gpui/

platform.rs

mod color_presentation;
pub use color_presentation::{WindowColorFallback, WindowColorMode, WindowColorStatus};

mod app_menu;
mod keyboard;
mod keystroke;

#[cfg(all(target_os = "linux", feature = "wayland"))]
#[expect(missing_docs)]
pub mod layer_shell;

/// Types for configuring parent-anchored popup windows such as menus, dropdowns and tooltips.
pub mod popup;

#[cfg(any(test, feature = "test-support", feature = "bench-support"))]
mod threaded_dispatcher;

#[cfg(any(test, feature = "test-support", feature = "bench-support"))]
mod test;

#[cfg(all(target_os = "macos", any(test, feature = "test-support")))]
mod visual_test;

#[cfg(all(
    feature = "screen-capture",
    any(target_os = "windows", target_os = "linux", target_os = "freebsd",)
))]
pub mod scap_screen_capture;

#[cfg(all(
    any(target_os = "windows", target_os = "linux"),
    feature = "screen-capture"
))]
pub(crate) type PlatformScreenCaptureFrame = scap::frame::Frame;
#[cfg(not(feature = "screen-capture"))]
pub(crate) type PlatformScreenCaptureFrame = ();
#[cfg(all(target_os = "macos", feature = "screen-capture"))]
pub(crate) type PlatformScreenCaptureFrame =
    objc2_core_foundation::CFRetained<objc2_core_video::CVImageBuffer>;

use crate::{
    Action, AnyWindowHandle, App, AsyncWindowContext, BackgroundExecutor, Bounds,
    DEFAULT_WINDOW_SIZE, DevicePixels, DispatchEventResult, Edges, ExternalDragPayload, Font,
    FontId, FontMetrics, FontRun, ForegroundExecutor, GlyphId, GpuSpecs, Hsla, ImageSource, Keymap,
    LineLayout, MissingGlyphSink, Pixels, PlatformGestures, PlatformInput, Point, Priority,
    RenderGlyphParams, RenderImage, RenderImageParams, RenderSvgParams, Scene, ShapedGlyph,
    ShapedRun, SharedString, Size, SvgRenderer, SystemWindowTab, Task, Window, WindowControlArea,
    hash, point, px, size,
};
#[cfg(any(target_os = "linux", target_os = "freebsd"))]
use anyhow::bail;
use anyhow::{Context as _, Result};
use async_task::Runnable;
use collections::FxHashMap;
use futures::channel::oneshot;
#[cfg(any(test, feature = "test-support", feature = "bench-support"))]
use image::RgbaImage;
use image::codecs::gif::GifDecoder;
use image::{AnimationDecoder as _, DynamicImage, Frame};
use raw_window_handle::{HasDisplayHandle, HasWindowHandle};
use scheduler::Instant;
pub use scheduler::RunnableMeta;
use schemars::JsonSchema;
use seahash::SeaHasher;
use serde::{Deserialize, Serialize};
use smallvec::SmallVec;
use std::borrow::Cow;
use std::collections::hash_map::Entry;
use std::hash::{Hash, Hasher};
use std::io::Cursor;
use std::ops;
use std::time::Duration;
use std::{
    ffi::OsString,
    fmt::{self, Debug},
    ops::Range,
    path::{Path, PathBuf},
    rc::Rc,
    sync::Arc,
};
use strum::EnumIter;
use uuid::Uuid;

pub use app_menu::*;
pub use keyboard::*;
pub use keystroke::*;

/// Whether the platform is presenting a window's frames.
///
/// This is about presentation, not the window's shown/hidden state: a shown
/// window that is fully covered by other windows, minimized, on another
/// Space or virtual desktop, or on a display that is asleep is `Hidden`. A
/// window only partly covered by other windows is `Visible`.
///
/// Each platform reports from a single source, and what that source can see
/// differs:
///
/// * macOS: `NSWindow.occlusionState`. Covers all of the cases above.
/// * Windows: `WS_VISIBLE` and the minimized state. Windows keeps compositing
///   covered windows for thumbnails and Alt-Tab and offers no occlusion
///   notification, so a fully covered window stays `Visible`. Display sleep is
///   not reported either.
/// * Wayland: the `xdg_toplevel` `suspended` state (xdg-shell v6). Compositors
///   that don't support it never report `Hidden`.
/// * X11: mapped state plus `VisibilityNotify`. Compositing window managers
///   generally never report a window as fully obscured, so covering is only
///   detected without compositing.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum WindowVisibility {
    /// At least part of the window is being presented; frames drawn for it
    /// will be shown.
    Visible,
    /// No part of the window is being presented. The platform will not
    /// request frames for it until it becomes visible again.
    Hidden,
}

impl WindowVisibility {
    /// Whether frames drawn for the window will be shown.
    pub fn is_visible(self) -> bool {
        self == Self::Visible
    }
}

/// A change to the connected displays, reported through
/// [`App::observe_displays`](crate::App::observe_displays).
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
#[non_exhaustive]
pub enum DisplayEvent {
    /// A display was connected.
    Added(DisplayId),
    /// A display was disconnected. Windows on it are moved to another
    /// display by the platform.
    Removed(DisplayId),
    /// A connected display's properties changed.
    Changed {
        /// The display that changed.
        id: DisplayId,
        /// Which of its properties changed.
        changes: DisplayChanges,
    },
}

bitflags::bitflags! {
    /// The properties of a display that a [`DisplayEvent::Changed`] reports.
    #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
    pub struct DisplayChanges: u8 {
        /// [`PlatformDisplay::bounds`] changed.
        const BOUNDS = 1 << 0;
        /// [`PlatformDisplay::refresh_interval`] changed.
        const REFRESH_INTERVAL = 1 << 1;
    }
}

/// Converts a refresh rate in hertz to the time between refreshes, rejecting
/// the zero, negative, and non-finite rates platforms use to mean "unknown".
pub fn refresh_interval_from_hz(hertz: f64) -> Option<Duration> {
    (hertz.is_finite() && hertz > 0.0).then(|| Duration::from_secs_f64(1.0 / hertz))
}

/// Controls whether the application participates in the system's foreground UI.
///
/// Only has an effect on macOS; other platforms ignore this setting. There,
/// [`App::request_windowing`] sets it: `Accessory` while headless and `Regular` while windowed.
/// Set it directly with [`App::set_activation_policy`] for the one case that doesn't cover: an
/// accessory app that shows windows, such as a menu bar utility.
#[derive(Debug, Default, Clone, Copy, PartialEq, Eq)]
pub enum ActivationPolicy {
    /// Participate in foreground application UI, such as the Dock and menu bar on macOS.
    #[default]
    Regular,
    /// Run without foreground application UI while retaining the ability to open windows.
    Accessory,
}

#[cfg(any(test, feature = "test-support", feature = "bench-support"))]
pub(crate) use test::*;

#[cfg(any(test, feature = "test-support"))]
pub use test::{TestDispatcher, TestScreenCaptureSource, TestScreenCaptureStream};

#[cfg(any(test, feature = "test-support", feature = "bench-support"))]
pub use threaded_dispatcher::ThreadedDispatcher;

#[cfg(all(target_os = "macos", any(test, feature = "test-support")))]
pub use visual_test::VisualTestPlatform;

/// Keeps an operating system activity, such as an idle sleep inhibitor, alive until dropped.
pub struct ActivityGuard {
    _release: gpui_util::Deferred<Box<dyn FnOnce() + Send>>,
}

impl ActivityGuard {
    /// Runs `release` when the guard is dropped.
    pub fn new(release: impl FnOnce() + Send + 'static) -> Self {
        Self {
            _release: gpui_util::defer(Box::new(release)),
        }
    }

    /// A guard for platforms without a corresponding activity.
    pub fn noop() -> Self {
        Self::new(|| {})
    }
}

// TODO(jk): return an enum instead of a string
/// Return which compositor we're guessing we'll use.
/// Does not attempt to connect to the given compositor.
#[cfg(any(target_os = "linux", target_os = "freebsd"))]
#[inline]
pub fn guess_compositor() -> &'static str {
    if std::env::var_os("ZED_HEADLESS").is_some() {
        return "Headless";
    }
    GraphicalEnvironment::detect().guess_compositor()
}

/// The graphical session to connect to: the variables that locate its display server, as some
/// process sees them.
///
/// A long-running process can outlive the graphical session it was started in, so a platform
/// that attaches to a display server later can be given a fresher environment than its own.
/// While connected, programs the platform launches (for example to open a URL) get these
/// variables instead of the ones this process started with. Apply
/// [`App::graphical_environment`] to the programs an app launches, for the same reason.
#[cfg(any(target_os = "linux", target_os = "freebsd"))]
#[derive(Clone, Debug, Default)]
pub struct GraphicalEnvironment {
    /// `WAYLAND_DISPLAY`: a socket name relative to `xdg_runtime_dir`, or an absolute path.
    pub wayland_display: Option<OsString>,
    /// `DISPLAY`: the X11 display name.
    pub x11_display: Option<OsString>,
    /// `XDG_RUNTIME_DIR`: the directory containing Wayland sockets.
    pub xdg_runtime_dir: Option<OsString>,
    /// `XDG_ACTIVATION_TOKEN`: lets the first window take focus on Wayland.
    ///
    /// A platform takes this process's token from its environment when it's created, and uses
    /// it if it starts windowed. Pass one here to switch to windowed mode later, for example
    /// the token of the process that asked for a window.
    pub activation_token: Option<String>,
}

/// The graphical session to connect to: the Windows session whose desktop windows appear on.
///
/// A process can only show windows in its own session, so switching to windowed mode fails if
/// this names another one, for example when a process started over SSH is asked to show a
/// window on the desktop.
#[cfg(target_os = "windows")]
#[derive(Clone, Debug, Default)]
pub struct GraphicalEnvironment {
    /// The session ID, as `ProcessIdToSessionId` reports it. `None` means this process's own
    /// session.
    pub session_id: Option<u32>,
}

#[cfg(target_os = "windows")]
impl GraphicalEnvironment {
    /// Returns the environment of this process's session.
    pub fn detect() -> Self {
        let mut session_id = 0;
        // SAFETY: `session_id` is a valid pointer for the call's duration.
        let result = unsafe {
            windows::Win32::System::RemoteDesktop::ProcessIdToSessionId(
                windows::Win32::System::Threading::GetCurrentProcessId(),
                &mut session_id,
            )
        };
        Self {
            session_id: result.is_ok().then_some(session_id),
        }
    }

    /// Does nothing on this platform: programs inherit the session of the process that
    /// starts them.
    pub fn apply_to(&self, _command: &mut std::process::Command) {}
}

/// The graphical session to connect to. Carries nothing yet on this platform.
#[cfg(not(any(target_os = "linux", target_os = "freebsd", target_os = "windows")))]
#[derive(Clone, Debug, Default)]
pub struct GraphicalEnvironment;

#[cfg(not(any(target_os = "linux", target_os = "freebsd", target_os = "windows")))]
impl GraphicalEnvironment {
    /// Returns the environment of this process's graphical session.
    pub fn detect() -> Self {
        Self
    }

    /// Does nothing on this platform.
    pub fn apply_to(&self, _command: &mut std::process::Command) {}
}

/// A display mode for [`App::request_windowing`] to switch to.
#[derive(Clone, Debug)]
pub enum WindowingRequest {
    /// No display server. Windows lay out and handle input but draw nothing.
    Headless,
    /// Connected to the display server that the environment names.
    Windowed(GraphicalEnvironment),
}

#[cfg(any(target_os = "linux", target_os = "freebsd"))]
impl GraphicalEnvironment {
    /// Reads the display variables from this process's environment.
    ///
    /// This only reads environment variables: whether they name a reachable display server is
    /// checked when a platform connects. Leaves `activation_token` unset: see its documentation.
    pub fn detect() -> Self {
        Self {
            wayland_display: std::env::var_os("WAYLAND_DISPLAY"),
            x11_display: std::env::var_os("DISPLAY"),
            xdg_runtime_dir: std::env::var_os("XDG_RUNTIME_DIR"),
            activation_token: None,
        }
    }

    /// Sets this environment's display variables on `command`, and removes the ones it doesn't
    /// set, so the program connects to this graphical session rather than the one this process
    /// started in. Leaves `XDG_ACTIVATION_TOKEN` alone.
    pub fn apply_to(&self, command: &mut std::process::Command) {
        for (name, value) in [
            ("WAYLAND_DISPLAY", &self.wayland_display),
            ("DISPLAY", &self.x11_display),
            ("XDG_RUNTIME_DIR", &self.xdg_runtime_dir),
        ] {
            match value {
                Some(value) => command.env(name, value),
                None => command.env_remove(name),
            };
        }
    }

    /// Returns the compositor this environment selects: Wayland, then X11, then headless.
    ///
    /// Does not attempt to connect to the compositor.
    pub fn guess_compositor(&self) -> &'static str {
        let is_set =
            |value: &Option<OsString>| value.as_ref().is_some_and(|value| !value.is_empty());
        if cfg!(feature = "wayland") && is_set(&self.wayland_display) {
            "Wayland"
        } else if cfg!(feature = "x11") && is_set(&self.x11_display) {
            "X11"
        } else {
            "Headless"
        }
    }
}

#[cfg(any(target_os = "linux", target_os = "freebsd"))]
bitflags::bitflags! {
    /// The windowing modes a platform may start in or switch to.
    #[derive(Clone, Copy, Debug, PartialEq, Eq)]
    pub struct WindowingModes: u8 {
        /// Connected to a Wayland compositor.
        const WAYLAND = 1 << 0;
        /// Connected to an X server.
        const X11 = 1 << 1;
        /// No display server. Windows lay out and handle input but draw nothing.
        const HEADLESS = 1 << 2;
    }
}

#[expect(missing_docs)]
pub trait Platform: 'static {
    fn background_executor(&self) -> BackgroundExecutor;
    fn foreground_executor(&self) -> ForegroundExecutor;
    fn text_system(&self) -> Arc<dyn PlatformTextSystem>;

    fn run(&self, on_finish_launching: Box<dyn 'static + FnOnce()>);
    fn quit(&self);
    /// Switches a capable platform between headless and windowed modes. See
    /// [`App::request_windowing`].
    /// Sets the windowing mode the platform starts in. Called before `run`. See
    /// [`Application::with_windowing`].
    fn set_initial_windowing(&self, _request: WindowingRequest) {}
    fn request_windowing(&self, _request: WindowingRequest) -> Task<anyhow::Result<()>> {
        Task::ready(Err(anyhow::anyhow!(
            "this platform cannot switch between headless and windowed modes"
        )))
    }
    fn restart(&self, binary_path: Option<PathBuf>, arguments: Vec<OsString>);
    fn activate(&self, ignoring_other_apps: bool);
    /// Sets the initial or current activation policy. Has no effect outside macOS.
    fn set_activation_policy(&self, _policy: ActivationPolicy) {}
    fn hide(&self);
    fn hide_other_apps(&self);
    fn unhide_other_apps(&self);

    fn displays(&self) -> Vec<Rc<dyn PlatformDisplay>>;
    fn primary_display(&self) -> Option<Rc<dyn PlatformDisplay>>;
    /// Registers the callback invoked when displays may have been added or
    /// removed, or a display's properties may have changed. GPUI rereads
    /// [`Self::displays`] to find out what changed, so calls may be spurious.
    /// The callback runs on the main thread outside of any window update.
    fn on_displays_changed(&self, callback: Box<dyn FnMut()>);
    fn active_window(&self) -> Option<AnyWindowHandle>;
    fn window_stack(&self) -> Option<Vec<AnyWindowHandle>> {
        None
    }

    fn is_screen_capture_supported(&self) -> bool {
        false
    }

    fn screen_capture_sources(
        &self,
    ) -> oneshot::Receiver<anyhow::Result<Vec<Rc<dyn ScreenCaptureSource>>>> {
        let (sources_tx, sources_rx) = oneshot::channel();
        sources_tx
            .send(Err(anyhow::anyhow!(
                "gpui was compiled without the screen-capture feature"
            )))
            .ok();
        sources_rx
    }

    fn open_window(
        &self,
        handle: AnyWindowHandle,
        options: WindowParams,
    ) -> anyhow::Result<Box<dyn PlatformWindow>>;

    /// Returns the appearance of the application's windows.
    fn window_appearance(&self) -> WindowAppearance;

    /// Overrides the appearance (light/dark) applied to the app's windows, independent
    /// of the OS-wide setting. Pass `None` to clear the override and follow the system
    /// again. The override is reflected by [`Platform::window_appearance`].
    ///
    /// Currently only implemented on macOS, where it sets `NSApplication.appearance` so
    /// the native window chrome (the window border and titlebar) of every window matches
    /// a dark app theme even when the system is in light mode (or vice versa). A no-op on
    /// other platforms.
    fn set_window_appearance(&self, _appearance: Option<WindowAppearance>) {}

    /// Returns the window button layout configuration when supported.
    fn button_layout(&self) -> Option<WindowButtonLayout> {
        None
    }

    fn open_url(&self, url: &str);
    fn on_open_urls(&self, callback: Box<dyn FnMut(Vec<String>)>);
    fn register_url_scheme(&self, url: &str) -> Task<Result<()>>;

    fn prompt_for_paths(
        &self,
        options: PathPromptOptions,
    ) -> oneshot::Receiver<Result<Option<Vec<PathBuf>>>>;
    fn prompt_for_new_path(
        &self,
        directory: &Path,
        suggested_name: Option<&str>,
    ) -> oneshot::Receiver<Result<Option<PathBuf>>>;
    fn can_select_mixed_files_and_dirs(&self) -> bool;
    fn reveal_path(&self, path: &Path);
    fn open_with_system(&self, path: &Path);

    fn on_quit(&self, callback: Box<dyn FnMut() -> bool>);
    fn on_reopen(&self, callback: Box<dyn FnMut()>);
    /// Registers the callback invoked when the system is about to sleep.
    fn on_system_sleep(&self, callback: Box<dyn FnMut()>);
    /// Registers the callback invoked when the system resumes from sleep.
    fn on_system_wake(&self, callback: Box<dyn FnMut()>);

    // Mobile platform methods. On mobile the OS owns the application
    // lifecycle: apps are backgrounded, foregrounded, and killed at the
    // system's discretion, and must react rather than decide.

