use anyhow::Result;
use feature_flags::{AgentV2FeatureFlag, FeatureFlagAppExt};
use gpui::{
    AnyView, App, Context, DragMoveEvent, Entity, EntityId, EventEmitter, FocusHandle, Focusable,
    ManagedView, MouseButton, Pixels, Render, Subscription, Task, Tiling, Window, WindowId,
    actions, deferred, px,
};
use project::DisableAiSettings;
use project::Project;
use remote::RemoteConnectionOptions;
use settings::Settings;
pub use settings::SidebarSide;
use std::future::Future;
use std::path::PathBuf;
use std::sync::Arc;
use ui::prelude::*;
use util::{ResultExt, path_list::PathList};
use zed_actions::agents_sidebar::{MoveWorkspaceToNewWindow, ToggleThreadSwitcher};

use agent_settings::AgentSettings;
use settings::SidebarDockPosition;
use ui::{ContextMenu, right_click_menu};

const SIDEBAR_RESIZE_HANDLE_SIZE: Pixels = px(6.0);

use crate::SerializedWorkspaceLocation;
use crate::{
    CloseIntent, CloseWindow, DockPosition, Event as WorkspaceEvent, Item, ModalView, OpenMode,
    Panel, Workspace, WorkspaceId, client_side_decorations,
};

actions!(
    multi_workspace,
    [
        /// Toggles the workspace switcher sidebar.
        ToggleWorkspaceSidebar,
        /// Closes the workspace sidebar.
        CloseWorkspaceSidebar,
        /// Moves focus to or from the workspace sidebar without closing it.
        FocusWorkspaceSidebar,
        /// Switches to the next workspace.
        NextWorkspace,
        /// Switches to the previous workspace.
        PreviousWorkspace,
    ]
);

#[derive(Default)]
pub struct SidebarRenderState {
    pub open: bool,
    pub side: SidebarSide,
}

pub fn sidebar_side_context_menu(
    id: impl Into<ElementId>,
    cx: &App,
) -> ui::RightClickMenu<ContextMenu> {
    let current_position = AgentSettings::get_global(cx).sidebar_side;
    right_click_menu(id).menu(move |window, cx| {
        let fs = <dyn fs::Fs>::global(cx);
        ContextMenu::build(window, cx, move |mut menu, _, _cx| {
            let positions: [(SidebarDockPosition, &str); 2] = [
                (SidebarDockPosition::Left, "Left"),
                (SidebarDockPosition::Right, "Right"),
            ];
            for (position, label) in positions {
                let fs = fs.clone();
                menu = menu.toggleable_entry(
                    label,
                    position == current_position,
                    IconPosition::Start,
                    None,
                    move |_window, cx| {
                        settings::update_settings_file(fs.clone(), cx, move |settings, _cx| {
                            settings
                                .agent
                                .get_or_insert_default()
                                .set_sidebar_side(position);
                        });
                    },
                );
            }
            menu
        })
    })
}

pub enum MultiWorkspaceEvent {
    ActiveWorkspaceChanged,
    WorkspaceAdded(Entity<Workspace>),
    WorkspaceRemoved,
}

pub enum SidebarEvent {
    SerializeNeeded,
}

pub trait Sidebar: Focusable + Render + EventEmitter<SidebarEvent> + Sized {
    fn width(&self, cx: &App) -> Pixels;
    fn set_width(&mut self, width: Option<Pixels>, cx: &mut Context<Self>);
    fn has_notifications(&self, cx: &App) -> bool;
    fn side(&self, _cx: &App) -> SidebarSide;

    fn is_threads_list_view_active(&self) -> bool {
        true
    }
    /// Makes focus reset back to the search editor upon toggling the sidebar from outside
    fn prepare_for_focus(&mut self, _window: &mut Window, _cx: &mut Context<Self>) {}
    /// Opens or cycles the thread switcher popup.
    fn toggle_thread_switcher(
        &mut self,
        _select_last: bool,
        _window: &mut Window,
        _cx: &mut Context<Self>,
    ) {
    }

    /// Return an opaque JSON blob of sidebar-specific state to persist.
    fn serialized_state(&self, _cx: &App) -> Option<String> {
        None
    }

    /// Restore sidebar state from a previously-serialized blob.
    fn restore_serialized_state(
        &mut self,
        _state: &str,
        _window: &mut Window,
        _cx: &mut Context<Self>,
    ) {
    }
}

pub trait SidebarHandle: 'static + Send + Sync {
    fn width(&self, cx: &App) -> Pixels;
    fn set_width(&self, width: Option<Pixels>, cx: &mut App);
    fn focus_handle(&self, cx: &App) -> FocusHandle;
    fn focus(&self, window: &mut Window, cx: &mut App);
    fn prepare_for_focus(&self, window: &mut Window, cx: &mut App);
    fn has_notifications(&self, cx: &App) -> bool;
    fn to_any(&self) -> AnyView;
    fn entity_id(&self) -> EntityId;
    fn toggle_thread_switcher(&self, select_last: bool, window: &mut Window, cx: &mut App);

    fn is_threads_list_view_active(&self, cx: &App) -> bool;

    fn side(&self, cx: &App) -> SidebarSide;
    fn serialized_state(&self, cx: &App) -> Option<String>;
    fn restore_serialized_state(&self, state: &str, window: &mut Window, cx: &mut App);
}

