xgpui-macos 5.0.0

use crate::{
    BoolExt, MacDisplay, MetalFrames, NSRange, NSStringExt, TISCopyCurrentKeyboardInputSource,
    TISGetInputSourceProperty, WindowFrameSource, events::platform_input_from_native,
    kTISPropertyInputSourceIsASCIICapable, kTISPropertyInputSourceType, kTISTypeKeyboardInputMode,
    ns_string, renderer,
};
use anyhow::Result;
use block2::RcBlock;
use dispatch2::DispatchQueue;
use gpui::{
    AnyWindowHandle, BackgroundExecutor, Bounds, Capslock, CursorStyle, ExternalDragPayload,
    ExternalPaths, FileDropEvent, ForegroundExecutor, FrameRequestSource, KeyDownEvent, Keystroke,
    Modifiers, ModifiersChangedEvent, MouseButton, MouseDownEvent, MouseMoveEvent, MouseUpEvent,
    Pixels, PlatformAtlas, PlatformDisplay, PlatformFrameSignal, PlatformInput,
    PlatformInputHandler, PlatformWindow, Point, PromptButton, PromptLevel, RequestFrameOptions,
    SharedString, Size, SystemWindowTab, WindowAppearance, WindowBackgroundAppearance,
    WindowBounds, WindowControlArea, WindowKind, WindowParams, WindowVisibility, point, px, size,
};
#[cfg(any(test, feature = "test-support"))]
use image::RgbaImage;

use core_foundation::base::{CFRelease, CFTypeRef};
use core_foundation_sys::base::CFEqual;
use core_foundation_sys::number::{CFBooleanGetValue, CFBooleanRef};
use core_graphics::display::CGDirectDisplayID;
use ctor::ctor;
use futures::channel::oneshot;
use gpui_apple::display_link::MetalFrameSource;
use gpui_util::ResultExt;
use objc2::{
    AnyThread, MainThreadMarker, Message, class, msg_send,
    rc::{Retained, autoreleasepool},
    runtime::{AnyClass, AnyObject, AnyProtocol, Bool, ClassBuilder, ProtocolObject, Sel},
    sel,
};
#[expect(
    deprecated,
    reason = "File-drop decoding expects a property-list array of paths; replacing NSFilenamesPboardType requires migrating both registration and decoding to file URLs"
)]
use objc2_app_kit::NSFilenamesPboardType;
use objc2_app_kit::{
    NSAlert, NSAlertStyle, NSAppearance, NSAutoresizingMaskOptions, NSBackingStoreType, NSBeep,
    NSButton, NSColor, NSDragOperation, NSDraggingContext, NSDraggingImageComponent,
    NSDraggingImageComponentIconKey, NSDraggingItem, NSEventModifierFlags, NSEventType,
    NSPasteboardWriting, NSRequestUserAttentionType, NSScreen, NSTrackingArea,
    NSTrackingAreaOptions, NSView, NSViewLayerContentsRedrawPolicy, NSVisualEffectBlendingMode,
    NSVisualEffectMaterial, NSVisualEffectState, NSWindow, NSWindowAnimationBehavior,
    NSWindowButton, NSWindowCollectionBehavior, NSWindowOcclusionState, NSWindowOrderingMode,
    NSWindowStyleMask, NSWindowTitleVisibility, NSWorkspace,
};
use objc2_core_graphics::CGColor;
use objc2_foundation::{
    NSArray, NSInteger, NSNotFound, NSOperatingSystemVersion, NSPoint, NSProcessInfo, NSRect,
    NSSize, NSString, NSUInteger, NSURL,
};
use objc2_uniform_type_identifiers::{UTType, UTTypeData, UTTypeFolder};
use parking_lot::Mutex;
use raw_window_handle as rwh;
use smallvec::SmallVec;
use std::{
    cell::Cell,
    ffi::{CStr, CString, c_void},
    mem,
    ops::Range,
    os::unix::ffi::OsStrExt,
    path::PathBuf,
    ptr::{self, NonNull},
    rc::{Rc, Weak},
    sync::{
        Arc, Once,
        atomic::{AtomicBool, Ordering},
    },
    time::Duration,
};

