zed/crates/terminal/src/terminal.rs

pub mod mappings;

pub use alacritty_terminal;

mod pty_info;
pub mod terminal_settings;

use alacritty_terminal::{
    event::{Event as AlacTermEvent, EventListener, Notify, WindowSize},
    event_loop::{EventLoop, Msg, Notifier},
    grid::{Dimensions, Scroll as AlacScroll},
    index::{Boundary, Column, Direction as AlacDirection, Line, Point as AlacPoint},
    selection::{Selection, SelectionRange, SelectionType},
    sync::FairMutex,
    term::{
        cell::Cell,
        search::{Match, RegexIter, RegexSearch},
        Config, RenderableCursor, TermMode,
    },
    tty::{self, setup_env},
    vte::ansi::{ClearMode, Handler, NamedPrivateMode, PrivateMode, Rgb},
    Term,
};
use anyhow::{bail, Result};

use futures::{
    channel::mpsc::{unbounded, UnboundedReceiver, UnboundedSender},
    FutureExt,
};

use mappings::mouse::{
    alt_scroll, grid_point, grid_point_and_side, mouse_button_report, mouse_moved_report,
    scroll_report,
};

use collections::{HashMap, VecDeque};
use futures::StreamExt;
use pty_info::PtyProcessInfo;
use serde::{Deserialize, Serialize};
use settings::Settings;
use smol::channel::{Receiver, Sender};
use task::TaskId;
use terminal_settings::{AlternateScroll, Shell, TerminalBlink, TerminalSettings};
use theme::{ActiveTheme, Theme};
use util::truncate_and_trailoff;

use std::{
    cmp::{self, min},
    fmt::Display,
    ops::{Deref, Index, RangeInclusive},
    path::PathBuf,
    sync::Arc,
    time::Duration,
};
use thiserror::Error;

use gpui::{
    actions, black, px, AnyWindowHandle, AppContext, Bounds, ClipboardItem, EventEmitter, Hsla,
    Keystroke, ModelContext, Modifiers, MouseButton, MouseDownEvent, MouseMoveEvent, MouseUpEvent,
    Pixels, Point, Rgba, ScrollWheelEvent, Size, Task, TouchPhase,
};

use crate::mappings::{colors::to_alac_rgb, keys::to_esc_str};

actions!(
    terminal,
    [Clear, Copy, Paste, ShowCharacterPalette, SearchTest,]
);

///Scrolling is unbearably sluggish by default. Alacritty supports a configurable
///Scroll multiplier that is set to 3 by default. This will be removed when I
///Implement scroll bars.
#[cfg(target_os = "macos")]
const SCROLL_MULTIPLIER: f32 = 4.;
#[cfg(not(target_os = "macos"))]
const SCROLL_MULTIPLIER: f32 = 1.;
const MAX_SEARCH_LINES: usize = 100;
const DEBUG_TERMINAL_WIDTH: Pixels = px(500.);
const DEBUG_TERMINAL_HEIGHT: Pixels = px(30.);
const DEBUG_CELL_WIDTH: Pixels = px(5.);
const DEBUG_LINE_HEIGHT: Pixels = px(5.);

///Upward flowing events, for changing the title and such
#[derive(Clone, Debug)]
pub enum Event {
    TitleChanged,
    BreadcrumbsChanged,
    CloseTerminal,
    Bell,
    Wakeup,
    BlinkChanged,
    SelectionsChanged,
    NewNavigationTarget(Option<MaybeNavigationTarget>),
    Open(MaybeNavigationTarget),
}

#[derive(Clone, Debug)]
pub struct PathLikeTarget {
    /// File system path, absolute or relative, existing or not.
    /// Might have line and column number(s) attached as `file.rs:1:23`
    pub maybe_path: String,
    /// Current working directory of the terminal
    pub terminal_dir: Option<PathBuf>,
}

/// A string inside terminal, potentially useful as a URI that can be opened.
#[derive(Clone, Debug)]
pub enum MaybeNavigationTarget {
    /// HTTP, git, etc. string determined by the [`URL_REGEX`] regex.
    Url(String),
    /// File system path, absolute or relative, existing or not.
    /// Might have line and column number(s) attached as `file.rs:1:23`
    PathLike(PathLikeTarget),
}

#[derive(Clone)]
enum InternalEvent {
    ColorRequest(usize, Arc<dyn Fn(Rgb) -> String + Sync + Send + 'static>),
    Resize(TerminalSize),
    Clear,
    // FocusNextMatch,
    Scroll(AlacScroll),
    ScrollToAlacPoint(AlacPoint),
    SetSelection(Option<(Selection, AlacPoint)>),
    UpdateSelection(Point<Pixels>),
    // Adjusted mouse position, should open
    FindHyperlink(Point<Pixels>, bool),
    Copy,
}

///A translation struct for Alacritty to communicate with us from their event loop
#[derive(Clone)]
pub struct ZedListener(UnboundedSender<AlacTermEvent>);

impl EventListener for ZedListener {
    fn send_event(&self, event: AlacTermEvent) {
        self.0.unbounded_send(event).ok();
    }
}

pub fn init(cx: &mut AppContext) {
    TerminalSettings::register(cx);
}

#[derive(Clone, Copy, Debug, PartialEq, Eq, Serialize, Deserialize)]
pub struct TerminalSize {
    pub cell_width: Pixels,
    pub line_height: Pixels,
    pub size: Size<Pixels>,
}

impl TerminalSize {
    pub fn new(line_height: Pixels, cell_width: Pixels, size: Size<Pixels>) -> Self {
        TerminalSize {
            cell_width,
            line_height,
            size,
        }
    }

    pub fn num_lines(&self) -> usize {
        (self.size.height / self.line_height).floor() as usize
    }

    pub fn num_columns(&self) -> usize {
        (self.size.width / self.cell_width).floor() as usize
    }

    pub fn height(&self) -> Pixels {
        self.size.height
    }

    pub fn width(&self) -> Pixels {
        self.size.width
    }

    pub fn cell_width(&self) -> Pixels {
        self.cell_width
    }

    pub fn line_height(&self) -> Pixels {
        self.line_height
    }
}

impl Default for TerminalSize {
    fn default() -> Self {
        TerminalSize::new(
            DEBUG_LINE_HEIGHT,
            DEBUG_CELL_WIDTH,
            Size {
                width: DEBUG_TERMINAL_WIDTH,
                height: DEBUG_TERMINAL_HEIGHT,
            },
        )
    }
}

impl From<TerminalSize> for WindowSize {
    fn from(val: TerminalSize) -> Self {
        WindowSize {
            num_lines: val.num_lines() as u16,
            num_cols: val.num_columns() as u16,
            cell_width: f32::from(val.cell_width()) as u16,
            cell_height: f32::from(val.line_height()) as u16,
        }
    }
}

impl Dimensions for TerminalSize {
    /// Note: this is supposed to be for the back buffer's length,
    /// but we exclusively use it to resize the terminal, which does not
    /// use this method. We still have to implement it for the trait though,
    /// hence, this comment.
    fn total_lines(&self) -> usize {
        self.screen_lines()
    }

    fn screen_lines(&self) -> usize {
        self.num_lines()
    }

    fn columns(&self) -> usize {
        self.num_columns()
    }
}

#[derive(Error, Debug)]
pub struct TerminalError {
    pub directory: Option<PathBuf>,
    pub shell: Shell,
    pub source: std::io::Error,
}