#[derive(Clone)]
pub struct DraggedSidebar;

impl Render for DraggedSidebar {
    fn render(&mut self, _window: &mut Window, _cx: &mut Context<Self>) -> impl IntoElement {
        gpui::Empty
    }
}

impl<T: Sidebar> SidebarHandle for Entity<T> {
    fn width(&self, cx: &App) -> Pixels {
        self.read(cx).width(cx)
    }

    fn set_width(&self, width: Option<Pixels>, cx: &mut App) {
        self.update(cx, |this, cx| this.set_width(width, cx))
    }

    fn focus_handle(&self, cx: &App) -> FocusHandle {
        self.read(cx).focus_handle(cx)
    }

    fn focus(&self, window: &mut Window, cx: &mut App) {
        let handle = self.read(cx).focus_handle(cx);
        window.focus(&handle, cx);
    }

    fn prepare_for_focus(&self, window: &mut Window, cx: &mut App) {
        self.update(cx, |this, cx| this.prepare_for_focus(window, cx));
    }

    fn has_notifications(&self, cx: &App) -> bool {
        self.read(cx).has_notifications(cx)
    }

    fn to_any(&self) -> AnyView {
        self.clone().into()
    }

    fn entity_id(&self) -> EntityId {
        Entity::entity_id(self)
    }

    fn toggle_thread_switcher(&self, select_last: bool, window: &mut Window, cx: &mut App) {
        let entity = self.clone();
        window.defer(cx, move |window, cx| {
            entity.update(cx, |this, cx| {
                this.toggle_thread_switcher(select_last, window, cx);
            });
        });
    }

    fn is_threads_list_view_active(&self, cx: &App) -> bool {
        self.read(cx).is_threads_list_view_active()
    }

    fn side(&self, cx: &App) -> SidebarSide {
        self.read(cx).side(cx)
    }

    fn serialized_state(&self, cx: &App) -> Option<String> {
        self.read(cx).serialized_state(cx)
    }

    fn restore_serialized_state(&self, state: &str, window: &mut Window, cx: &mut App) {
        self.update(cx, |this, cx| {
            this.restore_serialized_state(state, window, cx)
        })
    }
}

/// Identifies a project group by a set of paths the workspaces in this group
/// have.
///
/// Paths are mapped to their main worktree path first so we can group
/// workspaces by main repos.
#[derive(PartialEq, Eq, Hash, Clone)]
pub struct ProjectGroupKey {
    pub main_worktree_paths: PathList,
    pub host: Option<RemoteConnectionOptions>,
}

impl ProjectGroupKey {
    pub fn display_name(&self) -> SharedString {
        let mut names = Vec::with_capacity(self.main_worktree_paths.paths().len());
        for abs_path in self.main_worktree_paths.paths() {
            if let Some(name) = abs_path.file_name() {
                names.push(name.to_string_lossy().to_string());
            }
        }
        if names.is_empty() {
            // TODO: Can we do something better in this case?
            "Empty Workspace".into()
        } else {
            names.join(", ").into()
        }
    }

    pub fn path_list(&self) -> &PathList {
        &self.main_worktree_paths
    }

    pub fn from_paths(paths: &[PathBuf], host: Option<RemoteConnectionOptions>) -> Self {
        Self {
            main_worktree_paths: PathList::new(paths),
            host,
        }
    }

    pub fn from_location_and_paths(location: SerializedWorkspaceLocation, paths: PathList) -> Self {
        let host = match location {
            SerializedWorkspaceLocation::Local => None,
            SerializedWorkspaceLocation::Remote(options) => Some(options),
        };
        Self {
            main_worktree_paths: paths,
            host,
        }
    }
}

pub struct MultiWorkspace {
    window_id: WindowId,
    project_groups: Vec<ProjectGroup>,
    active_workspace: Entity<Workspace>,
    sidebar: Option<Box<dyn SidebarHandle>>,
    sidebar_open: bool,
    sidebar_overlay: Option<AnyView>,
    pending_removal_tasks: Vec<Task<()>>,
    _serialize_task: Option<Task<()>>,
    _subscriptions: Vec<Subscription>,
}

/// Represents a group of workspaces with the same project key (main worktree paths and host).
///
/// Invariant: a project group always has at least one workspace.
pub struct ProjectGroup {
    pub key: ProjectGroupKey,
    pub workspaces: Vec<Entity<Workspace>>,
}

impl ProjectGroup {
    fn from_workspace(workspace: Entity<Workspace>, cx: &App) -> Self {
        Self {
            key: workspace.read(cx).project_group_key(cx),
            workspaces: vec![workspace],
        }
    }
}

impl EventEmitter<MultiWorkspaceEvent> for MultiWorkspace {}

impl MultiWorkspace {
    pub fn sidebar_side(&self, cx: &App) -> SidebarSide {
        self.sidebar
            .as_ref()
            .map_or(SidebarSide::Left, |s| s.side(cx))
    }

    pub fn sidebar_render_state(&self, cx: &App) -> SidebarRenderState {
        SidebarRenderState {
            open: self.sidebar_open() && self.multi_workspace_enabled(cx),
            side: self.sidebar_side(cx),
        }
    }

