use crate::{
    pane::{self, Pane},
    persistence::model::ItemId,
    searchable::SearchableItemHandle,
    workspace_settings::{AutosaveSetting, WorkspaceSettings},
    DelayedDebouncedEditAction, FollowableItemBuilders, ItemNavHistory, ToolbarItemLocation,
    ViewId, Workspace, WorkspaceId,
};
use anyhow::Result;
use client2::{
    proto::{self, PeerId},
    Client,
};
use gpui::{
    AnyElement, AnyView, AppContext, Entity, EntityId, EventEmitter, FocusHandle, HighlightStyle,
    Model, Pixels, Point, Render, SharedString, Task, View, ViewContext, WeakView, WindowContext,
};
use project2::{Project, ProjectEntryId, ProjectPath};
use schemars::JsonSchema;
use serde::{Deserialize, Serialize};
use settings2::Settings;
use smallvec::SmallVec;
use std::{
    any::{Any, TypeId},
    cell::RefCell,
    ops::Range,
    path::PathBuf,
    rc::Rc,
    sync::{
        atomic::{AtomicBool, Ordering},
        Arc,
    },
    time::Duration,
};
use theme2::Theme;

#[derive(Deserialize)]
pub struct ItemSettings {
    pub git_status: bool,
    pub close_position: ClosePosition,
}

#[derive(Clone, Default, Serialize, Deserialize, JsonSchema)]
#[serde(rename_all = "lowercase")]
pub enum ClosePosition {
    Left,
    #[default]
    Right,
}

impl ClosePosition {
    pub fn right(&self) -> bool {
        match self {
            ClosePosition::Left => false,
            ClosePosition::Right => true,
        }
    }
}

#[derive(Clone, Default, Serialize, Deserialize, JsonSchema)]
pub struct ItemSettingsContent {
    git_status: Option<bool>,
    close_position: Option<ClosePosition>,
}

impl Settings for ItemSettings {
    const KEY: Option<&'static str> = Some("tabs");

    type FileContent = ItemSettingsContent;

    fn load(
        default_value: &Self::FileContent,
        user_values: &[&Self::FileContent],
        _: &mut AppContext,
    ) -> Result<Self> {
        Self::load_via_json_merge(default_value, user_values)
    }
}

#[derive(Eq, PartialEq, Hash, Debug)]
pub enum ItemEvent {
    CloseItem,
    UpdateTab,
    UpdateBreadcrumbs,
    Edit,
}

// TODO: Combine this with existing HighlightedText struct?
pub struct BreadcrumbText {
    pub text: String,
    pub highlights: Option<Vec<(Range<usize>, HighlightStyle)>>,
}

pub trait Item: Render + EventEmitter {
    fn focus_handle(&self) -> FocusHandle;
    fn deactivated(&mut self, _: &mut ViewContext<Self>) {}
    fn workspace_deactivated(&mut self, _: &mut ViewContext<Self>) {}
    fn navigate(&mut self, _: Box<dyn Any>, _: &mut ViewContext<Self>) -> bool {
        false
    }
    fn tab_tooltip_text(&self, _: &AppContext) -> Option<SharedString> {
        None
    }
    fn tab_description(&self, _: usize, _: &AppContext) -> Option<SharedString> {
        None
    }
    fn tab_content<V: 'static>(&self, detail: Option<usize>, cx: &AppContext) -> AnyElement<V>;

    fn for_each_project_item(
        &self,
        _: &AppContext,
        _: &mut dyn FnMut(EntityId, &dyn project2::Item),
    ) {
    } // (model id, Item)
    fn is_singleton(&self, _cx: &AppContext) -> bool {
        false
    }
    fn set_nav_history(&mut self, _: ItemNavHistory, _: &mut ViewContext<Self>) {}
    fn clone_on_split(
        &self,
        _workspace_id: WorkspaceId,
        _: &mut ViewContext<Self>,
    ) -> Option<View<Self>>
    where
        Self: Sized,
    {
        None
    }
    fn is_dirty(&self, _: &AppContext) -> bool {
        false
    }
    fn has_conflict(&self, _: &AppContext) -> bool {
        false
    }
    fn can_save(&self, _cx: &AppContext) -> bool {
        false
    }
    fn save(&mut self, _project: Model<Project>, _cx: &mut ViewContext<Self>) -> Task<Result<()>> {
        unimplemented!("save() must be implemented if can_save() returns true")
    }
    fn save_as(
        &mut self,
        _project: Model<Project>,
        _abs_path: PathBuf,
        _cx: &mut ViewContext<Self>,
    ) -> Task<Result<()>> {
        unimplemented!("save_as() must be implemented if can_save() returns true")
    }
    fn reload(
        &mut self,
        _project: Model<Project>,
        _cx: &mut ViewContext<Self>,
    ) -> Task<Result<()>> {
        unimplemented!("reload() must be implemented if can_save() returns true")
    }
    fn to_item_events(_event: &Self::Event) -> SmallVec<[ItemEvent; 2]> {
        SmallVec::new()
    }
    fn should_close_item_on_event(_: &Self::Event) -> bool {
        false
    }
    fn should_update_tab_on_event(_: &Self::Event) -> bool {
        false
    }

