event::Split(direction) => f
                .debug_struct("Split")
                .field("direction", direction)
                .finish(),
            Event::ChangeItemTitle => f.write_str("ChangeItemTitle"),
            Event::Focus => f.write_str("Focus"),
            Event::ZoomIn => f.write_str("ZoomIn"),
            Event::ZoomOut => f.write_str("ZoomOut"),
        }
    }
}

pub struct Pane {
    focus_handle: FocusHandle,
    items: Vec<Box<dyn ItemHandle>>,
    activation_history: Vec<EntityId>,
    zoomed: bool,
    active_item_index: usize,
    //     last_focused_view_by_item: HashMap<usize, AnyWeakViewHandle>,
    autoscroll: bool,
    nav_history: NavHistory,
    toolbar: View<Toolbar>,
    //     tab_bar_context_menu: TabBarContextMenu,
    //     tab_context_menu: ViewHandle<ContextMenu>,
    workspace: WeakView<Workspace>,
    project: Model<Project>,
    //     can_drop: Rc<dyn Fn(&DragAndDrop<Workspace>, &WindowContext) -> bool>,
    //     can_split: bool,
    //     render_tab_bar_buttons: Rc<dyn Fn(&mut Pane, &mut ViewContext<Pane>) -> AnyElement<Pane>>,
}

pub struct ItemNavHistory {
    history: NavHistory,
    item: Arc<dyn WeakItemHandle>,
}

#[derive(Clone)]
pub struct NavHistory(Arc<Mutex<NavHistoryState>>);

struct NavHistoryState {
    mode: NavigationMode,
    backward_stack: VecDeque<NavigationEntry>,
    forward_stack: VecDeque<NavigationEntry>,
    closed_stack: VecDeque<NavigationEntry>,
    paths_by_item: HashMap<EntityId, (ProjectPath, Option<PathBuf>)>,
    pane: WeakView<Pane>,
    next_timestamp: Arc<AtomicUsize>,
}

#[derive(Copy, Clone)]
pub enum NavigationMode {
    Normal,
    GoingBack,
    GoingForward,
    ClosingItem,
    ReopeningClosedItem,
    Disabled,
}

impl Default for NavigationMode {
    fn default() -> Self {
        Self::Normal
    }
}

pub struct NavigationEntry {
    pub item: Arc<dyn WeakItemHandle>,
    pub data: Option<Box<dyn Any + Send>>,
    pub timestamp: usize,
}

// pub struct DraggedItem {
//     pub handle: Box<dyn ItemHandle>,
//     pub pane: WeakView<Pane>,
// }

// pub enum ReorderBehavior {
//     None,
//     MoveAfterActive,
//     MoveToIndex(usize),
// }

// #[derive(Debug, Clone, Copy, PartialEq, Eq)]
// enum TabBarContextMenuKind {
//     New,
//     Split,
// }

// struct TabBarContextMenu {
//     kind: TabBarContextMenuKind,
//     handle: ViewHandle<ContextMenu>,
// }

// impl TabBarContextMenu {
//     fn handle_if_kind(&self, kind: TabBarContextMenuKind) -> Option<ViewHandle<ContextMenu>> {
//         if self.kind == kind {
//             return Some(self.handle.clone());
//         }
//         None
//     }
// }

// #[allow(clippy::too_many_arguments)]
// fn nav_button<A: Action, F: 'static + Fn(&mut Pane, &mut ViewContext<Pane>)>(
//     svg_path: &'static str,
//     style: theme2::Interactive<theme2::IconButton>,
//     nav_button_height: f32,
//     tooltip_style: TooltipStyle,
//     enabled: bool,
//     on_click: F,
//     tooltip_action: A,
//     action_name: &str,
//     cx: &mut ViewContext<Pane>,
// ) -> AnyElement<Pane> {
//     MouseEventHandler::new::<A, _>(0, cx, |state, _| {
//         let style = if enabled {
//             style.style_for(state)
//         } else {
//             style.disabled_style()
//         };
//         Svg::new(svg_path)
//             .with_color(style.color)
//             .constrained()
//             .with_width(style.icon_width)
//             .aligned()
//             .contained()
//             .with_style(style.container)
//             .constrained()
//             .with_width(style.button_width)
//             .with_height(nav_button_height)
//             .aligned()
//             .top()
//     })
//     .with_cursor_style(if enabled {
//         CursorStyle::PointingHand
//     } else {
//         CursorStyle::default()
//     })
//     .on_click(MouseButton::Left, move |_, toolbar, cx| {
//         on_click(toolbar, cx)
//     })
//     .with_tooltip::<A>(
//         0,
//         action_name.to_string(),
//         Some(Box::new(tooltip_action)),
//         tooltip_style,
//         cx,
//     )
//     .contained()
//     .into_any_named("nav button")
// }

impl EventEmitter<Event> for Pane {}

impl Pane {
    pub fn new(
        workspace: WeakView<Workspace>,
        project: Model<Project>,
        next_timestamp: Arc<AtomicUsize>,
        cx: &mut ViewContext<Self>,
    ) -> Self {
        // todo!("context menu")
        // let pane_view_id = cx.view_id();
        // let context_menu = cx.add_view(|cx| ContextMenu::new(pane_view_id, cx));
        // context_menu.update(cx, |menu, _| {
        //     menu.set_position_mode(OverlayPositionMode::Local)
        // });

        let handle = cx.view().downgrade();
        Self {
            focus_handle: cx.focus_handle(),
            items: Vec::new(),
            activation_history: Vec::new(),
            zoomed: false,
            active_item_index: 0,
            // last_focused_view_by_item: Default::default(),
            autoscroll: false,
            nav_history: NavHistory(Arc::new(Mutex::new(NavHistoryState {
                mode: NavigationMode::Normal,
                backward_stack: Default::default(),
                forward_stack: Default::default(),
                closed_stack: Default::default(),
                paths_by_item: Default::default(),
                pane: handle.clone(),
                next_timestamp,
            }))),
            toolbar: cx.build_view(|_| Toolbar::new()),
            // tab_bar_context_menu: TabBarContextMenu {
            //     kind: TabBarContextMenuKind::New,
            //     handle: context_menu,
            // },
            // tab_context_menu: cx.add_view(|cx| ContextMenu::new(pane_view_id, cx)),
            workspace,
            project,
            // can_drop: Rc::new(|_, _| true),
            // can_split: true,
            // render_tab_bar_buttons: Rc::new(move |pane, cx| {
            //     Flex::row()
            //         // New menu
            //         .with_child(Self::render_tab_bar_button(
            //             0,
            //             "icons/plus.svg",
            //             false,
            //             Some(("New...".into(), None)),
            //             cx,
            //             |pane, cx| pane.deploy_new_menu(cx),
            //             |pane, cx| {
            //                 pane.tab_bar_context_menu
            //                     .handle
            //                     .update(cx, |menu, _| menu.delay_cancel())
            //             },
            //             pane.tab_bar_context_menu
            //                 .handle_if_kind(TabBarContextMenuKind::New),
            //         ))
            //         .with_child(Self::render_tab_bar_button(
            //             1,
            //             "icons/split.svg",
            //             false,
            //             Some(("Split Pane".into(), None)),
            //             cx,
            //             |pane, cx| pane.deploy_split_menu(cx),
            //             |pane, cx| {
            //                 pane.tab_bar_context_menu
            //                     .handle
            //                     .update(cx, |menu, _| menu.delay_cancel())
            //             },
            //             pane.tab_bar_context_menu
            //                 .handle_if_kind(TabBarContextMenuKind::Split),
            //         ))
            //         .with_child({
            //             let icon_path;
            //             let tooltip_label;
            //             if pane.is_zoomed() {
            //                 icon_path = "icons/minimize.svg";
            //                 tooltip_label = "Zoom In";
            //             } else {
            //                 icon_path = "icons/maximize.svg";
            //                 tooltip_label = "Zoom In";
            //             }

            //             Pane::render_tab_bar_button(
            //                 2,
            //                 icon_path,
            //                 pane.is_zoomed(),
            //                 Some((tooltip_label, Some(Box::new(ToggleZoom)))),
            //                 cx,
            //                 move |pane, cx| pane.toggle_zoom(&Default::default(), cx),
            //                 move |_, _| {},
            //                 None,
            //             )
            //         })
            //         .into_any()
            // }),
        }
    }

    pub(crate) fn workspace(&self) -> &WeakView<Workspace> {
        &self.workspace
    }

    pub fn has_focus(&self, cx: &WindowContext) -> bool {
        self.focus_handle.contains_focused(cx)
    }

    pub fn active_item_index(&self) -> usize {
        self.active_item_index
    }

    //     pub fn on_can_drop<F>(&mut self, can_drop: F)
    //     where
    //         F: 'static + Fn(&DragAndDrop<Workspace>, &WindowContext) -> bool,
    //     {
    //         self.can_drop = Rc::new(can_drop);
    //     }

    //     pub fn set_can_split(&mut self, can_split: bool, cx: &mut ViewContext<Self>) {
    //         self.can_split = can_split;
    //         cx.notify();
    //     }

    //     pub fn set_can_navigate(&mut self, can_navigate: bool, cx: &mut ViewContext<Self>) {
    //         self.toolbar.update(cx, |toolbar, cx| {
    //             toolbar.set_can_navigate(can_navigate, cx);
    //         });
    //         cx.notify();
    //     }

    //     pub fn set_render_tab_bar_buttons<F>(&mut self, cx: &mut ViewContext<Self>, render: F)
    //     where
    //         F: 'static + Fn(&mut Pane, &mut ViewContext<Pane>) -> AnyElement<Pane>,
    //     {
    //         self.render_tab_bar_buttons = Rc::new(render);
    //         cx.notify();
    //     }

    pub fn nav_history_for_item<T: Item>(&self, item: &View<T>) -> ItemNavHistory {
        ItemNavHistory {
            history: self.nav_history.clone(),
            item: Arc::new(item.downgrade()),
        }
    }

    pub fn nav_history(&self) -> &NavHistory {
        &self.nav_history
    }

    pub fn nav_history_mut(&mut self) -> &mut NavHistory {
        &mut self.nav_history
    }

    pub fn disable_history(&mut self) {
        self.nav_history.disable();
    }

    pub fn enable_history(&mut self) {
        self.nav_history.enable();
    }

    pub fn can_navigate_backward(&self) -> bool {
        !self.nav_history.0.lock().backward_stack.is_empty()
    }

    pub fn can_navigate_forward(&self) -> bool {
        !self.nav_history.0.lock().forward_stack.is_empty()
    }

    fn history_updated(&mut self, cx: &mut ViewContext<Self>) {
        self.toolbar.update(cx, |_, cx| cx.notify());
    }

    pub(crate) fn open_item(
        &mut self,
        project_entry_id: ProjectEntryId,
        focus_item: bool,
        cx: &mut ViewContext<Self>,
        build_item: impl FnOnce(&mut ViewContext<Pane>) -> Box<dyn ItemHandle>,
    ) -> Box<dyn ItemHandle> {
        let mut existing_item = None;
        for (index, item) in self.items.iter().enumerate() {
            if item.is_singleton(cx) && item.project_entry_ids(cx).as_slice() == [project_entry_id]
            {
                let item = item.boxed_clone();
                existing_item = Some((index, item));
                break;
            }
        }

        if let Some((index, existing_item)) = existing_item {
            self.activate_item(index, focus_item, focus_item, cx);
            existing_item
        } else {
            let new_item = build_item(cx);
            self.add_item(new_item.clone(), true, focus_item, None, cx);
            new_item
        }
    }

    pub fn add_item(
        &mut self,
        item: Box<dyn ItemHandle>,
        activate_pane: bool,
        focus_item: bool,
        destination_index: Option<usize>,
        cx: &mut ViewContext<Self>,
    ) {
        if item.is_singleton(cx) {
            if let Some(&entry_id) = item.project_entry_ids(cx).get(0) {
                let project = self.project.read(cx);
                if let Some(project_path) = project.path_for_entry(entry_id, cx) {
                    let abs_path = project.absolute_path(&project_path, cx);
                    self.nav_history
                        .0
                        .lock()
                        .paths_by_item
                        .insert(item.id(), (project_path, abs_path));
                }
            }
        }
        // If no destination index is specified, add or move the item after the active item.
        let mut insertion_index = {
            cmp::min(
                if let Some(destination_index) = destination_index {
                    destination_index
                } else {
                    self.active_item_index + 1
                },
                self.items.len(),
            )
        };

