use crate::scroll::ScrollAmount;
use fuzzy::{StringMatch, StringMatchCandidate};
use gpui::{
    AnyElement, Entity, Focusable, FontWeight, ListSizingBehavior, ScrollHandle, ScrollStrategy,
    SharedString, Size, StrikethroughStyle, StyledText, Task, TaskExt, UniformListScrollHandle,
    div, px, uniform_list,
};
use itertools::Itertools;
use language::CodeLabel;
use language::{Buffer, LanguageName, LanguageRegistry};
use lsp::{CompletionItemKind, CompletionItemTag};
use markdown::{CopyButtonVisibility, Markdown, MarkdownElement};
use multi_buffer::Anchor;
use ordered_float::OrderedFloat;
use project::lsp_store::CompletionDocumentation;
use project::{CodeAction, Completion, CompletionGroup, TaskSourceKind};
use project::{CompletionDisplayOptions, CompletionSource};
use task::DebugScenario;
use task::TaskContext;

use std::sync::Arc;
use std::sync::atomic::{AtomicBool, Ordering};
use std::{
    cell::RefCell,
    cmp::{Reverse, min},
    iter,
    ops::Range,
    rc::Rc,
};
use task::ResolvedTask;
use ui::{
    Divider, ListItem, ListSubHeader, Popover, ScrollAxes, Scrollbars, Tooltip, WithScrollbar,
    prelude::*,
};
use util::ResultExt;

use crate::hover_popover::{hover_markdown_style, open_markdown_url};
use crate::{
    CodeActionProvider, CompletionId, CompletionProvider, DisplayRow, Editor, EditorStyle,
    ResolvedTasks,
    actions::{ConfirmCodeAction, ConfirmCompletion},
    split_words, styled_runs_for_code_label,
};
use crate::{CodeActionSource, EditorSettings};
use collections::{HashSet, VecDeque};
use settings::{CompletionDetailAlignment, CompletionMenuItemKind, Settings, SnippetSortOrder};

pub const MENU_GAP: Pixels = px(4.);
pub const MENU_ASIDE_X_PADDING: Pixels = px(16.);
pub const MENU_ASIDE_MIN_WIDTH: Pixels = px(260.);
pub const MENU_ASIDE_MAX_WIDTH: Pixels = px(500.);
pub const COMPLETION_MENU_MIN_WIDTH: Pixels = px(280.);
pub const COMPLETION_MENU_MAX_WIDTH: Pixels = px(540.);
pub const CODE_ACTION_MENU_MIN_WIDTH: Pixels = px(220.);
pub const CODE_ACTION_MENU_MAX_WIDTH: Pixels = px(540.);

// Constants for the markdown cache. The purpose of this cache is to reduce flickering due to
// documentation not yet being parsed.
//
// The size of the cache is set to 16, which is roughly 3 times more than the number of items
// fetched around the current selection. This way documentation is more often ready for render when
// revisiting previous entries, such as when pressing backspace.
const MARKDOWN_CACHE_MAX_SIZE: usize = 16;
const MARKDOWN_CACHE_BEFORE_ITEMS: usize = 2;
const MARKDOWN_CACHE_AFTER_ITEMS: usize = 2;

// Number of items beyond the visible items to resolve documentation.
const RESOLVE_BEFORE_ITEMS: usize = 4;
const RESOLVE_AFTER_ITEMS: usize = 4;

#[derive(Clone, Debug)]
pub enum CompletionMenuEntry {
    Match(StringMatch),
    Divider,
    GroupHeader(SharedString),
}

impl CompletionMenuEntry {
    pub fn as_match(&self) -> Option<&StringMatch> {
        match self {
            CompletionMenuEntry::Match(m) => Some(m),
            CompletionMenuEntry::Divider | CompletionMenuEntry::GroupHeader(_) => None,
        }
    }

    pub fn is_selectable(&self) -> bool {
        matches!(self, CompletionMenuEntry::Match(_))
    }
}

pub enum CodeContextMenu {
    Completions(CompletionsMenu),
    CodeActions(CodeActionsMenu),
}

impl CodeContextMenu {
    pub fn select_first(
        &mut self,
        provider: Option<&dyn CompletionProvider>,
        window: &mut Window,
        cx: &mut Context<Editor>,
    ) -> bool {
        if self.visible() {
            match self {
                CodeContextMenu::Completions(menu) => menu.select_first(provider, window, cx),
                CodeContextMenu::CodeActions(menu) => menu.select_first(cx),
            }
            true
        } else {
            false
        }
    }

    pub fn select_prev(
        &mut self,
        provider: Option<&dyn CompletionProvider>,
        window: &mut Window,
        cx: &mut Context<Editor>,
    ) -> bool {
        if self.visible() {
            match self {
                CodeContextMenu::Completions(menu) => menu.select_prev(provider, window, cx),
                CodeContextMenu::CodeActions(menu) => menu.select_prev(cx),
            }
            true
        } else {
            false
        }
    }

    pub fn select_next(
        &mut self,
        provider: Option<&dyn CompletionProvider>,
        window: &mut Window,
        cx: &mut Context<Editor>,
    ) -> bool {
        if self.visible() {
            match self {
                CodeContextMenu::Completions(menu) => menu.select_next(provider, window, cx),
                CodeContextMenu::CodeActions(menu) => menu.select_next(cx),
            }
            true
        } else {
            false
        }
    }

    pub fn select_last(
        &mut self,
        provider: Option<&dyn CompletionProvider>,
        window: &mut Window,
        cx: &mut Context<Editor>,
    ) -> bool {
        if self.visible() {
            match self {
                CodeContextMenu::Completions(menu) => menu.select_last(provider, window, cx),
                CodeContextMenu::CodeActions(menu) => menu.select_last(cx),
            }
            true
        } else {
            false
        }
    }

    pub fn visible(&self) -> bool {
        match self {
            CodeContextMenu::Completions(menu) => menu.visible(),
            CodeContextMenu::CodeActions(menu) => menu.visible(),
        }
    }

    pub fn origin(&self) -> ContextMenuOrigin {
        match self {
            CodeContextMenu::Completions(menu) => menu.origin(),
            CodeContextMenu::CodeActions(menu) => menu.origin(),
        }
    }

    pub fn render(
        &self,
        style: &EditorStyle,
        max_height_in_lines: u32,
        window: &mut Window,
        cx: &mut Context<Editor>,
    ) -> AnyElement {
        match self {
            CodeContextMenu::Completions(menu) => {
                menu.render(style, max_height_in_lines, window, cx)
            }
            CodeContextMenu::CodeActions(menu) => {
                menu.render(style, max_height_in_lines, window, cx)
            }
        }
    }

    pub fn render_aside(
        &mut self,
        max_size: Size<Pixels>,
        window: &mut Window,
        cx: &mut Context<Editor>,
    ) -> Option<AnyElement> {
        match self {
            CodeContextMenu::Completions(menu) => menu.render_aside(max_size, window, cx),
            CodeContextMenu::CodeActions(menu) => menu.render_aside(max_size, window, cx),
        }
    }

    pub fn focused(&self, window: &mut Window, cx: &mut Context<Editor>) -> bool {
        match self {
            CodeContextMenu::Completions(completions_menu) => completions_menu
                .get_or_create_entry_markdown(completions_menu.selected_item, cx)
                .as_ref()
                .is_some_and(|markdown| markdown.focus_handle(cx).contains_focused(window, cx)),
            CodeContextMenu::CodeActions(_) => false,
        }
    }

    pub fn scroll_aside(
        &mut self,
        scroll_amount: ScrollAmount,
        window: &mut Window,
        cx: &mut Context<Editor>,
    ) {
        match self {
            CodeContextMenu::Completions(completions_menu) => {
                completions_menu.scroll_aside(scroll_amount, window, cx)
            }
            CodeContextMenu::CodeActions(_) => (),
        }
    }

    pub fn primary_scroll_handle(&self) -> UniformListScrollHandle {
        match self {
            CodeContextMenu::Completions(menu) => menu.scroll_handle.clone(),
            CodeContextMenu::CodeActions(menu) => menu.scroll_handle.clone(),
        }
    }
}