impl TerminalError {
    pub fn fmt_directory(&self) -> String {
        self.directory
            .clone()
            .map(|path| {
                match path
                    .into_os_string()
                    .into_string()
                    .map_err(|os_str| format!("<non-utf8 path> {}", os_str.to_string_lossy()))
                {
                    Ok(s) => s,
                    Err(s) => s,
                }
            })
            .unwrap_or_else(|| {
                let default_dir =
                    dirs::home_dir().map(|buf| buf.into_os_string().to_string_lossy().to_string());
                match default_dir {
                    Some(dir) => format!("<none specified, using home directory> {}", dir),
                    None => "<none specified, could not find home directory>".to_string(),
                }
            })
    }

    pub fn shell_to_string(&self) -> String {
        match &self.shell {
            Shell::System => "<system shell>".to_string(),
            Shell::Program(p) => p.to_string(),
            Shell::WithArguments { program, args } => format!("{} {}", program, args.join(" ")),
        }
    }

    pub fn fmt_shell(&self) -> String {
        match &self.shell {
            Shell::System => "<system defined shell>".to_string(),
            Shell::Program(s) => s.to_string(),
            Shell::WithArguments { program, args } => format!("{} {}", program, args.join(" ")),
        }
    }
}

impl Display for TerminalError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        let dir_string: String = self.fmt_directory();
        let shell = self.fmt_shell();

        write!(
            f,
            "Working directory: {} Shell command: `{}`, IOError: {}",
            dir_string, shell, self.source
        )
    }
}

// https://github.com/alacritty/alacritty/blob/cb3a79dbf6472740daca8440d5166c1d4af5029e/extra/man/alacritty.5.scd?plain=1#L207-L213
const DEFAULT_SCROLL_HISTORY_LINES: usize = 10_000;
const MAX_SCROLL_HISTORY_LINES: usize = 100_000;

pub struct TerminalBuilder {
    terminal: Terminal,
    events_rx: UnboundedReceiver<AlacTermEvent>,
}

impl TerminalBuilder {
    #[allow(clippy::too_many_arguments)]
    pub fn new(
        working_directory: Option<PathBuf>,
        task: Option<TaskState>,
        shell: Shell,
        mut env: HashMap<String, String>,
        blink_settings: Option<TerminalBlink>,
        alternate_scroll: AlternateScroll,
        max_scroll_history_lines: Option<usize>,
        window: AnyWindowHandle,
        completion_tx: Sender<()>,
    ) -> Result<TerminalBuilder> {
        // TODO: Properly set the current locale,
        env.entry("LC_ALL".to_string())
            .or_insert_with(|| "en_US.UTF-8".to_string());

        env.insert("ZED_TERM".to_string(), "true".to_string());

        let pty_options = {
            let alac_shell = match shell.clone() {
                Shell::System => None,
                Shell::Program(program) => {
                    Some(alacritty_terminal::tty::Shell::new(program, Vec::new()))
                }
                Shell::WithArguments { program, args } => {
                    Some(alacritty_terminal::tty::Shell::new(program, args))
                }
            };

            alacritty_terminal::tty::Options {
                shell: alac_shell,
                working_directory: working_directory.clone(),
                hold: false,
                env: env.into_iter().collect(),
            }
        };

        // Setup Alacritty's env
        setup_env();

        let scrolling_history = if task.is_some() {
            // Tasks like `cargo build --all` may produce a lot of output, ergo allow maximum scrolling.
            // After the task finishes, we do not allow appending to that terminal, so small tasks output should not
            // cause excessive memory usage over time.
            MAX_SCROLL_HISTORY_LINES
        } else {
            max_scroll_history_lines
                .unwrap_or(DEFAULT_SCROLL_HISTORY_LINES)
                .min(MAX_SCROLL_HISTORY_LINES)
        };
        let config = Config {
            scrolling_history,
            ..Config::default()
        };

        //Spawn a task so the Alacritty EventLoop can communicate with us in a view context
        //TODO: Remove with a bounded sender which can be dispatched on &self
        let (events_tx, events_rx) = unbounded();
        //Set up the terminal...
        let mut term = Term::new(
            config,
            &TerminalSize::default(),
            ZedListener(events_tx.clone()),
        );

        //Start off blinking if we need to
        if let Some(TerminalBlink::On) = blink_settings {
            term.set_private_mode(PrivateMode::Named(NamedPrivateMode::BlinkingCursor));
        }

        //Alacritty defaults to alternate scrolling being on, so we just need to turn it off.
        if let AlternateScroll::Off = alternate_scroll {
            term.unset_private_mode(PrivateMode::Named(NamedPrivateMode::AlternateScroll));
        }

        let term = Arc::new(FairMutex::new(term));

        //Setup the pty...
        let pty = match tty::new(
            &pty_options,
            TerminalSize::default().into(),
            window.window_id().as_u64(),
        ) {
            Ok(pty) => pty,
            Err(error) => {
                bail!(TerminalError {
                    directory: working_directory,
                    shell,
                    source: error,
                });
            }
        };

        let pty_info = PtyProcessInfo::new(&pty);

        //And connect them together
        let event_loop = EventLoop::new(
            term.clone(),
            ZedListener(events_tx.clone()),
            pty,
            pty_options.hold,
            false,
        )?;

        //Kick things off
        let pty_tx = event_loop.channel();
        let _io_thread = event_loop.spawn(); // DANGER

        let url_regex = RegexSearch::new(r#"(ipfs:|ipns:|magnet:|mailto:|gemini://|gopher://|https://|http://|news:|file://|git://|ssh:|ftp://)[^\u{0000}-\u{001F}\u{007F}-\u{009F}<>"\s{-}\^⟨⟩`]+"#).unwrap();
        let word_regex = RegexSearch::new(r#"[\$\+\w.\[\]:/\\@\-~]+"#).unwrap();

        let terminal = Terminal {
            task,
            pty_tx: Notifier(pty_tx),
            completion_tx,
            term,
            events: VecDeque::with_capacity(10), //Should never get this high.
            last_content: Default::default(),
            last_mouse: None,
            matches: Vec::new(),
            selection_head: None,
            pty_info,
            breadcrumb_text: String::new(),
            scroll_px: px(0.),
            last_mouse_position: None,
            next_link_id: 0,
            selection_phase: SelectionPhase::Ended,
            secondary_pressed: false,
            hovered_word: false,
            url_regex,
            word_regex,
        };

        Ok(TerminalBuilder {
            terminal,
            events_rx,
        })
    }

    pub fn subscribe(mut self, cx: &mut ModelContext<Terminal>) -> Terminal {
        //Event loop
        cx.spawn(|terminal, mut cx| async move {
            while let Some(event) = self.events_rx.next().await {
                terminal.update(&mut cx, |terminal, cx| {
                    //Process the first event immediately for lowered latency
                    terminal.process_event(&event, cx);
                })?;

                'outer: loop {
                    let mut events = Vec::new();
                    let mut timer = cx
                        .background_executor()
                        .timer(Duration::from_millis(4))
                        .fuse();
                    let mut wakeup = false;
                    loop {
                        futures::select_biased! {
                            _ = timer => break,
                            event = self.events_rx.next() => {
                                if let Some(event) = event {
                                    if matches!(event, AlacTermEvent::Wakeup) {
                                        wakeup = true;
                                    } else {
                                        events.push(event);
                                    }