        // Does the item already exist?
        let project_entry_id = if item.is_singleton(cx) {
            item.project_entry_ids(cx).get(0).copied()
        } else {
            None
        };

        let existing_item_index = self.items.iter().position(|existing_item| {
            if existing_item.id() == item.id() {
                true
            } else if existing_item.is_singleton(cx) {
                existing_item
                    .project_entry_ids(cx)
                    .get(0)
                    .map_or(false, |existing_entry_id| {
                        Some(existing_entry_id) == project_entry_id.as_ref()
                    })
            } else {
                false
            }
        });

        if let Some(existing_item_index) = existing_item_index {
            // If the item already exists, move it to the desired destination and activate it

            if existing_item_index != insertion_index {
                let existing_item_is_active = existing_item_index == self.active_item_index;

                // If the caller didn't specify a destination and the added item is already
                // the active one, don't move it
                if existing_item_is_active && destination_index.is_none() {
                    insertion_index = existing_item_index;
                } else {
                    self.items.remove(existing_item_index);
                    if existing_item_index < self.active_item_index {
                        self.active_item_index -= 1;
                    }
                    insertion_index = insertion_index.min(self.items.len());

                    self.items.insert(insertion_index, item.clone());

                    if existing_item_is_active {
                        self.active_item_index = insertion_index;
                    } else if insertion_index <= self.active_item_index {
                        self.active_item_index += 1;
                    }
                }

                cx.notify();
            }

            self.activate_item(insertion_index, activate_pane, focus_item, cx);
        } else {
            self.items.insert(insertion_index, item.clone());
            if insertion_index <= self.active_item_index {
                self.active_item_index += 1;
            }

            self.activate_item(insertion_index, activate_pane, focus_item, cx);
            cx.notify();
        }

        cx.emit(Event::AddItem { item });
    }

    pub fn items_len(&self) -> usize {
        self.items.len()
    }

    pub fn items(&self) -> impl Iterator<Item = &Box<dyn ItemHandle>> + DoubleEndedIterator {
        self.items.iter()
    }

    //     pub fn items_of_type<T: View>(&self) -> impl '_ + Iterator<Item = ViewHandle<T>> {
    //         self.items
    //             .iter()
    //             .filter_map(|item| item.as_any().clone().downcast())
    //     }

    pub fn active_item(&self) -> Option<Box<dyn ItemHandle>> {
        self.items.get(self.active_item_index).cloned()
    }

    //     pub fn pixel_position_of_cursor(&self, cx: &AppContext) -> Option<Vector2F> {
    //         self.items
    //             .get(self.active_item_index)?
    //             .pixel_position_of_cursor(cx)
    //     }

    pub fn item_for_entry(
        &self,
        entry_id: ProjectEntryId,
        cx: &AppContext,
    ) -> Option<Box<dyn ItemHandle>> {
        self.items.iter().find_map(|item| {
            if item.is_singleton(cx) && item.project_entry_ids(cx).as_slice() == [entry_id] {
                Some(item.boxed_clone())
            } else {
                None
            }
        })
    }

    pub fn index_for_item(&self, item: &dyn ItemHandle) -> Option<usize> {
        self.items.iter().position(|i| i.id() == item.id())
    }

    //     pub fn toggle_zoom(&mut self, _: &ToggleZoom, cx: &mut ViewContext<Self>) {
    //         // Potentially warn the user of the new keybinding
    //         let workspace_handle = self.workspace().clone();
    //         cx.spawn(|_, mut cx| async move { notify_of_new_dock(&workspace_handle, &mut cx) })
    //             .detach();

    //         if self.zoomed {
    //             cx.emit(Event::ZoomOut);
    //         } else if !self.items.is_empty() {
    //             if !self.has_focus {
    //                 cx.focus_self();
    //             }
    //             cx.emit(Event::ZoomIn);
    //         }
    //     }

    pub fn activate_item(
        &mut self,
        index: usize,
        activate_pane: bool,
        focus_item: bool,
        cx: &mut ViewContext<Self>,
    ) {
        use NavigationMode::{GoingBack, GoingForward};

        if index < self.items.len() {
            let prev_active_item_ix = mem::replace(&mut self.active_item_index, index);
            if prev_active_item_ix != self.active_item_index
                || matches!(self.nav_history.mode(), GoingBack | GoingForward)
            {
                if let Some(prev_item) = self.items.get(prev_active_item_ix) {
                    prev_item.deactivated(cx);
                }

                cx.emit(Event::ActivateItem {
                    local: activate_pane,
                });
            }

            if let Some(newly_active_item) = self.items.get(index) {
                self.activation_history
                    .retain(|&previously_active_item_id| {
                        previously_active_item_id != newly_active_item.id()
                    });
                self.activation_history.push(newly_active_item.id());
            }

            self.update_toolbar(cx);

            if focus_item {
                self.focus_active_item(cx);
            }

            self.autoscroll = true;
            cx.notify();
        }
    }

    //     pub fn activate_prev_item(&mut self, activate_pane: bool, cx: &mut ViewContext<Self>) {
    //         let mut index = self.active_item_index;
    //         if index > 0 {
    //             index -= 1;
    //         } else if !self.items.is_empty() {
    //             index = self.items.len() - 1;
    //         }
    //         self.activate_item(index, activate_pane, activate_pane, cx);
    //     }

    //     pub fn activate_next_item(&mut self, activate_pane: bool, cx: &mut ViewContext<Self>) {
    //         let mut index = self.active_item_index;
    //         if index + 1 < self.items.len() {
    //             index += 1;
    //         } else {
    //             index = 0;
    //         }
    //         self.activate_item(index, activate_pane, activate_pane, cx);
    //     }

    pub fn close_active_item(
        &mut self,
        action: &CloseActiveItem,
        cx: &mut ViewContext<Self>,
    ) -> Option<Task<Result<()>>> {
        if self.items.is_empty() {
            return None;
        }
        let active_item_id = self.items[self.active_item_index].id();
        Some(self.close_item_by_id(
            active_item_id,
            action.save_intent.unwrap_or(SaveIntent::Close),
            cx,
        ))
    }

    pub fn close_item_by_id(
        &mut self,
        item_id_to_close: EntityId,
        save_intent: SaveIntent,
        cx: &mut ViewContext<Self>,
    ) -> Task<Result<()>> {
        self.close_items(cx, save_intent, move |view_id| view_id == item_id_to_close)
    }

    // pub fn close_inactive_items(
    //     &mut self,
    //     _: &CloseInactiveItems,
    //     cx: &mut ViewContext<Self>,
    // ) -> Option<Task<Result<()>>> {
    //     if self.items.is_empty() {
    //         return None;
    //     }

    //     let active_item_id = self.items[self.active_item_index].id();
    //     Some(self.close_items(cx, SaveIntent::Close, move |item_id| {
    //         item_id != active_item_id
    //     }))
    // }

    // pub fn close_clean_items(
    //     &mut self,
    //     _: &CloseCleanItems,
    //     cx: &mut ViewContext<Self>,
    // ) -> Option<Task<Result<()>>> {
    //     let item_ids: Vec<_> = self
    //         .items()
    //         .filter(|item| !item.is_dirty(cx))
    //         .map(|item| item.id())
    //         .collect();
    //     Some(self.close_items(cx, SaveIntent::Close, move |item_id| {
    //         item_ids.contains(&item_id)
    //     }))
    // }

    // pub fn close_items_to_the_left(
    //     &mut self,
    //     _: &CloseItemsToTheLeft,
    //     cx: &mut ViewContext<Self>,
    // ) -> Option<Task<Result<()>>> {
    //     if self.items.is_empty() {
    //         return None;
    //     }
    //     let active_item_id = self.items[self.active_item_index].id();
    //     Some(self.close_items_to_the_left_by_id(active_item_id, cx))
    // }

    // pub fn close_items_to_the_left_by_id(
    //     &mut self,
    //     item_id: usize,
    //     cx: &mut ViewContext<Self>,
    // ) -> Task<Result<()>> {
    //     let item_ids: Vec<_> = self
    //         .items()
    //         .take_while(|item| item.id() != item_id)
    //         .map(|item| item.id())
    //         .collect();
    //     self.close_items(cx, SaveIntent::Close, move |item_id| {
    //         item_ids.contains(&item_id)
    //     })
    // }

    // pub fn close_items_to_the_right(
    //     &mut self,
    //     _: &CloseItemsToTheRight,
    //     cx: &mut ViewContext<Self>,
    // ) -> Option<Task<Result<()>>> {
    //     if self.items.is_empty() {
    //         return None;
    //     }
    //     let active_item_id = self.items[self.active_item_index].id();
    //     Some(self.close_items_to_the_right_by_id(active_item_id, cx))
    // }

    // pub fn close_items_to_the_right_by_id(
    //     &mut self,
    //     item_id: usize,
    //     cx: &mut ViewContext<Self>,
    // ) -> Task<Result<()>> {
    //     let item_ids: Vec<_> = self
    //         .items()
    //         .rev()
    //         .take_while(|item| item.id() != item_id)
    //         .map(|item| item.id())
    //         .collect();
    //     self.close_items(cx, SaveIntent::Close, move |item_id| {
    //         item_ids.contains(&item_id)
    //     })
    // }

    // pub fn close_all_items(
    //     &mut self,
    //     action: &CloseAllItems,
    //     cx: &mut ViewContext<Self>,
    // ) -> Option<Task<Result<()>>> {
    //     if self.items.is_empty() {
    //         return None;
    //     }

    //     Some(
    //         self.close_items(cx, action.save_intent.unwrap_or(SaveIntent::Close), |_| {
    //             true
    //         }),
    //     )
    // }

    pub(super) fn file_names_for_prompt(
        items: &mut dyn Iterator<Item = &Box<dyn ItemHandle>>,
        all_dirty_items: usize,
        cx: &AppContext,
    ) -> String {
        /// Quantity of item paths displayed in prompt prior to cutoff..
        const FILE_NAMES_CUTOFF_POINT: usize = 10;
        let mut file_names: Vec<_> = items
            .filter_map(|item| {
                item.project_path(cx).and_then(|project_path| {
                    project_path
                        .path
                        .file_name()
                        .and_then(|name| name.to_str().map(ToOwned::to_owned))
                })
            })
            .take(FILE_NAMES_CUTOFF_POINT)
            .collect();
        let should_display_followup_text =
            all_dirty_items > FILE_NAMES_CUTOFF_POINT || file_names.len() != all_dirty_items;
        if should_display_followup_text {
            let not_shown_files = all_dirty_items - file_names.len();
            if not_shown_files == 1 {
                file_names.push(".. 1 file not shown".into());
            } else {
                file_names.push(format!(".. {} files not shown", not_shown_files).into());
            }
        }
        let file_names = file_names.join("\n");
        format!(
            "Do you want to save changes to the following {} files?\n{file_names}",
            all_dirty_items
        )
    }

    pub fn close_items(
        &mut self,
        cx: &mut ViewContext<Pane>,
        mut save_intent: SaveIntent,
        should_close: impl 'static + Fn(EntityId) -> bool,
    ) -> Task<Result<()>> {
        // Find the items to close.
        let mut items_to_close = Vec::new();
        let mut dirty_items = Vec::new();
        for item in &self.items {
            if should_close(item.id()) {
                items_to_close.push(item.boxed_clone());
                if item.is_dirty(cx) {
                    dirty_items.push(item.boxed_clone());
                }
            }
        }