pub enum ContextMenuOrigin {
    Cursor,
    GutterIndicator(DisplayRow),
    QuickActionBar,
}

pub struct CompletionsMenu {
    pub id: CompletionId,
    pub source: CompletionsMenuSource,
    sort_completions: bool,
    pub initial_position: Anchor,
    pub initial_query: Option<Arc<String>>,
    pub is_incomplete: bool,
    pub buffer: Entity<Buffer>,
    pub completions: Rc<RefCell<Box<[Completion]>>>,
    /// String match candidate for each completion, grouped by `match_start`.
    match_candidates: Arc<[(Option<text::Anchor>, Vec<StringMatchCandidate>)]>,
    /// Entries displayed in the menu, which is a filtered and sorted subset of `match_candidates`.
    pub entries: Rc<RefCell<Box<[CompletionMenuEntry]>>>,
    pub selected_item: usize,
    filter_task: Task<()>,
    cancel_filter: Arc<AtomicBool>,
    scroll_handle: UniformListScrollHandle,
    // The `ScrollHandle` used on the Markdown documentation rendered on the
    // side of the completions menu.
    pub scroll_handle_aside: ScrollHandle,
    resolve_completions: bool,
    show_completion_documentation: bool,
    last_rendered_range: Rc<RefCell<Option<Range<usize>>>>,
    markdown_cache: Rc<RefCell<VecDeque<(MarkdownCacheKey, Entity<Markdown>)>>>,
    language_registry: Option<Arc<LanguageRegistry>>,
    language: Option<LanguageName>,
    display_options: CompletionDisplayOptions,
    snippet_sort_order: SnippetSortOrder,
}

#[derive(Clone, Debug, PartialEq)]
enum MarkdownCacheKey {
    ForCandidate {
        candidate_id: usize,
    },
    ForCompletionMatch {
        new_text: String,
        markdown_source: SharedString,
    },
}

#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub enum CompletionsMenuSource {
    /// Show all completions (words, snippets, LSP)
    Normal,
    /// Show only snippets (not words or LSP)
    ///
    /// Used after typing a non-word character
    SnippetsOnly,
    /// Tab stops within a snippet that have a predefined finite set of choices
    SnippetChoices,
    /// Show only words (not snippets or LSP)
    ///
    /// Used when word completions are explicitly triggered
    Words { ignore_threshold: bool },
}

// TODO: There should really be a wrapper around fuzzy match tasks that does this.
impl Drop for CompletionsMenu {
    fn drop(&mut self) {
        self.cancel_filter.store(true, Ordering::Relaxed);
    }
}

#[derive(Default)]
struct CompletionMenuScrollBarSetting;

impl ui::scrollbars::ScrollbarVisibility for CompletionMenuScrollBarSetting {
    fn visibility(&self, cx: &App) -> ui::scrollbars::ShowScrollbar {
        EditorSettings::get_global(cx).completion_menu_scrollbar
    }
}

impl CompletionsMenu {
    pub fn new(
        id: CompletionId,
        source: CompletionsMenuSource,
        sort_completions: bool,
        show_completion_documentation: bool,
        initial_position: Anchor,
        initial_query: Option<Arc<String>>,
        is_incomplete: bool,
        buffer: Entity<Buffer>,
        completions: Box<[Completion]>,
        scroll_handle: Option<UniformListScrollHandle>,
        display_options: CompletionDisplayOptions,
        snippet_sort_order: SnippetSortOrder,
        language_registry: Option<Arc<LanguageRegistry>>,
        language: Option<LanguageName>,
        cx: &mut Context<Editor>,
    ) -> Self {
        let match_candidates = completions
            .iter()
            .enumerate()
            .map(|(id, completion)| StringMatchCandidate::new(id, completion.label.filter_text()))
            .into_group_map_by(|candidate| completions[candidate.id].match_start)
            .into_iter()
            .collect();

        let completions_menu = Self {
            id,
            source,
            sort_completions,
            initial_position,
            initial_query,
            is_incomplete,
            buffer,
            show_completion_documentation,
            completions: RefCell::new(completions).into(),
            match_candidates,
            entries: Rc::new(RefCell::new(Box::new([]))),
            selected_item: 0,
            filter_task: Task::ready(()),
            cancel_filter: Arc::new(AtomicBool::new(false)),
            scroll_handle: scroll_handle.unwrap_or_else(UniformListScrollHandle::new),
            scroll_handle_aside: ScrollHandle::new(),
            resolve_completions: true,
            last_rendered_range: RefCell::new(None).into(),
            markdown_cache: RefCell::new(VecDeque::new()).into(),
            language_registry,
            language,
            display_options,
            snippet_sort_order,
        };

        completions_menu.start_markdown_parse_for_nearby_entries(cx);

        completions_menu
    }

    pub fn new_snippet_choices(
        id: CompletionId,
        sort_completions: bool,
        choices: &Vec<String>,
        initial_position: Anchor,
        selection: Range<text::Anchor>,
        buffer: Entity<Buffer>,
        scroll_handle: Option<UniformListScrollHandle>,
        snippet_sort_order: SnippetSortOrder,
    ) -> Self {
        let completions = choices
            .iter()
            .map(|choice| Completion {
                replace_range: selection.clone(),
                new_text: choice.to_string(),
                label: CodeLabel::plain(choice.to_string(), None),
                match_start: None,
                snippet_deduplication_key: None,
                icon_path: None,
                documentation: None,
                confirm: None,
                insert_text_mode: None,
                source: CompletionSource::Custom,
                group: None,
            })
            .collect();

        let match_candidates = Arc::new([(
            None,
            choices
                .iter()
                .enumerate()
                .map(|(id, completion)| StringMatchCandidate::new(id, completion))
                .collect(),
        )]);
        let entries = choices
            .iter()
            .enumerate()
            .map(|(id, completion)| {
                CompletionMenuEntry::Match(StringMatch {
                    candidate_id: id,
                    score: 1.,
                    positions: vec![],
                    string: completion.clone(),
                })
            })
            .collect();
        Self {
            id,
            source: CompletionsMenuSource::SnippetChoices,
            sort_completions,
            initial_position,
            initial_query: None,
            is_incomplete: false,
            buffer,
            completions: RefCell::new(completions).into(),
            match_candidates,
            entries: RefCell::new(entries).into(),
            selected_item: 0,
            filter_task: Task::ready(()),
            cancel_filter: Arc::new(AtomicBool::new(false)),
            scroll_handle: scroll_handle.unwrap_or_else(UniformListScrollHandle::new),
            scroll_handle_aside: ScrollHandle::new(),
            resolve_completions: false,
            show_completion_documentation: false,
            last_rendered_range: RefCell::new(None).into(),
            markdown_cache: RefCell::new(VecDeque::new()).into(),
            language_registry: None,
            language: None,
            display_options: CompletionDisplayOptions::default(),
            snippet_sort_order,
        }
    }

    fn select_first(
        &mut self,
        provider: Option<&dyn CompletionProvider>,
        window: &mut Window,
        cx: &mut Context<Editor>,
    ) {
        let entries = self.entries.borrow();
        if entries.is_empty() {
            return;
        }
        let start = if self.scroll_handle.y_flipped() {
            entries.len() - 1
        } else {
            0
        };
        drop(entries);
        let index = self.find_selectable_entry(start, !self.scroll_handle.y_flipped());
        if let Some(index) = index {
            self.update_selection_index(index, provider, window, cx);
        }
    }

    fn select_last(
        &mut self,
        provider: Option<&dyn CompletionProvider>,
        window: &mut Window,
        cx: &mut Context<Editor>,
    ) {
        let entries = self.entries.borrow();
        if entries.is_empty() {
            return;
        }
        let start = if self.scroll_handle.y_flipped() {
            0
        } else {
            entries.len() - 1
        };
        drop(entries);
        let index = self.find_selectable_entry(start, self.scroll_handle.y_flipped());
        if let Some(index) = index {
            self.update_selection_index(index, provider, window, cx);
        }
    }