    /// Registers a callback invoked whenever the application's lifecycle
    /// phase changes. See [`AppLifecyclePhase`] for the phase vocabulary and
    /// its mapping onto iOS and Android.
    ///
    /// Desktop platforms never invoke this.
    fn on_app_lifecycle(&self, _callback: Box<dyn FnMut(AppLifecyclePhase)>) {}

    /// Registers a callback invoked when the OS signals memory pressure
    /// (iOS `didReceiveMemoryWarning`, Android `onTrimMemory`).
    ///
    /// Desktop platforms never invoke this.
    fn on_memory_warning(&self, _callback: Box<dyn FnMut()>) {}

    /// The platform's gesture recognition services, if it provides any
    /// beyond gpui's portable recognizers. See
    /// [`PlatformGestures`](crate::PlatformGestures).
    fn gestures(&self) -> Option<Rc<dyn PlatformGestures>> {
        None
    }

    fn set_menus(&self, menus: Vec<Menu>, keymap: &Keymap);
    fn get_menus(&self) -> Option<Vec<OwnedMenu>> {
        None
    }

    fn set_dock_menu(&self, menu: Vec<MenuItem>, keymap: &Keymap);
    fn perform_dock_menu_action(&self, _action: usize) {}
    fn add_recent_document(&self, _path: &Path) {}
    fn update_jump_list(
        &self,
        _menus: Vec<MenuItem>,
        _entries: Vec<SmallVec<[PathBuf; 2]>>,
    ) -> Task<Vec<SmallVec<[PathBuf; 2]>>> {
        Task::ready(Vec::new())
    }
    fn on_app_menu_action(&self, callback: Box<dyn FnMut(&dyn Action)>);
    fn on_will_open_app_menu(&self, callback: Box<dyn FnMut()>);
    fn on_validate_app_menu_command(&self, callback: Box<dyn FnMut(&dyn Action) -> bool>);

    fn thermal_state(&self) -> ThermalState;
    fn on_thermal_state_change(&self, callback: Box<dyn FnMut()>);
    fn prevent_idle_sleep(&self, reason: &str) -> Task<Result<ActivityGuard>>;

    /// Sets the application's process-wide identity and user-visible name.
    ///
    /// The identifier is used for platform identity mechanisms such as the
    /// Windows AppUserModelID. The name is used wherever the operating system
    /// presents the application to the user. Call this once, early in startup,
    /// before opening windows or posting notifications.
    fn set_app_identity(&self, identifier: &str, name: &str) {
        _ = (identifier, name);
    }

    /// Posts a notification to the operating system's notification center.
    ///
    /// Posting a notification whose [`SystemNotification::tag`] matches an
    /// earlier one replaces that notification where the platform supports it.
    /// No-op on platforms without notification support, or when delivery is
    /// unavailable (e.g. authorization was denied).
    fn show_system_notification(&self, notification: SystemNotification) {
        _ = notification;
    }

    /// Removes the delivered or pending notification with this tag.
    ///
    /// Best-effort: some platforms cannot retract a notification once shown,
    /// in which case it ages out of the notification center on its own.
    fn dismiss_system_notification(&self, tag: &str) {
        _ = tag;
    }

    /// Registers the callback invoked when the user activates a system
    /// notification, either by clicking its body or one of its action
    /// buttons.
    ///
    /// Implementations must invoke the callback on the main thread.
    fn on_system_notification_response(
        &self,
        callback: Box<dyn FnMut(SystemNotificationResponse)>,
    ) {
        _ = callback;
    }

    fn compositor_name(&self) -> &'static str {
        ""
    }
    /// The environment of the display server a platform that can switch windowing modes is
    /// connected to. See [`App::graphical_environment`].
    fn graphical_environment(&self) -> Option<GraphicalEnvironment> {
        None
    }
    fn app_path(&self) -> Result<PathBuf>;
    fn path_for_auxiliary_executable(&self, name: &str) -> Result<PathBuf>;

    fn set_cursor_style(&self, style: CursorStyle);

    /// Hides the mouse cursor until the user moves the mouse over one of
    /// this application's windows.
    fn hide_cursor_until_mouse_moves(&self);

    /// Returns whether the mouse cursor is currently visible.
    fn is_cursor_visible(&self) -> bool;

    fn should_auto_hide_scrollbars(&self) -> bool;

    fn read_from_clipboard(&self) -> Option<ClipboardItem>;
    fn write_to_clipboard(&self, item: ClipboardItem);

    /// Reads the clipboard, resolving once its contents are available.
    ///
    /// Most platforms read synchronously and return a ready task. Platforms
    /// whose clipboard access is inherently asynchronous and permission-gated
    /// (e.g. the browser's async clipboard API) override this method; on those
    /// platforms [`Platform::read_from_clipboard`] cannot return the clipboard
    /// contents, so callers that can await should prefer this method.
    fn read_from_clipboard_async(&self) -> Task<Result<Option<ClipboardItem>, ClipboardReadError>> {
        Task::ready(Ok(self.read_from_clipboard()))
    }

    #[cfg(any(target_os = "linux", target_os = "freebsd"))]
    fn read_from_primary(&self) -> Option<ClipboardItem>;
    #[cfg(any(target_os = "linux", target_os = "freebsd"))]
    fn write_to_primary(&self, item: ClipboardItem);

    #[cfg(target_os = "macos")]
    fn read_from_find_pasteboard(&self) -> Option<ClipboardItem>;
    #[cfg(target_os = "macos")]
    fn write_to_find_pasteboard(&self, item: ClipboardItem);

    fn write_credentials(&self, url: &str, username: &str, password: &[u8]) -> Task<Result<()>>;
    fn read_credentials(&self, url: &str) -> Task<Result<Option<(String, Vec<u8>)>>>;
    fn delete_credentials(&self, url: &str) -> Task<Result<()>>;

    fn keyboard_layout(&self) -> Box<dyn PlatformKeyboardLayout>;
    fn keyboard_mapper(&self) -> Rc<dyn PlatformKeyboardMapper>;
    fn on_keyboard_layout_change(&self, callback: Box<dyn FnMut()>);
}

/// A handle to a platform's display, e.g. a monitor or laptop screen.
pub trait PlatformDisplay: Debug {
    /// Get the ID for this display
    fn id(&self) -> DisplayId;

    /// Returns a stable identifier for this display that can be persisted and used
    /// across system restarts.
    fn uuid(&self) -> Result<Uuid>;

    /// Get the bounds for this display
    fn bounds(&self) -> Bounds<Pixels>;

    /// The time between the display's refreshes. Variable refresh rate
    /// displays report their maximum rate. `None` when the platform doesn't
    /// report it.
    ///
    /// May query the operating system; GPUI caches it per display, see
    /// [`Window::refresh_interval`](crate::Window::refresh_interval).
    fn refresh_interval(&self) -> Option<Duration>;

    /// Get the visible bounds for this display, excluding taskbar/dock areas.
    /// This is the usable area where windows can be placed without being obscured.
    /// Defaults to the full display bounds if not overridden.
    fn visible_bounds(&self) -> Bounds<Pixels> {
        self.bounds()
    }

    /// Get the default bounds for this display to place a window
    fn default_bounds(&self) -> Bounds<Pixels> {
        let bounds = self.bounds();
        let center = bounds.center();
        let clipped_window_size = DEFAULT_WINDOW_SIZE.min(&bounds.size);

        let offset = clipped_window_size / 2.0;
        let origin = point(center.x - offset.width, center.y - offset.height);
        Bounds::new(origin, clipped_window_size)
    }
}

/// A notification posted to the operating system's notification center,
/// rather than rendered as in-app UI.
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct SystemNotification {
    /// Stable identity for the notification. Posting a new notification with
    /// the same tag replaces the previous one where the platform supports it,
    /// and responses carry the tag back to the application.
    pub tag: SharedString,
    /// The notification's headline.
    pub title: SharedString,
    /// Additional text displayed below the title.
    pub body: SharedString,
    /// Buttons offered on the notification. Platforms that cannot display
    /// action buttons show the notification without them.
    pub actions: Vec<SystemNotificationAction>,
}

/// A button offered on a [`SystemNotification`].
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct SystemNotificationAction {
    /// Identifies the action in [`SystemNotificationResponse::action_id`]
    /// when the user presses this button.
    pub id: SharedString,
    /// The button's user-visible label.
    pub label: SharedString,
}

/// The user's activation of a [`SystemNotification`].
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct SystemNotificationResponse {
    /// The [`SystemNotification::tag`] of the activated notification.
    pub tag: SharedString,
    /// The pressed action button's [`SystemNotificationAction::id`], or
    /// `None` when the user activated the notification body itself.
    pub action_id: Option<SharedString>,
}

/// Thermal state of the system
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum ThermalState {
    /// System has no thermal constraints
    Nominal,
    /// System is slightly constrained, reduce discretionary work
    Fair,
    /// System is moderately constrained, reduce CPU/GPU intensive work
    Serious,
    /// System is critically constrained, minimize all resource usage
    Critical,
}

/// Metadata for a given [ScreenCaptureSource]
#[derive(Clone)]
pub struct SourceMetadata {
    /// Opaque identifier of this screen.
    pub id: u64,
    /// Human-readable label for this source.
    pub label: Option<SharedString>,
    /// Whether this source is the main display.
    pub is_main: Option<bool>,
    /// Video resolution of this source.
    pub resolution: Size<DevicePixels>,
}

/// A source of on-screen video content that can be captured.
pub trait ScreenCaptureSource {
    /// Returns metadata for this source.
    fn metadata(&self) -> Result<SourceMetadata>;

    /// Start capture video from this source, invoking the given callback
    /// with each frame.
    fn stream(
        &self,
        foreground_executor: &ForegroundExecutor,
        frame_callback: Box<dyn Fn(ScreenCaptureFrame) + Send>,
    ) -> oneshot::Receiver<Result<Box<dyn ScreenCaptureStream>>>;
}

/// A video stream captured from a screen.
pub trait ScreenCaptureStream {
    /// Returns metadata for this source.
    fn metadata(&self) -> Result<SourceMetadata>;
}

/// A frame of video captured from a screen.
pub struct ScreenCaptureFrame(pub PlatformScreenCaptureFrame);

/// An opaque identifier for a hardware display
#[derive(PartialEq, Eq, Hash, Copy, Clone)]
pub struct DisplayId(pub(crate) u64);

impl DisplayId {
    /// Create a new `DisplayId` from a raw platform display identifier.
    pub fn new(id: u64) -> Self {
        Self(id)
    }
}

impl From<u64> for DisplayId {
    fn from(id: u64) -> Self {
        Self(id)
    }
}

impl From<DisplayId> for u64 {
    fn from(id: DisplayId) -> Self {
        id.0
    }
}

impl Debug for DisplayId {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "DisplayId({})", self.0)
    }
}

/// Which part of the window to resize
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum ResizeEdge {
    /// The top edge
    Top,
    /// The top right corner
    TopRight,
    /// The right edge
    Right,
    /// The bottom right corner
    BottomRight,
    /// The bottom edge
    Bottom,
    /// The bottom left corner
    BottomLeft,
    /// The left edge
    Left,
    /// The top left corner
    TopLeft,
}

/// A type to describe the appearance of a window
#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash, Default)]
pub enum WindowDecorations {
    #[default]
    /// Server side decorations
    Server,
    /// Client side decorations
    Client,
}

/// A type to describe how this window is currently configured
#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash, Default)]
pub enum Decorations {
    /// The window is configured to use server side decorations
    #[default]
    Server,
    /// The window is configured to use client side decorations
    Client {
        /// The edge tiling state
        tiling: Tiling,
    },
}

/// What window controls this platform supports
#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
pub struct WindowControls {
    /// Whether this platform supports fullscreen
    pub fullscreen: bool,
    /// Whether this platform supports maximize
    pub maximize: bool,
    /// Whether this platform supports minimize
    pub minimize: bool,
    /// Whether this platform supports a window menu
    pub window_menu: bool,
}

impl Default for WindowControls {
    fn default() -> Self {
        // Assume that we can do anything, unless told otherwise
        Self {
            fullscreen: true,
            maximize: true,
            minimize: true,
            window_menu: true,
        }
    }
}

/// A window control button type used in [`WindowButtonLayout`].
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum WindowButton {
    /// The minimize button
    Minimize,
    /// The maximize button
    Maximize,
    /// The close button
    Close,
}

impl WindowButton {
    /// Returns a stable element ID for rendering this button.
    pub fn id(&self) -> &'static str {
        match self {
            WindowButton::Minimize => "minimize",
            WindowButton::Maximize => "maximize",
            WindowButton::Close => "close",
        }
    }

    #[cfg(any(target_os = "linux", target_os = "freebsd"))]
    fn index(&self) -> usize {
        match self {
            WindowButton::Minimize => 0,
            WindowButton::Maximize => 1,
            WindowButton::Close => 2,
        }
    }
}

/// Maximum number of [`WindowButton`]s per side in the titlebar.
pub const MAX_BUTTONS_PER_SIDE: usize = 3;

/// Describes which [`WindowButton`]s appear on each side of the titlebar.
///
/// On Linux, this is read from the desktop environment's configuration
/// (e.g. GNOME's `gtk-decoration-layout` gsetting) via [`WindowButtonLayout::parse`].
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct WindowButtonLayout {
    /// Buttons on the left side of the titlebar.
    pub left: [Option<WindowButton>; MAX_BUTTONS_PER_SIDE],
    /// Buttons on the right side of the titlebar.
    pub right: [Option<WindowButton>; MAX_BUTTONS_PER_SIDE],
}

#[cfg(any(target_os = "linux", target_os = "freebsd"))]
impl WindowButtonLayout {
    /// Returns Zed's built-in fallback button layout for Linux titlebars.
    pub fn linux_default() -> Self {
        Self {
            left: [None; MAX_BUTTONS_PER_SIDE],
            right: [
                Some(WindowButton::Minimize),
                Some(WindowButton::Maximize),
                Some(WindowButton::Close),
            ],
        }
    }

    /// Parses a GNOME-style `button-layout` string (e.g. `"close,minimize:maximize"`).
    pub fn parse(layout_string: &str) -> Result<Self> {
        fn parse_side(
            s: &str,
            seen_buttons: &mut [bool; MAX_BUTTONS_PER_SIDE],
            unrecognized: &mut Vec<String>,
        ) -> [Option<WindowButton>; MAX_BUTTONS_PER_SIDE] {
            let mut result = [None; MAX_BUTTONS_PER_SIDE];
            let mut i = 0;
            for name in s.split(',') {
                let trimmed = name.trim();
                if trimmed.is_empty() {
                    continue;
                }
                let button = match trimmed {
                    "minimize" => Some(WindowButton::Minimize),
                    "maximize" => Some(WindowButton::Maximize),
                    "close" => Some(WindowButton::Close),
                    other => {
                        unrecognized.push(other.to_string());
                        None
                    }
                };
                if let Some(button) = button {
                    if seen_buttons[button.index()] {
                        continue;
                    }
                    if let Some(slot) = result.get_mut(i) {
                        *slot = Some(button);
                        seen_buttons[button.index()] = true;
                        i += 1;
                    }
                }
            }
            result
        }

        let (left_str, right_str) = layout_string.split_once(':').unwrap_or(("", layout_string));
        let mut unrecognized = Vec::new();
        let mut seen_buttons = [false; MAX_BUTTONS_PER_SIDE];
        let layout = Self {
            left: parse_side(left_str, &mut seen_buttons, &mut unrecognized),
            right: parse_side(right_str, &mut seen_buttons, &mut unrecognized),
        };

        if !unrecognized.is_empty()
            && layout.left.iter().all(Option::is_none)
            && layout.right.iter().all(Option::is_none)
        {
            bail!(
                "button layout string {:?} contains no valid buttons (unrecognized: {})",
                layout_string,
                unrecognized.join(", ")
            );
        }