const WINDOW_STATE_IVAR: &CStr = c"windowState";

static RESTORES_WORKSPACE_AT_LAUNCH_DEFAULT: Once = Once::new();

static mut WINDOW_CLASS: *const AnyClass = ptr::null();
static mut PANEL_CLASS: *const AnyClass = ptr::null();
static mut VIEW_CLASS: *const AnyClass = ptr::null();
static mut BLURRED_VIEW_CLASS: *const AnyClass = ptr::null();
static mut WINDOW_STATE_ARCHIVER_DELEGATE_CLASS: *const AnyClass = ptr::null();
static mut WINDOW_STATE_UNARCHIVER_CLASS: *const AnyClass = ptr::null();

// WindowLevel const value ref: https://docs.rs/core-graphics2/0.4.1/src/core_graphics2/window_level.rs.html
#[allow(non_upper_case_globals)]
const NSNormalWindowLevel: NSInteger = 0;
#[allow(non_upper_case_globals)]
const NSFloatingWindowLevel: NSInteger = 3;
#[allow(non_upper_case_globals)]
const NSPopUpWindowLevel: NSInteger = 101;
#[derive(PartialEq)]
pub enum UserTabbingPreference {
    Never,
    Always,
    InFullScreen,
}

#[ctor(unsafe)]
unsafe fn build_classes() {
    unsafe {
        WINDOW_CLASS = build_window_class(c"GPUIWindow", class!(NSWindow));
        PANEL_CLASS = build_window_class(c"GPUIPanel", class!(NSPanel));
        VIEW_CLASS = {
            let mut decl = ClassBuilder::new(c"GPUIView", class!(NSView)).unwrap();
            decl.add_ivar::<*mut c_void>(WINDOW_STATE_IVAR);
            decl.add_method(sel!(dealloc), dealloc_view as extern "C" fn(_, Sel));

            decl.add_method(
                sel!(performKeyEquivalent:),
                handle_key_equivalent as extern "C" fn(_, Sel, *mut AnyObject) -> Bool,
            );
            decl.add_method(
                sel!(keyDown:),
                handle_key_down as extern "C" fn(_, Sel, *mut AnyObject),
            );
            decl.add_method(
                sel!(keyUp:),
                handle_key_up as extern "C" fn(_, Sel, *mut AnyObject),
            );
            decl.add_method(
                sel!(mouseDown:),
                handle_view_event as extern "C" fn(_, Sel, *mut AnyObject),
            );
            decl.add_method(
                sel!(mouseUp:),
                handle_view_event as extern "C" fn(_, Sel, *mut AnyObject),
            );
            decl.add_method(
                sel!(rightMouseDown:),
                handle_view_event as extern "C" fn(_, Sel, *mut AnyObject),
            );
            decl.add_method(
                sel!(rightMouseUp:),
                handle_view_event as extern "C" fn(_, Sel, *mut AnyObject),
            );
            decl.add_method(
                sel!(otherMouseDown:),
                handle_view_event as extern "C" fn(_, Sel, *mut AnyObject),
            );
            decl.add_method(
                sel!(otherMouseUp:),
                handle_view_event as extern "C" fn(_, Sel, *mut AnyObject),
            );
            decl.add_method(
                sel!(mouseMoved:),
                handle_view_event as extern "C" fn(_, Sel, *mut AnyObject),
            );
            decl.add_method(
                sel!(resetCursorRects),
                reset_cursor_rects as extern "C" fn(_, Sel),
            );
            decl.add_method(
                sel!(pressureChangeWithEvent:),
                handle_view_event as extern "C" fn(_, Sel, *mut AnyObject),
            );
            decl.add_method(
                sel!(mouseExited:),
                handle_view_event as extern "C" fn(_, Sel, *mut AnyObject),
            );
            decl.add_method(
                sel!(magnifyWithEvent:),
                handle_view_event as extern "C" fn(_, Sel, *mut AnyObject),
            );
            decl.add_method(
                sel!(mouseDragged:),
                handle_view_event as extern "C" fn(_, Sel, *mut AnyObject),
            );
            decl.add_method(
                sel!(rightMouseDragged:),
                handle_view_event as extern "C" fn(_, Sel, *mut AnyObject),
            );
            decl.add_method(
                sel!(otherMouseDragged:),
                handle_view_event as extern "C" fn(_, Sel, *mut AnyObject),
            );
            decl.add_method(
                sel!(scrollWheel:),
                handle_view_event as extern "C" fn(_, Sel, *mut AnyObject),
            );
            decl.add_method(
                sel!(swipeWithEvent:),
                handle_view_event as extern "C" fn(_, Sel, *mut AnyObject),
            );
            decl.add_method(
                sel!(flagsChanged:),
                handle_view_event as extern "C" fn(_, Sel, *mut AnyObject),
            );