    fn select_prev(
        &mut self,
        provider: Option<&dyn CompletionProvider>,
        window: &mut Window,
        cx: &mut Context<Editor>,
    ) {
        let index = if self.scroll_handle.y_flipped() {
            self.next_match_index()
        } else {
            self.prev_match_index()
        };
        self.update_selection_index(index, provider, window, cx);
    }

    fn select_next(
        &mut self,
        provider: Option<&dyn CompletionProvider>,
        window: &mut Window,
        cx: &mut Context<Editor>,
    ) {
        let index = if self.scroll_handle.y_flipped() {
            self.prev_match_index()
        } else {
            self.next_match_index()
        };
        self.update_selection_index(index, provider, window, cx);
    }

    fn update_selection_index(
        &mut self,
        match_index: usize,
        provider: Option<&dyn CompletionProvider>,
        window: &mut Window,
        cx: &mut Context<Editor>,
    ) {
        if self.selected_item != match_index {
            self.selected_item = match_index;
            self.handle_selection_changed(provider, window, cx);
        }
    }

    fn prev_match_index(&self) -> usize {
        let entries = self.entries.borrow();
        let len = entries.len();
        if len == 0 {
            return 0;
        }
        let mut index = if self.selected_item > 0 {
            self.selected_item - 1
        } else {
            len - 1
        };
        let start = index;
        loop {
            if entries[index].is_selectable() {
                return index;
            }
            index = if index > 0 { index - 1 } else { len - 1 };
            if index == start {
                return self.selected_item;
            }
        }
    }

    fn next_match_index(&self) -> usize {
        let entries = self.entries.borrow();
        let len = entries.len();
        if len == 0 {
            return 0;
        }
        let mut index = if self.selected_item + 1 < len {
            self.selected_item + 1
        } else {
            0
        };
        let start = index;
        loop {
            if entries[index].is_selectable() {
                return index;
            }
            index = if index + 1 < len { index + 1 } else { 0 };
            if index == start {
                return self.selected_item;
            }
        }
    }

    fn find_selectable_entry(&self, start: usize, forward: bool) -> Option<usize> {
        let entries = self.entries.borrow();
        let len = entries.len();
        if len == 0 {
            return None;
        }
        let mut index = start;
        loop {
            if entries[index].is_selectable() {
                return Some(index);
            }
            if forward {
                index = if index + 1 < len { index + 1 } else { 0 };
            } else {
                index = if index > 0 { index - 1 } else { len - 1 };
            }
            if index == start {
                return None;
            }
        }
    }

    fn handle_selection_changed(
        &mut self,
        provider: Option<&dyn CompletionProvider>,
        window: &mut Window,
        cx: &mut Context<Editor>,
    ) {
        self.scroll_handle
            .scroll_to_item(self.selected_item, ScrollStrategy::Nearest);
        if let Some(provider) = provider {
            let entries = self.entries.borrow();
            let entry = if self.selected_item < entries.len() {
                entries[self.selected_item].as_match()
            } else {
                None
            };
            provider.selection_changed(entry, window, cx);
        }
        self.resolve_visible_completions(provider, cx);
        self.start_markdown_parse_for_nearby_entries(cx);
        cx.notify();
    }

    pub fn resolve_visible_completions(
        &mut self,
        provider: Option<&dyn CompletionProvider>,
        cx: &mut Context<Editor>,
    ) {
        if !self.resolve_completions {
            return;
        }
        let Some(provider) = provider else {
            return;
        };

        let entries = self.entries.borrow();
        if entries.is_empty() {
            return;
        }
        if self.selected_item >= entries.len() {
            log::error!(
                "bug: completion selected_item >= entries.len(): {} >= {}",
                self.selected_item,
                entries.len()
            );
            self.selected_item = entries.len() - 1;
        }

        // Attempt to resolve completions for every item that will be displayed. This matters
        // because single line documentation may be displayed inline with the completion.
        //
        // When navigating to the very beginning or end of completions, `last_rendered_range` may
        // have no overlap with the completions that will be displayed, so instead use a range based
        // on the last rendered count.
        const APPROXIMATE_VISIBLE_COUNT: usize = 12;
        let last_rendered_range = self.last_rendered_range.borrow().clone();
        let visible_count = last_rendered_range
            .clone()
            .map_or(APPROXIMATE_VISIBLE_COUNT, |range| range.count());
        let entry_range = if self.selected_item == 0 {
            0..min(visible_count, entries.len())
        } else if self.selected_item == entries.len() - 1 {
            entries.len().saturating_sub(visible_count)..entries.len()
        } else {
            last_rendered_range.map_or(0..0, |range| {
                min(range.start, entries.len())..min(range.end, entries.len())
            })
        };

        // Expand the range to resolve more completions than are predicted to be visible, to reduce
        // jank on navigation.
        let entry_indices = util::expanded_and_wrapped_usize_range(
            entry_range,
            RESOLVE_BEFORE_ITEMS,
            RESOLVE_AFTER_ITEMS,
            entries.len(),
        );

        // Avoid work by sometimes filtering out completions that already have documentation.
        // This filtering doesn't happen if the completions are currently being updated.
        let completions = self.completions.borrow();
        let candidate_ids = entry_indices
            .filter_map(|i| entries[i].as_match().map(|m| m.candidate_id))
            .filter(|i| completions[*i].documentation.is_none());

        // Current selection is always resolved even if it already has documentation, to handle
        // out-of-spec language servers that return more results later.
        let Some(selected_candidate_id) = entries[self.selected_item]
            .as_match()
            .map(|m| m.candidate_id)
        else {
            drop(entries);
            drop(completions);
            return;
        };
        let candidate_ids = iter::once(selected_candidate_id)
            .chain(candidate_ids.filter(|id| *id != selected_candidate_id))
            .collect::<Vec<usize>>();
        drop(entries);

        if candidate_ids.is_empty() {
            return;
        }

        let resolve_task = provider.resolve_completions(
            self.buffer.clone(),
            candidate_ids,
            self.completions.clone(),
            cx,
        );

        let completion_id = self.id;
        cx.spawn(async move |editor, cx| {
            if let Some(true) = resolve_task.await.log_err() {
                editor
                    .update(cx, |editor, cx| {
                        // `resolve_completions` modified state affecting display.
                        cx.notify();
                        editor.with_completions_menu_matching_id(completion_id, |menu| {
                            if let Some(menu) = menu {
                                menu.start_markdown_parse_for_nearby_entries(cx)
                            }
                        });
                    })
                    .ok();
            }
        })
        .detach();
    }

    fn start_markdown_parse_for_nearby_entries(&self, cx: &mut Context<Editor>) {
        // Enqueue parse tasks of nearer items first.
        //
        // TODO: This means that the nearer items will actually be further back in the cache, which
        // is not ideal. In practice this is fine because `get_or_create_markdown` moves the current
        // selection to the front (when `is_render = true`).
        let entry_indices = util::wrapped_usize_outward_from(
            self.selected_item,
            MARKDOWN_CACHE_BEFORE_ITEMS,
            MARKDOWN_CACHE_AFTER_ITEMS,
            self.entries.borrow().len(),
        );

        for index in entry_indices {
            self.get_or_create_entry_markdown(index, cx);
        }
    }

    fn get_or_create_entry_markdown(
        &self,
        index: usize,
        cx: &mut Context<Editor>,
    ) -> Option<Entity<Markdown>> {
        let entries = self.entries.borrow();
        if index >= entries.len() {
            return None;
        }
        let candidate_id = entries[index].as_match()?.candidate_id;
        let completions = self.completions.borrow();
        match &completions[candidate_id].documentation {
            Some(CompletionDocumentation::MultiLineMarkdown(source)) if !source.is_empty() => self
                .get_or_create_markdown(candidate_id, Some(source), false, &completions, cx)
                .map(|(_, markdown)| markdown),
            Some(_) => None,
            _ => None,
        }
    }