    fn act_as_type<'a>(
        &'a self,
        type_id: TypeId,
        self_handle: &'a View<Self>,
        _: &'a AppContext,
    ) -> Option<AnyView> {
        if TypeId::of::<Self>() == type_id {
            Some(self_handle.clone().into())
        } else {
            None
        }
    }

    fn as_searchable(&self, _: &View<Self>) -> Option<Box<dyn SearchableItemHandle>> {
        None
    }

    fn breadcrumb_location(&self) -> ToolbarItemLocation {
        ToolbarItemLocation::Hidden
    }

    fn breadcrumbs(&self, _theme: &Theme, _cx: &AppContext) -> Option<Vec<BreadcrumbText>> {
        None
    }

    fn added_to_workspace(&mut self, _workspace: &mut Workspace, _cx: &mut ViewContext<Self>) {}

    fn serialized_item_kind() -> Option<&'static str> {
        None
    }

    fn deserialize(
        _project: Model<Project>,
        _workspace: WeakView<Workspace>,
        _workspace_id: WorkspaceId,
        _item_id: ItemId,
        _cx: &mut ViewContext<Pane>,
    ) -> Task<Result<View<Self>>> {
        unimplemented!(
            "deserialize() must be implemented if serialized_item_kind() returns Some(_)"
        )
    }
    fn show_toolbar(&self) -> bool {
        true
    }
    fn pixel_position_of_cursor(&self, _: &AppContext) -> Option<Point<Pixels>> {
        None
    }
}

pub trait ItemHandle: 'static + Send {
    fn focus_handle(&self, cx: &WindowContext) -> FocusHandle;
    fn subscribe_to_item_events(
        &self,
        cx: &mut WindowContext,
        handler: Box<dyn Fn(ItemEvent, &mut WindowContext) + Send>,
    ) -> gpui::Subscription;
    fn tab_tooltip_text(&self, cx: &AppContext) -> Option<SharedString>;
    fn tab_description(&self, detail: usize, cx: &AppContext) -> Option<SharedString>;
    fn tab_content(&self, detail: Option<usize>, cx: &AppContext) -> AnyElement<Pane>;
    fn dragged_tab_content(&self, detail: Option<usize>, cx: &AppContext) -> AnyElement<Workspace>;
    fn project_path(&self, cx: &AppContext) -> Option<ProjectPath>;
    fn project_entry_ids(&self, cx: &AppContext) -> SmallVec<[ProjectEntryId; 3]>;
    fn project_item_model_ids(&self, cx: &AppContext) -> SmallVec<[EntityId; 3]>;
    fn for_each_project_item(
        &self,
        _: &AppContext,
        _: &mut dyn FnMut(EntityId, &dyn project2::Item),
    );
    fn is_singleton(&self, cx: &AppContext) -> bool;
    fn boxed_clone(&self) -> Box<dyn ItemHandle>;
    fn clone_on_split(
        &self,
        workspace_id: WorkspaceId,
        cx: &mut WindowContext,
    ) -> Option<Box<dyn ItemHandle>>;
    fn added_to_pane(
        &self,
        workspace: &mut Workspace,
        pane: View<Pane>,
        cx: &mut ViewContext<Workspace>,
    );
    fn deactivated(&self, cx: &mut WindowContext);
    fn workspace_deactivated(&self, cx: &mut WindowContext);
    fn navigate(&self, data: Box<dyn Any>, cx: &mut WindowContext) -> bool;
    fn id(&self) -> EntityId;
    fn to_any(&self) -> AnyView;
    fn is_dirty(&self, cx: &AppContext) -> bool;
    fn has_conflict(&self, cx: &AppContext) -> bool;
    fn can_save(&self, cx: &AppContext) -> bool;
    fn save(&self, project: Model<Project>, cx: &mut WindowContext) -> Task<Result<()>>;
    fn save_as(
        &self,
        project: Model<Project>,
        abs_path: PathBuf,
        cx: &mut WindowContext,
    ) -> Task<Result<()>>;
    fn reload(&self, project: Model<Project>, cx: &mut WindowContext) -> Task<Result<()>>;
    fn act_as_type(&self, type_id: TypeId, cx: &AppContext) -> Option<AnyView>;
    fn to_followable_item_handle(&self, cx: &AppContext) -> Option<Box<dyn FollowableItemHandle>>;
    fn on_release(
        &self,
        cx: &mut AppContext,
        callback: Box<dyn FnOnce(&mut AppContext) + Send>,
    ) -> gpui::Subscription;
    fn to_searchable_item_handle(&self, cx: &AppContext) -> Option<Box<dyn SearchableItemHandle>>;
    fn breadcrumb_location(&self, cx: &AppContext) -> ToolbarItemLocation;
    fn breadcrumbs(&self, theme: &Theme, cx: &AppContext) -> Option<Vec<BreadcrumbText>>;
    fn serialized_item_kind(&self) -> Option<&'static str>;
    fn show_toolbar(&self, cx: &AppContext) -> bool;
    fn pixel_position_of_cursor(&self, cx: &AppContext) -> Option<Point<Pixels>>;
}