                                    if events.len() > 100 {
                                        break;
                                    }
                                } else {
                                    break;
                                }
                            },
                        }
                    }

                    if events.is_empty() && !wakeup {
                        smol::future::yield_now().await;
                        break 'outer;
                    }

                    terminal.update(&mut cx, |this, cx| {
                        if wakeup {
                            this.process_event(&AlacTermEvent::Wakeup, cx);
                        }

                        for event in events {
                            this.process_event(&event, cx);
                        }
                    })?;
                    smol::future::yield_now().await;
                }
            }

            anyhow::Ok(())
        })
        .detach();

        self.terminal
    }
}

#[derive(Debug, Clone, Deserialize, Serialize)]
pub struct IndexedCell {
    pub point: AlacPoint,
    pub cell: Cell,
}

impl Deref for IndexedCell {
    type Target = Cell;

    #[inline]
    fn deref(&self) -> &Cell {
        &self.cell
    }
}

// TODO: Un-pub
#[derive(Clone)]
pub struct TerminalContent {
    pub cells: Vec<IndexedCell>,
    pub mode: TermMode,
    pub display_offset: usize,
    pub selection_text: Option<String>,
    pub selection: Option<SelectionRange>,
    pub cursor: RenderableCursor,
    pub cursor_char: char,
    pub size: TerminalSize,
    pub last_hovered_word: Option<HoveredWord>,
}

#[derive(Clone)]
pub struct HoveredWord {
    pub word: String,
    pub word_match: RangeInclusive<AlacPoint>,
    pub id: usize,
}

impl Default for TerminalContent {
    fn default() -> Self {
        TerminalContent {
            cells: Default::default(),
            mode: Default::default(),
            display_offset: Default::default(),
            selection_text: Default::default(),
            selection: Default::default(),
            cursor: RenderableCursor {
                shape: alacritty_terminal::vte::ansi::CursorShape::Block,
                point: AlacPoint::new(Line(0), Column(0)),
            },
            cursor_char: Default::default(),
            size: Default::default(),
            last_hovered_word: None,
        }
    }
}

#[derive(PartialEq, Eq)]
pub enum SelectionPhase {
    Selecting,
    Ended,
}

pub struct Terminal {
    pty_tx: Notifier,
    completion_tx: Sender<()>,
    term: Arc<FairMutex<Term<ZedListener>>>,
    events: VecDeque<InternalEvent>,
    /// This is only used for mouse mode cell change detection
    last_mouse: Option<(AlacPoint, AlacDirection)>,
    /// This is only used for terminal hovered word checking
    last_mouse_position: Option<Point<Pixels>>,
    pub matches: Vec<RangeInclusive<AlacPoint>>,
    pub last_content: TerminalContent,
    pub selection_head: Option<AlacPoint>,
    pub breadcrumb_text: String,
    pub pty_info: PtyProcessInfo,
    scroll_px: Pixels,
    next_link_id: usize,
    selection_phase: SelectionPhase,
    secondary_pressed: bool,
    hovered_word: bool,
    url_regex: RegexSearch,
    word_regex: RegexSearch,
    task: Option<TaskState>,
}

pub struct TaskState {
    pub id: TaskId,
    pub full_label: String,
    pub label: String,
    pub command_label: String,
    pub status: TaskStatus,
    pub completion_rx: Receiver<()>,
}

/// A status of the current terminal tab's task.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum TaskStatus {
    /// The task had been started, but got cancelled or somehow otherwise it did not
    /// report its exit code before the terminal event loop was shut down.
    Unknown,
    /// The task is started and running currently.
    Running,
    /// After the start, the task stopped running and reported its error code back.
    Completed { success: bool },
}

impl TaskStatus {
    fn register_terminal_exit(&mut self) {
        if self == &Self::Running {
            *self = Self::Unknown;
        }
    }

    fn register_task_exit(&mut self, error_code: i32) {
        *self = TaskStatus::Completed {
            success: error_code == 0,
        };
    }
}

impl Terminal {
    fn process_event(&mut self, event: &AlacTermEvent, cx: &mut ModelContext<Self>) {
        match event {
            AlacTermEvent::Title(title) => {
                self.breadcrumb_text = title.to_string();
                cx.emit(Event::BreadcrumbsChanged);
            }
            AlacTermEvent::ResetTitle => {
                self.breadcrumb_text = String::new();
                cx.emit(Event::BreadcrumbsChanged);
            }
            AlacTermEvent::ClipboardStore(_, data) => {
                cx.write_to_clipboard(ClipboardItem::new(data.to_string()))
            }
            AlacTermEvent::ClipboardLoad(_, format) => self.write_to_pty(format(
                &cx.read_from_clipboard()
                    .map(|ci| ci.text().to_string())
                    .unwrap_or_else(|| "".to_string()),
            )),
            AlacTermEvent::PtyWrite(out) => self.write_to_pty(out.clone()),
            AlacTermEvent::TextAreaSizeRequest(format) => {
                self.write_to_pty(format(self.last_content.size.into()))
            }
            AlacTermEvent::CursorBlinkingChange => {
                cx.emit(Event::BlinkChanged);
            }
            AlacTermEvent::Bell => {
                cx.emit(Event::Bell);
            }
            AlacTermEvent::Exit => self.register_task_finished(None, cx),
            AlacTermEvent::MouseCursorDirty => {
                //NOOP, Handled in render
            }
            AlacTermEvent::Wakeup => {
                cx.emit(Event::Wakeup);

                if self.pty_info.has_changed() {
                    cx.emit(Event::TitleChanged);
                }
            }
            AlacTermEvent::ColorRequest(idx, fun_ptr) => {
                self.events
                    .push_back(InternalEvent::ColorRequest(*idx, fun_ptr.clone()));
            }
            AlacTermEvent::ChildExit(error_code) => {
                self.register_task_finished(Some(*error_code), cx);
            }
        }
    }

    pub fn selection_started(&self) -> bool {
        self.selection_phase == SelectionPhase::Selecting
    }

    pub fn get_cwd(&self) -> Option<PathBuf> {
        self.pty_info.current.as_ref().map(|info| info.cwd.clone())
    }

    ///Takes events from Alacritty and translates them to behavior on this view
    fn process_terminal_event(
        &mut self,
        event: &InternalEvent,
        term: &mut Term<ZedListener>,
        cx: &mut ModelContext<Self>,
    ) {
        match event {
            InternalEvent::ColorRequest(index, format) => {
                let color = term.colors()[*index].unwrap_or_else(|| {
                    to_alac_rgb(get_color_at_index(*index, cx.theme().as_ref()))
                });
                self.write_to_pty(format(color))
            }
            InternalEvent::Resize(mut new_size) => {
                new_size.size.height = cmp::max(new_size.line_height, new_size.height());
                new_size.size.width = cmp::max(new_size.cell_width, new_size.width());

                self.last_content.size = new_size;

                self.pty_tx.0.send(Msg::Resize(new_size.into())).ok();

                term.resize(new_size);
            }
            InternalEvent::Clear => {
                // Clear back buffer
                term.clear_screen(ClearMode::Saved);

                let cursor = term.grid().cursor.point;