    pub fn new(workspace: Entity<Workspace>, window: &mut Window, cx: &mut Context<Self>) -> Self {
        let release_subscription = cx.on_release(|this: &mut MultiWorkspace, _cx| {
            if let Some(task) = this._serialize_task.take() {
                task.detach();
            }
            for task in std::mem::take(&mut this.pending_removal_tasks) {
                task.detach();
            }
        });
        let quit_subscription = cx.on_app_quit(Self::app_will_quit);
        let settings_subscription =
            cx.observe_global_in::<settings::SettingsStore>(window, |this, window, cx| {
                if DisableAiSettings::get_global(cx).disable_ai && this.sidebar_open {
                    this.close_sidebar(window, cx);
                }
            });
        Self::subscribe_to_workspace(&workspace, window, cx);
        let weak_self = cx.weak_entity();
        workspace.update(cx, |workspace, cx| {
            workspace.set_multi_workspace(weak_self, cx);
        });
        Self {
            window_id: window.window_handle().window_id(),
            project_groups: vec![ProjectGroup::from_workspace(workspace.clone(), cx)],
            active_workspace: workspace,
            sidebar: None,
            sidebar_open: false,
            sidebar_overlay: None,
            pending_removal_tasks: Vec::new(),
            _serialize_task: None,
            _subscriptions: vec![
                release_subscription,
                quit_subscription,
                settings_subscription,
            ],
        }
    }

    pub fn register_sidebar<T: Sidebar>(&mut self, sidebar: Entity<T>, cx: &mut Context<Self>) {
        self._subscriptions
            .push(cx.observe(&sidebar, |_this, _, cx| {
                cx.notify();
            }));
        self._subscriptions
            .push(cx.subscribe(&sidebar, |this, _, event, cx| match event {
                SidebarEvent::SerializeNeeded => {
                    this.serialize(cx);
                }
            }));
        self.sidebar = Some(Box::new(sidebar));
    }

    pub fn sidebar(&self) -> Option<&dyn SidebarHandle> {
        self.sidebar.as_deref()
    }

    pub fn set_sidebar_overlay(&mut self, overlay: Option<AnyView>, cx: &mut Context<Self>) {
        self.sidebar_overlay = overlay;
        cx.notify();
    }

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

    pub fn sidebar_has_notifications(&self, cx: &App) -> bool {
        self.sidebar
            .as_ref()
            .map_or(false, |s| s.has_notifications(cx))
    }

    pub fn is_threads_list_view_active(&self, cx: &App) -> bool {
        self.sidebar
            .as_ref()
            .map_or(false, |s| s.is_threads_list_view_active(cx))
    }

    pub fn multi_workspace_enabled(&self, cx: &App) -> bool {
        cx.has_flag::<AgentV2FeatureFlag>() && !DisableAiSettings::get_global(cx).disable_ai
    }

    pub fn toggle_sidebar(&mut self, window: &mut Window, cx: &mut Context<Self>) {
        if !self.multi_workspace_enabled(cx) {
            return;
        }

        if self.sidebar_open {
            self.close_sidebar(window, cx);
        } else {
            self.open_sidebar(cx);
            if let Some(sidebar) = &self.sidebar {
                sidebar.prepare_for_focus(window, cx);
                sidebar.focus(window, cx);
            }
        }
    }

    pub fn close_sidebar_action(&mut self, window: &mut Window, cx: &mut Context<Self>) {
        if !self.multi_workspace_enabled(cx) {
            return;
        }

        if self.sidebar_open {
            self.close_sidebar(window, cx);
        }
    }

    pub fn focus_sidebar(&mut self, window: &mut Window, cx: &mut Context<Self>) {
        if !self.multi_workspace_enabled(cx) {
            return;
        }

        if self.sidebar_open {
            let sidebar_is_focused = self
                .sidebar
                .as_ref()
                .is_some_and(|s| s.focus_handle(cx).contains_focused(window, cx));

            if sidebar_is_focused {
                let pane = self.workspace().read(cx).active_pane().clone();
                let pane_focus = pane.read(cx).focus_handle(cx);
                window.focus(&pane_focus, cx);
            } else if let Some(sidebar) = &self.sidebar {
                sidebar.prepare_for_focus(window, cx);
                sidebar.focus(window, cx);
            }
        } else {
            self.open_sidebar(cx);
            if let Some(sidebar) = &self.sidebar {
                sidebar.prepare_for_focus(window, cx);
                sidebar.focus(window, cx);
            }
        }
    }

    pub fn workspaces(&self) -> impl Iterator<Item = Entity<Workspace>> + '_ {
        self.project_groups
            .iter()
            .flat_map(|group| group.workspaces.iter().cloned())
    }

    pub fn project_groups(&self) -> &[ProjectGroup] {
        &self.project_groups
    }

    pub fn project_group_keys(&self) -> impl Iterator<Item = &ProjectGroupKey> {
        self.project_groups.iter().map(|group| &group.key)
    }

    pub fn open_sidebar(&mut self, cx: &mut Context<Self>) {
        self.sidebar_open = true;
        let sidebar_focus_handle = self.sidebar.as_ref().map(|s| s.focus_handle(cx));
        for workspace in self.workspaces() {
            workspace.update(cx, |workspace, _cx| {
                workspace.set_sidebar_focus_handle(sidebar_focus_handle.clone());
            });
        }
        self.serialize(cx);
        cx.notify();
    }

    pub fn close_sidebar(&mut self, window: &mut Window, cx: &mut Context<Self>) {
        self.sidebar_open = false;
        for workspace in self.workspaces() {
            workspace.update(cx, |workspace, _cx| {
                workspace.set_sidebar_focus_handle(None);
            });
        }
        let pane = self.workspace().read(cx).active_pane().clone();
        let pane_focus = pane.read(cx).focus_handle(cx);
        window.focus(&pane_focus, cx);
        self.serialize(cx);
        cx.notify();
    }