pub trait WeakItemHandle: Send + Sync {
    fn id(&self) -> EntityId;
    fn upgrade(&self) -> Option<Box<dyn ItemHandle>>;
}

impl dyn ItemHandle {
    pub fn downcast<V: 'static>(&self) -> Option<View<V>> {
        self.to_any().downcast().ok()
    }

    pub fn act_as<V: 'static>(&self, cx: &AppContext) -> Option<View<V>> {
        self.act_as_type(TypeId::of::<V>(), cx)
            .and_then(|t| t.downcast().ok())
    }
}

impl<T: Item> ItemHandle for View<T> {
    fn focus_handle(&self, cx: &WindowContext) -> FocusHandle {
        self.read(cx).focus_handle()
    }

    fn subscribe_to_item_events(
        &self,
        cx: &mut WindowContext,
        handler: Box<dyn Fn(ItemEvent, &mut WindowContext) + Send>,
    ) -> gpui::Subscription {
        cx.subscribe(self, move |_, event, cx| {
            for item_event in T::to_item_events(event) {
                handler(item_event, cx)
            }
        })
    }

    fn tab_tooltip_text(&self, cx: &AppContext) -> Option<SharedString> {
        self.read(cx).tab_tooltip_text(cx)
    }

    fn tab_description(&self, detail: usize, cx: &AppContext) -> Option<SharedString> {
        self.read(cx).tab_description(detail, cx)
    }

    fn tab_content(&self, detail: Option<usize>, cx: &AppContext) -> AnyElement<Pane> {
        self.read(cx).tab_content(detail, cx)
    }

    fn dragged_tab_content(&self, detail: Option<usize>, cx: &AppContext) -> AnyElement<Workspace> {
        self.read(cx).tab_content(detail, cx)
    }

    fn project_path(&self, cx: &AppContext) -> Option<ProjectPath> {
        let this = self.read(cx);
        let mut result = None;
        if this.is_singleton(cx) {
            this.for_each_project_item(cx, &mut |_, item| {
                result = item.project_path(cx);
            });
        }
        result
    }

    fn project_entry_ids(&self, cx: &AppContext) -> SmallVec<[ProjectEntryId; 3]> {
        let mut result = SmallVec::new();
        self.read(cx).for_each_project_item(cx, &mut |_, item| {
            if let Some(id) = item.entry_id(cx) {
                result.push(id);
            }
        });
        result
    }

    fn project_item_model_ids(&self, cx: &AppContext) -> SmallVec<[EntityId; 3]> {
        let mut result = SmallVec::new();
        self.read(cx).for_each_project_item(cx, &mut |id, _| {
            result.push(id);
        });
        result
    }

    fn for_each_project_item(
        &self,
        cx: &AppContext,
        f: &mut dyn FnMut(EntityId, &dyn project2::Item),
    ) {
        self.read(cx).for_each_project_item(cx, f)
    }

    fn is_singleton(&self, cx: &AppContext) -> bool {
        self.read(cx).is_singleton(cx)
    }