                // Clear the lines above
                term.grid_mut().reset_region(..cursor.line);

                // Copy the current line up
                let line = term.grid()[cursor.line][..Column(term.grid().columns())]
                    .iter()
                    .cloned()
                    .enumerate()
                    .collect::<Vec<(usize, Cell)>>();

                for (i, cell) in line {
                    term.grid_mut()[Line(0)][Column(i)] = cell;
                }

                // Reset the cursor
                term.grid_mut().cursor.point =
                    AlacPoint::new(Line(0), term.grid_mut().cursor.point.column);
                let new_cursor = term.grid().cursor.point;

                // Clear the lines below the new cursor
                if (new_cursor.line.0 as usize) < term.screen_lines() - 1 {
                    term.grid_mut().reset_region((new_cursor.line + 1)..);
                }

                cx.emit(Event::Wakeup);
            }
            InternalEvent::Scroll(scroll) => {
                term.scroll_display(*scroll);
                self.refresh_hovered_word();
            }
            InternalEvent::SetSelection(selection) => {
                term.selection = selection.as_ref().map(|(sel, _)| sel.clone());

                #[cfg(target_os = "linux")]
                if let Some(selection_text) = term.selection_to_string() {
                    cx.write_to_primary(ClipboardItem::new(selection_text));
                }

                if let Some((_, head)) = selection {
                    self.selection_head = Some(*head);
                }
                cx.emit(Event::SelectionsChanged)
            }
            InternalEvent::UpdateSelection(position) => {
                if let Some(mut selection) = term.selection.take() {
                    let (point, side) = grid_point_and_side(
                        *position,
                        self.last_content.size,
                        term.grid().display_offset(),
                    );

                    selection.update(point, side);
                    term.selection = Some(selection);

                    #[cfg(target_os = "linux")]
                    if let Some(selection_text) = term.selection_to_string() {
                        cx.write_to_primary(ClipboardItem::new(selection_text));
                    }

                    self.selection_head = Some(point);
                    cx.emit(Event::SelectionsChanged)
                }
            }

            InternalEvent::Copy => {
                if let Some(txt) = term.selection_to_string() {
                    cx.write_to_clipboard(ClipboardItem::new(txt))
                }
            }
            InternalEvent::ScrollToAlacPoint(point) => {
                term.scroll_to_point(*point);
                self.refresh_hovered_word();
            }
            InternalEvent::FindHyperlink(position, open) => {
                let prev_hovered_word = self.last_content.last_hovered_word.take();

                let point = grid_point(
                    *position,
                    self.last_content.size,
                    term.grid().display_offset(),
                )
                .grid_clamp(term, Boundary::Grid);

                let link = term.grid().index(point).hyperlink();
                let found_word = if link.is_some() {
                    let mut min_index = point;
                    loop {
                        let new_min_index = min_index.sub(term, Boundary::Cursor, 1);
                        if new_min_index == min_index {
                            break;
                        } else if term.grid().index(new_min_index).hyperlink() != link {
                            break;
                        } else {
                            min_index = new_min_index
                        }
                    }

                    let mut max_index = point;
                    loop {
                        let new_max_index = max_index.add(term, Boundary::Cursor, 1);
                        if new_max_index == max_index {
                            break;
                        } else if term.grid().index(new_max_index).hyperlink() != link {
                            break;
                        } else {
                            max_index = new_max_index
                        }
                    }

                    let url = link.unwrap().uri().to_owned();
                    let url_match = min_index..=max_index;

                    Some((url, true, url_match))
                } else if let Some(word_match) = regex_match_at(term, point, &mut self.word_regex) {
                    let maybe_url_or_path =
                        term.bounds_to_string(*word_match.start(), *word_match.end());
                    let original_match = word_match.clone();
                    let (sanitized_match, sanitized_word) =
                        if maybe_url_or_path.starts_with('[') && maybe_url_or_path.ends_with(']') {
                            (
                                Match::new(
                                    word_match.start().add(term, Boundary::Cursor, 1),
                                    word_match.end().sub(term, Boundary::Cursor, 1),
                                ),
                                maybe_url_or_path[1..maybe_url_or_path.len() - 1].to_owned(),
                            )
                        } else {
                            (word_match, maybe_url_or_path)
                        };

                    let is_url = match regex_match_at(term, point, &mut self.url_regex) {
                        Some(url_match) => {
                            // `]` is a valid symbol in the `file://` URL, so the regex match will include it
                            // consider that when ensuring that the URL match is the same as the original word
                            if sanitized_match == original_match {
                                url_match == sanitized_match
                            } else {
                                url_match.start() == sanitized_match.start()
                                    && url_match.end() == original_match.end()
                            }
                        }
                        None => false,
                    };
                    Some((sanitized_word, is_url, sanitized_match))
                } else {
                    None
                };

                match found_word {
                    Some((maybe_url_or_path, is_url, url_match)) => {
                        if *open {
                            let target = if is_url {
                                MaybeNavigationTarget::Url(maybe_url_or_path)
                            } else {
                                MaybeNavigationTarget::PathLike(PathLikeTarget {
                                    maybe_path: maybe_url_or_path,
                                    terminal_dir: self.get_cwd(),
                                })
                            };
                            cx.emit(Event::Open(target));
                        } else {
                            self.update_selected_word(
                                prev_hovered_word,
                                url_match,
                                maybe_url_or_path,
                                is_url,
                                cx,
                            );
                        }
                        self.hovered_word = true;
                    }
                    None => {
                        if self.hovered_word {
                            cx.emit(Event::NewNavigationTarget(None));
                        }
                        self.hovered_word = false;
                    }
                }
            }
        }
    }

    fn update_selected_word(
        &mut self,
        prev_word: Option<HoveredWord>,
        word_match: RangeInclusive<AlacPoint>,
        word: String,
        is_url: bool,
        cx: &mut ModelContext<Self>,
    ) {
        if let Some(prev_word) = prev_word {
            if prev_word.word == word && prev_word.word_match == word_match {
                self.last_content.last_hovered_word = Some(HoveredWord {
                    word,
                    word_match,
                    id: prev_word.id,
                });
                return;
            }
        }

        self.last_content.last_hovered_word = Some(HoveredWord {
            word: word.clone(),
            word_match,
            id: self.next_link_id(),
        });
        let navigation_target = if is_url {
            MaybeNavigationTarget::Url(word)
        } else {
            MaybeNavigationTarget::PathLike(PathLikeTarget {
                maybe_path: word,
                terminal_dir: self.get_cwd(),
            })
        };
        cx.emit(Event::NewNavigationTarget(Some(navigation_target)));
    }

    fn next_link_id(&mut self) -> usize {
        let res = self.next_link_id;
        self.next_link_id = self.next_link_id.wrapping_add(1);
        res
    }

    pub fn last_content(&self) -> &TerminalContent {
        &self.last_content
    }