            decl.add_method(
                sel!(makeBackingLayer),
                make_backing_layer as extern "C" fn(_, Sel) -> *mut AnyObject,
            );

            decl.add_protocol(AnyProtocol::get(c"CALayerDelegate").unwrap());
            decl.add_method(
                sel!(viewDidChangeBackingProperties),
                view_did_change_backing_properties as extern "C" fn(_, Sel),
            );
            decl.add_method(
                sel!(setFrameSize:),
                set_frame_size as extern "C" fn(_, Sel, NSSize),
            );
            decl.add_method(
                sel!(displayLayer:),
                display_layer as extern "C" fn(_, Sel, *mut AnyObject),
            );

            decl.add_protocol(AnyProtocol::get(c"NSTextInputClient").unwrap());
            decl.add_method(
                sel!(validAttributesForMarkedText),
                valid_attributes_for_marked_text as extern "C" fn(_, Sel) -> *mut AnyObject,
            );
            decl.add_method(
                sel!(hasMarkedText),
                has_marked_text as extern "C" fn(_, Sel) -> Bool,
            );
            decl.add_method(
                sel!(markedRange),
                marked_range as extern "C" fn(_, Sel) -> NSRange,
            );
            decl.add_method(
                sel!(selectedRange),
                selected_range as extern "C" fn(_, Sel) -> NSRange,
            );
            decl.add_method(
                sel!(firstRectForCharacterRange:actualRange:),
                first_rect_for_character_range
                    as extern "C" fn(_, Sel, NSRange, *mut NSRange) -> NSRect,
            );
            decl.add_method(
                sel!(insertText:replacementRange:),
                insert_text as extern "C" fn(_, Sel, *mut AnyObject, NSRange),
            );
            decl.add_method(
                sel!(setMarkedText:selectedRange:replacementRange:),
                set_marked_text as extern "C" fn(_, Sel, *mut AnyObject, NSRange, NSRange),
            );
            decl.add_method(sel!(unmarkText), unmark_text as extern "C" fn(_, Sel));
            decl.add_method(
                sel!(attributedSubstringForProposedRange:actualRange:),
                attributed_substring_for_proposed_range
                    as extern "C" fn(_, Sel, NSRange, *mut NSRange) -> *mut AnyObject,
            );
            decl.add_method(
                sel!(viewDidChangeEffectiveAppearance),
                view_did_change_effective_appearance as extern "C" fn(_, Sel),
            );

            // Suppress beep on keystrokes with modifier keys.
            decl.add_method(
                sel!(doCommandBySelector:),
                do_command_by_selector as extern "C" fn(_, Sel, Sel),
            );

            decl.add_method(
                sel!(acceptsFirstMouse:),
                accepts_first_mouse as extern "C" fn(_, Sel, *mut AnyObject) -> Bool,
            );

            decl.add_method(
                sel!(_opaqueRectForWindowMoveWhenInTitlebar),
                opaque_rect_for_window_move_when_in_titlebar as extern "C" fn(_, Sel) -> NSRect,
            );