    fn boxed_clone(&self) -> Box<dyn ItemHandle> {
        Box::new(self.clone())
    }

    fn clone_on_split(
        &self,
        workspace_id: WorkspaceId,
        cx: &mut WindowContext,
    ) -> Option<Box<dyn ItemHandle>> {
        self.update(cx, |item, cx| item.clone_on_split(workspace_id, cx))
            .map(|handle| Box::new(handle) as Box<dyn ItemHandle>)
    }

    fn added_to_pane(
        &self,
        workspace: &mut Workspace,
        pane: View<Pane>,
        cx: &mut ViewContext<Workspace>,
    ) {
        let history = pane.read(cx).nav_history_for_item(self);
        self.update(cx, |this, cx| {
            this.set_nav_history(history, cx);
            this.added_to_workspace(workspace, cx);
        });

        if let Some(followed_item) = self.to_followable_item_handle(cx) {
            if let Some(message) = followed_item.to_state_proto(cx) {
                workspace.update_followers(
                    followed_item.is_project_item(cx),
                    proto::update_followers::Variant::CreateView(proto::View {
                        id: followed_item
                            .remote_id(&workspace.app_state.client, cx)
                            .map(|id| id.to_proto()),
                        variant: Some(message),
                        leader_id: workspace.leader_for_pane(&pane),
                    }),
                    cx,
                );
            }
        }

        if workspace
            .panes_by_item
            .insert(self.id(), pane.downgrade())
            .is_none()
        {
            let mut pending_autosave = DelayedDebouncedEditAction::new();
            let pending_update = Rc::new(RefCell::new(None));
            let pending_update_scheduled = Arc::new(AtomicBool::new(false));

            let mut event_subscription =
                Some(cx.subscribe(self, move |workspace, item, event, cx| {
                    let pane = if let Some(pane) = workspace
                        .panes_by_item
                        .get(&item.id())
                        .and_then(|pane| pane.upgrade())
                    {
                        pane
                    } else {
                        log::error!("unexpected item event after pane was dropped");
                        return;
                    };

                    if let Some(item) = item.to_followable_item_handle(cx) {
                        let is_project_item = item.is_project_item(cx);
                        let leader_id = workspace.leader_for_pane(&pane);

                        if leader_id.is_some() && item.should_unfollow_on_event(event, cx) {
                            workspace.unfollow(&pane, cx);
                        }

                        if item.add_event_to_update_proto(
                            event,
                            &mut *pending_update.borrow_mut(),
                            cx,
                        ) && !pending_update_scheduled.load(Ordering::SeqCst)
                        {
                            pending_update_scheduled.store(true, Ordering::SeqCst);
                            cx.on_next_frame({
                                let pending_update = pending_update.clone();
                                let pending_update_scheduled = pending_update_scheduled.clone();
                                move |this, cx| {
                                    pending_update_scheduled.store(false, Ordering::SeqCst);
                                    this.update_followers(
                                        is_project_item,
                                        proto::update_followers::Variant::UpdateView(
                                            proto::UpdateView {
                                                id: item
                                                    .remote_id(&this.app_state.client, cx)
                                                    .map(|id| id.to_proto()),
                                                variant: pending_update.borrow_mut().take(),
                                                leader_id,
                                            },
                                        ),
                                        cx,
                                    );
                                }
                            });
                        }
                    }

                    for item_event in T::to_item_events(event).into_iter() {
                        match item_event {
                            ItemEvent::CloseItem => {
                                pane.update(cx, |pane, cx| {
                                    pane.close_item_by_id(item.id(), crate::SaveIntent::Close, cx)
                                })
                                .detach_and_log_err(cx);
                                return;
                            }

                            ItemEvent::UpdateTab => {
                                pane.update(cx, |_, cx| {
                                    cx.emit(pane::Event::ChangeItemTitle);
                                    cx.notify();
                                });
                            }

                            ItemEvent::Edit => {
                                let autosave = WorkspaceSettings::get_global(cx).autosave;
                                if let AutosaveSetting::AfterDelay { milliseconds } = autosave {
                                    let delay = Duration::from_millis(milliseconds);
                                    let item = item.clone();
                                    pending_autosave.fire_new(delay, cx, move |workspace, cx| {
                                        Pane::autosave_item(&item, workspace.project().clone(), cx)
                                    });
                                }
                            }

                            _ => {}
                        }
                    }
                }));