        // If a buffer is open both in a singleton editor and in a multibuffer, make sure
        // to focus the singleton buffer when prompting to save that buffer, as opposed
        // to focusing the multibuffer, because this gives the user a more clear idea
        // of what content they would be saving.
        items_to_close.sort_by_key(|item| !item.is_singleton(cx));

        let workspace = self.workspace.clone();
        cx.spawn(|pane, mut cx| async move {
            if save_intent == SaveIntent::Close && dirty_items.len() > 1 {
                let answer = pane.update(&mut cx, |_, cx| {
                    let prompt =
                        Self::file_names_for_prompt(&mut dirty_items.iter(), dirty_items.len(), cx);
                    cx.prompt(
                        PromptLevel::Warning,
                        &prompt,
                        &["Save all", "Discard all", "Cancel"],
                    )
                })?;
                match answer.await {
                    Ok(0) => save_intent = SaveIntent::SaveAll,
                    Ok(1) => save_intent = SaveIntent::Skip,
                    _ => {}
                }
            }
            let mut saved_project_items_ids = HashSet::default();
            for item in items_to_close.clone() {
                // Find the item's current index and its set of project item models. Avoid
                // storing these in advance, in case they have changed since this task
                // was started.
                let (item_ix, mut project_item_ids) = pane.update(&mut cx, |pane, cx| {
                    (pane.index_for_item(&*item), item.project_item_model_ids(cx))
                })?;
                let item_ix = if let Some(ix) = item_ix {
                    ix
                } else {
                    continue;
                };

                // Check if this view has any project items that are not open anywhere else
                // in the workspace, AND that the user has not already been prompted to save.
                // If there are any such project entries, prompt the user to save this item.
                let project = workspace.update(&mut cx, |workspace, cx| {
                    for item in workspace.items(cx) {
                        if !items_to_close
                            .iter()
                            .any(|item_to_close| item_to_close.id() == item.id())
                        {
                            let other_project_item_ids = item.project_item_model_ids(cx);
                            project_item_ids.retain(|id| !other_project_item_ids.contains(id));
                        }
                    }
                    workspace.project().clone()
                })?;
                let should_save = project_item_ids
                    .iter()
                    .any(|id| saved_project_items_ids.insert(*id));

                if should_save
                    && !Self::save_item(
                        project.clone(),
                        &pane,
                        item_ix,
                        &*item,
                        save_intent,
                        &mut cx,
                    )
                    .await?
                {
                    break;
                }

                // Remove the item from the pane.
                pane.update(&mut cx, |pane, cx| {
                    if let Some(item_ix) = pane.items.iter().position(|i| i.id() == item.id()) {
                        pane.remove_item(item_ix, false, cx);
                    }
                })?;
            }

            pane.update(&mut cx, |_, cx| cx.notify())?;
            Ok(())
        })
    }

    pub fn remove_item(
        &mut self,
        item_index: usize,
        activate_pane: bool,
        cx: &mut ViewContext<Self>,
    ) {
        self.activation_history
            .retain(|&history_entry| history_entry != self.items[item_index].id());

        if item_index == self.active_item_index {
            let index_to_activate = self
                .activation_history
                .pop()
                .and_then(|last_activated_item| {
                    self.items.iter().enumerate().find_map(|(index, item)| {
                        (item.id() == last_activated_item).then_some(index)
                    })
                })
                // We didn't have a valid activation history entry, so fallback
                // to activating the item to the left
                .unwrap_or_else(|| item_index.min(self.items.len()).saturating_sub(1));

            let should_activate = activate_pane || self.has_focus(cx);
            self.activate_item(index_to_activate, should_activate, should_activate, cx);
        }

        let item = self.items.remove(item_index);

        cx.emit(Event::RemoveItem { item_id: item.id() });
        if self.items.is_empty() {
            item.deactivated(cx);
            self.update_toolbar(cx);
            cx.emit(Event::Remove);
        }

        if item_index < self.active_item_index {
            self.active_item_index -= 1;
        }

        self.nav_history.set_mode(NavigationMode::ClosingItem);
        item.deactivated(cx);
        self.nav_history.set_mode(NavigationMode::Normal);

        if let Some(path) = item.project_path(cx) {
            let abs_path = self
                .nav_history
                .0
                .lock()
                .paths_by_item
                .get(&item.id())
                .and_then(|(_, abs_path)| abs_path.clone());

            self.nav_history
                .0
                .lock()
                .paths_by_item
                .insert(item.id(), (path, abs_path));
        } else {
            self.nav_history.0.lock().paths_by_item.remove(&item.id());
        }

        if self.items.is_empty() && self.zoomed {
            cx.emit(Event::ZoomOut);
        }

        cx.notify();
    }

    pub async fn save_item(
        project: Model<Project>,
        pane: &WeakView<Pane>,
        item_ix: usize,
        item: &dyn ItemHandle,
        save_intent: SaveIntent,
        cx: &mut AsyncWindowContext,
    ) -> Result<bool> {
        const CONFLICT_MESSAGE: &str =
                "This file has changed on disk since you started editing it. Do you want to overwrite it?";

        if save_intent == SaveIntent::Skip {
            return Ok(true);
        }

        let (mut has_conflict, mut is_dirty, mut can_save, can_save_as) = cx.update(|_, cx| {
            (
                item.has_conflict(cx),
                item.is_dirty(cx),
                item.can_save(cx),
                item.is_singleton(cx),
            )
        })?;

        // when saving a single buffer, we ignore whether or not it's dirty.
        if save_intent == SaveIntent::Save {
            is_dirty = true;
        }

        if save_intent == SaveIntent::SaveAs {
            is_dirty = true;
            has_conflict = false;
            can_save = false;
        }

        if save_intent == SaveIntent::Overwrite {
            has_conflict = false;
        }

        if has_conflict && can_save {
            let answer = pane.update(cx, |pane, cx| {
                pane.activate_item(item_ix, true, true, cx);
                cx.prompt(
                    PromptLevel::Warning,
                    CONFLICT_MESSAGE,
                    &["Overwrite", "Discard", "Cancel"],
                )
            })?;
            match answer.await {
                Ok(0) => pane.update(cx, |_, cx| item.save(project, cx))?.await?,
                Ok(1) => pane.update(cx, |_, cx| item.reload(project, cx))?.await?,
                _ => return Ok(false),
            }
        } else if is_dirty && (can_save || can_save_as) {
            if save_intent == SaveIntent::Close {
                let will_autosave = cx.update(|_, cx| {
                    matches!(
                        WorkspaceSettings::get_global(cx).autosave,
                        AutosaveSetting::OnFocusChange | AutosaveSetting::OnWindowChange
                    ) && Self::can_autosave_item(&*item, cx)
                })?;
                if !will_autosave {
                    let answer = pane.update(cx, |pane, cx| {
                        pane.activate_item(item_ix, true, true, cx);
                        let prompt = dirty_message_for(item.project_path(cx));
                        cx.prompt(
                            PromptLevel::Warning,
                            &prompt,
                            &["Save", "Don't Save", "Cancel"],
                        )
                    })?;
                    match answer.await {
                        Ok(0) => {}
                        Ok(1) => return Ok(true), // Don't save this file
                        _ => return Ok(false),    // Cancel
                    }
                }
            }

            if can_save {
                pane.update(cx, |_, cx| item.save(project, cx))?.await?;
            } else if can_save_as {
                let start_abs_path = project
                    .update(cx, |project, cx| {
                        let worktree = project.visible_worktrees(cx).next()?;
                        Some(worktree.read(cx).as_local()?.abs_path().to_path_buf())
                    })?
                    .unwrap_or_else(|| Path::new("").into());

                let abs_path = cx.update(|_, cx| cx.prompt_for_new_path(&start_abs_path))?;
                if let Some(abs_path) = abs_path.await.ok().flatten() {
                    pane.update(cx, |_, cx| item.save_as(project, abs_path, cx))?
                        .await?;
                } else {
                    return Ok(false);
                }
            }
        }
        Ok(true)
    }

    fn can_autosave_item(item: &dyn ItemHandle, cx: &AppContext) -> bool {
        let is_deleted = item.project_entry_ids(cx).is_empty();
        item.is_dirty(cx) && !item.has_conflict(cx) && item.can_save(cx) && !is_deleted
    }

    pub fn autosave_item(
        item: &dyn ItemHandle,
        project: Model<Project>,
        cx: &mut WindowContext,
    ) -> Task<Result<()>> {
        if Self::can_autosave_item(item, cx) {
            item.save(project, cx)
        } else {
            Task::ready(Ok(()))
        }
    }

    pub fn focus(&mut self, cx: &mut ViewContext<Pane>) {
        cx.focus(&self.focus_handle);
    }

    pub fn focus_active_item(&mut self, cx: &mut ViewContext<Self>) {
        if let Some(active_item) = self.active_item() {
            let focus_handle = active_item.focus_handle(cx);
            cx.focus(&focus_handle);
        }
    }

    //     pub fn split(&mut self, direction: SplitDirection, cx: &mut ViewContext<Self>) {
    //         cx.emit(Event::Split(direction));
    //     }

    //     fn deploy_split_menu(&mut self, cx: &mut ViewContext<Self>) {
    //         self.tab_bar_context_menu.handle.update(cx, |menu, cx| {
    //             menu.toggle(
    //                 Default::default(),
    //                 AnchorCorner::TopRight,
    //                 vec![
    //                     ContextMenuItem::action("Split Right", SplitRight),
    //                     ContextMenuItem::action("Split Left", SplitLeft),
    //                     ContextMenuItem::action("Split Up", SplitUp),
    //                     ContextMenuItem::action("Split Down", SplitDown),
    //                 ],
    //                 cx,
    //             );
    //         });

    //         self.tab_bar_context_menu.kind = TabBarContextMenuKind::Split;
    //     }

    //     fn deploy_new_menu(&mut self, cx: &mut ViewContext<Self>) {
    //         self.tab_bar_context_menu.handle.update(cx, |menu, cx| {
    //             menu.toggle(
    //                 Default::default(),
    //                 AnchorCorner::TopRight,
    //                 vec![
    //                     ContextMenuItem::action("New File", NewFile),
    //                     ContextMenuItem::action("New Terminal", NewCenterTerminal),
    //                     ContextMenuItem::action("New Search", NewSearch),
    //                 ],
    //                 cx,
    //             );
    //         });

    //         self.tab_bar_context_menu.kind = TabBarContextMenuKind::New;
    //     }

    //     fn deploy_tab_context_menu(
    //         &mut self,
    //         position: Vector2F,
    //         target_item_id: usize,
    //         cx: &mut ViewContext<Self>,
    //     ) {
    //         let active_item_id = self.items[self.active_item_index].id();
    //         let is_active_item = target_item_id == active_item_id;
    //         let target_pane = cx.weak_handle();

    //         // The `CloseInactiveItems` action should really be called "CloseOthers" and the behaviour should be dynamically based on the tab the action is ran on.  Currently, this is a weird action because you can run it on a non-active tab and it will close everything by the actual active tab