            decl.add_method(
                sel!(characterIndexForPoint:),
                character_index_for_point as extern "C" fn(_, Sel, NSPoint) -> NSUInteger,
            );
            decl.register()
        };
        BLURRED_VIEW_CLASS = {
            let mut decl = ClassBuilder::new(c"BlurredView", class!(NSVisualEffectView)).unwrap();
            decl.add_method(
                sel!(initWithFrame:),
                blurred_view_init_with_frame as extern "C" fn(_, Sel, NSRect) -> *mut AnyObject,
            );
            decl.add_method(
                sel!(updateLayer),
                blurred_view_update_layer as extern "C" fn(_, Sel),
            );
            decl.register()
        };
        WINDOW_STATE_ARCHIVER_DELEGATE_CLASS = {
            let mut decl =
                ClassBuilder::new(c"GPUIWindowStateArchiverDelegate", class!(NSObject)).unwrap();
            decl.add_method(
                sel!(archiver:willEncodeObject:),
                window_state_archiver_will_encode_object
                    as extern "C" fn(_, Sel, *mut AnyObject, *mut AnyObject) -> *mut AnyObject,
            );
            decl.register()
        };
        WINDOW_STATE_UNARCHIVER_CLASS = {
            let mut decl =
                ClassBuilder::new(c"GPUIWindowStateKeyedUnarchiver", class!(NSKeyedUnarchiver))
                    .unwrap();
            decl.add_method(
                sel!(_windowRestorationOptions),
                window_state_unarchiver_restoration_options
                    as extern "C" fn(_, Sel) -> *mut AnyObject,
            );
            decl.register()
        };
    }
}

// NSKeyedArchiverDelegate callback that skips objects which don't adopt `NSSecureCoding`
// (the window itself and its NSView hierarchy), so encoding the window's restorable state
// succeeds. AppKit still encodes the window frame and its persistent window-management
// identifier, which is what the Space restoration on relaunch keys off.
extern "C" fn window_state_archiver_will_encode_object(
    _this: &AnyObject,
    _sel: Sel,
    _archiver: *mut AnyObject,
    object: *mut AnyObject,
) -> *mut AnyObject {
    // SAFETY: `object` is whatever AppKit hands the delegate during archiving; we only send it
    // `isKindOfClass:` with valid class arguments, which is safe for any Objective-C object.
    unsafe {
        if object.is_null() {
            return object;
        }
        let is_view: Bool = msg_send![object, isKindOfClass: class!(NSView)];
        let is_window: Bool = msg_send![object, isKindOfClass: class!(NSWindow)];
        if is_view == Bool::YES || is_window == Bool::YES {
            ptr::null_mut()
        } else {
            object
        }
    }
}

// Override of the private `_windowRestorationOptions` on our NSKeyedUnarchiver subclass.
// Returning a default-initialized `NSWindowRestorationOptions` tells AppKit to restore the
// window to its original Space. This is the macOS 15+ path (FB15644170: the
// `NSWindowRestoresWorkspaceAtLaunch` user default no longer works there).
extern "C" fn window_state_unarchiver_restoration_options(
    _this: &AnyObject,
    _sel: Sel,
) -> *mut AnyObject {
    if !is_macos_version_at_least(NSOperatingSystemVersion {
        majorVersion: 15,
        minorVersion: 0,
        patchVersion: 0,
    }) {
        return ptr::null_mut();
    }
    // SAFETY: we look the class up by name and only send it `alloc`/`init`/`autorelease`, all of
    // which have the standard `-> id` signature. Returning `nil` when the class is absent is valid.
    unsafe {
        match AnyClass::get(c"NSWindowRestorationOptions") {
            Some(class) => {
                let options: *mut AnyObject = msg_send![class, alloc];
                let options: *mut AnyObject = msg_send![options, init];
                msg_send![options, autorelease]
            }
            None => ptr::null_mut(),
        }
    }
}

pub(crate) fn convert_mouse_position(position: NSPoint, window_height: Pixels) -> Point<Pixels> {
    point(
        px(position.x as f32),
        // macOS screen coordinates are relative to bottom left
        window_height - px(position.y as f32),
    )
}