    //To test:
    //- Activate match on terminal (scrolling and selection)
    //- Editor search snapping behavior

    pub fn activate_match(&mut self, index: usize) {
        if let Some(search_match) = self.matches.get(index).cloned() {
            self.set_selection(Some((make_selection(&search_match), *search_match.end())));

            self.events
                .push_back(InternalEvent::ScrollToAlacPoint(*search_match.start()));
        }
    }

    pub fn select_matches(&mut self, matches: &[RangeInclusive<AlacPoint>]) {
        let matches_to_select = self
            .matches
            .iter()
            .filter(|self_match| matches.contains(self_match))
            .cloned()
            .collect::<Vec<_>>();
        for match_to_select in matches_to_select {
            self.set_selection(Some((
                make_selection(&match_to_select),
                *match_to_select.end(),
            )));
        }
    }

    pub fn select_all(&mut self) {
        let term = self.term.lock();
        let start = AlacPoint::new(term.topmost_line(), Column(0));
        let end = AlacPoint::new(term.bottommost_line(), term.last_column());
        drop(term);
        self.set_selection(Some((make_selection(&(start..=end)), end)));
    }

    fn set_selection(&mut self, selection: Option<(Selection, AlacPoint)>) {
        self.events
            .push_back(InternalEvent::SetSelection(selection));
    }

    pub fn copy(&mut self) {
        self.events.push_back(InternalEvent::Copy);
    }

    pub fn clear(&mut self) {
        self.events.push_back(InternalEvent::Clear)
    }

    ///Resize the terminal and the PTY.
    pub fn set_size(&mut self, new_size: TerminalSize) {
        if self.last_content.size != new_size {
            self.events.push_back(InternalEvent::Resize(new_size))
        }
    }

    ///Write the Input payload to the tty.
    fn write_to_pty(&self, input: String) {
        self.pty_tx.notify(input.into_bytes());
    }

    fn write_bytes_to_pty(&self, input: Vec<u8>) {
        self.pty_tx.notify(input);
    }

    pub fn input(&mut self, input: String) {
        self.events
            .push_back(InternalEvent::Scroll(AlacScroll::Bottom));
        self.events.push_back(InternalEvent::SetSelection(None));

        self.write_to_pty(input);
    }

    pub fn input_bytes(&mut self, input: Vec<u8>) {
        self.events
            .push_back(InternalEvent::Scroll(AlacScroll::Bottom));
        self.events.push_back(InternalEvent::SetSelection(None));

        self.write_bytes_to_pty(input);
    }

    pub fn try_keystroke(&mut self, keystroke: &Keystroke, alt_is_meta: bool) -> bool {
        let esc = to_esc_str(keystroke, &self.last_content.mode, alt_is_meta);
        if let Some(esc) = esc {
            self.input(esc);
            true
        } else {
            false
        }
    }

    pub fn try_modifiers_change(&mut self, modifiers: &Modifiers) -> bool {
        let changed = self.secondary_pressed != modifiers.secondary();
        if !self.secondary_pressed && modifiers.secondary() {
            self.refresh_hovered_word();
        }
        self.secondary_pressed = modifiers.secondary();
        changed
    }

    ///Paste text into the terminal
    pub fn paste(&mut self, text: &str) {
        let paste_text = if self.last_content.mode.contains(TermMode::BRACKETED_PASTE) {
            format!("{}{}{}", "\x1b[200~", text.replace('\x1b', ""), "\x1b[201~")
        } else {
            text.replace("\r\n", "\r").replace('\n', "\r")
        };

        self.input(paste_text);
    }

    pub fn sync(&mut self, cx: &mut ModelContext<Self>) {
        let term = self.term.clone();
        let mut terminal = term.lock_unfair();
        //Note that the ordering of events matters for event processing
        while let Some(e) = self.events.pop_front() {
            self.process_terminal_event(&e, &mut terminal, cx)
        }

        self.last_content = Self::make_content(&terminal, &self.last_content);
    }

    fn make_content(term: &Term<ZedListener>, last_content: &TerminalContent) -> TerminalContent {
        let content = term.renderable_content();
        TerminalContent {
            cells: content
                .display_iter
                //TODO: Add this once there's a way to retain empty lines
                // .filter(|ic| {
                //     !ic.flags.contains(Flags::HIDDEN)
                //         && !(ic.bg == Named(NamedColor::Background)
                //             && ic.c == ' '
                //             && !ic.flags.contains(Flags::INVERSE))
                // })
                .map(|ic| IndexedCell {
                    point: ic.point,
                    cell: ic.cell.clone(),
                })
                .collect::<Vec<IndexedCell>>(),
            mode: content.mode,
            display_offset: content.display_offset,
            selection_text: term.selection_to_string(),
            selection: content.selection,
            cursor: content.cursor,
            cursor_char: term.grid()[content.cursor.point].c,
            size: last_content.size,
            last_hovered_word: last_content.last_hovered_word.clone(),
        }
    }

    pub fn focus_in(&self) {
        if self.last_content.mode.contains(TermMode::FOCUS_IN_OUT) {
            self.write_to_pty("\x1b[I".to_string());
        }
    }

    pub fn focus_out(&mut self) {
        self.last_mouse_position = None;
        if self.last_content.mode.contains(TermMode::FOCUS_IN_OUT) {
            self.write_to_pty("\x1b[O".to_string());
        }
    }

    pub fn mouse_changed(&mut self, point: AlacPoint, side: AlacDirection) -> bool {
        match self.last_mouse {
            Some((old_point, old_side)) => {
                if old_point == point && old_side == side {
                    false
                } else {
                    self.last_mouse = Some((point, side));
                    true
                }
            }
            None => {
                self.last_mouse = Some((point, side));
                true
            }
        }
    }

    pub fn mouse_mode(&self, shift: bool) -> bool {
        self.last_content.mode.intersects(TermMode::MOUSE_MODE) && !shift
    }

    pub fn mouse_move(&mut self, e: &MouseMoveEvent, origin: Point<Pixels>) {
        let position = e.position - origin;
        self.last_mouse_position = Some(position);
        if self.mouse_mode(e.modifiers.shift) {
            let (point, side) = grid_point_and_side(
                position,
                self.last_content.size,
                self.last_content.display_offset,
            );

            if self.mouse_changed(point, side) {
                if let Some(bytes) = mouse_moved_report(point, e, self.last_content.mode) {
                    self.pty_tx.notify(bytes);
                }
            }
        } else if self.secondary_pressed {
            self.word_from_position(Some(position));
        }
    }

    fn word_from_position(&mut self, position: Option<Point<Pixels>>) {
        if self.selection_phase == SelectionPhase::Selecting {
            self.last_content.last_hovered_word = None;
        } else if let Some(position) = position {
            self.events
                .push_back(InternalEvent::FindHyperlink(position, false));
        }
    }

    pub fn mouse_drag(
        &mut self,
        e: &MouseMoveEvent,
        origin: Point<Pixels>,
        region: Bounds<Pixels>,
    ) {
        let position = e.position - origin;
        self.last_mouse_position = Some(position);

        if !self.mouse_mode(e.modifiers.shift) {
            self.selection_phase = SelectionPhase::Selecting;
            // Alacritty has the same ordering, of first updating the selection
            // then scrolling 15ms later
            self.events
                .push_back(InternalEvent::UpdateSelection(position));