    fn get_or_create_markdown(
        &self,
        candidate_id: usize,
        source: Option<&SharedString>,
        is_render: bool,
        completions: &[Completion],
        cx: &mut Context<Editor>,
    ) -> Option<(bool, Entity<Markdown>)> {
        let mut markdown_cache = self.markdown_cache.borrow_mut();

        let mut has_completion_match_cache_entry = false;
        let mut matching_entry = markdown_cache.iter().find_position(|(key, _)| match key {
            MarkdownCacheKey::ForCandidate { candidate_id: id } => *id == candidate_id,
            MarkdownCacheKey::ForCompletionMatch { .. } => {
                has_completion_match_cache_entry = true;
                false
            }
        });

        if has_completion_match_cache_entry && matching_entry.is_none() {
            if let Some(source) = source {
                matching_entry = markdown_cache.iter().find_position(|(key, _)| {
                    matches!(key, MarkdownCacheKey::ForCompletionMatch { markdown_source, .. }
                                if markdown_source == source)
                });
            } else {
                // Heuristic guess that documentation can be reused when new_text matches. This is
                // to mitigate documentation flicker while typing. If this is wrong, then resolution
                // should cause the correct documentation to be displayed soon.
                let completion = &completions[candidate_id];
                matching_entry = markdown_cache.iter().find_position(|(key, _)| {
                    matches!(key, MarkdownCacheKey::ForCompletionMatch { new_text, .. }
                                if new_text == &completion.new_text)
                });
            }
        }

        if let Some((cache_index, (key, markdown))) = matching_entry {
            let markdown = markdown.clone();

            // Since the markdown source matches, the key can now be ForCandidate.
            if source.is_some() && matches!(key, MarkdownCacheKey::ForCompletionMatch { .. }) {
                markdown_cache[cache_index].0 = MarkdownCacheKey::ForCandidate { candidate_id };
            }

            if is_render && cache_index != 0 {
                // Move the current selection's cache entry to the front.
                markdown_cache.rotate_right(1);
                let cache_len = markdown_cache.len();
                markdown_cache.swap(0, (cache_index + 1) % cache_len);
            }

            let is_parsing = markdown.update(cx, |markdown, cx| {
                if let Some(source) = source {
                    // `reset` is called as it's possible for documentation to change due to resolve
                    // requests. It does nothing if `source` is unchanged.
                    markdown.reset(source.clone(), cx);
                }
                markdown.is_parsing()
            });
            return Some((is_parsing, markdown));
        }

        let Some(source) = source else {
            // Can't create markdown as there is no source.
            return None;
        };

        if markdown_cache.len() < MARKDOWN_CACHE_MAX_SIZE {
            let markdown = cx.new(|cx| {
                Markdown::new(
                    source.clone(),
                    self.language_registry.clone(),
                    self.language.clone(),
                    cx,
                )
            });
            // Handles redraw when the markdown is done parsing. The current render is for a
            // deferred draw, and so without this did not redraw when `markdown` notified.
            cx.observe(&markdown, |_, _, cx| cx.notify()).detach();
            markdown_cache.push_front((
                MarkdownCacheKey::ForCandidate { candidate_id },
                markdown.clone(),
            ));
            Some((true, markdown))
        } else {
            debug_assert_eq!(markdown_cache.capacity(), MARKDOWN_CACHE_MAX_SIZE);
            // Moves the last cache entry to the start. The ring buffer is full, so this does no
            // copying and just shifts indexes.
            markdown_cache.rotate_right(1);
            markdown_cache[0].0 = MarkdownCacheKey::ForCandidate { candidate_id };
            let markdown = &markdown_cache[0].1;
            markdown.update(cx, |markdown, cx| markdown.reset(source.clone(), cx));
            Some((true, markdown.clone()))
        }
    }

    pub fn visible(&self) -> bool {
        self.entries.borrow().iter().any(|e| e.as_match().is_some())
    }

    fn origin(&self) -> ContextMenuOrigin {
        ContextMenuOrigin::Cursor
    }

    fn render(
        &self,
        style: &EditorStyle,
        max_height_in_lines: u32,
        window: &mut Window,
        cx: &mut Context<Editor>,
    ) -> AnyElement {
        let show_completion_documentation = self.show_completion_documentation;
        let editor_settings = EditorSettings::get_global(cx);
        let completion_detail_alignment = editor_settings.completion_detail_alignment;
        let completion_menu_item_kind = editor_settings.completion_menu_item_kind;
        let widest_completion_ix = if self.display_options.dynamic_width {
            let completions = self.completions.borrow();
            let widest_completion_ix = self
                .entries
                .borrow()
                .iter()
                .enumerate()
                .filter_map(|(ix, entry)| entry.as_match().map(|m| (ix, m)))
                .max_by_key(|(_, mat)| {
                    let completion = &completions[mat.candidate_id];
                    let documentation = &completion.documentation;

                    let mut len = completion.label.text.chars().count();
                    if let Some(CompletionDocumentation::SingleLine(text)) = documentation {
                        if show_completion_documentation {
                            len += text.chars().count();
                        }
                    }

                    len
                })
                .map(|(ix, _)| ix);
            drop(completions);
            widest_completion_ix
        } else {
            None
        };

        let selected_item = self.selected_item;
        let completions = self.completions.clone();
        let entries = self.entries.clone();
        let last_rendered_range = self.last_rendered_range.clone();
        let style = style.clone();
        let list = uniform_list(
            "completions",
            self.entries.borrow().len(),
            cx.processor(move |_editor, range: Range<usize>, _window, cx| {
                last_rendered_range.borrow_mut().replace(range.clone());
                let start_ix = range.start;
                let completions_guard = completions.borrow_mut();

                entries.borrow()[range]
                    .iter()
                    .enumerate()
                    .map(|(ix, entry)| {
                        let item_ix = start_ix + ix;

                        let Some(mat) = entry.as_match() else {
                            return match entry {
                                CompletionMenuEntry::GroupHeader(label) => div()
                                    .child(ListSubHeader::new(label.clone()).inset(true))
                                    .into_any_element(),
                                CompletionMenuEntry::Divider => h_flex()
                                    .flex_1()
                                    .size_full()
                                    .child(Divider::horizontal())
                                    .into_any_element(),
                                CompletionMenuEntry::Match(_) => unreachable!(),
                            };
                        };

                        let completion = &completions_guard[mat.candidate_id];
                        let documentation = if show_completion_documentation {
                            &completion.documentation
                        } else {
                            &None
                        };

                        let filter_start = completion.label.filter_range.start;

                        let highlights = gpui::combine_highlights(
                            mat.ranges().map(|range| {
                                (
                                    filter_start + range.start..filter_start + range.end,
                                    FontWeight::BOLD.into(),
                                )
                            }),
                            styled_runs_for_code_label(
                                &completion.label,
                                &style.syntax,
                                &style.local_player,
                            )
                            .map(|(range, mut highlight)| {
                                // Ignore font weight for syntax highlighting, as we'll use it
                                // for fuzzy matches.
                                highlight.font_weight = None;
                                if completion
                                    .source
                                    .lsp_completion(false)
                                    .and_then(|lsp_completion| {
                                        match (lsp_completion.deprecated, &lsp_completion.tags) {
                                            (Some(true), _) => Some(true),
                                            (_, Some(tags)) => {
                                                Some(tags.contains(&CompletionItemTag::DEPRECATED))
                                            }
                                            _ => None,
                                        }
                                    })
                                    .unwrap_or(false)
                                {
                                    highlight.strikethrough = Some(StrikethroughStyle {
                                        thickness: 1.0.into(),
                                        ..Default::default()
                                    });
                                    highlight.color = Some(cx.theme().colors().text_muted);
                                }

                                (range, highlight)
                            }),
                        );

                        let highlights: Vec<_> = highlights.collect();

                        let filter_range = &completion.label.filter_range;
                        let full_text = &completion.label.text;