    //         self.tab_context_menu.update(cx, |menu, cx| {
    //             menu.show(
    //                 position,
    //                 AnchorCorner::TopLeft,
    //                 if is_active_item {
    //                     vec![
    //                         ContextMenuItem::action(
    //                             "Close Active Item",
    //                             CloseActiveItem { save_intent: None },
    //                         ),
    //                         ContextMenuItem::action("Close Inactive Items", CloseInactiveItems),
    //                         ContextMenuItem::action("Close Clean Items", CloseCleanItems),
    //                         ContextMenuItem::action("Close Items To The Left", CloseItemsToTheLeft),
    //                         ContextMenuItem::action("Close Items To The Right", CloseItemsToTheRight),
    //                         ContextMenuItem::action(
    //                             "Close All Items",
    //                             CloseAllItems { save_intent: None },
    //                         ),
    //                     ]
    //                 } else {
    //                     // In the case of the user right clicking on a non-active tab, for some item-closing commands, we need to provide the id of the tab, for the others, we can reuse the existing command.
    //                     vec![
    //                         ContextMenuItem::handler("Close Inactive Item", {
    //                             let pane = target_pane.clone();
    //                             move |cx| {
    //                                 if let Some(pane) = pane.upgrade(cx) {
    //                                     pane.update(cx, |pane, cx| {
    //                                         pane.close_item_by_id(
    //                                             target_item_id,
    //                                             SaveIntent::Close,
    //                                             cx,
    //                                         )
    //                                         .detach_and_log_err(cx);
    //                                     })
    //                                 }
    //                             }
    //                         }),
    //                         ContextMenuItem::action("Close Inactive Items", CloseInactiveItems),
    //                         ContextMenuItem::action("Close Clean Items", CloseCleanItems),
    //                         ContextMenuItem::handler("Close Items To The Left", {
    //                             let pane = target_pane.clone();
    //                             move |cx| {
    //                                 if let Some(pane) = pane.upgrade(cx) {
    //                                     pane.update(cx, |pane, cx| {
    //                                         pane.close_items_to_the_left_by_id(target_item_id, cx)
    //                                             .detach_and_log_err(cx);
    //                                     })
    //                                 }
    //                             }
    //                         }),
    //                         ContextMenuItem::handler("Close Items To The Right", {
    //                             let pane = target_pane.clone();
    //                             move |cx| {
    //                                 if let Some(pane) = pane.upgrade(cx) {
    //                                     pane.update(cx, |pane, cx| {
    //                                         pane.close_items_to_the_right_by_id(target_item_id, cx)
    //                                             .detach_and_log_err(cx);
    //                                     })
    //                                 }
    //                             }
    //                         }),
    //                         ContextMenuItem::action(
    //                             "Close All Items",
    //                             CloseAllItems { save_intent: None },
    //                         ),
    //                     ]
    //                 },
    //                 cx,
    //             );
    //         });
    //     }

    pub fn toolbar(&self) -> &View<Toolbar> {
        &self.toolbar
    }

    pub fn handle_deleted_project_item(
        &mut self,
        entry_id: ProjectEntryId,
        cx: &mut ViewContext<Pane>,
    ) -> Option<()> {
        let (item_index_to_delete, item_id) = self.items().enumerate().find_map(|(i, item)| {
            if item.is_singleton(cx) && item.project_entry_ids(cx).as_slice() == [entry_id] {
                Some((i, item.id()))
            } else {
                None
            }
        })?;

        self.remove_item(item_index_to_delete, false, cx);
        self.nav_history.remove_item(item_id);

        Some(())
    }

    fn update_toolbar(&mut self, cx: &mut ViewContext<Self>) {
        let active_item = self
            .items
            .get(self.active_item_index)
            .map(|item| item.as_ref());
        self.toolbar.update(cx, |toolbar, cx| {
            toolbar.set_active_item(active_item, cx);
        });
    }

    fn render_tab(
        &self,
        ix: usize,
        item: &Box<dyn ItemHandle>,
        detail: usize,
        cx: &mut ViewContext<'_, Pane>,
    ) -> impl Component<Self> {
        let label = item.tab_content(Some(detail), cx);
        let close_icon = || {
            let id = item.id();

            div()
                .id(item.id())
                .invisible()
                .group_hover("", |style| style.visible())
                .child(IconButton::new("close_tab", Icon::Close).on_click(
                    move |pane: &mut Self, cx| {
                        pane.close_item_by_id(id, SaveIntent::Close, cx)
                            .detach_and_log_err(cx);
                    },
                ))
        };

        let (text_color, tab_bg, tab_hover_bg, tab_active_bg) = match ix == self.active_item_index {
            false => (
                cx.theme().colors().text_muted,
                cx.theme().colors().tab_inactive_background,
                cx.theme().colors().ghost_element_hover,
                cx.theme().colors().ghost_element_active,
            ),
            true => (
                cx.theme().colors().text,
                cx.theme().colors().tab_active_background,
                cx.theme().colors().element_hover,
                cx.theme().colors().element_active,
            ),
        };

        let close_right = ItemSettings::get_global(cx).close_position.right();

        div()
            .group("")
            .id(item.id())
            .cursor_pointer()
            .when_some(item.tab_tooltip_text(cx), |div, text| {
                div.tooltip(move |_, cx| cx.build_view(|cx| TextTooltip::new(text.clone())))
            })
            // .on_drag(move |pane, cx| pane.render_tab(ix, item.boxed_clone(), detail, cx))
            // .drag_over::<DraggedTab>(|d| d.bg(cx.theme().colors().element_drop_target))
            // .on_drop(|_view, state: View<DraggedTab>, cx| {
            //     eprintln!("{:?}", state.read(cx));
            // })
            .flex()
            .items_center()
            .justify_center()
            // todo!("Nate - I need to do some work to balance all the items in the tab once things stablize")
            .map(|this| {
                if close_right {
                    this.pl_3().pr_1()
                } else {
                    this.pr_1().pr_3()
                }
            })
            .py_1()
            .bg(tab_bg)
            .border_color(cx.theme().colors().border)
            .map(|this| match ix.cmp(&self.active_item_index) {
                cmp::Ordering::Less => this.border_l(),
                cmp::Ordering::Equal => this.border_r(),
                cmp::Ordering::Greater => this.border_l().border_r(),
            })
            // .hover(|h| h.bg(tab_hover_bg))
            // .active(|a| a.bg(tab_active_bg))
            .child(
                div()
                    .flex()
                    .items_center()
                    .gap_1()
                    .text_color(text_color)
                    .children(if item.has_conflict(cx) {
                        Some(
                            IconElement::new(Icon::ExclamationTriangle)
                                .size(ui::IconSize::Small)
                                .color(TextColor::Warning),
                        )
                    } else if item.is_dirty(cx) {
                        Some(
                            IconElement::new(Icon::ExclamationTriangle)
                                .size(ui::IconSize::Small)
                                .color(TextColor::Info),
                        )
                    } else {
                        None
                    })
                    .children(if !close_right {
                        Some(close_icon())
                    } else {
                        None
                    })
                    .child(label)
                    .children(if close_right {
                        Some(close_icon())
                    } else {
                        None
                    }),
            )
    }

    fn render_tab_bar(&mut self, cx: &mut ViewContext<'_, Pane>) -> impl Component<Self> {
        div()
            .group("tab_bar")
            .id("tab_bar")
            .w_full()
            .flex()
            .bg(cx.theme().colors().tab_bar_background)
            // Left Side
            .child(
                div()
                    .relative()
                    .px_1()
                    .flex()
                    .flex_none()
                    .gap_2()
                    // Nav Buttons
                    .child(
                        div()
                            .right_0()
                            .flex()
                            .items_center()
                            .gap_px()
                            .child(IconButton::new("navigate_backward", Icon::ArrowLeft).state(
                                InteractionState::Enabled.if_enabled(self.can_navigate_backward()),
                            ))
                            .child(IconButton::new("navigate_forward", Icon::ArrowRight).state(
                                InteractionState::Enabled.if_enabled(self.can_navigate_forward()),
                            )),
                    ),
            )
            .child(
                div().flex_1().h_full().child(
                    div().id("tabs").flex().overflow_x_scroll().children(
                        self.items
                            .iter()
                            .enumerate()
                            .zip(self.tab_details(cx))
                            .map(|((ix, item), detail)| self.render_tab(ix, item, detail, cx)),
                    ),
                ),
            )
            // Right Side
            .child(
                div()
                    // We only use absolute here since we don't
                    // have opacity or `hidden()` yet
                    .absolute()
                    .neg_top_7()
                    .px_1()
                    .flex()
                    .flex_none()
                    .gap_2()
                    .group_hover("tab_bar", |this| this.top_0())
                    // Nav Buttons
                    .child(
                        div()
                            .flex()
                            .items_center()
                            .gap_px()
                            .child(IconButton::new("plus", Icon::Plus))
                            .child(IconButton::new("split", Icon::Split)),
                    ),
            )
    }

    //     fn render_tabs(&mut self, cx: &mut ViewContext<Self>) -> impl Element<Self> {
    //         let theme = theme::current(cx).clone();

    //         let pane = cx.handle().downgrade();
    //         let autoscroll = if mem::take(&mut self.autoscroll) {
    //             Some(self.active_item_index)
    //         } else {
    //             None
    //         };

    //         let pane_active = self.has_focus;

    //         enum Tabs {}
    //         let mut row = Flex::row().scrollable::<Tabs>(1, autoscroll, cx);
    //         for (ix, (item, detail)) in self
    //             .items
    //             .iter()
    //             .cloned()
    //             .zip(self.tab_details(cx))
    //             .enumerate()
    //         {
    //             let git_status = item
    //                 .project_path(cx)
    //                 .and_then(|path| self.project.read(cx).entry_for_path(&path, cx))
    //                 .and_then(|entry| entry.git_status());

    //             let detail = if detail == 0 { None } else { Some(detail) };
    //             let tab_active = ix == self.active_item_index;

    //             row.add_child({
    //                 enum TabDragReceiver {}
    //                 let mut receiver =
    //                     dragged_item_receiver::<TabDragReceiver, _, _>(self, ix, ix, true, None, cx, {
    //                         let item = item.clone();
    //                         let pane = pane.clone();
    //                         let detail = detail.clone();

    //                         let theme = theme::current(cx).clone();
    //                         let mut tooltip_theme = theme.tooltip.clone();
    //                         tooltip_theme.max_text_width = None;
    //                         let tab_tooltip_text =
    //                             item.tab_tooltip_text(cx).map(|text| text.into_owned());

    //                         let mut tab_style = theme
    //                             .workspace
    //                             .tab_bar
    //                             .tab_style(pane_active, tab_active)
    //                             .clone();
    //                         let should_show_status = settings::get::<ItemSettings>(cx).git_status;
    //                         if should_show_status && git_status != None {
    //                             tab_style.label.text.color = match git_status.unwrap() {
    //                                 GitFileStatus::Added => tab_style.git.inserted,
    //                                 GitFileStatus::Modified => tab_style.git.modified,
    //                                 GitFileStatus::Conflict => tab_style.git.conflict,
    //                             };
    //                         }

    //                         move |mouse_state, cx| {
    //                             let hovered = mouse_state.hovered();

    //                             enum Tab {}
    //                             let mouse_event_handler =
    //                                 MouseEventHandler::new::<Tab, _>(ix, cx, |_, cx| {
    //                                     Self::render_tab(
    //                                         &item,
    //                                         pane.clone(),
    //                                         ix == 0,
    //                                         detail,
    //                                         hovered,
    //                                         &tab_style,
    //                                         cx,
    //                                     )
    //                                 })
    //                                 .on_down(MouseButton::Left, move |_, this, cx| {
    //                                     this.activate_item(ix, true, true, cx);
    //                                 })
    //                                 .on_click(MouseButton::Middle, {
    //                                     let item_id = item.id();
    //                                     move |_, pane, cx| {
    //                                         pane.close_item_by_id(item_id, SaveIntent::Close, cx)
    //                                             .detach_and_log_err(cx);
    //                                     }
    //                                 })
    //                                 .on_down(
    //                                     MouseButton::Right,
    //                                     move |event, pane, cx| {
    //                                         pane.deploy_tab_context_menu(event.position, item.id(), cx);
    //                                     },
    //                                 );