        Ok(layout)
    }

    /// Formats the layout back into a GNOME-style `button-layout` string.
    #[cfg(test)]
    pub fn format(&self) -> String {
        fn format_side(buttons: &[Option<WindowButton>; MAX_BUTTONS_PER_SIDE]) -> String {
            buttons
                .iter()
                .flatten()
                .map(|button| match button {
                    WindowButton::Minimize => "minimize",
                    WindowButton::Maximize => "maximize",
                    WindowButton::Close => "close",
                })
                .collect::<Vec<_>>()
                .join(",")
        }

        format!("{}:{}", format_side(&self.left), format_side(&self.right))
    }
}

/// A type to describe which sides of the window are currently tiled in some way
#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash, Default)]
pub struct Tiling {
    /// Whether the top edge is tiled
    pub top: bool,
    /// Whether the left edge is tiled
    pub left: bool,
    /// Whether the right edge is tiled
    pub right: bool,
    /// Whether the bottom edge is tiled
    pub bottom: bool,
}

impl Tiling {
    /// Initializes a [`Tiling`] type with all sides tiled
    pub fn tiled() -> Self {
        Self {
            top: true,
            left: true,
            right: true,
            bottom: true,
        }
    }

    /// Whether any edge is tiled
    pub fn is_tiled(&self) -> bool {
        self.top || self.left || self.right || self.bottom
    }
}

/// Callbacks for the accessibility adapter.
pub struct A11yCallbacks {
    /// Called when the adapter is activated (a screen reader connects).
    pub activation: Box<dyn Fn() -> Option<accesskit::TreeUpdate> + Send + 'static>,
    /// Called when an action is requested by the screen reader.
    pub action: Box<dyn Fn(accesskit::ActionRequest) + Send + 'static>,
    /// Called when the adapter is deactivated (screen reader disconnects).
    pub deactivation: Box<dyn Fn() + Send + 'static>,
}

/// The source of a platform frame request's timestamp.
#[derive(Debug, Copy, Clone, Eq, PartialEq, Default)]
pub enum FrameRequestSource {
    /// An OS callback or compositor-paced frame request.
    #[default]
    NativeCallback,
    /// A refresh timer, retry, queued wakeup, or fallback sleep paced by the app.
    LocalSchedule,
}

#[derive(Debug, Copy, Clone, Eq, PartialEq, Default)]
#[expect(missing_docs)]
pub struct RequestFrameOptions {
    /// Whether a presentation is required.
    pub require_presentation: bool,
    /// Force refresh of all rendering states when true.
    pub force_render: bool,
    /// When the platform first requested this frame, before main-thread dispatch.
    ///
    /// `None` means the captured request time is unavailable.
    /// Coalesced requests carry their first request time, not their delivery time.
    /// Built-in backends collect timestamps only with the `profiler` feature.
    pub signal_at: Option<Instant>,
    /// Distinguishes native callbacks from local scheduling requests.
    pub signal_source: FrameRequestSource,
}

/// Preserves the first platform frame request time across coalesced notifications.
///
/// Producers may record from a platform thread without waiting for the UI thread.
/// The consumer drains the timestamp before dispatching the request on the UI thread.
/// The timestamp offset and source share one atomic word so coalescing cannot
/// mix a request's time with another request's source. The low bit encodes the
/// source; the remaining bits encode nanoseconds from `origin`. `u64::MAX` is empty.
/// Without the `profiler` feature, this accumulator has no timestamp storage.
pub struct PlatformFrameSignal {
    #[cfg(feature = "profiler")]
    origin: Instant,
    #[cfg(feature = "profiler")]
    first_signal: std::sync::atomic::AtomicU64,
}

impl Default for PlatformFrameSignal {
    fn default() -> Self {
        Self::new()
    }
}

impl PlatformFrameSignal {
    /// Creates an empty signal accumulator.
    pub fn new() -> Self {
        Self {
            #[cfg(feature = "profiler")]
            origin: Instant::now(),
            #[cfg(feature = "profiler")]
            first_signal: std::sync::atomic::AtomicU64::new(u64::MAX),
        }
    }

    /// Captures a platform request timestamp only when profiling is enabled.
    ///
    /// The closure is not invoked in profiler-disabled builds.
    #[inline]
    pub fn capture(capture: impl FnOnce() -> Instant) -> Option<Instant> {
        if cfg!(feature = "profiler") {
            Some(capture())
        } else {
            None
        }
    }

    /// Records a platform frame request, retaining the first undrained timestamp.
    #[inline]
    #[cfg_attr(not(feature = "profiler"), expect(unused_variables))]
    pub fn record(&self, at: Instant, source: FrameRequestSource) {
        #[cfg(feature = "profiler")]
        {
            let nanoseconds = at
                .saturating_duration_since(self.origin)
                .as_nanos()
                .min(u128::from((u64::MAX >> 1) - 1)) as u64;
            let source_bit = match source {
                FrameRequestSource::NativeCallback => 0,
                FrameRequestSource::LocalSchedule => 1,
            };
            self.first_signal.fetch_min(
                (nanoseconds << 1) | source_bit,
                std::sync::atomic::Ordering::Relaxed,
            );
        }
    }

    /// Drains the first platform frame request time and source, leaving the accumulator empty.
    #[inline]
    pub fn take(&self) -> Option<(Instant, FrameRequestSource)> {
        #[cfg(feature = "profiler")]
        {
            let signal = self
                .first_signal
                .swap(u64::MAX, std::sync::atomic::Ordering::Relaxed);
            (signal != u64::MAX).then(|| {
                let source = match signal & 1 {
                    0 => FrameRequestSource::NativeCallback,
                    _ => FrameRequestSource::LocalSchedule,
                };
                (self.origin + Duration::from_nanos(signal >> 1), source)
            })
        }
        #[cfg(not(feature = "profiler"))]
        {
            None
        }
    }
}

/// The application's lifecycle phase, as owned and reported by a mobile OS.
///
/// `Inactive` means visible but not receiving input (a system dialog on
/// top), while `Background` means not visible at all, with process death
/// possible at any time thereafter.
///
/// | Phase        | iOS                          | Android      |
/// |--------------|------------------------------|--------------|
/// | `Active`     | `didBecomeActive`            | `onResume`   |
/// | `Inactive`   | `willResignActive`           | `onPause`    |
/// | `Background` | `didEnterBackground`         | `onStop`     |
/// | `Foreground` | `willEnterForeground`        | `onStart`    |
#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
pub enum AppLifecyclePhase {
    /// Foreground and receiving input.
    Active,
    /// Foreground (visible) but not receiving input.
    Inactive,
    /// Not visible. The GPU surface may be destroyed while backgrounded and
    /// the process may be killed without further notice.
    Background,
    /// Becoming visible again, before input is restored.
    Foreground,
}

/// Regions of a window that are obscured or reserved by the system.
///
/// Mobile applications often share space in their window with system-specific
/// geometry, from keyboards to camera notches. In GPUI, all this is abstracted
/// into a single "inset" which should be overlaid on the window's bounds.
/// It is up to the application develop to determine how to handle these cases.
#[derive(Debug, Clone, Default, PartialEq)]
pub struct WindowInsets {
    /// Regions covered by system UI or hardware: status bar, display
    /// cutouts/notch, home indicator, navigation bars.
    /// (iOS: `safeAreaInsets`. Android: `WindowInsets` of types
    /// `systemBars() | displayCutout()`.)
    pub safe_area: Edges<Pixels>,
    /// The region covered by the keyboard, when present.
    /// (iOS: derived from `keyboardWillShow`/frame-change notifications.
    /// Android: `WindowInsets.Type.ime()`.)
    pub ime: Edges<Pixels>,
}

impl WindowInsets {
    /// The combined inset content should avoid.
    pub fn effective(&self) -> Edges<Pixels> {
        Edges {
            top: self.safe_area.top.max(self.ime.top),
            right: self.safe_area.right.max(self.ime.right),
            bottom: self.safe_area.bottom.max(self.ime.bottom),
            left: self.safe_area.left.max(self.ime.left),
        }
    }
}

/// A change in the state of the focused text input.
#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
pub enum TextInputStateChange {
    /// The window changed from having no active text input to having one.
    FocusGained,
    /// The window no longer has an active text input.
    FocusLost,
    /// The selection or caret moved
    SelectionChanged,
    /// The document content changed outside of platform-initiated edits.
    ContentChanged,
}

#[expect(missing_docs)]
pub trait PlatformWindow: HasWindowHandle + HasDisplayHandle {
    /// Negotiate presentation for one window. Unsupported requests preserve state.
    fn set_color_mode(&mut self, mode: WindowColorMode) -> anyhow::Result<WindowColorStatus> {
        match mode {
            WindowColorMode::Default => Ok(self.color_status()),
            _ => anyhow::bail!("wide-gamut SDR presentation is unsupported"),
        }
    }
    /// Return a cached configuration snapshot without probing native state.
    fn color_status(&self) -> WindowColorStatus {
        WindowColorStatus::default()
    }

    fn bounds(&self) -> Bounds<Pixels>;
    fn is_maximized(&self) -> bool;
    fn window_bounds(&self) -> WindowBounds;
    fn content_size(&self) -> Size<Pixels>;
    /// Returns the visible viewport in logical pixels relative to the content origin.
    ///
    /// This may be smaller or offset when a keyboard or zoom obscures content;
    /// it must not change the full layout size returned by `content_size`.
    /// Implementations should return a frame snapshot, not query platform layout here.
    fn visual_viewport_bounds(&self) -> Bounds<Pixels> {
        Bounds::new(Point::default(), self.content_size())
    }
    /// Registers a callback when visible geometry may have changed.
    ///
    /// This requests a frame; backends can sample the new viewport and safe-area
    /// geometry in `prepare_frame` rather than updating it inside the callback.
    fn on_visual_viewport_changed(&self, _callback: Box<dyn FnMut()>) {}
    /// Samples platform geometry/presentation before a draw; returns whether views must be invalidated.
    ///
    /// Geometry and presentation getters must remain consistent throughout the ensuing draw.
    /// Do not invoke callbacks here: GPUI is already updating this window.
    fn prepare_frame(&self) -> bool {
        false
    }
    fn resize(&mut self, size: Size<Pixels>);
    fn scale_factor(&self) -> f32;
    fn appearance(&self) -> WindowAppearance;
    fn display(&self) -> Option<Rc<dyn PlatformDisplay>>;
    fn mouse_position(&self) -> Point<Pixels>;
    fn modifiers(&self) -> Modifiers;
    fn capslock(&self) -> Capslock;
    fn set_input_handler(&mut self, input_handler: PlatformInputHandler);
    fn take_input_handler(&mut self) -> Option<PlatformInputHandler>;
    /// Apply the focused text region's [`TextInputConfiguration`] to the
    /// platform's text input session (e.g. attributes of the hidden editable
    /// element on web). Called only when the configuration changes, because
    /// reconfiguring a live input session can restart the IME connection.
    fn set_text_input_configuration(&mut self, _configuration: TextInputConfiguration) {}
    fn prompt(
        &self,
        level: PromptLevel,
        msg: &str,
        detail: Option<&str>,
        answers: &[PromptButton],
    ) -> Option<oneshot::Receiver<usize>>;
    fn activate(&self);
    /// Requests that the operating system draw attention to this window.
    fn request_attention(&self) {}
    fn is_active(&self) -> bool;
    /// The current [`WindowVisibility`]. Read once when the window is created;
    /// afterwards changes arrive through [`Self::on_visibility_change`].
    fn visibility(&self) -> WindowVisibility;
    fn is_hovered(&self) -> bool;
    fn background_appearance(&self) -> WindowBackgroundAppearance;
    fn set_title(&mut self, title: &str);
    fn set_background_appearance(&self, background_appearance: WindowBackgroundAppearance);
    fn minimize(&self);
    fn zoom(&self);
    fn toggle_fullscreen(&self);
    fn is_fullscreen(&self) -> bool;
    fn frame_waker(&self) -> Option<Rc<dyn Fn()>> {
        None
    }
    fn on_request_frame(&self, callback: Box<dyn FnMut(RequestFrameOptions)>);
    fn on_input(&self, callback: Box<dyn FnMut(PlatformInput) -> DispatchEventResult>);
    fn on_active_status_change(&self, callback: Box<dyn FnMut(bool)>);
    /// Registers the callback invoked when [`Self::visibility`] changes. Only
    /// transitions are reported; the callback runs on the main thread outside
    /// of any window update.
    fn on_visibility_change(&self, callback: Box<dyn FnMut(WindowVisibility)>);
    fn on_hover_status_change(&self, callback: Box<dyn FnMut(bool)>);
    fn on_resize(&self, callback: Box<dyn FnMut(Size<Pixels>, f32)>);
    fn on_moved(&self, callback: Box<dyn FnMut()>);
    /// Registers the callback invoked when the window moves to another
    /// display. Calls may be spurious. The callback runs on the main thread
    /// outside of any window update.
    fn on_display_changed(&self, callback: Box<dyn FnMut()>);
    fn on_should_close(&self, callback: Box<dyn FnMut() -> bool>);
    fn on_hit_test_window_control(&self, callback: Box<dyn FnMut() -> Option<WindowControlArea>>);
    fn on_close(&self, callback: Box<dyn FnOnce()>);
    fn on_appearance_changed(&self, callback: Box<dyn FnMut()>);
    fn on_button_layout_changed(&self, _callback: Box<dyn FnMut()>) {}
    fn draw(&self, scene: &Scene);
    /// Submit on this window's native renderer without presentation or readback.
    #[cfg(any(test, feature = "test-support"))]
    fn submit_scene_for_validation(&self, _scene: &Scene) -> anyhow::Result<()> {
        anyhow::bail!("native window ownership validation is unsupported on this backend")
    }
    fn schedule_frame(&self) {}
    fn sprite_atlas(&self) -> Arc<dyn PlatformAtlas>;
    fn is_subpixel_rendering_supported(&self) -> bool;

    // macOS specific methods
    fn get_title(&self) -> String {
        String::new()
    }
    fn tabbed_windows(&self) -> Option<Vec<SystemWindowTab>> {
        None
    }
    fn tab_bar_visible(&self) -> bool {
        false
    }
    fn set_edited(&mut self, _edited: bool) {}
    fn set_document_path(&self, _path: Option<&std::path::Path>) {}
    fn toggle_simple_fullscreen(&self) {}
    fn is_simple_fullscreen(&self) -> bool {
        false
    }
    #[cfg(target_os = "macos")]
    fn set_traffic_light_position(&self, _position: Point<Pixels>) {}
    fn show_character_palette(&self) {}
    fn titlebar_double_click(&self, _is_resizable: bool, _is_minimizable: bool) {}
    fn on_move_tab_to_new_window(&self, _callback: Box<dyn FnMut()>) {}
    fn on_merge_all_windows(&self, _callback: Box<dyn FnMut()>) {}
    fn on_select_previous_tab(&self, _callback: Box<dyn FnMut()>) {}
    fn on_select_next_tab(&self, _callback: Box<dyn FnMut()>) {}
    fn on_toggle_tab_bar(&self, _callback: Box<dyn FnMut()>) {}
    fn merge_all_windows(&self) {}
    fn move_tab_to_new_window(&self) {}
    fn toggle_window_tab_overview(&self) {}
    fn set_tabbing_identifier(&self, _identifier: Option<String>) {}

    fn native_window_state(&self) -> Option<Vec<u8>> {
        None
    }
    fn restore_native_window_state(&self, _state: &[u8]) {}

    #[cfg(target_os = "windows")]
    fn get_raw_handle(&self) -> windows::Win32::Foundation::HWND;

    // Linux specific methods
    fn inner_window_bounds(&self) -> WindowBounds {
        self.window_bounds()
    }
    fn request_decorations(&self, _decorations: WindowDecorations) {}
    fn show_window_menu(&self, _position: Point<Pixels>) {}
    fn start_window_move(&self) {}
    fn can_start_external_drag(&self) -> bool {
        false
    }
    fn start_external_drag(&self, _payload: &ExternalDragPayload) -> bool {
        false
    }
    fn start_window_resize(&self, _edge: ResizeEdge) {}
    fn set_exclusive_zone(&self, _zone: Pixels) {}
    #[cfg(all(target_os = "linux", feature = "wayland"))]
    fn set_exclusive_edge(&self, _edge: layer_shell::Anchor) {}
    fn set_input_region(&self, _region: Option<&[Bounds<Pixels>]>) {}
    fn window_decorations(&self) -> Decorations {
        Decorations::Server
    }
    fn set_app_id(&mut self, _app_id: &str) {}
    fn map_window(&mut self) -> anyhow::Result<()> {
        Ok(())
    }
    fn window_controls(&self) -> WindowControls {
        WindowControls::default()
    }
    fn set_client_inset(&self, _inset: Pixels) {}
    fn gpu_specs(&self) -> Option<GpuSpecs>;

    fn update_ime_position(&self, _bounds: Bounds<Pixels>);

    // Mobile platform methods.