                        let main_text: String = full_text[filter_range.clone()].to_string();
                        let main_highlights: Vec<_> = highlights
                            .iter()
                            .filter_map(|(range, highlight)| {
                                if range.end <= filter_range.start
                                    || range.start >= filter_range.end
                                {
                                    return None;
                                }
                                let clamped_start =
                                    range.start.max(filter_range.start) - filter_range.start;
                                let clamped_end =
                                    range.end.min(filter_range.end) - filter_range.start;
                                Some((clamped_start..clamped_end, (*highlight)))
                            })
                            .collect();
                        let main_label = StyledText::new(main_text)
                            .with_default_highlights(&style.text, main_highlights);

                        let suffix_text: String = full_text[filter_range.end..].to_string();
                        let suffix_highlights: Vec<_> = highlights
                            .iter()
                            .filter_map(|(range, highlight)| {
                                if range.end <= filter_range.end {
                                    return None;
                                }
                                let shifted_start = range.start.saturating_sub(filter_range.end);
                                let shifted_end = range.end - filter_range.end;
                                Some((shifted_start..shifted_end, (*highlight)))
                            })
                            .collect();
                        let suffix_label = if !suffix_text.is_empty() {
                            Some(
                                StyledText::new(suffix_text)
                                    .with_default_highlights(&style.text, suffix_highlights),
                            )
                        } else {
                            None
                        };

                        let left_aligned_suffix =
                            matches!(completion_detail_alignment, CompletionDetailAlignment::Left);

                        let right_aligned_suffix = matches!(
                            completion_detail_alignment,
                            CompletionDetailAlignment::Right,
                        );

                        let documentation_label = match documentation {
                            Some(CompletionDocumentation::SingleLine(text))
                            | Some(CompletionDocumentation::SingleLineAndMultiLinePlainText {
                                single_line: text,
                                ..
                            }) => {
                                if text.trim().is_empty() {
                                    None
                                } else {
                                    Some(
                                        Label::new(text.trim().to_string())
                                            .ml_4()
                                            .size(LabelSize::Small)
                                            .color(Color::Muted),
                                    )
                                }
                            }
                            _ => None,
                        };

                        let icon_or_color_slot = completion
                            .color()
                            .map(|color| {
                                div()
                                    .flex_shrink_0()
                                    .size_3p5()
                                    .rounded_xs()
                                    .bg(color)
                                    .into_any_element()
                            })
                            .or_else(|| {
                                completion.icon_path.as_ref().map(|path| {
                                    Icon::from_path(path)
                                        .size(IconSize::XSmall)
                                        .color(Color::Muted)
                                        .into_any_element()
                                })
                            });

                        let kind_letter_slot = match completion_menu_item_kind {
                            CompletionMenuItemKind::Off => None,
                            CompletionMenuItemKind::Symbol => Some(render_completion_kind_letter(
                                completion.kind(),
                                item_ix,
                                &style,
                            )),
                        };

                        let start_slot = match (kind_letter_slot, icon_or_color_slot) {
                            (Some(letter), Some(icon_or_color)) => Some(
                                h_flex()
                                    .gap_0p5()
                                    .child(letter)
                                    .child(icon_or_color)
                                    .into_any_element(),
                            ),
                            (Some(letter), None) => Some(letter),
                            (None, slot) => slot,
                        };

                        div()
                            .min_w(COMPLETION_MENU_MIN_WIDTH)
                            .max_w(COMPLETION_MENU_MAX_WIDTH)
                            .child(
                                ListItem::new(mat.candidate_id)
                                    .inset(true)
                                    .toggle_state(item_ix == selected_item)
                                    .on_click(cx.listener(move |editor, _event, window, cx| {
                                        cx.stop_propagation();
                                        if let Some(task) = editor.confirm_completion(
                                            &ConfirmCompletion {
                                                item_ix: Some(item_ix),
                                            },
                                            window,
                                            cx,
                                        ) {
                                            task.detach_and_log_err(cx)
                                        }
                                    }))
                                    .start_slot::<AnyElement>(start_slot)
                                    .child(
                                        h_flex()
                                            .min_w_0()
                                            .w_full()
                                            .when(left_aligned_suffix, |this| this.justify_start())
                                            .when(right_aligned_suffix, |this| {
                                                this.justify_between()
                                            })
                                            .child(
                                                div()
                                                    .flex_none()
                                                    .whitespace_nowrap()
                                                    .child(main_label),
                                            )
                                            .when_some(suffix_label, |this, suffix| {
                                                this.child(div().truncate().child(suffix))
                                            }),
                                    )
                                    .end_slot::<Label>(documentation_label),
                            )
                            .into_any_element()
                    })
                    .collect()
            }),
        )
        .occlude()
        .max_h(max_height_in_lines as f32 * window.line_height())
        .track_scroll(&self.scroll_handle)
        .with_sizing_behavior(ListSizingBehavior::Infer)
        .map(|this| {
            if self.display_options.dynamic_width {
                this.with_width_from_item(widest_completion_ix)
            } else {
                this.w(rems(34.))
            }
        });

        Popover::new()
            .child(
                div().child(list).custom_scrollbars(
                    Scrollbars::for_settings::<CompletionMenuScrollBarSetting>()
                        .show_along(ScrollAxes::Vertical)
                        .tracked_scroll_handle(&self.scroll_handle),
                    window,
                    cx,
                ),
            )
            .into_any_element()
    }

    fn render_aside(
        &mut self,
        max_size: Size<Pixels>,
        window: &mut Window,
        cx: &mut Context<Editor>,
    ) -> Option<AnyElement> {
        if !self.show_completion_documentation {
            return None;
        }

        let entries = self.entries.borrow();
        let Some(mat) = entries[self.selected_item].as_match() else {
            return None;
        };
        let completions = self.completions.borrow();
        let multiline_docs = match completions[mat.candidate_id].documentation.as_ref() {
            Some(CompletionDocumentation::MultiLinePlainText(text)) => div().child(text.clone()),
            Some(CompletionDocumentation::SingleLineAndMultiLinePlainText {
                plain_text: Some(text),
                ..
            }) => div().child(text.clone()),
            Some(CompletionDocumentation::MultiLineMarkdown(source)) if !source.is_empty() => {
                let Some((false, markdown)) = self.get_or_create_markdown(
                    mat.candidate_id,
                    Some(source),
                    true,
                    &completions,
                    cx,
                ) else {
                    return None;
                };
                Self::render_markdown(markdown, window, cx)
            }
            None => {
                // Handle the case where documentation hasn't yet been resolved but there's a
                // `new_text` match in the cache.
                //
                // TODO: It's inconsistent that documentation caching based on matching `new_text`
                // only works for markdown. Consider generally caching the results of resolving
                // completions.
                let Some((false, markdown)) =
                    self.get_or_create_markdown(mat.candidate_id, None, true, &completions, cx)
                else {
                    return None;
                };
                Self::render_markdown(markdown, window, cx)
            }
            Some(CompletionDocumentation::MultiLineMarkdown(_)) => return None,
            Some(CompletionDocumentation::SingleLine(_)) => return None,
            Some(CompletionDocumentation::Undocumented) => return None,
            Some(CompletionDocumentation::SingleLineAndMultiLinePlainText {
                plain_text: None,
                ..
            }) => {
                return None;
            }
        };