/// Stores the cursor style on the active GPUI window and invalidates its cursor rects.
///
/// # Safety
///
/// This function is not thread safe. Callers must ensure this is called on the AppKit main
/// thread because it reads the active AppKit window and updates GPUI window state associated
/// with Objective-C objects.
pub(crate) unsafe fn set_active_window_cursor_style(style: CursorStyle) {
    // SAFETY: The caller guarantees AppKit main-thread access. `is_gpui_window` ensures the
    // window has our WINDOW_STATE_IVAR before reading it.
    unsafe {
        let app: *mut AnyObject = msg_send![class!(NSApplication), sharedApplication];
        let key_window: *mut AnyObject = msg_send![app, keyWindow];
        let main_window: *mut AnyObject = msg_send![app, mainWindow];
        let active_window = if !key_window.is_null() && is_gpui_window(key_window) {
            Some(key_window)
        } else if !main_window.is_null() && is_gpui_window(main_window) {
            Some(main_window)
        } else {
            None
        };

        let Some(active_window) = active_window else {
            return;
        };

        let window_state = get_window_state(&*active_window);
        let mut window_state = window_state.lock();
        if window_state.cursor_style != style {
            window_state.cursor_style = style;
            let _: () = msg_send![
                window_state.native_window,
                invalidateCursorRectsForView: window_state.native_view.as_ptr()
            ];
        }
    }
}

unsafe fn build_window_class(name: &CStr, superclass: &AnyClass) -> *const AnyClass {
    unsafe {
        let mut decl = ClassBuilder::new(name, superclass).unwrap();
        decl.add_ivar::<*mut c_void>(WINDOW_STATE_IVAR);
        decl.add_method(sel!(dealloc), dealloc_window as extern "C" fn(_, Sel));

        decl.add_method(
            sel!(canBecomeMainWindow),
            yes as extern "C" fn(_, Sel) -> Bool,
        );
        decl.add_method(
            sel!(canBecomeKeyWindow),
            yes as extern "C" fn(_, Sel) -> Bool,
        );
        decl.add_method(
            sel!(windowDidResize:),
            window_did_resize as extern "C" fn(_, Sel, *mut AnyObject),
        );
        decl.add_method(
            sel!(windowDidChangeOcclusionState:),
            window_did_change_occlusion_state as extern "C" fn(_, Sel, *mut AnyObject),
        );
        decl.add_method(
            sel!(windowWillEnterFullScreen:),
            window_will_enter_fullscreen as extern "C" fn(_, Sel, *mut AnyObject),
        );
        decl.add_method(
            sel!(windowWillExitFullScreen:),
            window_will_exit_fullscreen as extern "C" fn(_, Sel, *mut AnyObject),
        );
        decl.add_method(
            sel!(windowDidFailToExitFullScreen:),
            window_did_fail_to_exit_fullscreen as extern "C" fn(_, Sel, *mut AnyObject),
        );
        decl.add_method(
            sel!(windowDidExitFullScreen:),
            window_did_exit_fullscreen as extern "C" fn(_, Sel, *mut AnyObject),
        );
        decl.add_method(
            sel!(windowDidMove:),
            window_did_move as extern "C" fn(_, Sel, *mut AnyObject),
        );
        decl.add_method(
            sel!(windowDidChangeScreenProfile:),
            window_did_change_color_profile as extern "C" fn(_, Sel, *mut AnyObject),
        );
        decl.add_method(
            sel!(windowDidChangeScreen:),
            window_did_change_screen as extern "C" fn(_, Sel, *mut AnyObject),
        );
        decl.add_method(
            sel!(windowDidBecomeKey:),
            window_did_change_key_status as extern "C" fn(_, Sel, *mut AnyObject),
        );
        decl.add_method(
            sel!(windowDidResignKey:),
            window_did_change_key_status as extern "C" fn(_, Sel, *mut AnyObject),
        );
        decl.add_method(
            sel!(windowShouldClose:),
            window_should_close as extern "C" fn(_, Sel, *mut AnyObject) -> Bool,
        );

        decl.add_method(sel!(close), close_window as extern "C" fn(_, Sel));