    /// The regions of this window currently obscured or reserved by the
    /// system. Zero on platforms without such regions.
    fn insets(&self) -> WindowInsets {
        WindowInsets::default()
    }

    /// Registers a callback invoked whenever [`Self::insets`] change.
    ///
    /// Contract: fires continuously during animated transitions (Android
    /// `WindowInsetsAnimation` progress; on iOS the platform interpolates
    /// the keyboard animation curve on frame ticks) and is exact at rest.
    fn on_insets_changed(&self, _callback: Box<dyn FnMut(WindowInsets)>) {}

    /// Sets the handler for the system back action (Android back
    /// button/gesture; no source on iOS or desktop).
    fn set_back_handler(&self, _callback: Box<dyn FnMut()>) {}

    /// Declares whether the application would currently handle the system
    /// back action (e.g. navigation depth > 0).
    fn set_back_enabled(&self, _enabled: bool) {}

    /// Requests that the soft keyboard be shown.
    fn show_soft_keyboard(&self) {}

    /// Requests that the soft keyboard be hidden.
    fn hide_soft_keyboard(&self) {}

    /// Inform the operating system that the text input state has changed
    fn text_input_state_changed(&self, _change: TextInputStateChange) {}

    fn play_system_bell(&self) {}

    /// Initialize the accessibility adapter with callbacks.
    fn a11y_init(&self, _callbacks: A11yCallbacks) {}

    /// Provide a TreeUpdate to the accessibility adapter.
    fn a11y_tree_update(&self, _tree_update: accesskit::TreeUpdate) {}

    /// Inform the adapter of updated window bounds.
    fn a11y_update_window_bounds(&self) {}

    #[cfg(any(test, feature = "test-support", feature = "bench-support"))]
    fn as_test(&mut self) -> Option<&mut TestWindow> {
        None
    }

    /// Synchronously re-render and read associated extended linear-P3 FP16 pixels.
    /// Supported on Metal WideGamutSdr only; never silently returns an sRGB preview.
    #[cfg(any(test, feature = "test-support"))]
    fn render_to_linear_p3(&self, _scene: &Scene) -> Result<LinearP3Image> {
        anyhow::bail!("linear P3 readback is unsupported on this backend")
    }

    /// Renders the given scene to a texture and returns the pixel data as an RGBA image.
    /// This does not present the frame to screen - useful for visual testing where we want
    /// to capture what would be rendered without displaying it or requiring the window to be visible.
    #[cfg(any(test, feature = "test-support"))]
    fn render_to_image(&self, _scene: &Scene) -> Result<RgbaImage> {
        anyhow::bail!("render_to_image not implemented for this platform")
    }
}

/// Validation snapshot before display color management: row-major associated
/// extended linear Display-P3 RGBA, preserving the GPU's IEEE binary16 bits.
/// Negative and above-one RGB values are valid. This is not a screenshot or HDR.
#[cfg(any(test, feature = "test-support"))]
#[derive(Debug)]
pub struct LinearP3Image {
    /// Physical pixel dimensions.
    pub size: Size<DevicePixels>,
    /// Row-major RGBA binary16 words, without row padding.
    pub pixels: Vec<[u16; 4]>,
}

/// A renderer for headless windows that can produce real rendered output.
#[cfg(any(test, feature = "test-support", feature = "bench-support"))]
pub trait PlatformHeadlessRenderer {
    /// Render a scene and return the result as an RGBA image.
    fn render_scene_to_image(
        &mut self,
        scene: &Scene,
        size: Size<DevicePixels>,
    ) -> Result<RgbaImage>;

    /// Render a scene to an offscreen target without reading the result back.
    ///
    /// This is the headless analogue of presenting a frame: it performs the
    /// same CPU-side scene encoding and GPU submission as drawing to a real
    /// window, but doesn't block on GPU completion or copy pixels back.
    fn render_scene(&mut self, scene: &Scene, size: Size<DevicePixels>) -> Result<()>;

    /// Returns the sprite atlas used by this renderer.
    fn sprite_atlas(&self) -> Arc<dyn PlatformAtlas>;
}

/// Type alias for runnables with metadata.
/// Previously an enum with a single variant, now simplified to a direct type alias.
#[doc(hidden)]
pub type RunnableVariant = Runnable<RunnableMeta>;

#[doc(hidden)]
pub type TimerResolutionGuard = gpui_util::Deferred<Box<dyn FnOnce() + Send>>;

#[doc(hidden)]
pub enum TasksIncluded {
    OnlyCompleted,
    CompletedAndRunning,
}

/// This type is public so that our test macro can generate and use it, but it should not
/// be considered part of our public API.
#[doc(hidden)]
pub trait PlatformDispatcher: Send + Sync {
    fn is_main_thread(&self) -> bool;
    fn dispatch(&self, runnable: RunnableVariant, priority: Priority);
    fn dispatch_on_main_thread(&self, runnable: RunnableVariant, priority: Priority);
    fn dispatch_after(&self, duration: Duration, runnable: RunnableVariant);

    fn dispatch_on_main_thread_when_idle(
        &self,
        runnable: RunnableVariant,
        timeout: Option<Duration>,
    ) {
        let _ = timeout;
        self.dispatch_on_main_thread(runnable, Priority::Low);
    }

    fn idle_time_remaining(&self) -> Option<Duration> {
        None
    }

    fn spawn_realtime(&self, f: Box<dyn FnOnce() + Send>);

    fn now(&self) -> Instant {
        Instant::now()
    }

    fn increase_timer_resolution(&self) -> TimerResolutionGuard {
        gpui_util::defer(Box::new(|| {}))
    }

    fn prevent_app_nap(&self, _reason: &str) -> ActivityGuard {
        ActivityGuard::noop()
    }

    #[cfg(any(test, feature = "test-support", feature = "bench-support"))]
    fn as_test(&self) -> Option<&TestDispatcher> {
        None
    }

    // This cfg must match the `threaded_dispatcher` module's, which implements
    // this method whenever it compiles.
    #[cfg(any(test, feature = "test-support", feature = "bench-support"))]
    fn as_threaded(&self) -> Option<&ThreadedDispatcher> {
        None
    }
}

#[expect(missing_docs)]
pub trait PlatformTextSystem: Send + Sync {
    fn add_fonts(&self, fonts: Vec<Cow<'static, [u8]>>) -> Result<()>;
    /// Installs a nonblocking sink for unresolved grapheme clusters.
    fn set_missing_glyph_sink(&self, _sink: Option<Arc<dyn MissingGlyphSink>>) {}
    /// Get all available font names.
    fn all_font_names(&self) -> Vec<String>;
    /// Get the font ID for a font descriptor.
    fn font_id(&self, descriptor: &Font) -> Result<FontId>;
    /// Prewarm any system font caches needed to shape text.
    fn prewarm_fonts(&self, _font_ids: &[FontId]) {}
    /// Get metrics for a font.
    fn font_metrics(&self, font_id: FontId) -> FontMetrics;
    /// Get typographic bounds for a glyph.
    fn typographic_bounds(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Bounds<f32>>;
    /// Get the advance width for a glyph.
    fn advance(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Size<f32>>;
    /// Get the glyph ID for a character.
    fn glyph_for_char(&self, font_id: FontId, ch: char) -> Option<GlyphId>;
    /// Get raster bounds for a glyph.
    fn glyph_raster_bounds(&self, params: &RenderGlyphParams) -> Result<Bounds<DevicePixels>>;
    /// Rasterize a glyph.
    fn rasterize_glyph(
        &self,
        params: &RenderGlyphParams,
        raster_bounds: Bounds<DevicePixels>,
    ) -> Result<(Size<DevicePixels>, Vec<u8>)>;
    /// Layout a line of text with the given font runs.
    fn layout_line(&self, text: &str, font_size: Pixels, runs: &[FontRun]) -> LineLayout;
    /// Optional paragraph capability; native implementations need not opt in.
    fn shape_paragraph(
        &self,
        _request: crate::ParagraphRequest<'_>,
    ) -> Result<Arc<dyn crate::PlatformParagraphShape>> {
        anyhow::bail!("paragraph layout is unsupported by this text backend")
    }
    /// Returns the recommended text rendering mode for the given font and size.
    fn recommended_rendering_mode(&self, _font_id: FontId, _font_size: Pixels)
    -> TextRenderingMode;
    /// Returns the dilation level to use for a glyph painted in the given color.
    fn glyph_dilation_for_color(&self, _color: Hsla) -> u8 {
        0
    }
}

#[expect(missing_docs)]
pub struct NoopTextSystem;

#[expect(missing_docs)]
impl NoopTextSystem {
    #[allow(dead_code)]
    pub fn new() -> Self {
        Self
    }
}

impl PlatformTextSystem for NoopTextSystem {
    fn add_fonts(&self, _fonts: Vec<Cow<'static, [u8]>>) -> Result<()> {
        Ok(())
    }

    fn all_font_names(&self) -> Vec<String> {
        Vec::new()
    }

    fn font_id(&self, _descriptor: &Font) -> Result<FontId> {
        Ok(FontId(1))
    }

    fn font_metrics(&self, _font_id: FontId) -> FontMetrics {
        FontMetrics {
            units_per_em: 1000,
            ascent: 1025.0,
            descent: -275.0,
            line_gap: 0.0,
            underline_position: -95.0,
            underline_thickness: 60.0,
            cap_height: 698.0,
            x_height: 516.0,
            bounding_box: Bounds {
                origin: Point {
                    x: -260.0,
                    y: -245.0,
                },
                size: Size {
                    width: 1501.0,
                    height: 1364.0,
                },
            },
        }
    }

    fn typographic_bounds(&self, _font_id: FontId, _glyph_id: GlyphId) -> Result<Bounds<f32>> {
        Ok(Bounds {
            origin: Point { x: 54.0, y: 0.0 },
            size: size(392.0, 528.0),
        })
    }

    fn advance(&self, _font_id: FontId, glyph_id: GlyphId) -> Result<Size<f32>> {
        Ok(size(600.0 * glyph_id.0 as f32, 0.0))
    }

    fn glyph_for_char(&self, _font_id: FontId, ch: char) -> Option<GlyphId> {
        Some(GlyphId(ch.len_utf16() as u32))
    }

    fn glyph_raster_bounds(&self, _params: &RenderGlyphParams) -> Result<Bounds<DevicePixels>> {
        Ok(Default::default())
    }

    fn rasterize_glyph(
        &self,
        _params: &RenderGlyphParams,
        raster_bounds: Bounds<DevicePixels>,
    ) -> Result<(Size<DevicePixels>, Vec<u8>)> {
        Ok((raster_bounds.size, Vec::new()))
    }

    fn layout_line(&self, text: &str, font_size: Pixels, _runs: &[FontRun]) -> LineLayout {
        let mut position = px(0.);
        let metrics = self.font_metrics(FontId(0));
        let em_width = font_size
            * self
                .advance(FontId(0), self.glyph_for_char(FontId(0), 'm').unwrap())
                .unwrap()
                .width
            / metrics.units_per_em as f32;
        let mut glyphs = Vec::new();
        for (ix, c) in text.char_indices() {
            if let Some(glyph) = self.glyph_for_char(FontId(0), c) {
                glyphs.push(ShapedGlyph {
                    id: glyph,
                    position: point(position, px(0.)),
                    index: ix,
                    is_emoji: glyph.0 == 2,
                });
                if glyph.0 == 2 {
                    position += em_width * 2.0;
                } else {
                    position += em_width;
                }
            } else {
                position += em_width
            }
        }
        let mut runs = Vec::default();
        if !glyphs.is_empty() {
            runs.push(ShapedRun {
                font_id: FontId(0),
                glyphs,
            });
        } else {
            position = px(0.);
        }

        LineLayout {
            font_size,
            width: position,
            ascent: font_size * (metrics.ascent / metrics.units_per_em as f32),
            descent: font_size * (metrics.descent / metrics.units_per_em as f32),
            runs,
            len: text.len(),
        }
    }

    fn recommended_rendering_mode(
        &self,
        _font_id: FontId,
        _font_size: Pixels,
    ) -> TextRenderingMode {
        TextRenderingMode::Grayscale
    }
}

// Adapted from https://github.com/microsoft/terminal/blob/1283c0f5b99a2961673249fa77c6b986efb5086c/src/renderer/atlas/dwrite.cpp
// Copyright (c) Microsoft Corporation.
// Licensed under the MIT license.
/// Compute gamma correction ratios for subpixel text rendering.
#[allow(dead_code)]
pub fn get_gamma_correction_ratios(gamma: f32) -> [f32; 4] {
    const GAMMA_INCORRECT_TARGET_RATIOS: [[f32; 4]; 13] = [
        [0.0000 / 4.0, 0.0000 / 4.0, 0.0000 / 4.0, 0.0000 / 4.0], // gamma = 1.0
        [0.0166 / 4.0, -0.0807 / 4.0, 0.2227 / 4.0, -0.0751 / 4.0], // gamma = 1.1
        [0.0350 / 4.0, -0.1760 / 4.0, 0.4325 / 4.0, -0.1370 / 4.0], // gamma = 1.2
        [0.0543 / 4.0, -0.2821 / 4.0, 0.6302 / 4.0, -0.1876 / 4.0], // gamma = 1.3
        [0.0739 / 4.0, -0.3963 / 4.0, 0.8167 / 4.0, -0.2287 / 4.0], // gamma = 1.4
        [0.0933 / 4.0, -0.5161 / 4.0, 0.9926 / 4.0, -0.2616 / 4.0], // gamma = 1.5
        [0.1121 / 4.0, -0.6395 / 4.0, 1.1588 / 4.0, -0.2877 / 4.0], // gamma = 1.6
        [0.1300 / 4.0, -0.7649 / 4.0, 1.3159 / 4.0, -0.3080 / 4.0], // gamma = 1.7
        [0.1469 / 4.0, -0.8911 / 4.0, 1.4644 / 4.0, -0.3234 / 4.0], // gamma = 1.8
        [0.1627 / 4.0, -1.0170 / 4.0, 1.6051 / 4.0, -0.3347 / 4.0], // gamma = 1.9
        [0.1773 / 4.0, -1.1420 / 4.0, 1.7385 / 4.0, -0.3426 / 4.0], // gamma = 2.0
        [0.1908 / 4.0, -1.2652 / 4.0, 1.8650 / 4.0, -0.3476 / 4.0], // gamma = 2.1
        [0.2031 / 4.0, -1.3864 / 4.0, 1.9851 / 4.0, -0.3501 / 4.0], // gamma = 2.2
    ];

    const NORM13: f32 = ((0x10000 as f64) / (255.0 * 255.0) * 4.0) as f32;
    const NORM24: f32 = ((0x100 as f64) / (255.0) * 4.0) as f32;

    let index = ((gamma * 10.0).round() as usize).clamp(10, 22) - 10;
    let ratios = GAMMA_INCORRECT_TARGET_RATIOS[index];

    [
        ratios[0] * NORM13,
        ratios[1] * NORM24,
        ratios[2] * NORM13,
        ratios[3] * NORM24,
    ]
}

#[derive(PartialEq, Eq, Hash, Clone)]
#[expect(missing_docs)]
pub enum AtlasKey {
    Glyph(RenderGlyphParams),
    Svg(RenderSvgParams),
    Image(RenderImageParams),
}

impl AtlasKey {
    /// Returns the texture kind for this atlas key.
    pub fn texture_kind(&self) -> AtlasTextureKind {
        match self {
            AtlasKey::Glyph(params) => {
                if params.is_emoji {
                    AtlasTextureKind::Polychrome
                } else if params.subpixel_rendering {
                    AtlasTextureKind::Subpixel
                } else {
                    AtlasTextureKind::Monochrome
                }
            }
            AtlasKey::Svg(_) => AtlasTextureKind::Monochrome,
            AtlasKey::Image(_) => AtlasTextureKind::Polychrome,
        }
    }
}

impl From<RenderGlyphParams> for AtlasKey {
    fn from(params: RenderGlyphParams) -> Self {
        Self::Glyph(params)
    }
}

impl From<RenderSvgParams> for AtlasKey {
    fn from(params: RenderSvgParams) -> Self {
        Self::Svg(params)
    }
}

impl From<RenderImageParams> for AtlasKey {
    fn from(params: RenderImageParams) -> Self {
        Self::Image(params)
    }
}