            // todo!()
            // cx.observe_focus(self, move |workspace, item, focused, cx| {
            //     if !focused
            //         && WorkspaceSettings::get_global(cx).autosave == AutosaveSetting::OnFocusChange
            //     {
            //         Pane::autosave_item(&item, workspace.project.clone(), cx)
            //             .detach_and_log_err(cx);
            //     }
            // })
            // .detach();

            let item_id = self.id();
            cx.observe_release(self, move |workspace, _, _| {
                workspace.panes_by_item.remove(&item_id);
                event_subscription.take();
            })
            .detach();
        }

        cx.defer(|workspace, cx| {
            workspace.serialize_workspace(cx);
        });
    }

    fn deactivated(&self, cx: &mut WindowContext) {
        self.update(cx, |this, cx| this.deactivated(cx));
    }

    fn workspace_deactivated(&self, cx: &mut WindowContext) {
        self.update(cx, |this, cx| this.workspace_deactivated(cx));
    }

    fn navigate(&self, data: Box<dyn Any>, cx: &mut WindowContext) -> bool {
        self.update(cx, |this, cx| this.navigate(data, cx))
    }

    fn id(&self) -> EntityId {
        self.entity_id()
    }

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

    fn is_dirty(&self, cx: &AppContext) -> bool {
        self.read(cx).is_dirty(cx)
    }

    fn has_conflict(&self, cx: &AppContext) -> bool {
        self.read(cx).has_conflict(cx)
    }

    fn can_save(&self, cx: &AppContext) -> bool {
        self.read(cx).can_save(cx)
    }

    fn save(&self, project: Model<Project>, cx: &mut WindowContext) -> Task<Result<()>> {
        self.update(cx, |item, cx| item.save(project, cx))
    }

    fn save_as(
        &self,
        project: Model<Project>,
        abs_path: PathBuf,
        cx: &mut WindowContext,
    ) -> Task<anyhow::Result<()>> {
        self.update(cx, |item, cx| item.save_as(project, abs_path, cx))
    }

    fn reload(&self, project: Model<Project>, cx: &mut WindowContext) -> Task<Result<()>> {
        self.update(cx, |item, cx| item.reload(project, cx))
    }

    fn act_as_type<'a>(&'a self, type_id: TypeId, cx: &'a AppContext) -> Option<AnyView> {
        self.read(cx).act_as_type(type_id, self, cx)
    }

    fn to_followable_item_handle(&self, cx: &AppContext) -> Option<Box<dyn FollowableItemHandle>> {
        if cx.has_global::<FollowableItemBuilders>() {
            let builders = cx.global::<FollowableItemBuilders>();
            let item = self.to_any();
            Some(builders.get(&item.entity_type())?.1(&item))
        } else {
            None
        }
    }

    fn on_release(
        &self,
        cx: &mut AppContext,
        callback: Box<dyn FnOnce(&mut AppContext) + Send>,
    ) -> gpui::Subscription {
        cx.observe_release(self, move |_, cx| callback(cx))
    }

    fn to_searchable_item_handle(&self, cx: &AppContext) -> Option<Box<dyn SearchableItemHandle>> {
        self.read(cx).as_searchable(self)
    }

    fn breadcrumb_location(&self, cx: &AppContext) -> ToolbarItemLocation {
        self.read(cx).breadcrumb_location()
    }

    fn breadcrumbs(&self, theme: &Theme, cx: &AppContext) -> Option<Vec<BreadcrumbText>> {
        self.read(cx).breadcrumbs(theme, cx)
    }

    fn serialized_item_kind(&self) -> Option<&'static str> {
        T::serialized_item_kind()
    }

    fn show_toolbar(&self, cx: &AppContext) -> bool {
        self.read(cx).show_toolbar()
    }

    fn pixel_position_of_cursor(&self, cx: &AppContext) -> Option<Point<Pixels>> {
        self.read(cx).pixel_position_of_cursor(cx)
    }
}

impl From<Box<dyn ItemHandle>> for AnyView {
    fn from(val: Box<dyn ItemHandle>) -> Self {
        val.to_any()
    }
}

impl From<&Box<dyn ItemHandle>> for AnyView {
    fn from(val: &Box<dyn ItemHandle>) -> Self {
        val.to_any()
    }
}

impl Clone for Box<dyn ItemHandle> {
    fn clone(&self) -> Box<dyn ItemHandle> {
        self.boxed_clone()
    }
}

impl<T: Item> WeakItemHandle for WeakView<T> {
    fn id(&self) -> EntityId {
        self.entity_id()
    }