        decl.add_method(
            sel!(draggingEntered:),
            dragging_entered as extern "C" fn(_, Sel, *mut AnyObject) -> NSDragOperation,
        );
        decl.add_method(
            sel!(draggingUpdated:),
            dragging_updated as extern "C" fn(_, Sel, *mut AnyObject) -> NSDragOperation,
        );
        decl.add_method(
            sel!(draggingExited:),
            dragging_exited as extern "C" fn(_, Sel, *mut AnyObject),
        );
        decl.add_method(
            sel!(performDragOperation:),
            perform_drag_operation as extern "C" fn(_, Sel, *mut AnyObject) -> Bool,
        );
        decl.add_method(
            sel!(concludeDragOperation:),
            conclude_drag_operation as extern "C" fn(_, Sel, *mut AnyObject),
        );

        decl.add_protocol(AnyProtocol::get(c"NSDraggingSource").unwrap());
        decl.add_method(
            sel!(draggingSession:sourceOperationMaskForDraggingContext:),
            dragging_session_source_operation_mask
                as extern "C" fn(_, Sel, *mut AnyObject, NSDraggingContext) -> NSDragOperation,
        );
        decl.add_method(
            sel!(draggingSession:endedAtPoint:operation:),
            dragging_session_ended
                as extern "C" fn(_, Sel, *mut AnyObject, NSPoint, NSDragOperation),
        );

        decl.add_method(
            sel!(addTitlebarAccessoryViewController:),
            add_titlebar_accessory_view_controller as extern "C" fn(_, Sel, *mut AnyObject),
        );

        decl.add_method(
            sel!(moveTabToNewWindow:),
            move_tab_to_new_window as extern "C" fn(_, Sel, *mut AnyObject),
        );

        decl.add_method(
            sel!(mergeAllWindows:),
            merge_all_windows as extern "C" fn(_, Sel, *mut AnyObject),
        );

        decl.add_method(
            sel!(selectNextTab:),
            select_next_tab as extern "C" fn(_, Sel, *mut AnyObject),
        );

        decl.add_method(
            sel!(selectPreviousTab:),
            select_previous_tab as extern "C" fn(_, Sel, *mut AnyObject),
        );

        decl.add_method(
            sel!(toggleTabBar:),
            toggle_tab_bar as extern "C" fn(_, Sel, *mut AnyObject),
        );

        decl.register()
    }
}

#[derive(Clone, Copy)]
struct TrafficLightFrames {
    titlebar: NSRect,
    close: NSRect,
    minimize: NSRect,
    zoom: NSRect,
}

struct TrafficLightButtons {
    close: Retained<NSButton>,
    minimize: Retained<NSButton>,
    zoom: Retained<NSButton>,
}

// `NSApplicationPresentationOptions` bits (see `NSApplication.PresentationOptions`).
const NS_APPLICATION_PRESENTATION_AUTO_HIDE_DOCK: NSUInteger = 1 << 0;
const NS_APPLICATION_PRESENTATION_AUTO_HIDE_MENU_BAR: NSUInteger = 1 << 2;

// State captured when entering simple (borderless) fullscreen, used to restore
// the window on exit.
struct SimpleFullscreenState {
    frame: NSRect,
    bounds: Bounds<Pixels>,
    style_mask: NSWindowStyleMask,
}

enum SimpleFullscreenPlan {
    Enter { screen_frame: NSRect },
    Exit(SimpleFullscreenState),
}

struct SimpleFullscreenAppState {
    window_count: usize,
    saved_presentation_options: NSUInteger,
}

static SIMPLE_FULLSCREEN_APP_STATE: Mutex<Option<SimpleFullscreenAppState>> = Mutex::new(None);

unsafe fn push_simple_fullscreen_presentation_options() {
    let mut app_state = SIMPLE_FULLSCREEN_APP_STATE.lock();
    match app_state.as_mut() {
        Some(app_state) => app_state.window_count += 1,
        None => unsafe {
            let app: *mut AnyObject = msg_send![class!(NSApplication), sharedApplication];
            let saved_presentation_options: NSUInteger = msg_send![app, presentationOptions];
            let _: () = msg_send![
                app,
                setPresentationOptions: NS_APPLICATION_PRESENTATION_AUTO_HIDE_DOCK
                    | NS_APPLICATION_PRESENTATION_AUTO_HIDE_MENU_BAR
            ];
            *app_state = Some(SimpleFullscreenAppState {
                window_count: 1,
                saved_presentation_options,
            });
        },
    }
}