        Some(
            Popover::new()
                .child(
                    multiline_docs
                        .id("multiline_docs")
                        .px(MENU_ASIDE_X_PADDING / 2.)
                        .max_w(max_size.width)
                        .max_h(max_size.height)
                        .overflow_y_scroll()
                        .track_scroll(&self.scroll_handle_aside)
                        .occlude(),
                )
                .into_any_element(),
        )
    }

    fn render_markdown(
        markdown: Entity<Markdown>,
        window: &mut Window,
        cx: &mut Context<Editor>,
    ) -> Div {
        div().child(
            MarkdownElement::new(markdown, hover_markdown_style(window, cx))
                .code_block_renderer(markdown::CodeBlockRenderer::Default {
                    copy_button_visibility: CopyButtonVisibility::Hidden,
                    wrap_button_visibility: markdown::WrapButtonVisibility::Hidden,
                    border: false,
                })
                .on_url_click(open_markdown_url),
        )
    }

    pub fn filter(
        &mut self,
        query: Arc<String>,
        query_end: text::Anchor,
        buffer: &Entity<Buffer>,
        provider: Option<Rc<dyn CompletionProvider>>,
        window: &mut Window,
        cx: &mut Context<Editor>,
    ) {
        self.cancel_filter.store(true, Ordering::Relaxed);
        self.cancel_filter = Arc::new(AtomicBool::new(false));
        let matches = self.do_async_filtering(query, query_end, buffer, cx);
        let id = self.id;
        self.filter_task = cx.spawn_in(window, async move |editor, cx| {
            let matches = matches.await;
            editor
                .update_in(cx, |editor, window, cx| {
                    editor.with_completions_menu_matching_id(id, |this| {
                        if let Some(this) = this {
                            this.set_filter_results(matches, provider, window, cx);
                        }
                    });
                })
                .ok();
        });
    }

    pub fn do_async_filtering(
        &self,
        query: Arc<String>,
        query_end: text::Anchor,
        buffer: &Entity<Buffer>,
        cx: &Context<Editor>,
    ) -> Task<Vec<StringMatch>> {
        let buffer_snapshot = buffer.read(cx).snapshot();
        let background_executor = cx.background_executor().clone();
        let match_candidates = self.match_candidates.clone();
        let cancel_filter = self.cancel_filter.clone();
        let default_query = query.clone();

        let matches_task = cx.background_spawn(async move {
            let queries_and_candidates = match_candidates
                .iter()
                .map(|(query_start, candidates)| {
                    let query_for_batch = match query_start {
                        Some(start) => {
                            Arc::new(buffer_snapshot.text_for_range(*start..query_end).collect())
                        }
                        None => default_query.clone(),
                    };
                    (query_for_batch, candidates)
                })
                .collect_vec();

            let mut results = vec![];
            for (query, match_candidates) in queries_and_candidates {
                results.extend(
                    fuzzy::match_strings(
                        &match_candidates,
                        &query,
                        query.chars().any(|c| c.is_uppercase()),
                        false,
                        1000,
                        &cancel_filter,
                        background_executor.clone(),
                    )
                    .await,
                );
            }
            results
        });

        let completions = self.completions.clone();
        let sort_completions = self.sort_completions;
        let snippet_sort_order = self.snippet_sort_order;
        cx.foreground_executor().spawn(async move {
            let mut matches = matches_task.await;

            let completions_ref = completions.borrow();

            if sort_completions {
                matches = Self::sort_string_matches(
                    matches,
                    Some(&query), // used for non-snippets only
                    snippet_sort_order,
                    &completions_ref,
                );
            }

            // Remove duplicate snippet prefixes (e.g., "cool code" will match
            // the text "c c" in two places; we should only show the longer one)
            let mut snippets_seen = HashSet::<(usize, usize)>::default();
            matches.retain(|result| {
                match completions_ref[result.candidate_id].snippet_deduplication_key {
                    Some(key) => snippets_seen.insert(key),
                    None => true,
                }
            });

            matches
        })
    }

    pub fn set_filter_results(
        &mut self,
        matches: Vec<StringMatch>,
        provider: Option<Rc<dyn CompletionProvider>>,
        window: &mut Window,
        cx: &mut Context<Editor>,
    ) {
        let completions = self.completions.borrow();
        let mut entries: Vec<CompletionMenuEntry> = Vec::with_capacity(matches.len());
        let mut last_group: Option<&CompletionGroup> = None;
        for mat in matches {
            let group = completions[mat.candidate_id].group.as_ref();
            if group != last_group {
                if group.is_some() || last_group.is_some() {
                    if !entries.is_empty() {
                        entries.push(CompletionMenuEntry::Divider);
                    }
                    if let Some(label) = group.and_then(|g| g.label.as_ref()) {
                        entries.push(CompletionMenuEntry::GroupHeader(label.clone()));
                    }
                }
                last_group = group;
            }
            entries.push(CompletionMenuEntry::Match(mat));
        }
        drop(completions);
        *self.entries.borrow_mut() = entries.into_boxed_slice();
        self.selected_item = self.find_selectable_entry(0, true).unwrap_or(0);
        self.handle_selection_changed(provider.as_deref(), window, cx);
    }

    pub fn sort_string_matches(
        matches: Vec<StringMatch>,
        query: Option<&str>,
        snippet_sort_order: SnippetSortOrder,
        completions: &[Completion],
    ) -> Vec<StringMatch> {
        let mut matches = matches;

        #[derive(Debug, PartialEq, Eq, PartialOrd, Ord)]
        enum MatchTier<'a> {
            WordStartMatch {
                sort_exact: Reverse<i32>,
                sort_snippet: Reverse<i32>,
                sort_score: Reverse<OrderedFloat<f64>>,
                sort_positions: Vec<usize>,
                sort_exact_case_matches: Reverse<usize>,
                sort_text: Option<&'a str>,
                sort_kind: usize,
                sort_label: &'a str,
            },
            OtherMatch {
                sort_score: Reverse<OrderedFloat<f64>>,
            },
        }

        let query_start_lower = query
            .as_ref()
            .and_then(|q| q.chars().next())
            .and_then(|c| c.to_lowercase().next());

        if snippet_sort_order == SnippetSortOrder::None {
            matches
                .retain(|string_match| !completions[string_match.candidate_id].is_snippet_kind());
        }

        matches.sort_unstable_by_key(|string_match| {
            let completion = &completions[string_match.candidate_id];

            let sort_text = match &completion.source {
                CompletionSource::Lsp { lsp_completion, .. } => lsp_completion.sort_text.as_deref(),
                CompletionSource::Dap { sort_text } => Some(sort_text.as_str()),
                _ => None,
            };

            let (sort_kind, sort_label) = completion.sort_key();

            let score = string_match.score;
            let sort_score = Reverse(OrderedFloat(score));

            // Snippets do their own first-letter matching logic elsewhere.
            let is_snippet = completion.is_snippet_kind();
            let query_start_doesnt_match_split_words = !is_snippet
                && query_start_lower
                    .map(|query_char| {
                        !split_words(&string_match.string).any(|word| {
                            word.chars().next().and_then(|c| c.to_lowercase().next())
                                == Some(query_char)
                        })
                    })
                    .unwrap_or(false);

            if query_start_doesnt_match_split_words {
                MatchTier::OtherMatch { sort_score }
            } else {
                let sort_snippet = match snippet_sort_order {
                    SnippetSortOrder::Top => Reverse(if is_snippet { 1 } else { 0 }),
                    SnippetSortOrder::Bottom => Reverse(if is_snippet { 0 } else { 1 }),
                    SnippetSortOrder::Inline => Reverse(0),
                    SnippetSortOrder::None => Reverse(0),
                };
                let sort_positions = string_match.positions.clone();
                let sort_exact_case_matches = Reverse(exact_case_match_count(
                    query.unwrap_or_default(),
                    string_match,
                ));
                // This exact matching won't work for multi-word snippets, but it's fine
                let sort_exact = Reverse(if Some(completion.label.filter_text()) == query {
                    1
                } else {
                    0
                });

                MatchTier::WordStartMatch {
                    sort_exact,
                    sort_snippet,
                    sort_score,
                    sort_positions,
                    sort_exact_case_matches,
                    sort_text,
                    sort_kind,
                    sort_label,
                }
            }
        });

        matches
    }

    pub fn preserve_markdown_cache(&mut self, prev_menu: CompletionsMenu) {
        self.markdown_cache = prev_menu.markdown_cache.clone();