    pub fn close_window(&mut self, _: &CloseWindow, window: &mut Window, cx: &mut Context<Self>) {
        cx.spawn_in(window, async move |this, cx| {
            let workspaces: Vec<_> = this.update(cx, |multi_workspace, _cx| {
                multi_workspace.workspaces().collect()
            })?;

            for workspace in workspaces {
                let should_continue = workspace
                    .update_in(cx, |workspace, window, cx| {
                        workspace.prepare_to_close(CloseIntent::CloseWindow, window, cx)
                    })?
                    .await?;
                if !should_continue {
                    return anyhow::Ok(());
                }
            }

            cx.update(|window, _cx| {
                window.remove_window();
            })?;

            anyhow::Ok(())
        })
        .detach_and_log_err(cx);
    }

    fn subscribe_to_workspace(
        workspace: &Entity<Workspace>,
        window: &Window,
        cx: &mut Context<Self>,
    ) {
        cx.subscribe_in(workspace, window, |this, workspace, event, window, cx| {
            if let WorkspaceEvent::Activate = event {
                this.activate(workspace.clone(), window, cx);
            }
        })
        .detach();
    }

    pub fn workspace(&self) -> &Entity<Workspace> {
        &self.active_workspace
    }

    pub fn active_workspace(&self) -> Entity<Workspace> {
        self.active_workspace.clone()
    }

    /// Adds a workspace to this window without changing which workspace is
    /// active.
    pub fn add(&mut self, workspace: Entity<Workspace>, window: &Window, cx: &mut Context<Self>) {
        if !self.multi_workspace_enabled(cx) {
            self.set_single_workspace(workspace, cx);
            return;
        }

        self.insert_workspace(workspace, window, cx);
    }

    /// Returns the number of workspaces in this multiworkspace
    pub fn len(&self) -> usize {
        self.project_groups
            .iter()
            .fold(0, |acc, group| acc + group.workspaces.len())
    }

    /// Ensures the workspace is in the multiworkspace and makes it the active one.
    pub fn activate(
        &mut self,
        workspace: Entity<Workspace>,
        window: &mut Window,
        cx: &mut Context<Self>,
    ) {
        if !self.multi_workspace_enabled(cx) {
            self.set_single_workspace(workspace, cx);
            return;
        }

        self.insert_workspace(workspace.clone(), &*window, cx);
        let changed = self.active_workspace != workspace;
        self.active_workspace = workspace;
        if changed {
            cx.emit(MultiWorkspaceEvent::ActiveWorkspaceChanged);
            self.serialize(cx);
        }
        self.focus_active_workspace(window, cx);
        cx.notify();
    }

    /// Replaces the currently active workspace with a new one. If the
    /// workspace is already in the list, this just switches to it.
    pub fn replace(
        &mut self,
        workspace: Entity<Workspace>,
        window: &mut Window,
        cx: &mut Context<Self>,
    ) {
        if !self.multi_workspace_enabled(cx) {
            self.set_single_workspace(workspace, cx);
            return;
        }

        let exists = self.workspaces().any(|w| w == workspace);
        if exists {
            let changed = self.active_workspace != workspace;
            self.active_workspace = workspace;
            if changed {
                cx.emit(MultiWorkspaceEvent::ActiveWorkspaceChanged);
                self.serialize(cx);
            }
            cx.notify();
            return;
        }

        let key = workspace.read(cx).project_group_key(cx);
        if let Some(group) = self.project_groups.iter_mut().find(|g| g.key == key) {
            group.workspaces.push(workspace.clone());
        } else {
            let active_group_ix = self
                .project_groups
                .iter()
                .position(|group| group.workspaces.contains(&self.active_workspace));
            if let Some(ix) = active_group_ix {
                self.remove_group_at_index(ix, window, cx);
            }
            self.project_groups.push(ProjectGroup {
                key,
                workspaces: vec![workspace.clone()],
            });
        };

        self.active_workspace = workspace.clone();
        Self::subscribe_to_workspace(&workspace, window, cx);
        self.sync_sidebar_to_workspace(&workspace, cx);

        cx.emit(MultiWorkspaceEvent::WorkspaceRemoved);
        cx.emit(MultiWorkspaceEvent::WorkspaceAdded(workspace));
        cx.emit(MultiWorkspaceEvent::ActiveWorkspaceChanged);
        self.serialize(cx);
        cx.notify();
    }

    fn set_single_workspace(&mut self, workspace: Entity<Workspace>, cx: &mut Context<Self>) {
        self.project_groups.clear();
        self.project_groups
            .push(ProjectGroup::from_workspace(workspace.clone(), cx));
        self.active_workspace = workspace;
        cx.emit(MultiWorkspaceEvent::ActiveWorkspaceChanged);
        cx.notify();
    }

    /// Inserts a workspace into the matching project group, creating a new
    /// group if none exists. Does nothing if the workspace is already present.
    fn insert_workspace(
        &mut self,
        workspace: Entity<Workspace>,
        window: &Window,
        cx: &mut Context<Self>,
    ) {
        if self.workspaces().any(|w| w == workspace) {
            return;
        }