#[expect(missing_docs)]
pub trait PlatformAtlas {
    /// The builder runs with the atlas locked and must not re-enter the same atlas.
    fn get_or_insert_with<'a>(
        &self,
        key: AtlasKey,
        build: &mut dyn FnMut() -> Result<Option<(Size<DevicePixels>, Cow<'a, [u8]>)>>,
    ) -> Result<Option<AtlasTile>>;
    fn remove(&self, key: &AtlasKey);

    #[cfg(any(test, feature = "test-support", feature = "bench-support"))]
    fn contains(&self, _key: &AtlasKey) -> bool {
        false
    }
}

#[doc(hidden)]
pub trait AtlasBackend {
    fn insert(
        &mut self,
        kind: AtlasTextureKind,
        size: Size<DevicePixels>,
        bytes: &[u8],
    ) -> Result<AtlasTile>;

    fn remove(&mut self, tile: AtlasTile);
}

#[doc(hidden)]
pub struct AtlasState<Backend> {
    tiles_by_key: FxHashMap<AtlasKey, AtlasTile>,
    pub backend: Backend,
}

impl<Backend> AtlasState<Backend> {
    pub fn new(backend: Backend) -> Self {
        Self {
            tiles_by_key: FxHashMap::default(),
            backend,
        }
    }

    pub fn contains(&self, key: &AtlasKey) -> bool {
        self.tiles_by_key.contains_key(key)
    }

    pub fn clear(&mut self, reset_backend: impl FnOnce(&mut Backend)) {
        self.tiles_by_key.clear();
        reset_backend(&mut self.backend);
    }
}

impl<Backend: Default> Default for AtlasState<Backend> {
    fn default() -> Self {
        Self::new(Backend::default())
    }
}

impl<Backend: AtlasBackend> AtlasState<Backend> {
    pub fn get_or_insert_with<'a>(
        &mut self,
        key: AtlasKey,
        build: &mut dyn FnMut() -> Result<Option<(Size<DevicePixels>, Cow<'a, [u8]>)>>,
    ) -> Result<Option<AtlasTile>> {
        match self.tiles_by_key.entry(key) {
            Entry::Occupied(entry) => Ok(Some(*entry.get())),
            Entry::Vacant(entry) => {
                profiling::scope!("new tile");
                let Some((size, bytes)) = build()? else {
                    return Ok(None);
                };
                let tile = self
                    .backend
                    .insert(entry.key().texture_kind(), size, &bytes)?;
                entry.insert(tile);
                Ok(Some(tile))
            }
        }
    }

    pub fn remove(&mut self, key: &AtlasKey) {
        if let Some(tile) = self.tiles_by_key.remove(key) {
            self.backend.remove(tile);
        }
    }
}

/// A sprite atlas for windows without a GPU. It hands out uniquely identified
/// tiles without uploading any pixels, so glyph, SVG, and image painting can
/// run to completion in tests and headless platforms.
#[derive(Default)]
pub struct HeadlessAtlas(parking_lot::Mutex<AtlasState<HeadlessAtlasBackend>>);

#[doc(hidden)]
#[derive(Default)]
pub struct HeadlessAtlasBackend {
    next_id: u32,
}

impl AtlasBackend for HeadlessAtlasBackend {
    fn insert(
        &mut self,
        kind: AtlasTextureKind,
        size: Size<DevicePixels>,
        _bytes: &[u8],
    ) -> Result<AtlasTile> {
        self.next_id += 1;
        let texture_id = self.next_id;
        self.next_id += 1;
        let tile_id = self.next_id;
        Ok(AtlasTile {
            texture_id: AtlasTextureId {
                index: texture_id,
                kind,
            },
            tile_id: TileId(tile_id),
            padding: 0,
            bounds: Bounds {
                origin: Point::default(),
                size,
            },
        })
    }

    fn remove(&mut self, _tile: AtlasTile) {}
}

impl PlatformAtlas for HeadlessAtlas {
    fn get_or_insert_with<'a>(
        &self,
        key: AtlasKey,
        build: &mut dyn FnMut() -> Result<Option<(Size<DevicePixels>, Cow<'a, [u8]>)>>,
    ) -> Result<Option<AtlasTile>> {
        self.0.lock().get_or_insert_with(key, build)
    }

    fn remove(&self, key: &AtlasKey) {
        self.0.lock().remove(key);
    }

    #[cfg(any(test, feature = "test-support", feature = "bench-support"))]
    fn contains(&self, key: &AtlasKey) -> bool {
        self.0.lock().contains(key)
    }
}

#[doc(hidden)]
pub struct AtlasTextureList<T> {
    pub textures: Vec<Option<T>>,
    pub free_list: Vec<usize>,
}

impl<T> Default for AtlasTextureList<T> {
    fn default() -> Self {
        Self {
            textures: Vec::default(),
            free_list: Vec::default(),
        }
    }
}

impl<T> ops::Index<usize> for AtlasTextureList<T> {
    type Output = Option<T>;

    fn index(&self, index: usize) -> &Self::Output {
        &self.textures[index]
    }
}

impl<T> AtlasTextureList<T> {
    #[allow(unused)]
    pub fn drain(&mut self) -> std::vec::Drain<'_, Option<T>> {
        self.free_list.clear();
        self.textures.drain(..)
    }

    #[allow(dead_code)]
    pub fn iter_mut(&mut self) -> impl DoubleEndedIterator<Item = &mut T> {
        self.textures.iter_mut().flatten()
    }
}

#[derive(Copy, Clone, Debug, PartialEq, Eq)]
#[repr(C)]
#[expect(missing_docs)]
pub struct AtlasTile {
    /// The texture this tile belongs to.
    pub texture_id: AtlasTextureId,
    /// The unique ID of this tile within its texture.
    pub tile_id: TileId,
    /// Padding around the tile content in pixels.
    pub padding: u32,
    /// The bounds of this tile within the texture.
    pub bounds: Bounds<DevicePixels>,
}

#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
#[repr(C)]
#[expect(missing_docs)]
pub struct AtlasTextureId {
    // We use u32 instead of usize for Metal Shader Language compatibility
    /// The index of this texture in the atlas.
    pub index: u32,
    /// The kind of content stored in this texture.
    pub kind: AtlasTextureKind,
}

#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
#[repr(C)]
#[cfg_attr(
    all(
        any(target_os = "linux", target_os = "freebsd"),
        not(any(feature = "x11", feature = "wayland"))
    ),
    allow(dead_code)
)]
#[expect(missing_docs)]
pub enum AtlasTextureKind {
    Monochrome = 0,
    Polychrome = 1,
    Subpixel = 2,
}

#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
#[repr(C)]
#[expect(missing_docs)]
pub struct TileId(pub u32);

impl From<etagere::AllocId> for TileId {
    fn from(id: etagere::AllocId) -> Self {
        Self(id.serialize())
    }
}

impl From<TileId> for etagere::AllocId {
    fn from(id: TileId) -> Self {
        Self::deserialize(id.0)
    }
}

#[expect(missing_docs)]
pub struct PlatformInputHandler {
    cx: AsyncWindowContext,
    handler: Box<dyn InputHandler>,
}

#[expect(missing_docs)]
#[cfg_attr(
    all(
        any(target_os = "linux", target_os = "freebsd"),
        not(any(feature = "x11", feature = "wayland"))
    ),
    allow(dead_code)
)]
impl PlatformInputHandler {
    pub fn new(cx: AsyncWindowContext, handler: Box<dyn InputHandler>) -> Self {
        Self { cx, handler }
    }

    pub fn selected_text_range(&mut self, ignore_disabled_input: bool) -> Option<UTF16Selection> {
        self.cx
            .update(|window, cx| {
                self.handler
                    .selected_text_range(ignore_disabled_input, window, cx)
            })
            .ok()
            .flatten()
    }

    #[cfg_attr(target_os = "windows", allow(dead_code))]
    pub fn marked_text_range(&mut self) -> Option<Range<usize>> {
        self.cx
            .update(|window, cx| self.handler.marked_text_range(window, cx))
            .ok()
            .flatten()
    }

    #[cfg_attr(
        any(target_os = "linux", target_os = "freebsd", target_os = "windows"),
        allow(dead_code)
    )]
    pub fn text_for_range(
        &mut self,
        range_utf16: Range<usize>,
        adjusted: &mut Option<Range<usize>>,
    ) -> Option<String> {
        self.cx
            .update(|window, cx| {
                self.handler
                    .text_for_range(range_utf16, adjusted, window, cx)
            })
            .ok()
            .flatten()
    }

    pub fn replace_text_in_range(&mut self, replacement_range: Option<Range<usize>>, text: &str) {
        self.cx
            .update(|window, cx| {
                self.handler
                    .replace_text_in_range(replacement_range, text, window, cx);
            })
            .ok();
    }

    pub fn replace_and_mark_text_in_range(
        &mut self,
        range_utf16: Option<Range<usize>>,
        new_text: &str,
        new_selected_range: Option<Range<usize>>,
    ) {
        self.cx
            .update(|window, cx| {
                self.handler.replace_and_mark_text_in_range(
                    range_utf16,
                    new_text,
                    new_selected_range,
                    window,
                    cx,
                )
            })
            .ok();
    }

    #[cfg_attr(target_os = "windows", allow(dead_code))]
    pub fn unmark_text(&mut self) {
        self.cx
            .update(|window, cx| self.handler.unmark_text(window, cx))
            .ok();
    }

    pub fn paste(&mut self, item: ClipboardItem) {
        self.cx
            .update(|window, cx| self.handler.paste(item, window, cx))
            .ok();
    }

    pub fn bounds_for_range(&mut self, range_utf16: Range<usize>) -> Option<Bounds<Pixels>> {
        self.cx
            .update(|window, cx| self.handler.bounds_for_range(range_utf16, window, cx))
            .ok()
            .flatten()
    }

    #[allow(dead_code)]
    pub fn apple_press_and_hold_enabled(&mut self) -> bool {
        self.handler.apple_press_and_hold_enabled()
    }

    pub fn dispatch_input(&mut self, input: &str, window: &mut Window, cx: &mut App) {
        self.handler.replace_text_in_range(None, input, window, cx);
    }

    pub fn compute_ime_candidate_bounds(
        marked_range: Option<Range<usize>>,
        selection: &UTF16Selection,
        mut bounds_for_range: impl FnMut(Range<usize>) -> Option<Bounds<Pixels>>,
    ) -> Option<Bounds<Pixels>> {
        if let Some(marked_range) = marked_range {
            // Default to the start of the marked (composing) range.
            let mut line_start = marked_range.start;

            // Walk backward from the caret looking for a line break. A change in
            // the Y coordinate means we crossed into the previous visual line, so
            // the line start is one position after the break point.
            let caret = selection.range.end;
            if let Some(caret_bounds) = bounds_for_range(caret..caret) {
                for i in (marked_range.start..caret).rev() {
                    if let Some(b) = bounds_for_range(i..i) {
                        if (b.origin.y - caret_bounds.origin.y).abs() > px(0.1) {
                            line_start = i + 1;
                            break;
                        }
                    }
                }
            }
            bounds_for_range(line_start..line_start)
        } else {
            // No active composition — use the selection endpoint.
            let offset = if selection.reversed {
                selection.range.start
            } else {
                selection.range.end
            };
            bounds_for_range(offset..offset)
        }
    }

    pub fn selected_bounds(&mut self, window: &mut Window, cx: &mut App) -> Option<Bounds<Pixels>> {
        let marked_range = self.handler.marked_text_range(window, cx);
        let selection = self.handler.selected_text_range(true, window, cx)?;
        Self::compute_ime_candidate_bounds(marked_range, &selection, |range| {
            self.handler.bounds_for_range(range, window, cx)
        })
    }

    pub fn ime_candidate_bounds(&mut self) -> Option<Bounds<Pixels>> {
        let marked_range = self.marked_text_range();
        let selection = self.selected_text_range(true)?;
        Self::compute_ime_candidate_bounds(marked_range, &selection, |range| {
            self.bounds_for_range(range)
        })
    }

    #[allow(unused)]
    pub fn character_index_for_point(&mut self, point: Point<Pixels>) -> Option<usize> {
        self.cx
            .update(|window, cx| self.handler.character_index_for_point(point, window, cx))
            .ok()
            .flatten()
    }

    /// See [`InputHandler::set_selected_text_range`].
    pub fn set_selected_text_range(&mut self, range_utf16: Range<usize>) {
        self.cx
            .update(|window, cx| {
                self.handler
                    .set_selected_text_range(range_utf16, window, cx)
            })
            .ok();
    }

    /// See [`InputHandler::element_bounds`].
    pub fn element_bounds(&mut self) -> Option<Bounds<Pixels>> {
        self.cx
            .update(|window, cx| self.handler.element_bounds(window, cx))
            .ok()
            .flatten()
    }

    /// See [`InputHandler::text_length_utf16`].
    pub fn text_length_utf16(&mut self) -> Option<usize> {
        self.cx
            .update(|window, cx| self.handler.text_length_utf16(window, cx))
            .ok()
            .flatten()
    }

    #[allow(dead_code)]
    pub fn accepts_text_input(&mut self, window: &mut Window, cx: &mut App) -> bool {
        self.handler.accepts_text_input(window, cx)
    }

    #[allow(dead_code)]
    pub fn query_accepts_text_input(&mut self) -> bool {
        self.cx
            .update(|window, cx| self.handler.accepts_text_input(window, cx))
            .unwrap_or(true)
    }

    /// See [`InputHandler::prefers_ime_for_printable_keys`].
    ///
    /// This is not a pure delegation to the handler: while a multi-stroke binding is pending this
    /// returns `false` regardless of the handler's preference, because the next printable key may
    /// complete a binding whose prefix already bypassed the IME.
    pub fn query_prefers_ime_for_printable_keys(&mut self) -> bool {
        self.cx
            .update(|window, cx| {
                // The next printable key may complete a chord whose prefix bypassed the IME.
                !window.has_pending_keystrokes()
                    && self.handler.prefers_ime_for_printable_keys(window, cx)
            })
            .unwrap_or(false)
    }

    /// See [`InputHandler::text_input_configuration`].
    pub fn text_input_configuration(
        &mut self,
        window: &mut Window,
        cx: &mut App,
    ) -> TextInputConfiguration {
        self.handler.text_input_configuration(window, cx)
    }

    /// See [`InputHandler::text_input_editable_range`].
    pub fn text_input_editable_range(&mut self) -> Option<Range<usize>> {
        self.cx
            .update(|window, cx| self.handler.text_input_editable_range(window, cx))
            .ok()
            .flatten()
    }
}

/// A struct representing a selection in a text buffer, in UTF16 characters.
/// This is different from a range because the head may be before the tail.
#[derive(Debug)]
pub struct UTF16Selection {
    /// The range of text in the document this selection corresponds to
    /// in UTF16 characters.
    pub range: Range<usize>,
    /// Whether the head of this selection is at the start (true), or end (false)
    /// of the range
    pub reversed: bool,
}

/// Zed's interface for handling text input from the platform's IME system
/// This is currently a 1:1 exposure of the NSTextInputClient API:
///
/// <https://developer.apple.com/documentation/appkit/nstextinputclient>
pub trait InputHandler: 'static {
    /// Get the range of the user's currently selected text, if any
    /// Corresponds to [selectedRange()](https://developer.apple.com/documentation/appkit/nstextinputclient/1438242-selectedrange)
    ///
    /// Return value is in terms of UTF-16 characters, from 0 to the length of the document
    fn selected_text_range(
        &mut self,
        ignore_disabled_input: bool,
        window: &mut Window,
        cx: &mut App,
    ) -> Option<UTF16Selection>;

    /// Get the range of the currently marked text, if any
    /// Corresponds to [markedRange()](https://developer.apple.com/documentation/appkit/nstextinputclient/1438250-markedrange)
    ///
    /// Return value is in terms of UTF-16 characters, from 0 to the length of the document
    fn marked_text_range(&mut self, window: &mut Window, cx: &mut App) -> Option<Range<usize>>;

    /// Get the text for the given document range in UTF-16 characters
    /// Corresponds to [attributedSubstring(forProposedRange: actualRange:)](https://developer.apple.com/documentation/appkit/nstextinputclient/1438238-attributedsubstring)
    ///
    /// range_utf16 is in terms of UTF-16 characters
    fn text_for_range(
        &mut self,
        range_utf16: Range<usize>,
        adjusted_range: &mut Option<Range<usize>>,
        window: &mut Window,
        cx: &mut App,
    ) -> Option<String>;