            // Doesn't make sense to scroll the alt screen
            if !self.last_content.mode.contains(TermMode::ALT_SCREEN) {
                let scroll_delta = match self.drag_line_delta(e, region) {
                    Some(value) => value,
                    None => return,
                };

                let scroll_lines = (scroll_delta / self.last_content.size.line_height) as i32;

                self.events
                    .push_back(InternalEvent::Scroll(AlacScroll::Delta(scroll_lines)));
            }
        }
    }

    fn drag_line_delta(&mut self, e: &MouseMoveEvent, region: Bounds<Pixels>) -> Option<Pixels> {
        //TODO: Why do these need to be doubled? Probably the same problem that the IME has
        let top = region.origin.y + (self.last_content.size.line_height * 2.);
        let bottom = region.lower_left().y - (self.last_content.size.line_height * 2.);
        let scroll_delta = if e.position.y < top {
            (top - e.position.y).pow(1.1)
        } else if e.position.y > bottom {
            -((e.position.y - bottom).pow(1.1))
        } else {
            return None; //Nothing to do
        };
        Some(scroll_delta)
    }

    pub fn mouse_down(
        &mut self,
        e: &MouseDownEvent,
        origin: Point<Pixels>,
        _cx: &mut ModelContext<Self>,
    ) {
        let position = e.position - origin;
        let point = grid_point(
            position,
            self.last_content.size,
            self.last_content.display_offset,
        );

        if self.mouse_mode(e.modifiers.shift) {
            if let Some(bytes) =
                mouse_button_report(point, e.button, e.modifiers, true, self.last_content.mode)
            {
                self.pty_tx.notify(bytes);
            }
        } else {
            match e.button {
                MouseButton::Left => {
                    let position = e.position - origin;
                    let (point, side) = grid_point_and_side(
                        position,
                        self.last_content.size,
                        self.last_content.display_offset,
                    );

                    let selection_type = match e.click_count {
                        0 => return, //This is a release
                        1 => Some(SelectionType::Simple),
                        2 => Some(SelectionType::Semantic),
                        3 => Some(SelectionType::Lines),
                        _ => None,
                    };

                    let selection = selection_type
                        .map(|selection_type| Selection::new(selection_type, point, side));

                    if let Some(sel) = selection {
                        self.events
                            .push_back(InternalEvent::SetSelection(Some((sel, point))));
                    }
                }
                #[cfg(target_os = "linux")]
                MouseButton::Middle => {
                    if let Some(item) = _cx.read_from_primary() {
                        let text = item.text().to_string();
                        self.input(text);
                    }
                }
                _ => {}
            }
        }
    }

    pub fn mouse_up(
        &mut self,
        e: &MouseUpEvent,
        origin: Point<Pixels>,
        cx: &mut ModelContext<Self>,
    ) {
        let setting = TerminalSettings::get_global(cx);

        let position = e.position - origin;
        if self.mouse_mode(e.modifiers.shift) {
            let point = grid_point(
                position,
                self.last_content.size,
                self.last_content.display_offset,
            );

            if let Some(bytes) =
                mouse_button_report(point, e.button, e.modifiers, false, self.last_content.mode)
            {
                self.pty_tx.notify(bytes);
            }
        } else {
            if e.button == MouseButton::Left && setting.copy_on_select {
                self.copy();
            }

            //Hyperlinks
            if self.selection_phase == SelectionPhase::Ended {
                let mouse_cell_index = content_index_for_mouse(position, &self.last_content.size);
                if let Some(link) = self.last_content.cells[mouse_cell_index].hyperlink() {
                    cx.open_url(link.uri());
                } else if self.secondary_pressed {
                    self.events
                        .push_back(InternalEvent::FindHyperlink(position, true));
                }
            }
        }

        self.selection_phase = SelectionPhase::Ended;
        self.last_mouse = None;
    }

    ///Scroll the terminal
    pub fn scroll_wheel(&mut self, e: &ScrollWheelEvent, origin: Point<Pixels>) {
        let mouse_mode = self.mouse_mode(e.shift);

        if let Some(scroll_lines) = self.determine_scroll_lines(e, mouse_mode) {
            if mouse_mode {
                let point = grid_point(
                    e.position - origin,
                    self.last_content.size,
                    self.last_content.display_offset,
                );

                if let Some(scrolls) = scroll_report(point, scroll_lines, e, self.last_content.mode)
                {
                    for scroll in scrolls {
                        self.pty_tx.notify(scroll);
                    }
                };
            } else if self
                .last_content
                .mode
                .contains(TermMode::ALT_SCREEN | TermMode::ALTERNATE_SCROLL)
                && !e.shift
            {
                self.pty_tx.notify(alt_scroll(scroll_lines))
            } else {
                if scroll_lines != 0 {
                    let scroll = AlacScroll::Delta(scroll_lines);

                    self.events.push_back(InternalEvent::Scroll(scroll));
                }
            }
        }
    }

    fn refresh_hovered_word(&mut self) {
        self.word_from_position(self.last_mouse_position);
    }

    fn determine_scroll_lines(&mut self, e: &ScrollWheelEvent, mouse_mode: bool) -> Option<i32> {
        let scroll_multiplier = if mouse_mode { 1. } else { SCROLL_MULTIPLIER };
        let line_height = self.last_content.size.line_height;
        match e.touch_phase {
            /* Reset scroll state on started */
            TouchPhase::Started => {
                self.scroll_px = px(0.);
                None
            }
            /* Calculate the appropriate scroll lines */
            TouchPhase::Moved => {
                let old_offset = (self.scroll_px / line_height) as i32;

                self.scroll_px += e.delta.pixel_delta(line_height).y * scroll_multiplier;

                let new_offset = (self.scroll_px / line_height) as i32;

                // Whenever we hit the edges, reset our stored scroll to 0
                // so we can respond to changes in direction quickly
                self.scroll_px %= self.last_content.size.height();

                Some(new_offset - old_offset)
            }
            TouchPhase::Ended => None,
        }
    }

    pub fn find_matches(
        &mut self,
        mut searcher: RegexSearch,
        cx: &mut ModelContext<Self>,
    ) -> Task<Vec<RangeInclusive<AlacPoint>>> {
        let term = self.term.clone();
        cx.background_executor().spawn(async move {
            let term = term.lock();

            all_search_matches(&term, &mut searcher).collect()
        })
    }

    pub fn title(&self, truncate: bool) -> String {
        const MAX_CHARS: usize = 25;
        match &self.task {
            Some(task_state) => {
                if truncate {
                    truncate_and_trailoff(&task_state.label, MAX_CHARS)
                } else {
                    task_state.full_label.clone()
                }
            }
            None => self
                .pty_info
                .current
                .as_ref()
                .map(|fpi| {
                    let process_file = fpi
                        .cwd
                        .file_name()
                        .map(|name| name.to_string_lossy().to_string())
                        .unwrap_or_default();

                    let argv = fpi.argv.clone();
                    let process_name = format!(
                        "{}{}",
                        fpi.name,
                        if argv.len() >= 1 {
                            format!(" {}", (argv[1..]).join(" "))
                        } else {
                            "".to_string()
                        }
                    );
                    let (process_file, process_name) = if truncate {
                        (
                            truncate_and_trailoff(&process_file, MAX_CHARS),
                            truncate_and_trailoff(&process_name, MAX_CHARS),
                        )
                    } else {
                        (process_file, process_name)
                    };
                    format!("{process_file} — {process_name}")
                })
                .unwrap_or_else(|| "Terminal".to_string()),
        }
    }