        Self::subscribe_to_workspace(&workspace, window, cx);
        self.sync_sidebar_to_workspace(&workspace, cx);
        let weak_self = cx.weak_entity();
        workspace.update(cx, |workspace, cx| {
            workspace.set_multi_workspace(weak_self, cx);
        });

        let key = workspace.read(cx).project_group_key(cx);
        if let Some(group) = self.project_groups.iter_mut().find(|g| g.key == key) {
            group.workspaces.push(workspace.clone());
        } else {
            self.project_groups.push(ProjectGroup {
                key,
                workspaces: vec![workspace.clone()],
            });
        }

        cx.emit(MultiWorkspaceEvent::WorkspaceAdded(workspace));
        cx.notify();
    }

    /// Clears session state and DB binding for a workspace that is being
    /// removed or replaced. The DB row is preserved so the workspace still
    /// appears in the recent-projects list.
    fn detach_workspace(&mut self, workspace: &Entity<Workspace>, cx: &mut Context<Self>) {
        workspace.update(cx, |workspace, _cx| {
            workspace.session_id.take();
            workspace._schedule_serialize_workspace.take();
            workspace._serialize_workspace_task.take();
        });

        if let Some(workspace_id) = workspace.read(cx).database_id() {
            let db = crate::persistence::WorkspaceDb::global(cx);
            self.pending_removal_tasks.retain(|task| !task.is_ready());
            self.pending_removal_tasks
                .push(cx.background_spawn(async move {
                    db.set_session_binding(workspace_id, None, None)
                        .await
                        .log_err();
                }));
        }
    }

    fn sync_sidebar_to_workspace(&self, workspace: &Entity<Workspace>, cx: &mut Context<Self>) {
        if self.sidebar_open {
            let sidebar_focus_handle = self.sidebar.as_ref().map(|s| s.focus_handle(cx));
            workspace.update(cx, |workspace, _| {
                workspace.set_sidebar_focus_handle(sidebar_focus_handle);
            });
        }
    }

    fn cycle_workspace(&mut self, delta: isize, window: &mut Window, cx: &mut Context<Self>) {
        let count = self.len();
        let current_ix = self
            .workspaces()
            .position(|w| w == self.active_workspace)
            .unwrap_or(0);
        let next_ix = ((current_ix as isize + delta).rem_euclid(count as isize)) as usize;
        let next_workspace = self.workspaces().nth(next_ix);
        if let Some(next_workspace) = next_workspace {
            self.activate(next_workspace, window, cx);
        }
    }

    fn next_workspace(&mut self, _: &NextWorkspace, window: &mut Window, cx: &mut Context<Self>) {
        self.cycle_workspace(1, window, cx);
    }

    fn previous_workspace(
        &mut self,
        _: &PreviousWorkspace,
        window: &mut Window,
        cx: &mut Context<Self>,
    ) {
        self.cycle_workspace(-1, window, cx);
    }

    pub(crate) fn serialize(&mut self, cx: &mut Context<Self>) {
        self._serialize_task = Some(cx.spawn(async move |this, cx| {
            let Some((window_id, state)) = this
                .read_with(cx, |this, cx| {
                    let state = crate::persistence::model::MultiWorkspaceState {
                        active_workspace_id: this.workspace().read(cx).database_id(),
                        sidebar_open: this.sidebar_open,
                        sidebar_state: this.sidebar.as_ref().and_then(|s| s.serialized_state(cx)),
                    };
                    (this.window_id, state)
                })
                .ok()
            else {
                return;
            };
            let kvp = cx.update(|cx| db::kvp::KeyValueStore::global(cx));
            crate::persistence::write_multi_workspace_state(&kvp, window_id, state).await;
        }));
    }

    /// Returns the in-flight serialization task (if any) so the caller can
    /// await it. Used by the quit handler to ensure pending DB writes
    /// complete before the process exits.
    pub fn flush_serialization(&mut self) -> Task<()> {
        self._serialize_task.take().unwrap_or(Task::ready(()))
    }

    fn app_will_quit(&mut self, _cx: &mut Context<Self>) -> impl Future<Output = ()> + use<> {
        let mut tasks: Vec<Task<()>> = Vec::new();
        if let Some(task) = self._serialize_task.take() {
            tasks.push(task);
        }
        tasks.extend(std::mem::take(&mut self.pending_removal_tasks));

        async move {
            futures::future::join_all(tasks).await;
        }
    }

    pub fn focus_active_workspace(&self, window: &mut Window, cx: &mut App) {
        // If a dock panel is zoomed, focus it instead of the center pane.
        // Otherwise, focusing the center pane triggers dismiss_zoomed_items_to_reveal
        // which closes the zoomed dock.
        let focus_handle = {
            let workspace = self.workspace().read(cx);
            let mut target = None;
            for dock in workspace.all_docks() {
                let dock = dock.read(cx);
                if dock.is_open() {
                    if let Some(panel) = dock.active_panel() {
                        if panel.is_zoomed(window, cx) {
                            target = Some(panel.panel_focus_handle(cx));
                            break;
                        }
                    }
                }
            }
            target.unwrap_or_else(|| {
                let pane = workspace.active_pane().clone();
                pane.read(cx).focus_handle(cx)
            })
        };
        window.focus(&focus_handle, cx);
    }

    pub fn panel<T: Panel>(&self, cx: &App) -> Option<Entity<T>> {
        self.workspace().read(cx).panel::<T>(cx)
    }

    pub fn active_modal<V: ManagedView + 'static>(&self, cx: &App) -> Option<Entity<V>> {
        self.workspace().read(cx).active_modal::<V>(cx)
    }

    pub fn add_panel<T: Panel>(
        &mut self,
        panel: Entity<T>,
        window: &mut Window,
        cx: &mut Context<Self>,
    ) {
        self.workspace().update(cx, |workspace, cx| {
            workspace.add_panel(panel, window, cx);
        });
    }

    pub fn focus_panel<T: Panel>(
        &mut self,
        window: &mut Window,
        cx: &mut Context<Self>,
    ) -> Option<Entity<T>> {
        self.workspace()
            .update(cx, |workspace, cx| workspace.focus_panel::<T>(window, cx))
    }