    /// Replace the text in the given document range with the given text
    /// Corresponds to [insertText(_:replacementRange:)](https://developer.apple.com/documentation/appkit/nstextinputclient/1438258-inserttext)
    ///
    /// replacement_range is in terms of UTF-16 characters
    fn replace_text_in_range(
        &mut self,
        replacement_range: Option<Range<usize>>,
        text: &str,
        window: &mut Window,
        cx: &mut App,
    );

    /// Replace the text in the given document range with the given text,
    /// and mark the given text as part of an IME 'composing' state
    /// Corresponds to [setMarkedText(_:selectedRange:replacementRange:)](https://developer.apple.com/documentation/appkit/nstextinputclient/1438246-setmarkedtext)
    ///
    /// range_utf16 is in terms of UTF-16 characters
    /// new_selected_range is in terms of UTF-16 characters
    fn replace_and_mark_text_in_range(
        &mut self,
        range_utf16: Option<Range<usize>>,
        new_text: &str,
        new_selected_range: Option<Range<usize>>,
        window: &mut Window,
        cx: &mut App,
    );

    /// Remove the IME 'composing' state from the document
    /// Corresponds to [unmarkText()](https://developer.apple.com/documentation/appkit/nstextinputclient/1438239-unmarktext)
    fn unmark_text(&mut self, window: &mut Window, cx: &mut App);

    /// Insert a platform-initiated paste at the current selection.
    ///
    /// Platforms that deliver paste as an input event rather than through an
    /// application-defined action (e.g. the DOM `paste` event on web) call
    /// this with the full clipboard contents. The default implementation
    /// inserts only the plain-text portion of the item.
    fn paste(&mut self, item: ClipboardItem, window: &mut Window, cx: &mut App) {
        if let Some(text) = item.text() {
            self.replace_text_in_range(None, &text, window, cx);
        }
    }

    /// Get the bounds of the given document range in screen coordinates
    /// Corresponds to [firstRect(forCharacterRange:actualRange:)](https://developer.apple.com/documentation/appkit/nstextinputclient/1438240-firstrect)
    ///
    /// This is used for positioning the IME candidate window
    fn bounds_for_range(
        &mut self,
        range_utf16: Range<usize>,
        window: &mut Window,
        cx: &mut App,
    ) -> Option<Bounds<Pixels>>;

    /// Get the character offset for the given point in terms of UTF16 characters
    ///
    /// Corresponds to [characterIndexForPoint:](https://developer.apple.com/documentation/appkit/nstextinputclient/characterindex(for:))
    fn character_index_for_point(
        &mut self,
        point: Point<Pixels>,
        window: &mut Window,
        cx: &mut App,
    ) -> Option<usize>;

    /// Set the range of the user's currently selected text.
    ///
    /// This is the reverse data-flow direction from [`Self::selected_text_range`]:
    /// platforms call it when the system text machinery moves the selection on the
    /// application's behalf — e.g. the user drags a system selection handle or
    /// invokes Select All from system UI (iOS `UITextInput setSelectedTextRange:`,
    /// Android `InputConnection.setSelection`).
    ///
    /// range_utf16 is in terms of UTF-16 characters, from 0 to the length of the document
    fn set_selected_text_range(
        &mut self,
        _range_utf16: Range<usize>,
        _window: &mut Window,
        _cx: &mut App,
    ) {
    }

    /// Get the bounds of the focused text element in window coordinates, if known.
    ///
    /// This is the pull counterpart to the [`PlatformWindow::update_ime_position`]
    /// push: mobile platforms ask for the focused element's geometry when they
    /// need it (e.g. to frame system text-interaction UI overlaid on the focused
    /// element).
    fn element_bounds(&mut self, _window: &mut Window, _cx: &mut App) -> Option<Bounds<Pixels>> {
        None
    }

    /// Get the length of the document in UTF-16 characters, if known.
    fn text_length_utf16(&mut self, _window: &mut Window, _cx: &mut App) -> Option<usize> {
        None
    }

    /// Allows a given input context to opt into getting raw key repeats instead of
    /// sending these to the platform.
    /// TODO: Ideally we should be able to set ApplePressAndHoldEnabled in NSUserDefaults
    /// (which is how iTerm does it) but it doesn't seem to work for me.
    #[allow(dead_code)]
    fn apple_press_and_hold_enabled(&mut self) -> bool {
        true
    }

    /// Returns whether this handler is accepting text input to be inserted.
    fn accepts_text_input(&mut self, _window: &mut Window, _cx: &mut App) -> bool {
        true
    }

    /// The contiguous range of text, in UTF-16 code units, that platform text
    /// input may read and edit around the current selection.
    ///
    /// Platforms that mirror document text into an IME-editable buffer clamp
    /// the mirrored window to this range, so multi-step IME edit gestures
    /// (word deletion, autocorrect rewrites, suggestion picks) cannot reach
    /// content outside it. The range should contain the current selection;
    /// when it cannot (a selection spanning a region boundary), platforms
    /// degrade the mirrored IME context rather than widening the range.
    /// `None` places no bound.
    fn text_input_editable_range(
        &mut self,
        _window: &mut Window,
        _cx: &mut App,
    ) -> Option<Range<usize>> {
        None
    }

    /// Returns whether printable keys should be routed to the IME before keybinding
    /// matching when a non-ASCII input source (e.g. Japanese, Korean, Chinese IME)
    /// is active. This prevents multi-stroke keybindings like `jj` from intercepting
    /// keys that the IME should compose.
    ///
    /// Defaults to `false`. The editor overrides this based on whether it expects
    /// character input (e.g. Vim insert mode returns `true`, normal mode returns `false`).
    /// The terminal keeps the default `false` so that raw keys reach the terminal process.
    fn prefers_ime_for_printable_keys(&mut self, _window: &mut Window, _cx: &mut App) -> bool {
        false
    }

    /// Get this handler's preferences for platform text assistance.
    ///
    /// GPUI re-queries this every frame and forwards it to the platform window
    /// only when it changes, so implementations must be cheap and may vary the
    /// result with application state (e.g. with the cursor's position).
    fn text_input_configuration(
        &mut self,
        _window: &mut Window,
        _cx: &mut App,
    ) -> TextInputConfiguration {
        TextInputConfiguration::default()
    }
}

/// Platform text-assistance preferences for the focused text region.
///
/// Returned by [`InputHandler::text_input_configuration`] and forwarded to the
/// platform whenever it changes; the platform maps the fields onto its native
/// input-session attributes (on web, DOM attributes of the hidden editable
/// element such as `autocorrect` and `enterkeyhint`).
///
/// The default disables all text assistance and requests no particular action
/// key presentation.
#[derive(Clone, Debug, Default, PartialEq, Eq)]
pub struct TextInputConfiguration {
    /// Whether the platform may automatically correct entered text.
    pub autocorrect: bool,
    /// How software keyboards automatically capitalize entered text.
    pub autocapitalize: Autocapitalize,
    /// Whether software keyboards may offer word suggestions and spellcheck.
    pub suggestions: bool,
    /// The action advertised on a software keyboard's confirm ("enter") key.
    pub input_action: TextInputAction,
}

/// Automatic capitalization applied by software keyboards.
#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
pub enum Autocapitalize {
    /// No automatic capitalization.
    #[default]
    None,
    /// Capitalize the first letter of each word.
    Words,
    /// Capitalize the first letter of each sentence.
    Sentences,
    /// Capitalize every letter.
    Characters,
}

/// The action a software keyboard advertises on its confirm ("enter") key.
///
/// This affects only how the key is presented (icon or label); pressing it is
/// still delivered as ordinary input.
///
/// The variants are the HTML `enterkeyhint` attribute's value set
/// (<https://html.spec.whatwg.org/multipage/interaction.html#input-modalities:-the-enterkeyhint-attribute>),
/// which also maps onto Android's `IME_ACTION_*` constants and iOS's
/// `UIReturnKeyType`; [`TextInputAction::Unspecified`] means "emit no hint".
#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
pub enum TextInputAction {
    /// Let the platform choose its default presentation.
    #[default]
    Unspecified,
    /// Inserting a line break.
    Enter,
    /// Committing the field's value.
    Done,
    /// Navigating to the typed target.
    Go,
    /// Moving to the next field.
    Next,
    /// Moving to the previous field.
    Previous,
    /// Executing a search.
    Search,
    /// Sending a message.
    Send,
}

/// The variables that can be configured when creating a new window
#[derive(Debug)]
pub struct WindowOptions {
    /// Specifies the state and bounds of the window in screen coordinates.
    /// - `None`: Inherit the bounds.
    /// - `Some(WindowBounds)`: Open a window with corresponding state and its restore size.
    pub window_bounds: Option<WindowBounds>,

    /// The titlebar configuration of the window
    pub titlebar: Option<TitlebarOptions>,

    /// Whether the window should be focused when created
    pub focus: bool,

    /// Whether the window should be shown when created
    pub show: bool,

    /// The kind of window to create
    pub kind: WindowKind,

    /// Whether the window can be moved by the user. When `false`, the user cannot drag
    /// the window (on macOS this sets `NSWindow.isMovable`, which also disables the
    /// Window-menu tiling items); programmatic moves are still allowed.
    pub is_movable: bool,

    /// Whether the application owns dragging of the (custom) titlebar, rather than
    /// AppKit. Only has an effect on macOS.
    ///
    /// Set this to `true` for windows that draw their own titlebar and move the window
    /// themselves via [`Window::start_window_move`]. It marks the whole content view as
    /// app-owned titlebar content, so AppKit neither drags the window from the titlebar
    /// nor delays titlebar clicks while disambiguating double-clicks (a delay first
    /// observed on macOS 27). It is independent of `is_movable`, so such windows stay
    /// user-movable (via their own drag) and keep the Window-menu tiling items enabled.
    ///
    /// Leave this `false` for windows that rely on AppKit's native titlebar dragging.
    pub app_owns_titlebar_drag: bool,

    /// The minimum interval between animation frames while the window is inactive.
    ///
    /// Set to `None` to disable inactive-window animation frame throttling.
    pub inactive_frame_interval: Option<Duration>,

    /// Whether the window should be resizable by the user
    pub is_resizable: bool,

    /// Whether the window should be minimized by the user
    pub is_minimizable: bool,

    /// The display to create the window on, if this is None,
    /// the window will be created on the main display
    pub display_id: Option<DisplayId>,

    /// The appearance of the window background.
    pub window_background: WindowBackgroundAppearance,

    /// Application identifier of the window. Can by used by desktop environments to group applications together.
    pub app_id: Option<String>,

    /// Window minimum size
    pub window_min_size: Option<Size<Pixels>>,

    /// Whether to use client or server-side decorations on X11 and Wayland.
    /// The platform may ignore requests it cannot satisfy.
    pub window_decorations: Option<WindowDecorations>,

    /// Icon image (X11 only)
    pub icon: Option<Arc<image::RgbaImage>>,

    /// Tab group name, allows opening the window as a native tab on macOS 10.12+. Windows with the same tabbing identifier will be grouped together.
    pub tabbing_identifier: Option<String>,
}

/// The variables that can be configured when creating a new window
#[derive(Debug)]
#[cfg_attr(
    all(
        any(target_os = "linux", target_os = "freebsd"),
        not(any(feature = "x11", feature = "wayland"))
    ),
    allow(dead_code)
)]
#[allow(missing_docs)]
pub struct WindowParams {
    pub bounds: Bounds<Pixels>,

    /// The titlebar configuration of the window
    #[cfg_attr(feature = "wayland", allow(dead_code))]
    pub titlebar: Option<TitlebarOptions>,

    /// The kind of window to create
    #[cfg_attr(any(target_os = "linux", target_os = "freebsd"), allow(dead_code))]
    pub kind: WindowKind,

    /// Whether the window should be movable by the user
    #[cfg_attr(any(target_os = "linux", target_os = "freebsd"), allow(dead_code))]
    pub is_movable: bool,

    /// Whether the application owns dragging of the (custom) titlebar (macOS only)
    #[cfg_attr(
        any(target_os = "linux", target_os = "freebsd", target_os = "windows"),
        allow(dead_code)
    )]
    pub app_owns_titlebar_drag: bool,

    /// Whether the window should be resizable by the user
    #[cfg_attr(any(target_os = "linux", target_os = "freebsd"), allow(dead_code))]
    pub is_resizable: bool,

    /// Whether the window should be minimized by the user
    #[cfg_attr(any(target_os = "linux", target_os = "freebsd"), allow(dead_code))]
    pub is_minimizable: bool,

    #[cfg_attr(
        any(target_os = "linux", target_os = "freebsd", target_os = "windows"),
        allow(dead_code)
    )]
    pub focus: bool,

    #[cfg_attr(any(target_os = "linux", target_os = "freebsd"), allow(dead_code))]
    pub show: bool,

    /// An image to set as the window icon (x11 only)
    #[cfg_attr(feature = "wayland", allow(dead_code))]
    pub icon: Option<Arc<image::RgbaImage>>,

    #[cfg_attr(feature = "wayland", allow(dead_code))]
    pub display_id: Option<DisplayId>,

    #[cfg_attr(feature = "wayland", allow(dead_code))]
    pub app_id: Option<String>,

    pub window_min_size: Option<Size<Pixels>>,

    #[cfg(target_os = "macos")]
    pub tabbing_identifier: Option<String>,
}

/// Represents the status of how a window should be opened.
#[derive(Debug, Copy, Clone, PartialEq)]
pub enum WindowBounds {
    /// Indicates that the window should open in a windowed state with the given bounds.
    Windowed(Bounds<Pixels>),
    /// Indicates that the window should open in a maximized state.
    /// The bounds provided here represent the restore size of the window.
    Maximized(Bounds<Pixels>),
    /// Indicates that the window should open in fullscreen mode.
    /// The bounds provided here represent the restore size of the window.
    Fullscreen(Bounds<Pixels>),
}

impl Default for WindowBounds {
    fn default() -> Self {
        WindowBounds::Windowed(Bounds::default())
    }
}

impl WindowBounds {
    /// Retrieve the inner bounds
    pub fn get_bounds(&self) -> Bounds<Pixels> {
        match self {
            WindowBounds::Windowed(bounds) => *bounds,
            WindowBounds::Maximized(bounds) => *bounds,
            WindowBounds::Fullscreen(bounds) => *bounds,
        }
    }

    /// Creates a new window bounds that centers the window on the screen.
    pub fn centered(size: Size<Pixels>, cx: &App) -> Self {
        WindowBounds::Windowed(Bounds::centered(None, size, cx))
    }
}

impl Default for WindowOptions {
    fn default() -> Self {
        Self {
            window_bounds: None,
            titlebar: Some(TitlebarOptions {
                title: Default::default(),
                appears_transparent: Default::default(),
                traffic_light_position: Default::default(),
            }),
            focus: true,
            show: true,
            kind: WindowKind::Normal,
            is_movable: true,
            app_owns_titlebar_drag: false,
            inactive_frame_interval: Some(Duration::from_micros(33_333)),
            is_resizable: true,
            is_minimizable: true,
            display_id: None,
            window_background: WindowBackgroundAppearance::default(),
            icon: None,
            app_id: None,
            window_min_size: None,
            window_decorations: None,
            tabbing_identifier: None,
        }
    }
}

/// The options that can be configured for a window's titlebar
#[derive(Debug, Default)]
pub struct TitlebarOptions {
    /// The initial title of the window
    pub title: Option<SharedString>,

    /// Should the default system titlebar be hidden to allow for a custom-drawn titlebar? (macOS and Windows only)
    /// Refer to [`WindowOptions::window_decorations`] on Linux
    pub appears_transparent: bool,

    /// The position of the macOS traffic light buttons
    pub traffic_light_position: Option<Point<Pixels>>,
}

/// The kind of window to create
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum WindowKind {
    /// A normal application window
    Normal,

    /// A window that appears above all other windows, usually used for alerts or popups
    /// use sparingly!
    PopUp,

    /// A parent-anchored, platform-native popup window for menus, comboboxes, context menus and
    /// tooltips. Unlike [`WindowKind::PopUp`], it is positioned relative to a parent window.
    ///
    /// The popup's size comes from [`WindowOptions::window_bounds`], whose origin is ignored.
    /// See [`popup::PopupOptions`] for the placement options. Platforms without a native
    /// implementation reject it with [`popup::PopupNotSupportedError`].
    AnchoredPopup(popup::PopupOptions),