        // Convert ForCandidate cache keys to ForCompletionMatch keys.
        let prev_completions = prev_menu.completions.borrow();
        self.markdown_cache
            .borrow_mut()
            .retain_mut(|(key, _markdown)| match key {
                MarkdownCacheKey::ForCompletionMatch { .. } => true,
                MarkdownCacheKey::ForCandidate { candidate_id } => {
                    if let Some(completion) = prev_completions.get(*candidate_id) {
                        match &completion.documentation {
                            Some(CompletionDocumentation::MultiLineMarkdown(source)) => {
                                *key = MarkdownCacheKey::ForCompletionMatch {
                                    new_text: completion.new_text.clone(),
                                    markdown_source: source.clone(),
                                };
                                true
                            }
                            _ => false,
                        }
                    } else {
                        false
                    }
                }
            });
    }

    pub fn scroll_aside(
        &mut self,
        amount: ScrollAmount,
        window: &mut Window,
        cx: &mut Context<Editor>,
    ) {
        let mut offset = self.scroll_handle_aside.offset();

        offset.y -= amount.pixels(
            window.line_height(),
            self.scroll_handle_aside.bounds().size.height - px(16.),
        ) / 2.0;

        cx.notify();
        self.scroll_handle_aside.set_offset(offset);
    }
}

fn render_completion_kind_letter(
    kind: Option<CompletionItemKind>,
    item_ix: usize,
    style: &EditorStyle,
) -> AnyElement {
    let badge = div()
        .flex_none()
        .w(IconSize::XSmall.rems())
        .text_center()
        .text_size(rems_from_px(11.))
        .line_height(rems_from_px(14.));

    let Some(kind) = kind else {
        return badge.into_any_element();
    };
    let Some(letter) = completion_kind_letter(kind) else {
        return badge.into_any_element();
    };

    let color = completion_kind_highlight_name(kind)
        .and_then(|name| {
            style.syntax.style_for_name(name).or_else(|| {
                let (parent, _) = name.rsplit_once('.')?;
                style.syntax.style_for_name(parent)
            })
        })
        .and_then(|hl| hl.color);

    badge
        .id(("completion-kind", item_ix))
        .tooltip(Tooltip::text(completion_kind_name(kind)))
        .child(letter)
        .when_some(color, |element, color| element.text_color(color))
        .into_any_element()
}

fn completion_kind_name(kind: CompletionItemKind) -> &'static str {
    match kind {
        CompletionItemKind::TEXT => "Text",
        CompletionItemKind::METHOD => "Method",
        CompletionItemKind::FUNCTION => "Function",
        CompletionItemKind::CONSTRUCTOR => "Constructor",
        CompletionItemKind::FIELD => "Field",
        CompletionItemKind::VARIABLE => "Variable",
        CompletionItemKind::CLASS => "Class",
        CompletionItemKind::INTERFACE => "Interface",
        CompletionItemKind::MODULE => "Module",
        CompletionItemKind::PROPERTY => "Property",
        CompletionItemKind::UNIT => "Unit",
        CompletionItemKind::VALUE => "Value",
        CompletionItemKind::ENUM => "Enum",
        CompletionItemKind::KEYWORD => "Keyword",
        CompletionItemKind::SNIPPET => "Snippet",
        CompletionItemKind::COLOR => "Color",
        CompletionItemKind::FILE => "File",
        CompletionItemKind::REFERENCE => "Reference",
        CompletionItemKind::FOLDER => "Folder",
        CompletionItemKind::ENUM_MEMBER => "Enum Member",
        CompletionItemKind::CONSTANT => "Constant",
        CompletionItemKind::STRUCT => "Struct",
        CompletionItemKind::EVENT => "Event",
        CompletionItemKind::OPERATOR => "Operator",
        CompletionItemKind::TYPE_PARAMETER => "Type Parameter",
        _ => "Unknown",
    }
}

fn completion_kind_letter(kind: CompletionItemKind) -> Option<&'static str> {
    Some(match kind {
        CompletionItemKind::TEXT => "t",
        CompletionItemKind::METHOD => "m",
        CompletionItemKind::FUNCTION => "f",
        CompletionItemKind::CONSTRUCTOR => "C",
        CompletionItemKind::FIELD => "f",
        CompletionItemKind::VARIABLE => "v",
        CompletionItemKind::CLASS => "c",
        CompletionItemKind::INTERFACE => "i",
        CompletionItemKind::MODULE => "M",
        CompletionItemKind::PROPERTY => "p",
        CompletionItemKind::UNIT => "u",
        CompletionItemKind::VALUE => "v",
        CompletionItemKind::ENUM => "e",
        CompletionItemKind::KEYWORD => "k",
        CompletionItemKind::SNIPPET => "s",
        CompletionItemKind::COLOR => "c",
        CompletionItemKind::FILE => "F",
        CompletionItemKind::REFERENCE => "r",
        CompletionItemKind::FOLDER => "D",
        CompletionItemKind::ENUM_MEMBER => "e",
        CompletionItemKind::CONSTANT => "c",
        CompletionItemKind::STRUCT => "S",
        CompletionItemKind::EVENT => "E",
        CompletionItemKind::OPERATOR => "o",
        CompletionItemKind::TYPE_PARAMETER => "T",
        _ => return None,
    })
}

fn completion_kind_highlight_name(kind: CompletionItemKind) -> Option<&'static str> {
    Some(match kind {
        CompletionItemKind::CLASS => "type",
        CompletionItemKind::CONSTANT => "constant",
        CompletionItemKind::CONSTRUCTOR => "constructor",
        CompletionItemKind::ENUM => "enum",
        CompletionItemKind::ENUM_MEMBER => "variant",
        CompletionItemKind::FIELD => "property",
        CompletionItemKind::FUNCTION => "function",
        CompletionItemKind::INTERFACE => "type",
        CompletionItemKind::METHOD => "function.method",
        CompletionItemKind::MODULE => "namespace",
        CompletionItemKind::OPERATOR => "operator",
        CompletionItemKind::PROPERTY => "property",
        CompletionItemKind::STRUCT => "type",
        CompletionItemKind::TYPE_PARAMETER => "type",
        CompletionItemKind::VARIABLE => "variable",
        CompletionItemKind::KEYWORD => "keyword",
        CompletionItemKind::SNIPPET => "string",
        _ => return None,
    })
}

fn exact_case_match_count(query: &str, string_match: &StringMatch) -> usize {
    let mut exact_matches = 0;
    let mut query_chars = query.chars();
    let mut next_query_char = query_chars.next();
    let mut matched_positions = string_match.positions.iter().copied().peekable();

    for (index, candidate_char) in string_match.string.char_indices() {
        if matched_positions.peek() == Some(&index) {
            let Some(query_char) = next_query_char else {
                break;
            };

            if query_char == candidate_char {
                exact_matches += 1;
            }

            matched_positions.next();
            next_query_char = query_chars.next();
        }
    }

    exact_matches
}

#[derive(Clone)]
pub struct AvailableCodeAction {
    pub action: CodeAction,
    pub provider: Rc<dyn CodeActionProvider>,
}

#[derive(Clone)]
pub struct CodeActionContents {
    tasks: Option<Rc<ResolvedTasks>>,
    actions: Option<Rc<[AvailableCodeAction]>>,
    debug_scenarios: Vec<DebugScenario>,
    pub(crate) context: TaskContext,
}

impl CodeActionContents {
    pub(crate) fn new(
        tasks: Option<ResolvedTasks>,
        actions: Option<Rc<[AvailableCodeAction]>>,
        debug_scenarios: Vec<DebugScenario>,
        context: TaskContext,
    ) -> Self {
        Self {
            tasks: tasks.map(Rc::new),
            actions,
            debug_scenarios,
            context,
        }
    }

    pub fn tasks(&self) -> Option<&ResolvedTasks> {
        self.tasks.as_deref()
    }

    fn len(&self) -> usize {
        let tasks_len = self.tasks.as_ref().map_or(0, |tasks| tasks.templates.len());
        let code_actions_len = self.actions.as_ref().map_or(0, |actions| actions.len());
        tasks_len + code_actions_len + self.debug_scenarios.len()
    }