    pub fn can_navigate_to_selected_word(&self) -> bool {
        self.secondary_pressed && self.hovered_word
    }

    pub fn task(&self) -> Option<&TaskState> {
        self.task.as_ref()
    }

    pub fn wait_for_completed_task(&self, cx: &mut AppContext) -> Task<()> {
        if let Some(task) = self.task() {
            if task.status == TaskStatus::Running {
                let mut completion_receiver = task.completion_rx.clone();
                return cx.spawn(|_| async move {
                    completion_receiver.next().await;
                });
            }
        }
        Task::ready(())
    }

    fn register_task_finished(
        &mut self,
        error_code: Option<i32>,
        cx: &mut ModelContext<'_, Terminal>,
    ) {
        self.completion_tx.try_send(()).ok();
        let task = match &mut self.task {
            Some(task) => task,
            None => {
                if error_code.is_none() {
                    cx.emit(Event::CloseTerminal);
                }
                return;
            }
        };
        if task.status != TaskStatus::Running {
            return;
        }
        match error_code {
            Some(error_code) => {
                task.status.register_task_exit(error_code);
            }
            None => {
                task.status.register_terminal_exit();
            }
        };

        let (task_line, command_line) = task_summary(task, error_code);
        // SAFETY: the invocation happens on non `TaskStatus::Running` tasks, once,
        // after either `AlacTermEvent::Exit` or `AlacTermEvent::ChildExit` events that are spawned
        // when Zed task finishes and no more output is made.
        // After the task summary is output once, no more text is appended to the terminal.
        unsafe { append_text_to_term(&mut self.term.lock(), &[&task_line, &command_line]) };
    }
}

const TASK_DELIMITER: &str = "⏵ ";
fn task_summary(task: &TaskState, error_code: Option<i32>) -> (String, String) {
    let escaped_full_label = task.full_label.replace("\r\n", "\r").replace('\n', "\r");
    let task_line = match error_code {
        Some(0) => {
            format!("{TASK_DELIMITER}Task `{escaped_full_label}` finished successfully")
        }
        Some(error_code) => {
            format!("{TASK_DELIMITER}Task `{escaped_full_label}` finished with non-zero error code: {error_code}")
        }
        None => {
            format!("{TASK_DELIMITER}Task `{escaped_full_label}` finished")
        }
    };
    let escaped_command_label = task.command_label.replace("\r\n", "\r").replace('\n', "\r");
    let command_line = format!("{TASK_DELIMITER}Command: '{escaped_command_label}'");
    (task_line, command_line)
}

/// Appends a stringified task summary to the terminal, after its output.
///
/// SAFETY: This function should only be called after terminal's PTY is no longer alive.
/// New text being added to the terminal here, uses "less public" APIs,
/// which are not maintaining the entire terminal state intact.
///
///
/// The library
///
/// * does not increment inner grid cursor's _lines_ on `input` calls
/// (but displaying the lines correctly and incrementing cursor's columns)
///
/// * ignores `\n` and \r` character input, requiring the `newline` call instead
///
/// * does not alter grid state after `newline` call
/// so its `bottommost_line` is always the same additions, and
/// the cursor's `point` is not updated to the new line and column values
///
/// * ??? there could be more consequences, and any further "proper" streaming from the PTY might bug and/or panic.
/// Still, concequent `append_text_to_term` invocations are possible and display the contents correctly.
///
/// Despite the quirks, this is the simplest approach to appending text to the terminal: its alternative, `grid_mut` manipulations,
/// do not properly set the scrolling state and display odd text after appending; also those manipulations are more tedious and error-prone.
/// The function achieves proper display and scrolling capabilities, at a cost of grid state not properly synchronized.
/// This is enough for printing moderately-sized texts like task summaries, but might break or perform poorly for larger texts.
unsafe fn append_text_to_term(term: &mut Term<ZedListener>, text_lines: &[&str]) {
    term.newline();
    term.grid_mut().cursor.point.column = Column(0);
    for line in text_lines {
        for c in line.chars() {
            term.input(c);
        }
        term.newline();
        term.grid_mut().cursor.point.column = Column(0);
    }
}

impl Drop for Terminal {
    fn drop(&mut self) {
        self.pty_tx.0.send(Msg::Shutdown).ok();
    }
}

impl EventEmitter<Event> for Terminal {}

/// Based on alacritty/src/display/hint.rs > regex_match_at
/// Retrieve the match, if the specified point is inside the content matching the regex.
fn regex_match_at<T>(term: &Term<T>, point: AlacPoint, regex: &mut RegexSearch) -> Option<Match> {
    visible_regex_match_iter(term, regex).find(|rm| rm.contains(&point))
}

/// Copied from alacritty/src/display/hint.rs:
/// Iterate over all visible regex matches.
pub fn visible_regex_match_iter<'a, T>(
    term: &'a Term<T>,
    regex: &'a mut RegexSearch,
) -> impl Iterator<Item = Match> + 'a {
    let viewport_start = Line(-(term.grid().display_offset() as i32));
    let viewport_end = viewport_start + term.bottommost_line();
    let mut start = term.line_search_left(AlacPoint::new(viewport_start, Column(0)));
    let mut end = term.line_search_right(AlacPoint::new(viewport_end, Column(0)));
    start.line = start.line.max(viewport_start - MAX_SEARCH_LINES);
    end.line = end.line.min(viewport_end + MAX_SEARCH_LINES);

    RegexIter::new(start, end, AlacDirection::Right, term, regex)
        .skip_while(move |rm| rm.end().line < viewport_start)
        .take_while(move |rm| rm.start().line <= viewport_end)
}

fn make_selection(range: &RangeInclusive<AlacPoint>) -> Selection {
    let mut selection = Selection::new(SelectionType::Simple, *range.start(), AlacDirection::Left);
    selection.update(*range.end(), AlacDirection::Right);
    selection
}

fn all_search_matches<'a, T>(
    term: &'a Term<T>,
    regex: &'a mut RegexSearch,
) -> impl Iterator<Item = Match> + 'a {
    let start = AlacPoint::new(term.grid().topmost_line(), Column(0));
    let end = AlacPoint::new(term.grid().bottommost_line(), term.grid().last_column());
    RegexIter::new(start, end, AlacDirection::Right, term, regex)
}

fn content_index_for_mouse(pos: Point<Pixels>, size: &TerminalSize) -> usize {
    let col = (pos.x / size.cell_width()).round() as usize;
    let clamped_col = min(col, size.columns() - 1);
    let row = (pos.y / size.line_height()).round() as usize;
    let clamped_row = min(row, size.screen_lines() - 1);
    clamped_row * size.columns() + clamped_col
}