    /// A floating window that appears on top of its parent window
    Floating,

    /// A Wayland LayerShell window, used to draw overlays or backgrounds for applications such as
    /// docks, notifications or wallpapers.
    #[cfg(all(target_os = "linux", feature = "wayland"))]
    LayerShell(layer_shell::LayerShellOptions),

    /// A window that appears on top of its parent window and blocks interaction with it
    /// until the modal window is closed
    Dialog,
}

/// The appearance of the window, as defined by the operating system.
///
/// On macOS, this corresponds to named [`NSAppearance`](https://developer.apple.com/documentation/appkit/nsappearance)
/// values.
#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
pub enum WindowAppearance {
    /// A light appearance.
    ///
    /// On macOS, this corresponds to the `aqua` appearance.
    #[default]
    Light,

    /// A light appearance with vibrant colors.
    ///
    /// On macOS, this corresponds to the `NSAppearanceNameVibrantLight` appearance.
    VibrantLight,

    /// A dark appearance.
    ///
    /// On macOS, this corresponds to the `darkAqua` appearance.
    Dark,

    /// A dark appearance with vibrant colors.
    ///
    /// On macOS, this corresponds to the `NSAppearanceNameVibrantDark` appearance.
    VibrantDark,
}

/// The appearance of the background of the window itself, when there is
/// no content or the content is transparent.
#[derive(Copy, Clone, Debug, Default, PartialEq)]
pub enum WindowBackgroundAppearance {
    /// Opaque.
    ///
    /// This lets the window manager know that content behind this
    /// window does not need to be drawn.
    ///
    /// Actual color depends on the system and themes should define a fully
    /// opaque background color instead.
    #[default]
    Opaque,
    /// Plain alpha transparency.
    Transparent,
    /// Transparency, but the contents behind the window are blurred.
    ///
    /// Not always supported.
    Blurred,
    /// The Mica backdrop material, supported on Windows 11.
    MicaBackdrop,
    /// The Mica Alt backdrop material, supported on Windows 11.
    MicaAltBackdrop,
}

/// The text rendering mode to use for drawing glyphs.
#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
pub enum TextRenderingMode {
    /// Use the platform's default text rendering mode.
    #[default]
    PlatformDefault,
    /// Use subpixel (ClearType-style) text rendering.
    Subpixel,
    /// Use grayscale text rendering.
    Grayscale,
}

/// The options that can be configured for a file dialog prompt
#[derive(Clone, Debug)]
pub struct PathPromptOptions {
    /// Should the prompt allow files to be selected?
    pub files: bool,
    /// Should the prompt allow directories to be selected?
    pub directories: bool,
    /// Should the prompt allow multiple files to be selected?
    pub multiple: bool,
    /// The prompt to show to a user when selecting a path
    pub prompt: Option<SharedString>,
}

/// What kind of prompt styling to show
#[derive(Copy, Clone, Debug, PartialEq)]
pub enum PromptLevel {
    /// A prompt that is shown when the user should be notified of something
    Info,

    /// A prompt that is shown when the user needs to be warned of a potential problem
    Warning,

    /// A prompt that is shown when a critical problem has occurred
    Critical,
}

/// Prompt Button
#[derive(Clone, Debug, PartialEq)]
pub enum PromptButton {
    /// Ok button
    Ok(SharedString),
    /// Cancel button
    Cancel(SharedString),
    /// Other button
    Other(SharedString),
}

impl PromptButton {
    /// Create a button with label
    pub fn new(label: impl Into<SharedString>) -> Self {
        PromptButton::Other(label.into())
    }

    /// Create an Ok button
    pub fn ok(label: impl Into<SharedString>) -> Self {
        PromptButton::Ok(label.into())
    }

    /// Create a Cancel button
    pub fn cancel(label: impl Into<SharedString>) -> Self {
        PromptButton::Cancel(label.into())
    }

    /// Returns true if this button is a cancel button.
    #[allow(dead_code)]
    pub fn is_cancel(&self) -> bool {
        matches!(self, PromptButton::Cancel(_))
    }

    /// Returns the label of the button
    pub fn label(&self) -> &SharedString {
        match self {
            PromptButton::Ok(label) => label,
            PromptButton::Cancel(label) => label,
            PromptButton::Other(label) => label,
        }
    }
}

impl From<&str> for PromptButton {
    fn from(value: &str) -> Self {
        match value.to_lowercase().as_str() {
            "ok" => PromptButton::Ok("OK".into()),
            "cancel" => PromptButton::Cancel("Cancel".into()),
            _ => PromptButton::Other(SharedString::from(value.to_owned())),
        }
    }
}

/// The style of the cursor (pointer)
#[derive(Copy, Clone, Default, Debug, PartialEq, Eq, Hash, Serialize, Deserialize, JsonSchema)]
pub enum CursorStyle {
    /// The default cursor
    #[default]
    Arrow,

    /// A text input cursor
    /// corresponds to the CSS cursor value `text`
    IBeam,

    /// A crosshair cursor
    /// corresponds to the CSS cursor value `crosshair`
    Crosshair,

    /// A closed hand cursor
    /// corresponds to the CSS cursor value `grabbing`
    ClosedHand,

    /// An open hand cursor
    /// corresponds to the CSS cursor value `grab`
    OpenHand,

    /// A pointing hand cursor
    /// corresponds to the CSS cursor value `pointer`
    PointingHand,

    /// A resize left cursor
    /// corresponds to the CSS cursor value `w-resize`
    ResizeLeft,

    /// A resize right cursor
    /// corresponds to the CSS cursor value `e-resize`
    ResizeRight,

    /// A resize cursor to the left and right
    /// corresponds to the CSS cursor value `ew-resize`
    ResizeLeftRight,

    /// A resize up cursor
    /// corresponds to the CSS cursor value `n-resize`
    ResizeUp,

    /// A resize down cursor
    /// corresponds to the CSS cursor value `s-resize`
    ResizeDown,

    /// A resize cursor directing up and down
    /// corresponds to the CSS cursor value `ns-resize`
    ResizeUpDown,

    /// A resize cursor directing up-left and down-right
    /// corresponds to the CSS cursor value `nesw-resize`
    ResizeUpLeftDownRight,

    /// A resize cursor directing up-right and down-left
    /// corresponds to the CSS cursor value `nwse-resize`
    ResizeUpRightDownLeft,

    /// A cursor indicating that the item/column can be resized horizontally.
    /// corresponds to the CSS cursor value `col-resize`
    ResizeColumn,

    /// A cursor indicating that the item/row can be resized vertically.
    /// corresponds to the CSS cursor value `row-resize`
    ResizeRow,

    /// A text input cursor for vertical layout
    /// corresponds to the CSS cursor value `vertical-text`
    IBeamCursorForVerticalLayout,

    /// A cursor indicating that the operation is not allowed
    /// corresponds to the CSS cursor value `not-allowed`
    OperationNotAllowed,

    /// A cursor indicating that the operation will result in a link
    /// corresponds to the CSS cursor value `alias`
    DragLink,

    /// A cursor indicating that the operation will result in a copy
    /// corresponds to the CSS cursor value `copy`
    DragCopy,

    /// A cursor indicating that the operation will result in a context menu
    /// corresponds to the CSS cursor value `context-menu`
    ContextualMenu,
}

/// A clipboard item that should be copied to the clipboard
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct ClipboardItem {
    /// The entries in this clipboard item.
    pub entries: Vec<ClipboardEntry>,
}

/// An error produced by [`Platform::read_from_clipboard_async`].
///
/// Callers surface these failures to users, so the variants distinguish
/// conditions that call for different user-facing guidance.
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum ClipboardReadError {
    /// The platform clipboard is not available in this context, e.g. the
    /// browser does not expose the async clipboard API or the page is not a
    /// secure context.
    Unavailable,
    /// The platform refused access, e.g. the user declined the browser's
    /// clipboard permission prompt or paste confirmation.
    Denied(String),
    /// The clipboard contents could not be converted into a
    /// [`ClipboardItem`].
    UnsupportedContent,
}

impl std::fmt::Display for ClipboardReadError {
    fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::Unavailable => formatter.write_str("the clipboard is unavailable"),
            Self::Denied(message) => {
                write!(formatter, "clipboard access was denied: {message}")
            }
            Self::UnsupportedContent => {
                formatter.write_str("the clipboard contents are unsupported")
            }
        }
    }
}

impl std::error::Error for ClipboardReadError {}

/// Either a ClipboardString or a ClipboardImage
#[derive(Clone, Debug, Eq, PartialEq)]
pub enum ClipboardEntry {
    /// A string entry
    String(ClipboardString),
    /// An image entry
    Image(Image),
    /// A file entry
    ExternalPaths(crate::ExternalPaths),
}

impl ClipboardItem {
    /// Create a new ClipboardItem::String with no associated metadata
    pub fn new_string(text: String) -> Self {
        Self {
            entries: vec![ClipboardEntry::String(ClipboardString::new(text))],
        }
    }

    /// Create a new ClipboardItem::String with the given text and associated metadata
    pub fn new_string_with_metadata(text: String, metadata: String) -> Self {
        Self {
            entries: vec![ClipboardEntry::String(ClipboardString {
                text,
                metadata: Some(metadata),
            })],
        }
    }

    /// Create a new ClipboardItem::String with the given text and associated metadata
    pub fn new_string_with_json_metadata<T: Serialize>(text: String, metadata: T) -> Self {
        Self {
            entries: vec![ClipboardEntry::String(
                ClipboardString::new(text).with_json_metadata(metadata),
            )],
        }
    }

    /// Create a new ClipboardItem::Image with the given image with no associated metadata
    pub fn new_image(image: &Image) -> Self {
        Self {
            entries: vec![ClipboardEntry::Image(image.clone())],
        }
    }

    /// Concatenates together all the ClipboardString entries in the item.
    /// Returns None if there were no ClipboardString entries.
    pub fn text(&self) -> Option<String> {
        let mut answer = String::new();

        for entry in self.entries.iter() {
            if let ClipboardEntry::String(ClipboardString { text, metadata: _ }) = entry {
                answer.push_str(text);
            }
        }

        if answer.is_empty() {
            for entry in self.entries.iter() {
                if let ClipboardEntry::ExternalPaths(paths) = entry {
                    for path in &paths.0 {
                        use std::fmt::Write as _;
                        _ = write!(answer, "{}", path.display());
                    }
                }
            }
        }

        if !answer.is_empty() {
            Some(answer)
        } else {
            None
        }
    }

    /// If this item is one ClipboardEntry::String, returns its metadata.
    #[cfg_attr(not(target_os = "windows"), allow(dead_code))]
    pub fn metadata(&self) -> Option<&String> {
        match self.entries().first() {
            Some(ClipboardEntry::String(clipboard_string)) if self.entries.len() == 1 => {
                clipboard_string.metadata.as_ref()
            }
            _ => None,
        }
    }

    /// Get the item's entries
    pub fn entries(&self) -> &[ClipboardEntry] {
        &self.entries
    }

    /// Get owned versions of the item's entries
    pub fn into_entries(self) -> impl Iterator<Item = ClipboardEntry> {
        self.entries.into_iter()
    }
}

impl From<ClipboardString> for ClipboardEntry {
    fn from(value: ClipboardString) -> Self {
        Self::String(value)
    }
}

impl From<String> for ClipboardEntry {
    fn from(value: String) -> Self {
        Self::from(ClipboardString::from(value))
    }
}

impl From<Image> for ClipboardEntry {
    fn from(value: Image) -> Self {
        Self::Image(value)
    }
}

impl From<ClipboardEntry> for ClipboardItem {
    fn from(value: ClipboardEntry) -> Self {
        Self {
            entries: vec![value],
        }
    }
}

impl From<String> for ClipboardItem {
    fn from(value: String) -> Self {
        Self::from(ClipboardEntry::from(value))
    }
}

impl From<Image> for ClipboardItem {
    fn from(value: Image) -> Self {
        Self::from(ClipboardEntry::from(value))
    }
}

/// One of the editor's supported image formats (e.g. PNG, JPEG) - used when dealing with images in the clipboard
#[derive(Clone, Copy, Debug, Eq, PartialEq, EnumIter, Hash)]
pub enum ImageFormat {
    // Sorted from most to least likely to be pasted into an editor,
    // which matters when we iterate through them trying to see if
    // clipboard content matches them.
    /// .png
    Png,
    /// .jpeg or .jpg
    Jpeg,
    /// .webp
    Webp,
    /// .gif
    Gif,
    /// .svg
    Svg,
    /// .bmp
    Bmp,
    /// .tif or .tiff
    Tiff,
    /// .ico
    Ico,
    /// Netpbm image formats (.pbm, .ppm, .pgm).
    Pnm,
}

impl ImageFormat {
    /// Returns the mime type for the ImageFormat
    pub const fn mime_type(self) -> &'static str {
        match self {
            ImageFormat::Png => "image/png",
            ImageFormat::Jpeg => "image/jpeg",
            ImageFormat::Webp => "image/webp",
            ImageFormat::Gif => "image/gif",
            ImageFormat::Svg => "image/svg+xml",
            ImageFormat::Bmp => "image/bmp",
            ImageFormat::Tiff => "image/tiff",
            ImageFormat::Ico => "image/ico",
            ImageFormat::Pnm => "image/x-portable-anymap",
        }
    }

    /// Returns the file extension for this image format (without leading dot).
    pub const fn extension(self) -> &'static str {
        match self {
            ImageFormat::Png => "png",
            ImageFormat::Jpeg => "jpg",
            ImageFormat::Webp => "webp",
            ImageFormat::Gif => "gif",
            ImageFormat::Svg => "svg",
            ImageFormat::Bmp => "bmp",
            ImageFormat::Tiff => "tiff",
            ImageFormat::Ico => "ico",
            ImageFormat::Pnm => "pnm",
        }
    }

    /// Returns the ImageFormat for the given mime type, including known aliases.
    pub fn from_mime_type(mime_type: &str) -> Option<Self> {
        use strum::IntoEnumIterator;
        Self::iter()
            .find(|format| format.mime_type() == mime_type)
            .or_else(|| Self::from_mime_type_alias(mime_type))
    }

    /// Non-canonical mime types that some producers use in the wild.
    /// Unlike `mime_type()` which returns the single canonical form,
    /// these are legacy or shortened variants we still need to recognize.
    fn from_mime_type_alias(mime_type: &str) -> Option<Self> {
        match mime_type {
            "image/jpg" => Some(Self::Jpeg),
            "image/tif" => Some(Self::Tiff),
            _ => None,
        }
    }
}

/// An image, with a format and certain bytes
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct Image {
    /// The image format the bytes represent (e.g. PNG)
    pub format: ImageFormat,
    /// The raw image bytes
    pub bytes: Vec<u8>,
    /// The unique ID for the image
    pub id: u64,
}

pub(crate) fn decode_static_image(
    bytes: &[u8],
    format: image::ImageFormat,
) -> Result<SmallVec<[Frame; 1]>> {
    let decoder = image::ImageReader::with_format(Cursor::new(bytes), format)
        .into_decoder()
        .context("creating image decoder")?;
    decode_static_image_from_decoder(decoder)
}

pub(crate) fn decode_static_image_from_decoder(
    mut decoder: impl image::ImageDecoder,
) -> Result<SmallVec<[Frame; 1]>> {
    let orientation = decoder
        .orientation()
        .context("reading decoder's orientation")?;
    let mut image = DynamicImage::from_decoder(decoder).context("decoding image")?;
    image.apply_orientation(orientation);

    let mut data = image.into_rgba8();
    for pixel in data.chunks_exact_mut(4) {
        pixel.swap(0, 2);
    }

    Ok(SmallVec::from_elem(Frame::new(data), 1))
}

impl Hash for Image {
    fn hash<H: Hasher>(&self, state: &mut H) {
        state.write_u64(self.id);
    }
}

impl Image {
    /// An empty image containing no data
    pub fn empty() -> Self {
        Self::from_bytes(ImageFormat::Png, Vec::new())
    }

    /// Create an image from a format and bytes
    pub fn from_bytes(format: ImageFormat, bytes: Vec<u8>) -> Self {
        Self {
            id: hash(&bytes),
            format,
            bytes,
        }
    }

    /// Get this image's ID
    pub fn id(&self) -> u64 {
        self.id
    }

    /// Use the GPUI `use_asset` API to make this image renderable
    pub fn use_render_image(
        self: Arc<Self>,
        window: &mut Window,
        cx: &mut App,
    ) -> Option<Arc<RenderImage>> {
        ImageSource::Image(self)
            .use_data(None, window, cx)
            .and_then(|result| result.ok())
    }

    /// Use the GPUI `get_asset` API to make this image renderable
    pub fn get_render_image(
        self: Arc<Self>,
        window: &mut Window,
        cx: &mut App,
    ) -> Option<Arc<RenderImage>> {
        ImageSource::Image(self)
            .get_data(None, window, cx)
            .and_then(|result| result.ok())
    }