    fn upgrade(&self) -> Option<Box<dyn ItemHandle>> {
        self.upgrade().map(|v| Box::new(v) as Box<dyn ItemHandle>)
    }
}

pub trait ProjectItem: Item {
    type Item: project2::Item;

    fn for_project_item(
        project: Model<Project>,
        item: Model<Self::Item>,
        cx: &mut ViewContext<Self>,
    ) -> Self
    where
        Self: Sized;
}

pub trait FollowableItem: Item {
    fn remote_id(&self) -> Option<ViewId>;
    fn to_state_proto(&self, cx: &AppContext) -> Option<proto::view::Variant>;
    fn from_state_proto(
        pane: View<Pane>,
        project: View<Workspace>,
        id: ViewId,
        state: &mut Option<proto::view::Variant>,
        cx: &mut AppContext,
    ) -> Option<Task<Result<View<Self>>>>;
    fn add_event_to_update_proto(
        &self,
        event: &Self::Event,
        update: &mut Option<proto::update_view::Variant>,
        cx: &AppContext,
    ) -> bool;
    fn apply_update_proto(
        &mut self,
        project: &Model<Project>,
        message: proto::update_view::Variant,
        cx: &mut ViewContext<Self>,
    ) -> Task<Result<()>>;
    fn is_project_item(&self, cx: &AppContext) -> bool;

    fn set_leader_peer_id(&mut self, leader_peer_id: Option<PeerId>, cx: &mut ViewContext<Self>);
    fn should_unfollow_on_event(event: &Self::Event, cx: &AppContext) -> bool;
}

pub trait FollowableItemHandle: ItemHandle {
    fn remote_id(&self, client: &Arc<Client>, cx: &AppContext) -> Option<ViewId>;
    fn set_leader_peer_id(&self, leader_peer_id: Option<PeerId>, cx: &mut WindowContext);
    fn to_state_proto(&self, cx: &AppContext) -> Option<proto::view::Variant>;
    fn add_event_to_update_proto(
        &self,
        event: &dyn Any,
        update: &mut Option<proto::update_view::Variant>,
        cx: &AppContext,
    ) -> bool;
    fn apply_update_proto(
        &self,
        project: &Model<Project>,
        message: proto::update_view::Variant,
        cx: &mut WindowContext,
    ) -> Task<Result<()>>;
    fn should_unfollow_on_event(&self, event: &dyn Any, cx: &AppContext) -> bool;
    fn is_project_item(&self, cx: &AppContext) -> bool;
}

impl<T: FollowableItem> FollowableItemHandle for View<T> {
    fn remote_id(&self, client: &Arc<Client>, cx: &AppContext) -> Option<ViewId> {
        self.read(cx).remote_id().or_else(|| {
            client.peer_id().map(|creator| ViewId {
                creator,
                id: self.id().as_u64(),
            })
        })
    }

    fn set_leader_peer_id(&self, leader_peer_id: Option<PeerId>, cx: &mut WindowContext) {
        self.update(cx, |this, cx| this.set_leader_peer_id(leader_peer_id, cx))
    }

    fn to_state_proto(&self, cx: &AppContext) -> Option<proto::view::Variant> {
        self.read(cx).to_state_proto(cx)
    }

    fn add_event_to_update_proto(
        &self,
        event: &dyn Any,
        update: &mut Option<proto::update_view::Variant>,
        cx: &AppContext,
    ) -> bool {
        if let Some(event) = event.downcast_ref() {
            self.read(cx).add_event_to_update_proto(event, update, cx)
        } else {
            false
        }
    }

    fn apply_update_proto(
        &self,
        project: &Model<Project>,
        message: proto::update_view::Variant,
        cx: &mut WindowContext,
    ) -> Task<Result<()>> {
        self.update(cx, |this, cx| this.apply_update_proto(project, message, cx))
    }

    fn should_unfollow_on_event(&self, event: &dyn Any, cx: &AppContext) -> bool {
        if let Some(event) = event.downcast_ref() {
            T::should_unfollow_on_event(event, cx)
        } else {
            false
        }
    }

    fn is_project_item(&self, cx: &AppContext) -> bool {
        self.read(cx).is_project_item(cx)
    }
}