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

    fn iter(&self) -> impl Iterator<Item = CodeActionsItem> + '_ {
        self.tasks
            .iter()
            .flat_map(|tasks| {
                tasks
                    .templates
                    .iter()
                    .map(|(kind, task)| CodeActionsItem::Task(kind.clone(), task.clone()))
            })
            .chain(self.actions.iter().flat_map(|actions| {
                actions.iter().map(|available| CodeActionsItem::CodeAction {
                    action: available.action.clone(),
                    provider: available.provider.clone(),
                })
            }))
            .chain(
                self.debug_scenarios
                    .iter()
                    .cloned()
                    .map(CodeActionsItem::DebugScenario),
            )
    }

    pub fn get(&self, mut index: usize) -> Option<CodeActionsItem> {
        if let Some(tasks) = &self.tasks {
            if let Some((kind, task)) = tasks.templates.get(index) {
                return Some(CodeActionsItem::Task(kind.clone(), task.clone()));
            } else {
                index -= tasks.templates.len();
            }
        }
        if let Some(actions) = &self.actions {
            if let Some(available) = actions.get(index) {
                return Some(CodeActionsItem::CodeAction {
                    action: available.action.clone(),
                    provider: available.provider.clone(),
                });
            } else {
                index -= actions.len();
            }
        }

        self.debug_scenarios
            .get(index)
            .cloned()
            .map(CodeActionsItem::DebugScenario)
    }
}

#[derive(Clone)]
pub enum CodeActionsItem {
    Task(TaskSourceKind, ResolvedTask),
    CodeAction {
        action: CodeAction,
        provider: Rc<dyn CodeActionProvider>,
    },
    DebugScenario(DebugScenario),
}

impl CodeActionsItem {
    pub fn label(&self) -> String {
        match self {
            Self::CodeAction { action, .. } => action.lsp_action.title().to_owned(),
            Self::Task(_, task) => task.resolved_label.clone(),
            Self::DebugScenario(scenario) => scenario.label.to_string(),
        }
    }

    pub fn menu_label(&self) -> String {
        match self {
            Self::CodeAction { action, .. } => action.lsp_action.title().replace("\n", ""),
            Self::Task(_, task) => task.resolved_label.replace("\n", ""),
            Self::DebugScenario(scenario) => format!("debug: {}", scenario.label),
        }
    }
}

pub struct CodeActionsMenu {
    pub actions: CodeActionContents,
    pub buffer: Entity<Buffer>,
    pub selected_item: usize,
    pub scroll_handle: UniformListScrollHandle,
    pub deployed_from: Option<CodeActionSource>,
}

impl CodeActionsMenu {
    fn select_first(&mut self, cx: &mut Context<Editor>) {
        self.selected_item = if self.scroll_handle.y_flipped() {
            self.actions.len() - 1
        } else {
            0
        };
        self.scroll_handle
            .scroll_to_item(self.selected_item, ScrollStrategy::Top);
        cx.notify()
    }

    fn select_last(&mut self, cx: &mut Context<Editor>) {
        self.selected_item = if self.scroll_handle.y_flipped() {
            0
        } else {
            self.actions.len() - 1
        };
        self.scroll_handle
            .scroll_to_item(self.selected_item, ScrollStrategy::Top);
        cx.notify()
    }

    fn select_prev(&mut self, cx: &mut Context<Editor>) {
        self.selected_item = if self.scroll_handle.y_flipped() {
            self.next_match_index()
        } else {
            self.prev_match_index()
        };
        self.scroll_handle
            .scroll_to_item(self.selected_item, ScrollStrategy::Top);
        cx.notify();
    }

    fn select_next(&mut self, cx: &mut Context<Editor>) {
        self.selected_item = if self.scroll_handle.y_flipped() {
            self.prev_match_index()
        } else {
            self.next_match_index()
        };
        self.scroll_handle
            .scroll_to_item(self.selected_item, ScrollStrategy::Top);
        cx.notify();
    }

    fn prev_match_index(&self) -> usize {
        if self.selected_item > 0 {
            self.selected_item - 1
        } else {
            self.actions.len() - 1
        }
    }

    fn next_match_index(&self) -> usize {
        if self.selected_item + 1 < self.actions.len() {
            self.selected_item + 1
        } else {
            0
        }
    }

    pub fn visible(&self) -> bool {
        !self.actions.is_empty()
    }

    fn origin(&self) -> ContextMenuOrigin {
        match &self.deployed_from {
            Some(CodeActionSource::Indicator(row)) | Some(CodeActionSource::RunMenu(row)) => {
                ContextMenuOrigin::GutterIndicator(*row)
            }
            Some(CodeActionSource::QuickActionBar) => ContextMenuOrigin::QuickActionBar,
            None => ContextMenuOrigin::Cursor,
        }
    }

    fn render(
        &self,
        _style: &EditorStyle,
        max_height_in_lines: u32,
        window: &mut Window,
        cx: &mut Context<Editor>,
    ) -> AnyElement {
        let actions = self.actions.clone();
        let selected_item = self.selected_item;
        let is_quick_action_bar = matches!(self.origin(), ContextMenuOrigin::QuickActionBar);

        let list = uniform_list(
            "code_actions_menu",
            self.actions.len(),
            cx.processor(move |_this, range: Range<usize>, _, cx| {
                actions
                    .iter()
                    .skip(range.start)
                    .take(range.end - range.start)
                    .enumerate()
                    .map(|(ix, action)| {
                        let item_ix = range.start + ix;
                        let selected = item_ix == selected_item;
                        let colors = cx.theme().colors();

                        ListItem::new(item_ix)
                            .inset(true)
                            .toggle_state(selected)
                            .overflow_x()
                            .child(
                                div()
                                    .min_w(CODE_ACTION_MENU_MIN_WIDTH)
                                    .max_w(CODE_ACTION_MENU_MAX_WIDTH)
                                    .overflow_hidden()
                                    .text_ellipsis()
                                    .when(is_quick_action_bar, |this| this.text_ui(cx))
                                    .when(selected, |this| this.text_color(colors.text_accent))
                                    .child(action.menu_label()),
                            )
                            .on_click(cx.listener(move |editor, _, window, cx| {
                                cx.stop_propagation();
                                if let Some(task) = editor.confirm_code_action(
                                    &ConfirmCodeAction {
                                        item_ix: Some(item_ix),
                                    },
                                    window,
                                    cx,
                                ) {
                                    task.detach_and_log_err(cx)
                                }
                            }))
                    })
                    .collect()
            }),
        )
        .occlude()
        .max_h(max_height_in_lines as f32 * window.line_height())
        .track_scroll(&self.scroll_handle)
        .with_width_from_item(
            self.actions
                .iter()
                .enumerate()
                .max_by_key(|(_, action)| match action {
                    CodeActionsItem::Task(_, task) => task.resolved_label.chars().count(),
                    CodeActionsItem::CodeAction { action, .. } => {
                        action.lsp_action.title().chars().count()
                    }
                    CodeActionsItem::DebugScenario(scenario) => {
                        format!("debug: {}", scenario.label).chars().count()
                    }
                })
                .map(|(ix, _)| ix),
        )
        .with_sizing_behavior(ListSizingBehavior::Infer);

        Popover::new().child(list).into_any_element()
    }

    fn render_aside(
        &mut self,
        max_size: Size<Pixels>,
        window: &mut Window,
        _cx: &mut Context<Editor>,
    ) -> Option<AnyElement> {
        let Some(action) = self.actions.get(self.selected_item) else {
            return None;
        };

        let label = action.menu_label();
        let text_system = window.text_system();
        let mut line_wrapper = text_system.line_wrapper(
            window.text_style().font(),
            window.text_style().font_size.to_pixels(window.rem_size()),
        );
        let is_truncated = line_wrapper.should_truncate_line(
            &label,
            CODE_ACTION_MENU_MAX_WIDTH,
            "…",
            gpui::TruncateFrom::End,
        );

        if is_truncated.is_none() {
            return None;
        }

        Some(
            Popover::new()
                .child(
                    div()
                        .child(label)
                        .id("code_actions_menu_extended")
                        .px(MENU_ASIDE_X_PADDING / 2.)
                        .max_w(max_size.width)
                        .max_h(max_size.height)
                        .occlude(),
                )
                .into_any_element(),
        )
    }
}