    // used in a test
    pub fn toggle_modal<V: ModalView, B>(
        &mut self,
        window: &mut Window,
        cx: &mut Context<Self>,
        build: B,
    ) where
        B: FnOnce(&mut Window, &mut gpui::Context<V>) -> V,
    {
        self.workspace().update(cx, |workspace, cx| {
            workspace.toggle_modal(window, cx, build);
        });
    }

    pub fn toggle_dock(
        &mut self,
        dock_side: DockPosition,
        window: &mut Window,
        cx: &mut Context<Self>,
    ) {
        self.workspace().update(cx, |workspace, cx| {
            workspace.toggle_dock(dock_side, window, cx);
        });
    }

    pub fn active_item_as<I: 'static>(&self, cx: &App) -> Option<Entity<I>> {
        self.workspace().read(cx).active_item_as::<I>(cx)
    }

    pub fn items_of_type<'a, T: Item>(
        &'a self,
        cx: &'a App,
    ) -> impl 'a + Iterator<Item = Entity<T>> {
        self.workspace().read(cx).items_of_type::<T>(cx)
    }

    pub fn database_id(&self, cx: &App) -> Option<WorkspaceId> {
        self.workspace().read(cx).database_id()
    }

    pub fn take_pending_removal_tasks(&mut self) -> Vec<Task<()>> {
        let tasks: Vec<Task<()>> = std::mem::take(&mut self.pending_removal_tasks)
            .into_iter()
            .filter(|task| !task.is_ready())
            .collect();
        tasks
    }

    #[cfg(any(test, feature = "test-support"))]
    pub fn set_random_database_id(&mut self, cx: &mut Context<Self>) {
        self.workspace().update(cx, |workspace, _cx| {
            workspace.set_random_database_id();
        });
    }

    #[cfg(any(test, feature = "test-support"))]
    pub fn test_new(project: Entity<Project>, window: &mut Window, cx: &mut Context<Self>) -> Self {
        let workspace = cx.new(|cx| Workspace::test_new(project, window, cx));
        Self::new(workspace, window, cx)
    }

    #[cfg(any(test, feature = "test-support"))]
    pub fn test_add_workspace(
        &mut self,
        project: Entity<Project>,
        window: &mut Window,
        cx: &mut Context<Self>,
    ) -> Entity<Workspace> {
        let workspace = cx.new(|cx| Workspace::test_new(project, window, cx));
        self.activate(workspace.clone(), window, cx);
        workspace
    }

    #[cfg(any(test, feature = "test-support"))]
    pub fn create_test_workspace(
        &mut self,
        window: &mut Window,
        cx: &mut Context<Self>,
    ) -> Task<()> {
        let app_state = self.workspace().read(cx).app_state().clone();
        let project = Project::local(
            app_state.client.clone(),
            app_state.node_runtime.clone(),
            app_state.user_store.clone(),
            app_state.languages.clone(),
            app_state.fs.clone(),
            None,
            project::LocalProjectFlags::default(),
            cx,
        );
        let new_workspace = cx.new(|cx| Workspace::new(None, project, app_state, window, cx));
        self.activate(new_workspace.clone(), window, cx);

        let weak_workspace = new_workspace.downgrade();
        let db = crate::persistence::WorkspaceDb::global(cx);
        cx.spawn_in(window, async move |this, cx| {
            let workspace_id = db.next_id().await.unwrap();
            let workspace = weak_workspace.upgrade().unwrap();
            let task: Task<()> = this
                .update_in(cx, |this, window, cx| {
                    let session_id = workspace.read(cx).session_id();
                    let window_id = window.window_handle().window_id().as_u64();
                    workspace.update(cx, |workspace, _cx| {
                        workspace.set_database_id(workspace_id);
                    });
                    this.serialize(cx);
                    let db = db.clone();
                    cx.background_spawn(async move {
                        db.set_session_binding(workspace_id, session_id, Some(window_id))
                            .await
                            .log_err();
                    })
                })
                .unwrap();
            task.await
        })
    }

    /// Removes the group that contains this workspace.
    #[deprecated = "use remove_group instead"]
    pub fn remove_group_containing_workspace(
        &mut self,
        workspace: &Entity<Workspace>,
        window: &mut Window,
        cx: &mut Context<Self>,
    ) -> bool {
        let Some(group_ix) = self
            .project_groups
            .iter_mut()
            .position(|g| g.workspaces.contains(workspace))
        else {
            return false;
        };
        self.remove_group_at_index(group_ix, window, cx);
        true
    }

    pub fn remove_group(
        &mut self,
        key: ProjectGroupKey,
        window: &mut Window,
        cx: &mut Context<Self>,
    ) -> bool {
        let Some(group_ix) = self.project_groups.iter_mut().position(|g| g.key == key) else {
            return false;
        };
        self.remove_group_at_index(group_ix, window, cx);
        true
    }

    fn remove_group_at_index(
        &mut self,
        group_ix: usize,
        window: &mut Window,
        cx: &mut Context<Self>,
    ) {
        let removed_group = self.project_groups.remove(group_ix);