unsafe fn pop_simple_fullscreen_presentation_options() {
    let mut app_state = SIMPLE_FULLSCREEN_APP_STATE.lock();
    if let Some(state) = app_state.as_mut() {
        state.window_count = state.window_count.saturating_sub(1);
        if state.window_count == 0 {
            unsafe {
                let app: *mut AnyObject = msg_send![class!(NSApplication), sharedApplication];
                let _: () = msg_send![
                    app,
                    setPresentationOptions: state.saved_presentation_options
                ];
            }
            *app_state = None;
        }
    }
}

unsafe fn apply_simple_fullscreen_plan(
    native_window: *mut AnyObject,
    native_view: *mut AnyObject,
    plan: SimpleFullscreenPlan,
) {
    unsafe {
        match plan {
            SimpleFullscreenPlan::Exit(saved) => {
                pop_simple_fullscreen_presentation_options();
                let _: () = msg_send![native_window, setStyleMask: saved.style_mask];
                let _: () = msg_send![native_window, setFrame: saved.frame, display: Bool::YES];
            }
            SimpleFullscreenPlan::Enter { screen_frame } => {
                push_simple_fullscreen_presentation_options();
                let _: () = msg_send![native_window, setStyleMask: NSWindowStyleMask::Borderless];
                let _: () = msg_send![native_window, setFrame: screen_frame, display: Bool::YES];
            }
        }

        // Changing the style mask makes AppKit resign the window's key status and
        // first responder, so keyboard input stops reaching the editor. Re-make the
        // window key and restore the GPUI view as first responder.
        let _: () = msg_send![native_window, makeKeyAndOrderFront: ptr::null_mut::<AnyObject>()];
        let _: Bool = msg_send![native_window, makeFirstResponder: native_view];
    }
}

/// What paces a window's frames. The choice depends only on the OS version,
/// so it is made once per window.
enum FrameSource {
    /// macOS 14+: a `CAMetalDisplayLink` that hands out each frame's drawable.
    Metal(Rc<MetalFrames>),
    /// Earlier systems: the shared `CVDisplayLink` registry, joined on first start.
    DisplayLink(Option<WindowFrameSource>),
}