    //                             if let Some(tab_tooltip_text) = tab_tooltip_text {
    //                                 mouse_event_handler
    //                                     .with_tooltip::<Self>(
    //                                         ix,
    //                                         tab_tooltip_text,
    //                                         None,
    //                                         tooltip_theme,
    //                                         cx,
    //                                     )
    //                                     .into_any()
    //                             } else {
    //                                 mouse_event_handler.into_any()
    //                             }
    //                         }
    //                     });

    //                 if !pane_active || !tab_active {
    //                     receiver = receiver.with_cursor_style(CursorStyle::PointingHand);
    //                 }

    //                 receiver.as_draggable(
    //                     DraggedItem {
    //                         handle: item,
    //                         pane: pane.clone(),
    //                     },
    //                     {
    //                         let theme = theme::current(cx).clone();

    //                         let detail = detail.clone();
    //                         move |_, dragged_item: &DraggedItem, cx: &mut ViewContext<Workspace>| {
    //                             let tab_style = &theme.workspace.tab_bar.dragged_tab;
    //                             Self::render_dragged_tab(
    //                                 &dragged_item.handle,
    //                                 dragged_item.pane.clone(),
    //                                 false,
    //                                 detail,
    //                                 false,
    //                                 &tab_style,
    //                                 cx,
    //                             )
    //                         }
    //                     },
    //                 )
    //             })
    //         }

    //         // Use the inactive tab style along with the current pane's active status to decide how to render
    //         // the filler
    //         let filler_index = self.items.len();
    //         let filler_style = theme.workspace.tab_bar.tab_style(pane_active, false);
    //         enum Filler {}
    //         row.add_child(
    //             dragged_item_receiver::<Filler, _, _>(self, 0, filler_index, true, None, cx, |_, _| {
    //                 Empty::new()
    //                     .contained()
    //                     .with_style(filler_style.container)
    //                     .with_border(filler_style.container.border)
    //             })
    //             .flex(1., true)
    //             .into_any_named("filler"),
    //         );

    //         row
    //     }

    fn tab_details(&self, cx: &AppContext) -> Vec<usize> {
        let mut tab_details = self.items.iter().map(|_| 0).collect::<Vec<_>>();

        let mut tab_descriptions = HashMap::default();
        let mut done = false;
        while !done {
            done = true;

            // Store item indices by their tab description.
            for (ix, (item, detail)) in self.items.iter().zip(&tab_details).enumerate() {
                if let Some(description) = item.tab_description(*detail, cx) {
                    if *detail == 0
                        || Some(&description) != item.tab_description(detail - 1, cx).as_ref()
                    {
                        tab_descriptions
                            .entry(description)
                            .or_insert(Vec::new())
                            .push(ix);
                    }
                }
            }

            // If two or more items have the same tab description, increase eir level
            // of detail and try again.
            for (_, item_ixs) in tab_descriptions.drain() {
                if item_ixs.len() > 1 {
                    done = false;
                    for ix in item_ixs {
                        tab_details[ix] += 1;
                    }
                }
            }
        }

        tab_details
    }

    //     fn render_tab(
    //         item: &Box<dyn ItemHandle>,
    //         pane: WeakView<Pane>,
    //         first: bool,
    //         detail: Option<usize>,
    //         hovered: bool,
    //         tab_style: &theme::Tab,
    //         cx: &mut ViewContext<Self>,
    //     ) -> AnyElement<Self> {
    //         let title = item.tab_content(detail, &tab_style, cx);
    //         Self::render_tab_with_title(title, item, pane, first, hovered, tab_style, cx)
    //     }

    //     fn render_dragged_tab(
    //         item: &Box<dyn ItemHandle>,
    //         pane: WeakView<Pane>,
    //         first: bool,
    //         detail: Option<usize>,
    //         hovered: bool,
    //         tab_style: &theme::Tab,
    //         cx: &mut ViewContext<Workspace>,
    //     ) -> AnyElement<Workspace> {
    //         let title = item.dragged_tab_content(detail, &tab_style, cx);
    //         Self::render_tab_with_title(title, item, pane, first, hovered, tab_style, cx)
    //     }

    //     fn render_tab_with_title<T: View>(
    //         title: AnyElement<T>,
    //         item: &Box<dyn ItemHandle>,
    //         pane: WeakView<Pane>,
    //         first: bool,
    //         hovered: bool,
    //         tab_style: &theme::Tab,
    //         cx: &mut ViewContext<T>,
    //     ) -> AnyElement<T> {
    //         let mut container = tab_style.container.clone();
    //         if first {
    //             container.border.left = false;
    //         }

    //         let buffer_jewel_element = {
    //             let diameter = 7.0;
    //             let icon_color = if item.has_conflict(cx) {
    //                 Some(tab_style.icon_conflict)
    //             } else if item.is_dirty(cx) {
    //                 Some(tab_style.icon_dirty)
    //             } else {
    //                 None
    //             };

    //             Canvas::new(move |bounds, _, _, cx| {
    //                 if let Some(color) = icon_color {
    //                     let square = RectF::new(bounds.origin(), vec2f(diameter, diameter));
    //                     cx.scene().push_quad(Quad {
    //                         bounds: square,
    //                         background: Some(color),
    //                         border: Default::default(),
    //                         corner_radii: (diameter / 2.).into(),
    //                     });
    //                 }
    //             })
    //             .constrained()
    //             .with_width(diameter)
    //             .with_height(diameter)
    //             .aligned()
    //         };

    //         let title_element = title.aligned().contained().with_style(ContainerStyle {
    //             margin: Margin {
    //                 left: tab_style.spacing,
    //                 right: tab_style.spacing,
    //                 ..Default::default()
    //             },
    //             ..Default::default()
    //         });

    //         let close_element = if hovered {
    //             let item_id = item.id();
    //             enum TabCloseButton {}
    //             let icon = Svg::new("icons/x.svg");
    //             MouseEventHandler::new::<TabCloseButton, _>(item_id, cx, |mouse_state, _| {
    //                 if mouse_state.hovered() {
    //                     icon.with_color(tab_style.icon_close_active)
    //                 } else {
    //                     icon.with_color(tab_style.icon_close)
    //                 }
    //             })
    //             .with_padding(Padding::uniform(4.))
    //             .with_cursor_style(CursorStyle::PointingHand)
    //             .on_click(MouseButton::Left, {
    //                 let pane = pane.clone();
    //                 move |_, _, cx| {
    //                     let pane = pane.clone();
    //                     cx.window_context().defer(move |cx| {
    //                         if let Some(pane) = pane.upgrade(cx) {
    //                             pane.update(cx, |pane, cx| {
    //                                 pane.close_item_by_id(item_id, SaveIntent::Close, cx)
    //                                     .detach_and_log_err(cx);
    //                             });
    //                         }
    //                     });
    //                 }
    //             })
    //             .into_any_named("close-tab-icon")
    //             .constrained()
    //         } else {
    //             Empty::new().constrained()
    //         }
    //         .with_width(tab_style.close_icon_width)
    //         .aligned();

    //         let close_right = settings::get::<ItemSettings>(cx).close_position.right();

    //         if close_right {
    //             Flex::row()
    //                 .with_child(buffer_jewel_element)
    //                 .with_child(title_element)
    //                 .with_child(close_element)
    //         } else {
    //             Flex::row()
    //                 .with_child(close_element)
    //                 .with_child(title_element)
    //                 .with_child(buffer_jewel_element)
    //         }
    //         .contained()
    //         .with_style(container)
    //         .constrained()
    //         .with_height(tab_style.height)
    //         .into_any()
    //     }

    //     pub fn render_tab_bar_button<
    //         F1: 'static + Fn(&mut Pane, &mut EventContext<Pane>),
    //         F2: 'static + Fn(&mut Pane, &mut EventContext<Pane>),
    //     >(
    //         index: usize,
    //         icon: &'static str,
    //         is_active: bool,
    //         tooltip: Option<(&'static str, Option<Box<dyn Action>>)>,
    //         cx: &mut ViewContext<Pane>,
    //         on_click: F1,
    //         on_down: F2,
    //         context_menu: Option<ViewHandle<ContextMenu>>,
    //     ) -> AnyElement<Pane> {
    //         enum TabBarButton {}

    //         let mut button = MouseEventHandler::new::<TabBarButton, _>(index, cx, |mouse_state, cx| {
    //             let theme = &settings2::get::<ThemeSettings>(cx).theme.workspace.tab_bar;
    //             let style = theme.pane_button.in_state(is_active).style_for(mouse_state);
    //             Svg::new(icon)
    //                 .with_color(style.color)
    //                 .constrained()
    //                 .with_width(style.icon_width)
    //                 .aligned()
    //                 .constrained()
    //                 .with_width(style.button_width)
    //                 .with_height(style.button_width)
    //         })
    //         .with_cursor_style(CursorStyle::PointingHand)
    //         .on_down(MouseButton::Left, move |_, pane, cx| on_down(pane, cx))
    //         .on_click(MouseButton::Left, move |_, pane, cx| on_click(pane, cx))
    //         .into_any();
    //         if let Some((tooltip, action)) = tooltip {
    //             let tooltip_style = settings::get::<ThemeSettings>(cx).theme.tooltip.clone();
    //             button = button
    //                 .with_tooltip::<TabBarButton>(index, tooltip, action, tooltip_style, cx)
    //                 .into_any();
    //         }

    //         Stack::new()
    //             .with_child(button)
    //             .with_children(
    //                 context_menu.map(|menu| ChildView::new(&menu, cx).aligned().bottom().right()),
    //             )
    //             .flex(1., false)
    //             .into_any_named("tab bar button")
    //     }

    //     fn render_blank_pane(&self, theme: &Theme, _cx: &mut ViewContext<Self>) -> AnyElement<Self> {
    //         let background = theme.workspace.background;
    //         Empty::new()
    //             .contained()
    //             .with_background_color(background)
    //             .into_any()
    //     }

    pub fn set_zoomed(&mut self, zoomed: bool, cx: &mut ViewContext<Self>) {
        self.zoomed = zoomed;
        cx.notify();
    }

    pub fn is_zoomed(&self) -> bool {
        self.zoomed
    }
}

// impl Entity for Pane {
//     type Event = Event;
// }

impl Render for Pane {
    type Element = Div<Self>;

    fn render(&mut self, cx: &mut ViewContext<Self>) -> Self::Element {
        v_stack()
            .key_context("Pane")
            .size_full()
            .on_action(|pane: &mut Self, action, cx| {
                pane.close_active_item(action, cx)
                    .map(|task| task.detach_and_log_err(cx));
            })
            .child(self.render_tab_bar(cx))
            .child(div() /* todo!(toolbar) */)
            .child(if let Some(item) = self.active_item() {
                div().flex_1().child(item.to_any())
            } else {
                // todo!()
                div().child("Empty Pane")
            })

        // enum MouseNavigationHandler {}

        // MouseEventHandler::new::<MouseNavigationHandler, _>(0, cx, |_, cx| {
        //     let active_item_index = self.active_item_index;

        //     if let Some(active_item) = self.active_item() {
        //         Flex::column()
        //             .with_child({
        //                 let theme = theme::current(cx).clone();

        //                 let mut stack = Stack::new();

        //                 enum TabBarEventHandler {}
        //                 stack.add_child(
        //                     MouseEventHandler::new::<TabBarEventHandler, _>(0, cx, |_, _| {
        //                         Empty::new()
        //                             .contained()
        //                             .with_style(theme.workspace.tab_bar.container)
        //                     })
        //                     .on_down(
        //                         MouseButton::Left,
        //                         move |_, this, cx| {
        //                             this.activate_item(active_item_index, true, true, cx);
        //                         },
        //                     ),
        //                 );
        //                 let tooltip_style = theme.tooltip.clone();
        //                 let tab_bar_theme = theme.workspace.tab_bar.clone();