        // If we removed the active workspace, pick a new one.
        let app_state = self.active_workspace.read(cx).app_state().clone();
        if removed_group.workspaces.contains(&self.active_workspace) {
            let workspace = self.workspaces().next();
            if let Some(workspace) = workspace {
                self.active_workspace = workspace;
            } else {
                let project = Project::local(
                    app_state.client.clone(),
                    app_state.node_runtime.clone(),
                    app_state.user_store.clone(),
                    app_state.languages.clone(),
                    app_state.fs.clone(),
                    None,
                    project::LocalProjectFlags::default(),
                    cx,
                );
                let empty_workspace =
                    cx.new(|cx| Workspace::new(None, project, app_state, window, cx));
                self.project_groups
                    .push(ProjectGroup::from_workspace(empty_workspace.clone(), cx));
                self.active_workspace = empty_workspace;
            }
        }

        for workspace in removed_group.workspaces {
            self.detach_workspace(&workspace, cx);
        }

        self.serialize(cx);
        self.focus_active_workspace(window, cx);
        cx.emit(MultiWorkspaceEvent::WorkspaceRemoved);
        cx.emit(MultiWorkspaceEvent::ActiveWorkspaceChanged);
        cx.notify();
    }

    pub fn move_workspace_to_new_window(
        &mut self,
        workspace: &Entity<Workspace>,
        window: &mut Window,
        cx: &mut Context<Self>,
    ) {
        let workspace = workspace.clone();
        if !self.remove_group_containing_workspace(&workspace, window, cx) {
            return;
        }

        let app_state: Arc<crate::AppState> = workspace.read(cx).app_state().clone();

        cx.defer(move |cx| {
            let options = (app_state.build_window_options)(None, cx);

            let Ok(window) = cx.open_window(options, |window, cx| {
                cx.new(|cx| MultiWorkspace::new(workspace, window, cx))
            }) else {
                return;
            };

            let _ = window.update(cx, |_, window, _| {
                window.activate_window();
            });
        });
    }

    pub fn move_group_to_new_window(
        &mut self,
        key: ProjectGroupKey,
        window: &mut Window,
        cx: &mut Context<Self>,
    ) {
        let Some(group_ix) = self.project_groups.iter().position(|g| g.key == key) else {
            return;
        };

        let group_workspaces: Vec<_> = self.project_groups[group_ix].workspaces.clone();
        if group_workspaces.is_empty() {
            return;
        }

        self.remove_group_at_index(group_ix, window, cx);

        let app_state: Arc<crate::AppState> = group_workspaces[0].read(cx).app_state().clone();

        cx.defer(move |cx| {
            let options = (app_state.build_window_options)(None, cx);

            let first_workspace = group_workspaces[0].clone();
            let remaining: Vec<_> = group_workspaces.into_iter().skip(1).collect();
            let Ok(window_handle) = cx.open_window(options, |window, cx| {
                cx.new(|cx| MultiWorkspace::new(first_workspace, window, cx))
            }) else {
                return;
            };

            window_handle
                .update(cx, |multi_workspace, window, cx| {
                    for workspace in remaining {
                        multi_workspace.add(workspace, &*window, cx);
                    }
                    window.activate_window();
                })
                .ok();
        });
    }

    fn move_active_workspace_to_new_window(
        &mut self,
        _: &MoveWorkspaceToNewWindow,
        window: &mut Window,
        cx: &mut Context<Self>,
    ) {
        let workspace = self.workspace().clone();
        self.move_workspace_to_new_window(&workspace, window, cx);
    }

    pub fn open_project(
        &mut self,
        paths: Vec<PathBuf>,
        open_mode: OpenMode,
        window: &mut Window,
        cx: &mut Context<Self>,
    ) -> Task<Result<Entity<Workspace>>> {
        let workspace = self.workspace().clone();

        let needs_close_prompt =
            open_mode == OpenMode::Replace || !self.multi_workspace_enabled(cx);
        let open_mode = if self.multi_workspace_enabled(cx) {
            open_mode
        } else {
            OpenMode::Replace
        };

        if needs_close_prompt {
            cx.spawn_in(window, async move |_this, cx| {
                let should_continue = workspace
                    .update_in(cx, |workspace, window, cx| {
                        workspace.prepare_to_close(crate::CloseIntent::ReplaceWindow, window, cx)
                    })?
                    .await?;
                if should_continue {
                    workspace
                        .update_in(cx, |workspace, window, cx| {
                            workspace.open_workspace_for_paths(open_mode, paths, window, cx)
                        })?
                        .await
                } else {
                    Ok(workspace)
                }
            })
        } else {
            workspace.update(cx, |workspace, cx| {
                workspace.open_workspace_for_paths(open_mode, paths, window, cx)
            })
        }
    }
}

impl Render for MultiWorkspace {
    fn render(&mut self, window: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
        let multi_workspace_enabled = self.multi_workspace_enabled(cx);
        let sidebar_side = self.sidebar_side(cx);
        let sidebar_on_right = sidebar_side == SidebarSide::Right;