/// Converts an 8 bit ANSI color to its GPUI equivalent.
/// Accepts `usize` for compatibility with the `alacritty::Colors` interface,
/// Other than that use case, should only be called with values in the [0,255] range
pub fn get_color_at_index(index: usize, theme: &Theme) -> Hsla {
    let colors = theme.colors();

    match index {
        // 0-15 are the same as the named colors above
        0 => colors.terminal_ansi_black,
        1 => colors.terminal_ansi_red,
        2 => colors.terminal_ansi_green,
        3 => colors.terminal_ansi_yellow,
        4 => colors.terminal_ansi_blue,
        5 => colors.terminal_ansi_magenta,
        6 => colors.terminal_ansi_cyan,
        7 => colors.terminal_ansi_white,
        8 => colors.terminal_ansi_bright_black,
        9 => colors.terminal_ansi_bright_red,
        10 => colors.terminal_ansi_bright_green,
        11 => colors.terminal_ansi_bright_yellow,
        12 => colors.terminal_ansi_bright_blue,
        13 => colors.terminal_ansi_bright_magenta,
        14 => colors.terminal_ansi_bright_cyan,
        15 => colors.terminal_ansi_bright_white,
        // 16-231 are mapped to their RGB colors on a 0-5 range per channel
        16..=231 => {
            let (r, g, b) = rgb_for_index(index as u8); // Split the index into its ANSI-RGB components
            let step = (u8::MAX as f32 / 5.).floor() as u8; // Split the RGB range into 5 chunks, with floor so no overflow
            rgba_color(r * step, g * step, b * step) // Map the ANSI-RGB components to an RGB color
        }
        // 232-255 are a 24 step grayscale from black to white
        232..=255 => {
            let i = index as u8 - 232; // Align index to 0..24
            let step = (u8::MAX as f32 / 24.).floor() as u8; // Split the RGB grayscale values into 24 chunks
            rgba_color(i * step, i * step, i * step) // Map the ANSI-grayscale components to the RGB-grayscale
        }
        // For compatibility with the alacritty::Colors interface
        256 => colors.text,
        257 => colors.background,
        258 => theme.players().local().cursor,
        259 => colors.terminal_ansi_dim_black,
        260 => colors.terminal_ansi_dim_red,
        261 => colors.terminal_ansi_dim_green,
        262 => colors.terminal_ansi_dim_yellow,
        263 => colors.terminal_ansi_dim_blue,
        264 => colors.terminal_ansi_dim_magenta,
        265 => colors.terminal_ansi_dim_cyan,
        266 => colors.terminal_ansi_dim_white,
        267 => colors.terminal_bright_foreground,
        268 => colors.terminal_ansi_black, // 'Dim Background', non-standard color

        _ => black(),
    }
}

/// Generates the RGB channels in [0, 5] for a given index into the 6x6x6 ANSI color cube.
/// See: [8 bit ANSI color](https://en.wikipedia.org/wiki/ANSI_escape_code#8-bit).
///
/// Wikipedia gives a formula for calculating the index for a given color:
///
/// ```
/// index = 16 + 36 × r + 6 × g + b (0 ≤ r, g, b ≤ 5)
/// ```
///
/// This function does the reverse, calculating the `r`, `g`, and `b` components from a given index.
fn rgb_for_index(i: u8) -> (u8, u8, u8) {
    debug_assert!((16..=231).contains(&i));
    let i = i - 16;
    let r = (i - (i % 36)) / 36;
    let g = ((i % 36) - (i % 6)) / 6;
    let b = (i % 36) % 6;
    (r, g, b)
}

pub fn rgba_color(r: u8, g: u8, b: u8) -> Hsla {
    Rgba {
        r: (r as f32 / 255.),
        g: (g as f32 / 255.),
        b: (b as f32 / 255.),
        a: 1.,
    }
    .into()
}

#[cfg(test)]
mod tests {
    use alacritty_terminal::{
        index::{Column, Line, Point as AlacPoint},
        term::cell::Cell,
    };
    use gpui::{point, size, Pixels};
    use rand::{distributions::Alphanumeric, rngs::ThreadRng, thread_rng, Rng};

    use crate::{
        content_index_for_mouse, rgb_for_index, IndexedCell, TerminalContent, TerminalSize,
    };

    #[test]
    fn test_rgb_for_index() {
        // Test every possible value in the color cube.
        for i in 16..=231 {
            let (r, g, b) = rgb_for_index(i);
            assert_eq!(i, 16 + 36 * r + 6 * g + b);
        }
    }

    #[test]
    fn test_mouse_to_cell_test() {
        let mut rng = thread_rng();
        const ITERATIONS: usize = 10;
        const PRECISION: usize = 1000;

        for _ in 0..ITERATIONS {
            let viewport_cells = rng.gen_range(15..20);
            let cell_size = rng.gen_range(5 * PRECISION..20 * PRECISION) as f32 / PRECISION as f32;

            let size = crate::TerminalSize {
                cell_width: Pixels::from(cell_size),
                line_height: Pixels::from(cell_size),
                size: size(
                    Pixels::from(cell_size * (viewport_cells as f32)),
                    Pixels::from(cell_size * (viewport_cells as f32)),
                ),
            };

            let cells = get_cells(size, &mut rng);
            let content = convert_cells_to_content(size, &cells);

            for row in 0..(viewport_cells - 1) {
                let row = row as usize;
                for col in 0..(viewport_cells - 1) {
                    let col = col as usize;

                    let row_offset = rng.gen_range(0..PRECISION) as f32 / PRECISION as f32;
                    let col_offset = rng.gen_range(0..PRECISION) as f32 / PRECISION as f32;

                    let mouse_pos = point(
                        Pixels::from(col as f32 * cell_size + col_offset),
                        Pixels::from(row as f32 * cell_size + row_offset),
                    );

                    let content_index = content_index_for_mouse(mouse_pos, &content.size);
                    let mouse_cell = content.cells[content_index].c;
                    let real_cell = cells[row][col];

                    assert_eq!(mouse_cell, real_cell);
                }
            }
        }
    }

    #[test]
    fn test_mouse_to_cell_clamp() {
        let mut rng = thread_rng();

        let size = crate::TerminalSize {
            cell_width: Pixels::from(10.),
            line_height: Pixels::from(10.),
            size: size(Pixels::from(100.), Pixels::from(100.)),
        };

        let cells = get_cells(size, &mut rng);
        let content = convert_cells_to_content(size, &cells);

        assert_eq!(
            content.cells[content_index_for_mouse(
                point(Pixels::from(-10.), Pixels::from(-10.)),
                &content.size,
            )]
            .c,
            cells[0][0]
        );
        assert_eq!(
            content.cells[content_index_for_mouse(
                point(Pixels::from(1000.), Pixels::from(1000.)),
                &content.size,
            )]
            .c,
            cells[9][9]
        );
    }

    fn get_cells(size: TerminalSize, rng: &mut ThreadRng) -> Vec<Vec<char>> {
        let mut cells = Vec::new();

        for _ in 0..((size.height() / size.line_height()) as usize) {
            let mut row_vec = Vec::new();
            for _ in 0..((size.width() / size.cell_width()) as usize) {
                let cell_char = rng.sample(Alphanumeric) as char;
                row_vec.push(cell_char)
            }
            cells.push(row_vec)
        }

        cells
    }

    fn convert_cells_to_content(size: TerminalSize, cells: &Vec<Vec<char>>) -> TerminalContent {
        let mut ic = Vec::new();

        for row in 0..cells.len() {
            for col in 0..cells[row].len() {
                let cell_char = cells[row][col];
                ic.push(IndexedCell {
                    point: AlacPoint::new(Line(row as i32), Column(col)),
                    cell: Cell {
                        c: cell_char,
                        ..Default::default()
                    },
                });
            }
        }

        TerminalContent {
            cells: ic,
            size,
            ..Default::default()
        }
    }
}