        //                 let nav_button_height = tab_bar_theme.height;
        //                 let button_style = tab_bar_theme.nav_button;
        //                 let border_for_nav_buttons = tab_bar_theme
        //                     .tab_style(false, false)
        //                     .container
        //                     .border
        //                     .clone();

        //                 let mut tab_row = Flex::row()
        //                     .with_child(nav_button(
        //                         "icons/arrow_left.svg",
        //                         button_style.clone(),
        //                         nav_button_height,
        //                         tooltip_style.clone(),
        //                         self.can_navigate_backward(),
        //                         {
        //                             move |pane, cx| {
        //                                 if let Some(workspace) = pane.workspace.upgrade(cx) {
        //                                     let pane = cx.weak_handle();
        //                                     cx.window_context().defer(move |cx| {
        //                                         workspace.update(cx, |workspace, cx| {
        //                                             workspace
        //                                                 .go_back(pane, cx)
        //                                                 .detach_and_log_err(cx)
        //                                         })
        //                                     })
        //                                 }
        //                             }
        //                         },
        //                         super::GoBack,
        //                         "Go Back",
        //                         cx,
        //                     ))
        //                     .with_child(
        //                         nav_button(
        //                             "icons/arrow_right.svg",
        //                             button_style.clone(),
        //                             nav_button_height,
        //                             tooltip_style,
        //                             self.can_navigate_forward(),
        //                             {
        //                                 move |pane, cx| {
        //                                     if let Some(workspace) = pane.workspace.upgrade(cx) {
        //                                         let pane = cx.weak_handle();
        //                                         cx.window_context().defer(move |cx| {
        //                                             workspace.update(cx, |workspace, cx| {
        //                                                 workspace
        //                                                     .go_forward(pane, cx)
        //                                                     .detach_and_log_err(cx)
        //                                             })
        //                                         })
        //                                     }
        //                                 }
        //                             },
        //                             super::GoForward,
        //                             "Go Forward",
        //                             cx,
        //                         )
        //                         .contained()
        //                         .with_border(border_for_nav_buttons),
        //                     )
        //                     .with_child(self.render_tabs(cx).flex(1., true).into_any_named("tabs"));

        //                 if self.has_focus {
        //                     let render_tab_bar_buttons = self.render_tab_bar_buttons.clone();
        //                     tab_row.add_child(
        //                         (render_tab_bar_buttons)(self, cx)
        //                             .contained()
        //                             .with_style(theme.workspace.tab_bar.pane_button_container)
        //                             .flex(1., false)
        //                             .into_any(),
        //                     )
        //                 }

        //                 stack.add_child(tab_row);
        //                 stack
        //                     .constrained()
        //                     .with_height(theme.workspace.tab_bar.height)
        //                     .flex(1., false)
        //                     .into_any_named("tab bar")
        //             })
        //             .with_child({
        //                 enum PaneContentTabDropTarget {}
        //                 dragged_item_receiver::<PaneContentTabDropTarget, _, _>(
        //                     self,
        //                     0,
        //                     self.active_item_index + 1,
        //                     !self.can_split,
        //                     if self.can_split { Some(100.) } else { None },
        //                     cx,
        //                     {
        //                         let toolbar = self.toolbar.clone();
        //                         let toolbar_hidden = toolbar.read(cx).hidden();
        //                         move |_, cx| {
        //                             Flex::column()
        //                                 .with_children(
        //                                     (!toolbar_hidden)
        //                                         .then(|| ChildView::new(&toolbar, cx).expanded()),
        //                                 )
        //                                 .with_child(
        //                                     ChildView::new(active_item.as_any(), cx).flex(1., true),
        //                                 )
        //                         }
        //                     },
        //                 )
        //                 .flex(1., true)
        //             })
        //             .with_child(ChildView::new(&self.tab_context_menu, cx))
        //             .into_any()
        //     } else {
        //         enum EmptyPane {}
        //         let theme = theme::current(cx).clone();

        //         dragged_item_receiver::<EmptyPane, _, _>(self, 0, 0, false, None, cx, |_, cx| {
        //             self.render_blank_pane(&theme, cx)
        //         })
        //         .on_down(MouseButton::Left, |_, _, cx| {
        //             cx.focus_parent();
        //         })
        //         .into_any()
        //     }
        // })
        // .on_down(
        //     MouseButton::Navigate(NavigationDirection::Back),
        //     move |_, pane, cx| {
        //         if let Some(workspace) = pane.workspace.upgrade(cx) {
        //             let pane = cx.weak_handle();
        //             cx.window_context().defer(move |cx| {
        //                 workspace.update(cx, |workspace, cx| {
        //                     workspace.go_back(pane, cx).detach_and_log_err(cx)
        //                 })
        //             })
        //         }
        //     },
        // )
        // .on_down(MouseButton::Navigate(NavigationDirection::Forward), {
        //     move |_, pane, cx| {
        //         if let Some(workspace) = pane.workspace.upgrade(cx) {
        //             let pane = cx.weak_handle();
        //             cx.window_context().defer(move |cx| {
        //                 workspace.update(cx, |workspace, cx| {
        //                     workspace.go_forward(pane, cx).detach_and_log_err(cx)
        //                 })
        //             })
        //         }
        //     }
        // })
        // .into_any_named("pane")
    }

    // fn focus_in(&mut self, focused: AnyViewHandle, cx: &mut ViewContext<Self>) {
    //     if !self.has_focus {
    //         self.has_focus = true;
    //         cx.emit(Event::Focus);
    //         cx.notify();
    //     }

    //     self.toolbar.update(cx, |toolbar, cx| {
    //         toolbar.focus_changed(true, cx);
    //     });

    //     if let Some(active_item) = self.active_item() {
    //         if cx.is_self_focused() {
    //             // Pane was focused directly. We need to either focus a view inside the active item,
    //             // or focus the active item itself
    //             if let Some(weak_last_focused_view) =
    //                 self.last_focused_view_by_item.get(&active_item.id())
    //             {
    //                 if let Some(last_focused_view) = weak_last_focused_view.upgrade(cx) {
    //                     cx.focus(&last_focused_view);
    //                     return;
    //                 } else {
    //                     self.last_focused_view_by_item.remove(&active_item.id());
    //                 }
    //             }

    //             cx.focus(active_item.as_any());
    //         } else if focused != self.tab_bar_context_menu.handle {
    //             self.last_focused_view_by_item
    //                 .insert(active_item.id(), focused.downgrade());
    //         }
    //     }
    // }

    // fn focus_out(&mut self, _: AnyViewHandle, cx: &mut ViewContext<Self>) {
    //     self.has_focus = false;
    //     self.toolbar.update(cx, |toolbar, cx| {
    //         toolbar.focus_changed(false, cx);
    //     });
    //     cx.notify();
    // }

    // fn update_keymap_context(&self, keymap: &mut KeymapContext, _: &AppContext) {
    //     Self::reset_to_default_keymap_context(keymap);
    // }
}

impl ItemNavHistory {
    pub fn push<D: 'static + Send + Any>(&mut self, data: Option<D>, cx: &mut WindowContext) {
        self.history.push(data, self.item.clone(), cx);
    }

    pub fn pop_backward(&mut self, cx: &mut WindowContext) -> Option<NavigationEntry> {
        self.history.pop(NavigationMode::GoingBack, cx)
    }

    pub fn pop_forward(&mut self, cx: &mut WindowContext) -> Option<NavigationEntry> {
        self.history.pop(NavigationMode::GoingForward, cx)
    }
}

impl NavHistory {
    pub fn for_each_entry(
        &self,
        cx: &AppContext,
        mut f: impl FnMut(&NavigationEntry, (ProjectPath, Option<PathBuf>)),
    ) {
        let borrowed_history = self.0.lock();
        borrowed_history
            .forward_stack
            .iter()
            .chain(borrowed_history.backward_stack.iter())
            .chain(borrowed_history.closed_stack.iter())
            .for_each(|entry| {
                if let Some(project_and_abs_path) =
                    borrowed_history.paths_by_item.get(&entry.item.id())
                {
                    f(entry, project_and_abs_path.clone());
                } else if let Some(item) = entry.item.upgrade() {
                    if let Some(path) = item.project_path(cx) {
                        f(entry, (path, None));
                    }
                }
            })
    }

    pub fn set_mode(&mut self, mode: NavigationMode) {
        self.0.lock().mode = mode;
    }

    pub fn mode(&self) -> NavigationMode {
        self.0.lock().mode
    }

    pub fn disable(&mut self) {
        self.0.lock().mode = NavigationMode::Disabled;
    }

    pub fn enable(&mut self) {
        self.0.lock().mode = NavigationMode::Normal;
    }

    pub fn pop(&mut self, mode: NavigationMode, cx: &mut WindowContext) -> Option<NavigationEntry> {
        let mut state = self.0.lock();
        let entry = match mode {
            NavigationMode::Normal | NavigationMode::Disabled | NavigationMode::ClosingItem => {
                return None
            }
            NavigationMode::GoingBack => &mut state.backward_stack,
            NavigationMode::GoingForward => &mut state.forward_stack,
            NavigationMode::ReopeningClosedItem => &mut state.closed_stack,
        }
        .pop_back();
        if entry.is_some() {
            state.did_update(cx);
        }
        entry
    }

    pub fn push<D: 'static + Send + Any>(
        &mut self,
        data: Option<D>,
        item: Arc<dyn WeakItemHandle>,
        cx: &mut WindowContext,
    ) {
        let state = &mut *self.0.lock();
        match state.mode {
            NavigationMode::Disabled => {}
            NavigationMode::Normal | NavigationMode::ReopeningClosedItem => {
                if state.backward_stack.len() >= MAX_NAVIGATION_HISTORY_LEN {
                    state.backward_stack.pop_front();
                }
                state.backward_stack.push_back(NavigationEntry {
                    item,
                    data: data.map(|data| Box::new(data) as Box<dyn Any + Send>),
                    timestamp: state.next_timestamp.fetch_add(1, Ordering::SeqCst),
                });
                state.forward_stack.clear();
            }
            NavigationMode::GoingBack => {
                if state.forward_stack.len() >= MAX_NAVIGATION_HISTORY_LEN {
                    state.forward_stack.pop_front();
                }
                state.forward_stack.push_back(NavigationEntry {
                    item,
                    data: data.map(|data| Box::new(data) as Box<dyn Any + Send>),
                    timestamp: state.next_timestamp.fetch_add(1, Ordering::SeqCst),
                });
            }
            NavigationMode::GoingForward => {
                if state.backward_stack.len() >= MAX_NAVIGATION_HISTORY_LEN {
                    state.backward_stack.pop_front();
                }
                state.backward_stack.push_back(NavigationEntry {
                    item,
                    data: data.map(|data| Box::new(data) as Box<dyn Any + Send>),
                    timestamp: state.next_timestamp.fetch_add(1, Ordering::SeqCst),
                });
            }
            NavigationMode::ClosingItem => {
                if state.closed_stack.len() >= MAX_NAVIGATION_HISTORY_LEN {
                    state.closed_stack.pop_front();
                }
                state.closed_stack.push_back(NavigationEntry {
                    item,
                    data: data.map(|data| Box::new(data) as Box<dyn Any + Send>),
                    timestamp: state.next_timestamp.fetch_add(1, Ordering::SeqCst),
                });
            }
        }
        state.did_update(cx);
    }

    pub fn remove_item(&mut self, item_id: EntityId) {
        let mut state = self.0.lock();
        state.paths_by_item.remove(&item_id);
        state
            .backward_stack
            .retain(|entry| entry.item.id() != item_id);
        state
            .forward_stack
            .retain(|entry| entry.item.id() != item_id);
        state
            .closed_stack
            .retain(|entry| entry.item.id() != item_id);
    }

    pub fn path_for_item(&self, item_id: EntityId) -> Option<(ProjectPath, Option<PathBuf>)> {
        self.0.lock().paths_by_item.get(&item_id).cloned()
    }
}

impl NavHistoryState {
    pub fn did_update(&self, cx: &mut WindowContext) {
        if let Some(pane) = self.pane.upgrade() {
            cx.defer(move |cx| {
                pane.update(cx, |pane, cx| pane.history_updated(cx));
            });
        }
    }
}