    /// Use the GPUI `remove_asset` API to drop this image, if possible.
    pub fn remove_asset(self: Arc<Self>, cx: &mut App) {
        ImageSource::Image(self).remove_asset(cx);
    }

    /// Check whether this image is present in GPUI's asset cache (loading or
    /// loaded), without fetching it.
    #[cfg(any(test, feature = "test-support"))]
    pub fn is_asset_cached(self: &Arc<Self>, cx: &App) -> bool {
        ImageSource::Image(self.clone()).is_asset_cached(cx)
    }

    /// Convert the clipboard image to an `ImageData` object.
    pub fn to_image_data(&self, svg_renderer: SvgRenderer) -> Result<Arc<RenderImage>> {
        let frames = match self.format {
            ImageFormat::Gif => {
                let decoder = GifDecoder::new(Cursor::new(&self.bytes))?;
                let mut frames = SmallVec::new();

                for frame in decoder.into_frames() {
                    match frame {
                        Ok(mut frame) => {
                            // Convert from RGBA to BGRA.
                            for pixel in frame.buffer_mut().chunks_exact_mut(4) {
                                pixel.swap(0, 2);
                            }
                            frames.push(frame);
                        }
                        Err(err) => {
                            log::debug!("Skipping GIF frame due to decode error: {err}");
                        }
                    }
                }

                if frames.is_empty() {
                    anyhow::bail!("GIF could not be decoded: all frames failed");
                }

                frames
            }
            ImageFormat::Png => decode_static_image(&self.bytes, image::ImageFormat::Png)?,
            ImageFormat::Jpeg => decode_static_image(&self.bytes, image::ImageFormat::Jpeg)?,
            ImageFormat::Webp => decode_static_image(&self.bytes, image::ImageFormat::WebP)?,
            ImageFormat::Bmp => decode_static_image(&self.bytes, image::ImageFormat::Bmp)?,
            ImageFormat::Tiff => decode_static_image(&self.bytes, image::ImageFormat::Tiff)?,
            ImageFormat::Ico => decode_static_image(&self.bytes, image::ImageFormat::Ico)?,
            ImageFormat::Svg => {
                return svg_renderer
                    .render_single_frame(&self.bytes, 1.0)
                    .map_err(Into::into);
            }
            ImageFormat::Pnm => decode_static_image(&self.bytes, image::ImageFormat::Pnm)?,
        };

        Ok(Arc::new(RenderImage::new(frames)))
    }

    /// Get the format of the clipboard image
    pub fn format(&self) -> ImageFormat {
        self.format
    }

    /// Get the raw bytes of the clipboard image
    pub fn bytes(&self) -> &[u8] {
        self.bytes.as_slice()
    }
}

/// A clipboard item that should be copied to the clipboard
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct ClipboardString {
    /// The text content.
    pub text: String,
    /// Optional metadata associated with this clipboard string.
    pub metadata: Option<String>,
}

impl ClipboardString {
    /// Create a new clipboard string with the given text
    pub fn new(text: String) -> Self {
        Self {
            text,
            metadata: None,
        }
    }

    /// Return a new clipboard item with the metadata replaced by the given metadata,
    /// after serializing it as JSON.
    pub fn with_json_metadata<T: Serialize>(mut self, metadata: T) -> Self {
        self.metadata = Some(serde_json::to_string(&metadata).unwrap());
        self
    }

    /// Get the text of the clipboard string
    pub fn text(&self) -> &String {
        &self.text
    }

    /// Get the owned text of the clipboard string
    pub fn into_text(self) -> String {
        self.text
    }

    /// Get the metadata of the clipboard string, formatted as JSON
    pub fn metadata_json<T>(&self) -> Option<T>
    where
        T: for<'a> Deserialize<'a>,
    {
        self.metadata
            .as_ref()
            .and_then(|m| serde_json::from_str(m).ok())
    }

    #[cfg_attr(any(target_os = "linux", target_os = "freebsd"), allow(dead_code))]
    /// Compute a hash of the given text for clipboard change detection.
    pub fn text_hash(text: &str) -> u64 {
        let mut hasher = SeaHasher::new();
        text.hash(&mut hasher);
        hasher.finish()
    }
}

impl From<String> for ClipboardString {
    fn from(value: String) -> Self {
        Self {
            text: value,
            metadata: None,
        }
    }
}

#[cfg(test)]
mod image_tests {
    use super::*;
    use std::sync::Arc;

    #[test]
    fn test_image_to_image_data_applies_exif_orientation() {
        let image = Image::from_bytes(
            ImageFormat::Jpeg,
            include_bytes!("../examples/image/exif-orientation-rotate-180.jpg").to_vec(),
        );

        let render_image = image.to_image_data(SvgRenderer::new(Arc::new(()))).unwrap();

        assert_eq!(render_image.size(0), size(16.into(), 32.into()));

        let bytes = render_image.as_bytes(0).unwrap();
        assert_eq!(&bytes[..4], &[255, 255, 255, 255]);
        assert_eq!(&bytes[(16 * 32 - 1) * 4..], &[0, 0, 0, 255]);
    }

    #[test]
    fn test_svg_image_to_image_data_converts_to_bgra() {
        let image = Image::from_bytes(
            ImageFormat::Svg,
            br##"<svg xmlns="http://www.w3.org/2000/svg" width="1" height="1">
<rect width="1" height="1" fill="#38BDF8"/>
</svg>"##
                .to_vec(),
        );

        let render_image = image.to_image_data(SvgRenderer::new(Arc::new(()))).unwrap();
        let bytes = render_image.as_bytes(0).unwrap();

        for pixel in bytes.chunks_exact(4) {
            assert_eq!(pixel, &[0xF8, 0xBD, 0x38, 0xFF]);
        }
    }
}

#[cfg(test)]
mod atlas_tests {
    use super::*;

    const TILE_SIZE: Size<DevicePixels> = Size {
        width: DevicePixels(1),
        height: DevicePixels(1),
    };

    #[derive(Default)]
    struct RecordingAtlasBackend {
        insert_calls: u32,
        fail_next_insert: bool,
        removed_tiles: Vec<AtlasTile>,
    }

    impl AtlasBackend for RecordingAtlasBackend {
        fn insert(
            &mut self,
            kind: AtlasTextureKind,
            size: Size<DevicePixels>,
            _bytes: &[u8],
        ) -> Result<AtlasTile> {
            self.insert_calls += 1;
            if std::mem::take(&mut self.fail_next_insert) {
                anyhow::bail!("backend failed");
            }
            Ok(AtlasTile {
                texture_id: AtlasTextureId { index: 0, kind },
                tile_id: TileId(self.insert_calls),
                padding: 0,
                bounds: Bounds {
                    origin: Point::default(),
                    size,
                },
            })
        }

        fn remove(&mut self, tile: AtlasTile) {
            self.removed_tiles.push(tile);
        }
    }

    fn image_key(image_id: usize) -> AtlasKey {
        AtlasKey::Image(RenderImageParams {
            image_id: crate::ImageId(image_id),
            frame_index: 0,
        })
    }

    fn build_tile() -> Result<Option<(Size<DevicePixels>, Cow<'static, [u8]>)>> {
        Ok(Some((TILE_SIZE, Cow::Borrowed(&[0, 0, 0, 255]))))
    }

    #[test]
    fn only_successful_inserts_are_cached() -> Result<()> {
        let mut state = AtlasState::new(RecordingAtlasBackend::default());
        let key = image_key(1);

        assert_eq!(
            state.get_or_insert_with(key.clone(), &mut || Ok(None))?,
            None
        );
        state
            .get_or_insert_with(key.clone(), &mut || anyhow::bail!("builder failed"))
            .expect_err("builder error should propagate");
        assert!(!state.contains(&key));
        assert_eq!(state.backend.insert_calls, 0);

        state.backend.fail_next_insert = true;
        state
            .get_or_insert_with(key.clone(), &mut build_tile)
            .expect_err("backend error should propagate");
        assert!(!state.contains(&key));
        assert_eq!(state.backend.insert_calls, 1);

        let tile = state
            .get_or_insert_with(key.clone(), &mut build_tile)?
            .context("builder should produce a tile")?;
        assert_eq!(tile.texture_id.kind, key.texture_kind());
        assert_eq!(
            state.get_or_insert_with(key.clone(), &mut || {
                anyhow::bail!("cache hit must not call the builder")
            })?,
            Some(tile)
        );
        assert!(state.contains(&key));
        assert_eq!(state.backend.insert_calls, 2);
        Ok(())
    }

    #[test]
    fn remove_and_clear_invalidate_keys() -> Result<()> {
        let mut state = AtlasState::new(RecordingAtlasBackend::default());
        let key = image_key(1);
        let other_key = image_key(2);
        let tile = state
            .get_or_insert_with(key.clone(), &mut build_tile)?
            .context("builder should produce a tile")?;
        state
            .get_or_insert_with(other_key.clone(), &mut build_tile)?
            .context("builder should produce another tile")?;

        state.remove(&key);
        state.remove(&key);
        assert!(!state.contains(&key));
        assert!(state.contains(&other_key));
        assert_eq!(state.backend.removed_tiles, vec![tile]);

        let mut reset_calls = 0;
        state.clear(|_| reset_calls += 1);
        assert_eq!(reset_calls, 1);
        assert!(!state.contains(&other_key));
        assert_eq!(state.backend.removed_tiles, vec![tile]);
        Ok(())
    }
}

#[cfg(test)]
mod frame_signal_tests {
    use super::*;

    #[cfg(feature = "profiler")]
    #[test]
    fn coalesced_signals_retain_the_earliest_until_drained() {
        for (first_source, later_source) in [
            (
                FrameRequestSource::NativeCallback,
                FrameRequestSource::LocalSchedule,
            ),
            (
                FrameRequestSource::LocalSchedule,
                FrameRequestSource::NativeCallback,
            ),
        ] {
            let signal = PlatformFrameSignal::new();
            let first =
                PlatformFrameSignal::capture(Instant::now).expect("profiling captures requests");
            assert_eq!(signal.take(), None);
            signal.record(first + Duration::from_millis(16), later_source);
            signal.record(first, first_source);
            signal.record(first + Duration::from_millis(32), later_source);
            assert_eq!(signal.take(), Some((first, first_source)));
            assert_eq!(signal.take(), None);
            let next = first + Duration::from_millis(48);
            signal.record(next, later_source);
            assert_eq!(signal.take(), Some((next, later_source)));
        }
    }

    #[cfg(not(feature = "profiler"))]
    #[test]
    fn disabled_profiling_does_not_capture_or_store_timestamps() {
        let captured = PlatformFrameSignal::capture(|| {
            panic!("profiler-disabled builds must not evaluate the capture closure");
        });
        assert_eq!(captured, None);
        let signal = PlatformFrameSignal::new();
        signal.record(Instant::now(), FrameRequestSource::LocalSchedule);
        assert_eq!(signal.take(), None);
    }
}

#[cfg(all(test, any(target_os = "linux", target_os = "freebsd")))]
mod tests {
    use super::*;
    use std::collections::HashSet;

    #[test]
    fn test_refresh_interval_from_hz() {
        assert_eq!(
            refresh_interval_from_hz(50.0),
            Some(Duration::from_millis(20))
        );
        assert_eq!(
            refresh_interval_from_hz(120.0),
            Some(Duration::from_secs(1) / 120)
        );
        for unknown in [0.0, -60.0, f64::NAN, f64::INFINITY] {
            assert_eq!(refresh_interval_from_hz(unknown), None);
        }
    }

    #[test]
    fn test_window_button_layout_parse_standard() {
        let layout = WindowButtonLayout::parse("close,minimize:maximize").unwrap();
        assert_eq!(
            layout.left,
            [
                Some(WindowButton::Close),
                Some(WindowButton::Minimize),
                None
            ]
        );
        assert_eq!(layout.right, [Some(WindowButton::Maximize), None, None]);
    }

    #[test]
    fn test_window_button_layout_parse_right_only() {
        let layout = WindowButtonLayout::parse("minimize,maximize,close").unwrap();
        assert_eq!(layout.left, [None, None, None]);
        assert_eq!(
            layout.right,
            [
                Some(WindowButton::Minimize),
                Some(WindowButton::Maximize),
                Some(WindowButton::Close)
            ]
        );
    }

    #[test]
    fn test_window_button_layout_parse_left_only() {
        let layout = WindowButtonLayout::parse("close,minimize,maximize:").unwrap();
        assert_eq!(
            layout.left,
            [
                Some(WindowButton::Close),
                Some(WindowButton::Minimize),
                Some(WindowButton::Maximize)
            ]
        );
        assert_eq!(layout.right, [None, None, None]);
    }

    #[test]
    fn test_window_button_layout_parse_with_whitespace() {
        let layout = WindowButtonLayout::parse(" close , minimize : maximize ").unwrap();
        assert_eq!(
            layout.left,
            [
                Some(WindowButton::Close),
                Some(WindowButton::Minimize),
                None
            ]
        );
        assert_eq!(layout.right, [Some(WindowButton::Maximize), None, None]);
    }

    #[test]
    fn test_window_button_layout_parse_empty() {
        let layout = WindowButtonLayout::parse("").unwrap();
        assert_eq!(layout.left, [None, None, None]);
        assert_eq!(layout.right, [None, None, None]);
    }

    #[test]
    fn test_window_button_layout_parse_intentionally_empty() {
        let layout = WindowButtonLayout::parse(":").unwrap();
        assert_eq!(layout.left, [None, None, None]);
        assert_eq!(layout.right, [None, None, None]);
    }

    #[test]
    fn test_window_button_layout_parse_invalid_buttons() {
        let layout = WindowButtonLayout::parse("close,invalid,minimize:maximize,foo").unwrap();
        assert_eq!(
            layout.left,
            [
                Some(WindowButton::Close),
                Some(WindowButton::Minimize),
                None
            ]
        );
        assert_eq!(layout.right, [Some(WindowButton::Maximize), None, None]);
    }

    #[test]
    fn test_window_button_layout_parse_deduplicates_same_side_buttons() {
        let layout = WindowButtonLayout::parse("close,close,minimize").unwrap();
        assert_eq!(
            layout.right,
            [
                Some(WindowButton::Close),
                Some(WindowButton::Minimize),
                None
            ]
        );
        assert_eq!(layout.format(), ":close,minimize");
    }

    #[test]
    fn test_window_button_layout_parse_deduplicates_buttons_across_sides() {
        let layout = WindowButtonLayout::parse("close:maximize,close,minimize").unwrap();
        assert_eq!(layout.left, [Some(WindowButton::Close), None, None]);
        assert_eq!(
            layout.right,
            [
                Some(WindowButton::Maximize),
                Some(WindowButton::Minimize),
                None
            ]
        );

        let button_ids: Vec<_> = layout
            .left
            .iter()
            .chain(layout.right.iter())
            .flatten()
            .map(WindowButton::id)
            .collect();
        let unique_button_ids = button_ids.iter().copied().collect::<HashSet<_>>();
        assert_eq!(unique_button_ids.len(), button_ids.len());
        assert_eq!(layout.format(), "close:maximize,minimize");
    }

    #[test]
    fn test_window_button_layout_parse_gnome_style() {
        let layout = WindowButtonLayout::parse("close").unwrap();
        assert_eq!(layout.left, [None, None, None]);
        assert_eq!(layout.right, [Some(WindowButton::Close), None, None]);
    }

    #[test]
    fn test_window_button_layout_parse_elementary_style() {
        let layout = WindowButtonLayout::parse("close:maximize").unwrap();
        assert_eq!(layout.left, [Some(WindowButton::Close), None, None]);
        assert_eq!(layout.right, [Some(WindowButton::Maximize), None, None]);
    }

    #[test]
    fn test_window_button_layout_round_trip() {
        let cases = [
            "close:minimize,maximize",
            "minimize,maximize,close:",
            ":close",
            "close:",
            "close:maximize",
            ":",
        ];

        for case in cases {
            let layout = WindowButtonLayout::parse(case).unwrap();
            assert_eq!(layout.format(), case, "Round-trip failed for: {}", case);
        }
    }

    #[test]
    fn test_window_button_layout_linux_default() {
        let layout = WindowButtonLayout::linux_default();
        assert_eq!(layout.left, [None, None, None]);
        assert_eq!(
            layout.right,
            [
                Some(WindowButton::Minimize),
                Some(WindowButton::Maximize),
                Some(WindowButton::Close)
            ]
        );

        let round_tripped = WindowButtonLayout::parse(&layout.format()).unwrap();
        assert_eq!(round_tripped, layout);
    }

    #[test]
    fn test_window_button_layout_parse_all_invalid() {
        assert!(WindowButtonLayout::parse("asdfghjkl").is_err());
    }
}