// #[cfg(any(test, feature = "test-support"))]
// pub mod test {
//     use super::{Item, ItemEvent};
//     use crate::{ItemId, ItemNavHistory, Pane, Workspace, WorkspaceId};
//     use gpui::{
//         elements::Empty, AnyElement, AppContext, Element, Entity, Model, Task, View,
//         ViewContext, View, WeakViewHandle,
//     };
//     use project2::{Project, ProjectEntryId, ProjectPath, WorktreeId};
//     use smallvec::SmallVec;
//     use std::{any::Any, borrow::Cow, cell::Cell, path::Path};

//     pub struct TestProjectItem {
//         pub entry_id: Option<ProjectEntryId>,
//         pub project_path: Option<ProjectPath>,
//     }

//     pub struct TestItem {
//         pub workspace_id: WorkspaceId,
//         pub state: String,
//         pub label: String,
//         pub save_count: usize,
//         pub save_as_count: usize,
//         pub reload_count: usize,
//         pub is_dirty: bool,
//         pub is_singleton: bool,
//         pub has_conflict: bool,
//         pub project_items: Vec<Model<TestProjectItem>>,
//         pub nav_history: Option<ItemNavHistory>,
//         pub tab_descriptions: Option<Vec<&'static str>>,
//         pub tab_detail: Cell<Option<usize>>,
//     }

//     impl Entity for TestProjectItem {
//         type Event = ();
//     }

//     impl project2::Item for TestProjectItem {
//         fn entry_id(&self, _: &AppContext) -> Option<ProjectEntryId> {
//             self.entry_id
//         }

//         fn project_path(&self, _: &AppContext) -> Option<ProjectPath> {
//             self.project_path.clone()
//         }
//     }

//     pub enum TestItemEvent {
//         Edit,
//     }

//     impl Clone for TestItem {
//         fn clone(&self) -> Self {
//             Self {
//                 state: self.state.clone(),
//                 label: self.label.clone(),
//                 save_count: self.save_count,
//                 save_as_count: self.save_as_count,
//                 reload_count: self.reload_count,
//                 is_dirty: self.is_dirty,
//                 is_singleton: self.is_singleton,
//                 has_conflict: self.has_conflict,
//                 project_items: self.project_items.clone(),
//                 nav_history: None,
//                 tab_descriptions: None,
//                 tab_detail: Default::default(),
//                 workspace_id: self.workspace_id,
//             }
//         }
//     }

//     impl TestProjectItem {
//         pub fn new(id: u64, path: &str, cx: &mut AppContext) -> Model<Self> {
//             let entry_id = Some(ProjectEntryId::from_proto(id));
//             let project_path = Some(ProjectPath {
//                 worktree_id: WorktreeId::from_usize(0),
//                 path: Path::new(path).into(),
//             });
//             cx.add_model(|_| Self {
//                 entry_id,
//                 project_path,
//             })
//         }

//         pub fn new_untitled(cx: &mut AppContext) -> Model<Self> {
//             cx.add_model(|_| Self {
//                 project_path: None,
//                 entry_id: None,
//             })
//         }
//     }

//     impl TestItem {
//         pub fn new() -> Self {
//             Self {
//                 state: String::new(),
//                 label: String::new(),
//                 save_count: 0,
//                 save_as_count: 0,
//                 reload_count: 0,
//                 is_dirty: false,
//                 has_conflict: false,
//                 project_items: Vec::new(),
//                 is_singleton: true,
//                 nav_history: None,
//                 tab_descriptions: None,
//                 tab_detail: Default::default(),
//                 workspace_id: 0,
//             }
//         }

//         pub fn new_deserialized(id: WorkspaceId) -> Self {
//             let mut this = Self::new();
//             this.workspace_id = id;
//             this
//         }

//         pub fn with_label(mut self, state: &str) -> Self {
//             self.label = state.to_string();
//             self
//         }

//         pub fn with_singleton(mut self, singleton: bool) -> Self {
//             self.is_singleton = singleton;
//             self
//         }

//         pub fn with_dirty(mut self, dirty: bool) -> Self {
//             self.is_dirty = dirty;
//             self
//         }

//         pub fn with_conflict(mut self, has_conflict: bool) -> Self {
//             self.has_conflict = has_conflict;
//             self
//         }

//         pub fn with_project_items(mut self, items: &[Model<TestProjectItem>]) -> Self {
//             self.project_items.clear();
//             self.project_items.extend(items.iter().cloned());
//             self
//         }

//         pub fn set_state(&mut self, state: String, cx: &mut ViewContext<Self>) {
//             self.push_to_nav_history(cx);
//             self.state = state;
//         }