// pub struct PaneBackdrop<V> {
//     child_view: usize,
//     child: AnyElement<V>,
// }

// impl<V> PaneBackdrop<V> {
//     pub fn new(pane_item_view: usize, child: AnyElement<V>) -> Self {
//         PaneBackdrop {
//             child,
//             child_view: pane_item_view,
//         }
//     }
// }

// impl<V: 'static> Element<V> for PaneBackdrop<V> {
//     type LayoutState = ();

//     type PaintState = ();

//     fn layout(
//         &mut self,
//         constraint: gpui::SizeConstraint,
//         view: &mut V,
//         cx: &mut ViewContext<V>,
//     ) -> (Vector2F, Self::LayoutState) {
//         let size = self.child.layout(constraint, view, cx);
//         (size, ())
//     }

//     fn paint(
//         &mut self,
//         bounds: RectF,
//         visible_bounds: RectF,
//         _: &mut Self::LayoutState,
//         view: &mut V,
//         cx: &mut ViewContext<V>,
//     ) -> Self::PaintState {
//         let background = theme::current(cx).editor.background;

//         let visible_bounds = bounds.intersection(visible_bounds).unwrap_or_default();

//         cx.scene().push_quad(gpui::Quad {
//             bounds: RectF::new(bounds.origin(), bounds.size()),
//             background: Some(background),
//             ..Default::default()
//         });

//         let child_view_id = self.child_view;
//         cx.scene().push_mouse_region(
//             MouseRegion::new::<Self>(child_view_id, 0, visible_bounds).on_down(
//                 gpui::platform::MouseButton::Left,
//                 move |_, _: &mut V, cx| {
//                     let window = cx.window();
//                     cx.app_context().focus(window, Some(child_view_id))
//                 },
//             ),
//         );

//         cx.scene().push_layer(Some(bounds));
//         self.child.paint(bounds.origin(), visible_bounds, view, cx);
//         cx.scene().pop_layer();
//     }

//     fn rect_for_text_range(
//         &self,
//         range_utf16: std::ops::Range<usize>,
//         _bounds: RectF,
//         _visible_bounds: RectF,
//         _layout: &Self::LayoutState,
//         _paint: &Self::PaintState,
//         view: &V,
//         cx: &gpui::ViewContext<V>,
//     ) -> Option<RectF> {
//         self.child.rect_for_text_range(range_utf16, view, cx)
//     }

//     fn debug(
//         &self,
//         _bounds: RectF,
//         _layout: &Self::LayoutState,
//         _paint: &Self::PaintState,
//         view: &V,
//         cx: &gpui::ViewContext<V>,
//     ) -> serde_json::Value {
//         gpui::json::json!({
//             "type": "Pane Back Drop",
//             "view": self.child_view,
//             "child": self.child.debug(view, cx),
//         })
//     }
// }

fn dirty_message_for(buffer_path: Option<ProjectPath>) -> String {
    let path = buffer_path
        .as_ref()
        .and_then(|p| p.path.to_str())
        .unwrap_or(&"This buffer");
    let path = truncate_and_remove_front(path, 80);
    format!("{path} contains unsaved edits. Do you want to save it?")
}

// todo!("uncomment tests")
// #[cfg(test)]
// mod tests {
//     use super::*;
//     use crate::item::test::{TestItem, TestProjectItem};
//     use gpui::TestAppContext;
//     use project::FakeFs;
//     use settings::SettingsStore;

//     #[gpui::test]
//     async fn test_remove_active_empty(cx: &mut TestAppContext) {
//         init_test(cx);
//         let fs = FakeFs::new(cx.background());

//         let project = Project::test(fs, None, cx).await;
//         let window = cx.add_window(|cx| Workspace::test_new(project.clone(), cx));
//         let workspace = window.root(cx);
//         let pane = workspace.read_with(cx, |workspace, _| workspace.active_pane().clone());

//         pane.update(cx, |pane, cx| {
//             assert!(pane
//                 .close_active_item(&CloseActiveItem { save_intent: None }, cx)
//                 .is_none())
//         });
//     }

//     #[gpui::test]
//     async fn test_add_item_with_new_item(cx: &mut TestAppContext) {
//         cx.foreground().forbid_parking();
//         init_test(cx);
//         let fs = FakeFs::new(cx.background());

//         let project = Project::test(fs, None, cx).await;
//         let window = cx.add_window(|cx| Workspace::test_new(project.clone(), cx));
//         let workspace = window.root(cx);
//         let pane = workspace.read_with(cx, |workspace, _| workspace.active_pane().clone());

//         // 1. Add with a destination index
//         //   a. Add before the active item
//         set_labeled_items(&pane, ["A", "B*", "C"], cx);
//         pane.update(cx, |pane, cx| {
//             pane.add_item(
//                 Box::new(cx.add_view(|_| TestItem::new().with_label("D"))),
//                 false,
//                 false,
//                 Some(0),
//                 cx,
//             );
//         });
//         assert_item_labels(&pane, ["D*", "A", "B", "C"], cx);

//         //   b. Add after the active item
//         set_labeled_items(&pane, ["A", "B*", "C"], cx);
//         pane.update(cx, |pane, cx| {
//             pane.add_item(
//                 Box::new(cx.add_view(|_| TestItem::new().with_label("D"))),
//                 false,
//                 false,
//                 Some(2),
//                 cx,
//             );
//         });
//         assert_item_labels(&pane, ["A", "B", "D*", "C"], cx);

//         //   c. Add at the end of the item list (including off the length)
//         set_labeled_items(&pane, ["A", "B*", "C"], cx);
//         pane.update(cx, |pane, cx| {
//             pane.add_item(
//                 Box::new(cx.add_view(|_| TestItem::new().with_label("D"))),
//                 false,
//                 false,
//                 Some(5),
//                 cx,
//             );
//         });
//         assert_item_labels(&pane, ["A", "B", "C", "D*"], cx);

//         // 2. Add without a destination index
//         //   a. Add with active item at the start of the item list
//         set_labeled_items(&pane, ["A*", "B", "C"], cx);
//         pane.update(cx, |pane, cx| {
//             pane.add_item(
//                 Box::new(cx.add_view(|_| TestItem::new().with_label("D"))),
//                 false,
//                 false,
//                 None,
//                 cx,
//             );
//         });
//         set_labeled_items(&pane, ["A", "D*", "B", "C"], cx);

//         //   b. Add with active item at the end of the item list
//         set_labeled_items(&pane, ["A", "B", "C*"], cx);
//         pane.update(cx, |pane, cx| {
//             pane.add_item(
//                 Box::new(cx.add_view(|_| TestItem::new().with_label("D"))),
//                 false,
//                 false,
//                 None,
//                 cx,
//             );
//         });
//         assert_item_labels(&pane, ["A", "B", "C", "D*"], cx);
//     }

//     #[gpui::test]
//     async fn test_add_item_with_existing_item(cx: &mut TestAppContext) {
//         cx.foreground().forbid_parking();
//         init_test(cx);
//         let fs = FakeFs::new(cx.background());

//         let project = Project::test(fs, None, cx).await;
//         let window = cx.add_window(|cx| Workspace::test_new(project.clone(), cx));
//         let workspace = window.root(cx);
//         let pane = workspace.read_with(cx, |workspace, _| workspace.active_pane().clone());

//         // 1. Add with a destination index
//         //   1a. Add before the active item
//         let [_, _, _, d] = set_labeled_items(&pane, ["A", "B*", "C", "D"], cx);
//         pane.update(cx, |pane, cx| {
//             pane.add_item(d, false, false, Some(0), cx);
//         });
//         assert_item_labels(&pane, ["D*", "A", "B", "C"], cx);

//         //   1b. Add after the active item
//         let [_, _, _, d] = set_labeled_items(&pane, ["A", "B*", "C", "D"], cx);
//         pane.update(cx, |pane, cx| {
//             pane.add_item(d, false, false, Some(2), cx);
//         });
//         assert_item_labels(&pane, ["A", "B", "D*", "C"], cx);

//         //   1c. Add at the end of the item list (including off the length)
//         let [a, _, _, _] = set_labeled_items(&pane, ["A", "B*", "C", "D"], cx);
//         pane.update(cx, |pane, cx| {
//             pane.add_item(a, false, false, Some(5), cx);
//         });
//         assert_item_labels(&pane, ["B", "C", "D", "A*"], cx);

//         //   1d. Add same item to active index
//         let [_, b, _] = set_labeled_items(&pane, ["A", "B*", "C"], cx);
//         pane.update(cx, |pane, cx| {
//             pane.add_item(b, false, false, Some(1), cx);
//         });
//         assert_item_labels(&pane, ["A", "B*", "C"], cx);

//         //   1e. Add item to index after same item in last position
//         let [_, _, c] = set_labeled_items(&pane, ["A", "B*", "C"], cx);
//         pane.update(cx, |pane, cx| {
//             pane.add_item(c, false, false, Some(2), cx);
//         });
//         assert_item_labels(&pane, ["A", "B", "C*"], cx);

//         // 2. Add without a destination index
//         //   2a. Add with active item at the start of the item list
//         let [_, _, _, d] = set_labeled_items(&pane, ["A*", "B", "C", "D"], cx);
//         pane.update(cx, |pane, cx| {
//             pane.add_item(d, false, false, None, cx);
//         });
//         assert_item_labels(&pane, ["A", "D*", "B", "C"], cx);

//         //   2b. Add with active item at the end of the item list
//         let [a, _, _, _] = set_labeled_items(&pane, ["A", "B", "C", "D*"], cx);
//         pane.update(cx, |pane, cx| {
//             pane.add_item(a, false, false, None, cx);
//         });
//         assert_item_labels(&pane, ["B", "C", "D", "A*"], cx);

//         //   2c. Add active item to active item at end of list
//         let [_, _, c] = set_labeled_items(&pane, ["A", "B", "C*"], cx);
//         pane.update(cx, |pane, cx| {
//             pane.add_item(c, false, false, None, cx);
//         });
//         assert_item_labels(&pane, ["A", "B", "C*"], cx);

//         //   2d. Add active item to active item at start of list
//         let [a, _, _] = set_labeled_items(&pane, ["A*", "B", "C"], cx);
//         pane.update(cx, |pane, cx| {
//             pane.add_item(a, false, false, None, cx);
//         });
//         assert_item_labels(&pane, ["A*", "B", "C"], cx);
//     }

//     #[gpui::test]
//     async fn test_add_item_with_same_project_entries(cx: &mut TestAppContext) {
//         cx.foreground().forbid_parking();
//         init_test(cx);
//         let fs = FakeFs::new(cx.background());

//         let project = Project::test(fs, None, cx).await;
//         let window = cx.add_window(|cx| Workspace::test_new(project.clone(), cx));
//         let workspace = window.root(cx);
//         let pane = workspace.read_with(cx, |workspace, _| workspace.active_pane().clone());

//         // singleton view
//         pane.update(cx, |pane, cx| {
//             let item = TestItem::new()
//                 .with_singleton(true)
//                 .with_label("buffer 1")
//                 .with_project_items(&[TestProjectItem::new(1, "one.txt", cx)]);

//             pane.add_item(Box::new(cx.add_view(|_| item)), false, false, None, cx);
//         });
//         assert_item_labels(&pane, ["buffer 1*"], cx);

//         // new singleton view with the same project entry
//         pane.update(cx, |pane, cx| {
//             let item = TestItem::new()
//                 .with_singleton(true)
//                 .with_label("buffer 1")
//                 .with_project_items(&[TestProjectItem::new(1, "1.txt", cx)]);