        let sidebar: Option<AnyElement> = if multi_workspace_enabled && self.sidebar_open() {
            self.sidebar.as_ref().map(|sidebar_handle| {
                let weak = cx.weak_entity();

                let sidebar_width = sidebar_handle.width(cx);
                let resize_handle = deferred(
                    div()
                        .id("sidebar-resize-handle")
                        .absolute()
                        .when(!sidebar_on_right, |el| {
                            el.right(-SIDEBAR_RESIZE_HANDLE_SIZE / 2.)
                        })
                        .when(sidebar_on_right, |el| {
                            el.left(-SIDEBAR_RESIZE_HANDLE_SIZE / 2.)
                        })
                        .top(px(0.))
                        .h_full()
                        .w(SIDEBAR_RESIZE_HANDLE_SIZE)
                        .cursor_col_resize()
                        .on_drag(DraggedSidebar, |dragged, _, _, cx| {
                            cx.stop_propagation();
                            cx.new(|_| dragged.clone())
                        })
                        .on_mouse_down(MouseButton::Left, |_, _, cx| {
                            cx.stop_propagation();
                        })
                        .on_mouse_up(MouseButton::Left, move |event, _, cx| {
                            if event.click_count == 2 {
                                weak.update(cx, |this, cx| {
                                    if let Some(sidebar) = this.sidebar.as_mut() {
                                        sidebar.set_width(None, cx);
                                    }
                                    this.serialize(cx);
                                })
                                .ok();
                                cx.stop_propagation();
                            } else {
                                weak.update(cx, |this, cx| {
                                    this.serialize(cx);
                                })
                                .ok();
                            }
                        })
                        .occlude(),
                );

                div()
                    .id("sidebar-container")
                    .relative()
                    .h_full()
                    .w(sidebar_width)
                    .flex_shrink_0()
                    .child(sidebar_handle.to_any())
                    .child(resize_handle)
                    .into_any_element()
            })
        } else {
            None
        };

        let (left_sidebar, right_sidebar) = if sidebar_on_right {
            (None, sidebar)
        } else {
            (sidebar, None)
        };

        let ui_font = theme_settings::setup_ui_font(window, cx);
        let text_color = cx.theme().colors().text;

        let workspace = self.workspace().clone();
        let workspace_key_context = workspace.update(cx, |workspace, cx| workspace.key_context(cx));
        let root = workspace.update(cx, |workspace, cx| workspace.actions(h_flex(), window, cx));

        client_side_decorations(
            root.key_context(workspace_key_context)
                .relative()
                .size_full()
                .font(ui_font)
                .text_color(text_color)
                .on_action(cx.listener(Self::close_window))
                .when(self.multi_workspace_enabled(cx), |this| {
                    this.on_action(cx.listener(
                        |this: &mut Self, _: &ToggleWorkspaceSidebar, window, cx| {
                            this.toggle_sidebar(window, cx);
                        },
                    ))
                    .on_action(cx.listener(
                        |this: &mut Self, _: &CloseWorkspaceSidebar, window, cx| {
                            this.close_sidebar_action(window, cx);
                        },
                    ))
                    .on_action(cx.listener(
                        |this: &mut Self, _: &FocusWorkspaceSidebar, window, cx| {
                            this.focus_sidebar(window, cx);
                        },
                    ))
                    .on_action(cx.listener(Self::next_workspace))
                    .on_action(cx.listener(Self::previous_workspace))
                    .on_action(cx.listener(Self::move_active_workspace_to_new_window))
                    .on_action(cx.listener(
                        |this: &mut Self, action: &ToggleThreadSwitcher, window, cx| {
                            if let Some(sidebar) = &this.sidebar {
                                sidebar.toggle_thread_switcher(action.select_last, window, cx);
                            }
                        },
                    ))
                })
                .when(
                    self.sidebar_open() && self.multi_workspace_enabled(cx),
                    |this| {
                        this.on_drag_move(cx.listener(
                            move |this: &mut Self,
                                  e: &DragMoveEvent<DraggedSidebar>,
                                  window,
                                  cx| {
                                if let Some(sidebar) = &this.sidebar {
                                    let new_width = if sidebar_on_right {
                                        window.bounds().size.width - e.event.position.x
                                    } else {
                                        e.event.position.x
                                    };
                                    sidebar.set_width(Some(new_width), cx);
                                }
                            },
                        ))
                    },
                )
                .children(left_sidebar)
                .child(
                    div()
                        .flex()
                        .flex_1()
                        .size_full()
                        .overflow_hidden()
                        .child(self.workspace().clone()),
                )
                .children(right_sidebar)
                .child(self.workspace().read(cx).modal_layer.clone())
                .children(self.sidebar_overlay.as_ref().map(|view| {
                    deferred(div().absolute().size_full().inset_0().occlude().child(
                        v_flex().h(px(0.0)).top_20().items_center().child(
                            h_flex().occlude().child(view.clone()).on_mouse_down(
                                MouseButton::Left,
                                |_, _, cx| {
                                    cx.stop_propagation();
                                },
                            ),
                        ),
                    ))
                    .with_priority(2)
                })),
            window,
            cx,
            Tiling {
                left: !sidebar_on_right && multi_workspace_enabled && self.sidebar_open(),
                right: sidebar_on_right && multi_workspace_enabled && self.sidebar_open(),
                ..Tiling::default()
            },
        )
    }
}