//         fn push_to_nav_history(&mut self, cx: &mut ViewContext<Self>) {
//             if let Some(history) = &mut self.nav_history {
//                 history.push(Some(Box::new(self.state.clone())), cx);
//             }
//         }
//     }

//     impl Entity for TestItem {
//         type Event = TestItemEvent;
//     }

//     impl View for TestItem {
//         fn ui_name() -> &'static str {
//             "TestItem"
//         }

//         fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
//             Empty::new().into_any()
//         }
//     }

//     impl Item for TestItem {
//         fn tab_description(&self, detail: usize, _: &AppContext) -> Option<Cow<str>> {
//             self.tab_descriptions.as_ref().and_then(|descriptions| {
//                 let description = *descriptions.get(detail).or_else(|| descriptions.last())?;
//                 Some(description.into())
//             })
//         }

//         fn tab_content<V: 'static>(
//             &self,
//             detail: Option<usize>,
//             _: &theme2::Tab,
//             _: &AppContext,
//         ) -> AnyElement<V> {
//             self.tab_detail.set(detail);
//             Empty::new().into_any()
//         }

//         fn for_each_project_item(
//             &self,
//             cx: &AppContext,
//             f: &mut dyn FnMut(usize, &dyn project2::Item),
//         ) {
//             self.project_items
//                 .iter()
//                 .for_each(|item| f(item.id(), item.read(cx)))
//         }

// fn is_singleton(&self, _: &AppContext) -> bool {
//     self.is_singleton
// }

//         fn set_nav_history(&mut self, history: ItemNavHistory, _: &mut ViewContext<Self>) {
//             self.nav_history = Some(history);
//         }

//         fn navigate(&mut self, state: Box<dyn Any>, _: &mut ViewContext<Self>) -> bool {
//             let state = *state.downcast::<String>().unwrap_or_default();
//             if state != self.state {
//                 self.state = state;
//                 true
//             } else {
//                 false
//             }
//         }

//         fn deactivated(&mut self, cx: &mut ViewContext<Self>) {
//             self.push_to_nav_history(cx);
//         }

//         fn clone_on_split(
//             &self,
//             _workspace_id: WorkspaceId,
//             _: &mut ViewContext<Self>,
//         ) -> Option<Self>
//         where
//             Self: Sized,
//         {
//             Some(self.clone())
//         }

//         fn is_dirty(&self, _: &AppContext) -> bool {
//             self.is_dirty
//         }

//         fn has_conflict(&self, _: &AppContext) -> bool {
//             self.has_conflict
//         }

//         fn can_save(&self, cx: &AppContext) -> bool {
//             !self.project_items.is_empty()
//                 && self
//                     .project_items
//                     .iter()
//                     .all(|item| item.read(cx).entry_id.is_some())
//         }

//         fn save(
//             &mut self,
//             _: Model<Project>,
//             _: &mut ViewContext<Self>,
//         ) -> Task<anyhow::Result<()>> {
//             self.save_count += 1;
//             self.is_dirty = false;
//             Task::ready(Ok(()))
//         }

//         fn save_as(
//             &mut self,
//             _: Model<Project>,
//             _: std::path::PathBuf,
//             _: &mut ViewContext<Self>,
//         ) -> Task<anyhow::Result<()>> {
//             self.save_as_count += 1;
//             self.is_dirty = false;
//             Task::ready(Ok(()))
//         }

//         fn reload(
//             &mut self,
//             _: Model<Project>,
//             _: &mut ViewContext<Self>,
//         ) -> Task<anyhow::Result<()>> {
//             self.reload_count += 1;
//             self.is_dirty = false;
//             Task::ready(Ok(()))
//         }

//         fn to_item_events(_: &Self::Event) -> SmallVec<[ItemEvent; 2]> {
//             [ItemEvent::UpdateTab, ItemEvent::Edit].into()
//         }

//         fn serialized_item_kind() -> Option<&'static str> {
//             Some("TestItem")
//         }

//         fn deserialize(
//             _project: Model<Project>,
//             _workspace: WeakViewHandle<Workspace>,
//             workspace_id: WorkspaceId,
//             _item_id: ItemId,
//             cx: &mut ViewContext<Pane>,
//         ) -> Task<anyhow::Result<View<Self>>> {
//             let view = cx.add_view(|_cx| Self::new_deserialized(workspace_id));
//             Task::Ready(Some(anyhow::Ok(view)))
//         }
//     }
// }