//             pane.add_item(Box::new(cx.add_view(|_| item)), false, false, None, cx);
//         });
//         assert_item_labels(&pane, ["buffer 1*"], cx);

//         // new singleton view with different project entry
//         pane.update(cx, |pane, cx| {
//             let item = TestItem::new()
//                 .with_singleton(true)
//                 .with_label("buffer 2")
//                 .with_project_items(&[TestProjectItem::new(2, "2.txt", cx)]);
//             pane.add_item(Box::new(cx.add_view(|_| item)), false, false, None, cx);
//         });
//         assert_item_labels(&pane, ["buffer 1", "buffer 2*"], cx);

//         // new multibuffer view with the same project entry
//         pane.update(cx, |pane, cx| {
//             let item = TestItem::new()
//                 .with_singleton(false)
//                 .with_label("multibuffer 1")
//                 .with_project_items(&[TestProjectItem::new(1, "1.txt", cx)]);

//             pane.add_item(Box::new(cx.add_view(|_| item)), false, false, None, cx);
//         });
//         assert_item_labels(&pane, ["buffer 1", "buffer 2", "multibuffer 1*"], cx);

//         // another multibuffer view with the same project entry
//         pane.update(cx, |pane, cx| {
//             let item = TestItem::new()
//                 .with_singleton(false)
//                 .with_label("multibuffer 1b")
//                 .with_project_items(&[TestProjectItem::new(1, "1.txt", cx)]);

//             pane.add_item(Box::new(cx.add_view(|_| item)), false, false, None, cx);
//         });
//         assert_item_labels(
//             &pane,
//             ["buffer 1", "buffer 2", "multibuffer 1", "multibuffer 1b*"],
//             cx,
//         );
//     }

//     #[gpui::test]
//     async fn test_remove_item_ordering(cx: &mut TestAppContext) {
//         init_test(cx);
//         let fs = FakeFs::new(cx.background());

//         let project = Project::test(fs, None, cx).await;
//         let window = cx.add_window(|cx| Workspace::test_new(project.clone(), cx));
//         let workspace = window.root(cx);
//         let pane = workspace.read_with(cx, |workspace, _| workspace.active_pane().clone());

//         add_labeled_item(&pane, "A", false, cx);
//         add_labeled_item(&pane, "B", false, cx);
//         add_labeled_item(&pane, "C", false, cx);
//         add_labeled_item(&pane, "D", false, cx);
//         assert_item_labels(&pane, ["A", "B", "C", "D*"], cx);

//         pane.update(cx, |pane, cx| pane.activate_item(1, false, false, cx));
//         add_labeled_item(&pane, "1", false, cx);
//         assert_item_labels(&pane, ["A", "B", "1*", "C", "D"], cx);

//         pane.update(cx, |pane, cx| {
//             pane.close_active_item(&CloseActiveItem { save_intent: None }, cx)
//         })
//         .unwrap()
//         .await
//         .unwrap();
//         assert_item_labels(&pane, ["A", "B*", "C", "D"], cx);

//         pane.update(cx, |pane, cx| pane.activate_item(3, false, false, cx));
//         assert_item_labels(&pane, ["A", "B", "C", "D*"], cx);

//         pane.update(cx, |pane, cx| {
//             pane.close_active_item(&CloseActiveItem { save_intent: None }, cx)
//         })
//         .unwrap()
//         .await
//         .unwrap();
//         assert_item_labels(&pane, ["A", "B*", "C"], cx);

//         pane.update(cx, |pane, cx| {
//             pane.close_active_item(&CloseActiveItem { save_intent: None }, cx)
//         })
//         .unwrap()
//         .await
//         .unwrap();
//         assert_item_labels(&pane, ["A", "C*"], cx);

//         pane.update(cx, |pane, cx| {
//             pane.close_active_item(&CloseActiveItem { save_intent: None }, cx)
//         })
//         .unwrap()
//         .await
//         .unwrap();
//         assert_item_labels(&pane, ["A*"], cx);
//     }

//     #[gpui::test]
//     async fn test_close_inactive_items(cx: &mut TestAppContext) {
//         init_test(cx);
//         let fs = FakeFs::new(cx.background());

//         let project = Project::test(fs, None, cx).await;
//         let window = cx.add_window(|cx| Workspace::test_new(project.clone(), cx));
//         let workspace = window.root(cx);
//         let pane = workspace.read_with(cx, |workspace, _| workspace.active_pane().clone());

//         set_labeled_items(&pane, ["A", "B", "C*", "D", "E"], cx);

//         pane.update(cx, |pane, cx| {
//             pane.close_inactive_items(&CloseInactiveItems, cx)
//         })
//         .unwrap()
//         .await
//         .unwrap();
//         assert_item_labels(&pane, ["C*"], cx);
//     }

//     #[gpui::test]
//     async fn test_close_clean_items(cx: &mut TestAppContext) {
//         init_test(cx);
//         let fs = FakeFs::new(cx.background());

//         let project = Project::test(fs, None, cx).await;
//         let window = cx.add_window(|cx| Workspace::test_new(project.clone(), cx));
//         let workspace = window.root(cx);
//         let pane = workspace.read_with(cx, |workspace, _| workspace.active_pane().clone());

//         add_labeled_item(&pane, "A", true, cx);
//         add_labeled_item(&pane, "B", false, cx);
//         add_labeled_item(&pane, "C", true, cx);
//         add_labeled_item(&pane, "D", false, cx);
//         add_labeled_item(&pane, "E", false, cx);
//         assert_item_labels(&pane, ["A^", "B", "C^", "D", "E*"], cx);

//         pane.update(cx, |pane, cx| pane.close_clean_items(&CloseCleanItems, cx))
//             .unwrap()
//             .await
//             .unwrap();
//         assert_item_labels(&pane, ["A^", "C*^"], cx);
//     }

//     #[gpui::test]
//     async fn test_close_items_to_the_left(cx: &mut TestAppContext) {
//         init_test(cx);
//         let fs = FakeFs::new(cx.background());

//         let project = Project::test(fs, None, cx).await;
//         let window = cx.add_window(|cx| Workspace::test_new(project.clone(), cx));
//         let workspace = window.root(cx);
//         let pane = workspace.read_with(cx, |workspace, _| workspace.active_pane().clone());

//         set_labeled_items(&pane, ["A", "B", "C*", "D", "E"], cx);

//         pane.update(cx, |pane, cx| {
//             pane.close_items_to_the_left(&CloseItemsToTheLeft, cx)
//         })
//         .unwrap()
//         .await
//         .unwrap();
//         assert_item_labels(&pane, ["C*", "D", "E"], cx);
//     }

//     #[gpui::test]
//     async fn test_close_items_to_the_right(cx: &mut TestAppContext) {
//         init_test(cx);
//         let fs = FakeFs::new(cx.background());

//         let project = Project::test(fs, None, cx).await;
//         let window = cx.add_window(|cx| Workspace::test_new(project.clone(), cx));
//         let workspace = window.root(cx);
//         let pane = workspace.read_with(cx, |workspace, _| workspace.active_pane().clone());

//         set_labeled_items(&pane, ["A", "B", "C*", "D", "E"], cx);

//         pane.update(cx, |pane, cx| {
//             pane.close_items_to_the_right(&CloseItemsToTheRight, cx)
//         })
//         .unwrap()
//         .await
//         .unwrap();
//         assert_item_labels(&pane, ["A", "B", "C*"], cx);
//     }

//     #[gpui::test]
//     async fn test_close_all_items(cx: &mut TestAppContext) {
//         init_test(cx);
//         let fs = FakeFs::new(cx.background());

//         let project = Project::test(fs, None, cx).await;
//         let window = cx.add_window(|cx| Workspace::test_new(project.clone(), cx));
//         let workspace = window.root(cx);
//         let pane = workspace.read_with(cx, |workspace, _| workspace.active_pane().clone());

//         add_labeled_item(&pane, "A", false, cx);
//         add_labeled_item(&pane, "B", false, cx);
//         add_labeled_item(&pane, "C", false, cx);
//         assert_item_labels(&pane, ["A", "B", "C*"], cx);

//         pane.update(cx, |pane, cx| {
//             pane.close_all_items(&CloseAllItems { save_intent: None }, cx)
//         })
//         .unwrap()
//         .await
//         .unwrap();
//         assert_item_labels(&pane, [], cx);

//         add_labeled_item(&pane, "A", true, cx);
//         add_labeled_item(&pane, "B", true, cx);
//         add_labeled_item(&pane, "C", true, cx);
//         assert_item_labels(&pane, ["A^", "B^", "C*^"], cx);

//         let save = pane
//             .update(cx, |pane, cx| {
//                 pane.close_all_items(&CloseAllItems { save_intent: None }, cx)
//             })
//             .unwrap();

//         cx.foreground().run_until_parked();
//         window.simulate_prompt_answer(2, cx);
//         save.await.unwrap();
//         assert_item_labels(&pane, [], cx);
//     }

//     fn init_test(cx: &mut TestAppContext) {
//         cx.update(|cx| {
//             cx.set_global(SettingsStore::test(cx));
//             theme::init((), cx);
//             crate::init_settings(cx);
//             Project::init_settings(cx);
//         });
//     }

//     fn add_labeled_item(
//         pane: &ViewHandle<Pane>,
//         label: &str,
//         is_dirty: bool,
//         cx: &mut TestAppContext,
//     ) -> Box<ViewHandle<TestItem>> {
//         pane.update(cx, |pane, cx| {
//             let labeled_item =
//                 Box::new(cx.add_view(|_| TestItem::new().with_label(label).with_dirty(is_dirty)));
//             pane.add_item(labeled_item.clone(), false, false, None, cx);
//             labeled_item
//         })
//     }

//     fn set_labeled_items<const COUNT: usize>(
//         pane: &ViewHandle<Pane>,
//         labels: [&str; COUNT],
//         cx: &mut TestAppContext,
//     ) -> [Box<ViewHandle<TestItem>>; COUNT] {
//         pane.update(cx, |pane, cx| {
//             pane.items.clear();
//             let mut active_item_index = 0;

//             let mut index = 0;
//             let items = labels.map(|mut label| {
//                 if label.ends_with("*") {
//                     label = label.trim_end_matches("*");
//                     active_item_index = index;
//                 }

//                 let labeled_item = Box::new(cx.add_view(|_| TestItem::new().with_label(label)));
//                 pane.add_item(labeled_item.clone(), false, false, None, cx);
//                 index += 1;
//                 labeled_item
//             });

//             pane.activate_item(active_item_index, false, false, cx);

//             items
//         })
//     }

//     // Assert the item label, with the active item label suffixed with a '*'
//     fn assert_item_labels<const COUNT: usize>(
//         pane: &ViewHandle<Pane>,
//         expected_states: [&str; COUNT],
//         cx: &mut TestAppContext,
//     ) {
//         pane.read_with(cx, |pane, cx| {
//             let actual_states = pane
//                 .items
//                 .iter()
//                 .enumerate()
//                 .map(|(ix, item)| {
//                     let mut state = item
//                         .as_any()
//                         .downcast_ref::<TestItem>()
//                         .unwrap()
//                         .read(cx)
//                         .label
//                         .clone();
//                     if ix == pane.active_item_index {
//                         state.push('*');
//                     }
//                     if item.is_dirty(cx) {
//                         state.push('^');
//                     }
//                     state
//                 })
//                 .collect::<Vec<_>>();

//             assert_eq!(
//                 actual_states, expected_states,
//                 "pane items do not match expectation"
//             );
//         })
//     }
// }

#[derive(Clone, Debug)]
struct DraggedTab {
    title: String,
}

impl Render for DraggedTab {
    type Element = Div<Self>;

    fn render(&mut self, cx: &mut ViewContext<Self>) -> Self::Element {
        div().w_8().h_4().bg(gpui::red())
    }
}