struct MacWindowState {
    handle: AnyWindowHandle,
    foreground_executor: ForegroundExecutor,
    background_executor: BackgroundExecutor,
    native_window: *mut AnyObject,
    native_view: NonNull<AnyObject>,
    blurred_view: Option<*mut AnyObject>,
    background_appearance: WindowBackgroundAppearance,
    cursor_style: CursorStyle,
    cursor_visible: Arc<AtomicBool>,
    frame_source: FrameSource,
    renderer: renderer::Renderer,
    request_frame_callback: Option<Box<dyn FnMut(RequestFrameOptions)>>,
    event_callback: Option<Box<dyn FnMut(PlatformInput) -> gpui::DispatchEventResult>>,
    activate_callback: Option<Box<dyn FnMut(bool)>>,
    visibility_callback: Option<Box<dyn FnMut(WindowVisibility)>>,
    // `None` until a callback is registered, so notifications during
    // construction are not queued for delivery to a callback registered later.
    last_visibility: Option<WindowVisibility>,
    resize_callback: Option<Box<dyn FnMut(Size<Pixels>, f32)>>,
    moved_callback: Option<Box<dyn FnMut()>>,
    display_changed_callback: Option<Box<dyn FnMut()>>,
    should_close_callback: Option<Box<dyn FnMut() -> bool>>,
    close_callback: Option<Box<dyn FnOnce()>>,
    appearance_changed_callback: Option<Box<dyn FnMut()>>,
    input_handler: Option<PlatformInputHandler>,
    last_key_equivalent: Option<KeyDownEvent>,
    last_left_mouse_down_event: Option<Retained<AnyObject>>,
    synthetic_drag_counter: usize,
    traffic_light_position: Option<Point<Pixels>>,
    traffic_light_frames: Option<TrafficLightFrames>,
    pre_fullscreen_traffic_light_frames: Option<TrafficLightFrames>,
    transparent_titlebar: bool,
    previous_modifiers_changed_event: Option<PlatformInput>,
    keystroke_for_do_command: Option<Keystroke>,
    do_command_handled: Option<bool>,
    external_files_dragged: bool,
    // Whether the next left-mouse click is also the focusing click.
    first_mouse: bool,
    // When true, the whole content view is reported as app-owned titlebar content via
    // `_opaqueRectForWindowMoveWhenInTitlebar`, so AppKit does not drag the window from
    // the titlebar or delay titlebar clicks (a delay first observed on macOS 27). Such
    // windows draw their own titlebar and move the window via `start_window_move`.
    app_owns_titlebar_drag: bool,
    fullscreen_restore_bounds: Bounds<Pixels>,
    is_exiting_fullscreen: bool,
    simple_fullscreen_state: Option<SimpleFullscreenState>,
    move_tab_to_new_window_callback: Option<Box<dyn FnMut()>>,
    merge_all_windows_callback: Option<Box<dyn FnMut()>>,
    select_next_tab_callback: Option<Box<dyn FnMut()>>,
    select_previous_tab_callback: Option<Box<dyn FnMut()>>,
    toggle_tab_bar_callback: Option<Box<dyn FnMut()>>,
    activated_least_once: bool,
    color_status: gpui::WindowColorStatus,
    color_profile_dirty: bool,
    closed: Arc<AtomicBool>,
    accesskit_adapter: Option<accesskit_macos::SubclassingAdapter>,
    // The parent window if this window is a sheet (Dialog kind)
    sheet_parent: Option<*mut AnyObject>,
}

impl MacWindowState {
    fn move_traffic_light(&mut self) {
        if let Some(traffic_light_position) = self.traffic_light_position {
            if self.is_fullscreen() && !self.is_exiting_fullscreen {
                self.restore_traffic_light();
                return;
            }

            if self.traffic_light_frames.is_none() {
                self.traffic_light_frames = self.capture_traffic_light_frames();
            }

            let window_height = Pixels::from(self.native_window().frame().size.height);
            if self.traffic_light_frames.is_some() {
                // AppKit can recreate standard buttons, so fetch the live views for each layout pass.
                let Some(buttons) = self.traffic_light_buttons() else {
                    return;
                };
                let Some(titlebar_container) = Self::titlebar_container(&buttons.close) else {
                    return;
                };

                let close_frame = buttons.close.frame();
                let minimize_frame = buttons.minimize.frame();
                let button_width = Pixels::from(close_frame.size.width);
                let button_height = Pixels::from(close_frame.size.height);
                let button_padding = Pixels::from(
                    minimize_frame.origin.x - close_frame.origin.x - close_frame.size.width,
                );
                let container_height =
                    button_height + traffic_light_position.y + traffic_light_position.y;

                let mut titlebar_frame = titlebar_container.frame();
                titlebar_frame.size.height = container_height.to_f64();
                titlebar_frame.origin.y = (window_height - container_height).to_f64();

                let minimize_x = traffic_light_position.x + button_width + button_padding;
                let zoom_x = minimize_x + button_width + button_padding;

                titlebar_container.setFrame(titlebar_frame);
                buttons.close.setFrameOrigin(NSPoint::new(
                    traffic_light_position.x.to_f64(),
                    traffic_light_position.y.to_f64(),
                ));
                buttons.minimize.setFrameOrigin(NSPoint::new(
                    minimize_x.to_f64(),
                    traffic_light_position.y.to_f64(),
                ));
                buttons.zoom.setFrameOrigin(NSPoint::new(
                    zoom_x.to_f64(),
                    traffic_light_position.y.to_f64(),
                ));

                titlebar_container.updateTrackingAreas();
                buttons.close.updateTrackingAreas();
                buttons.minimize.updateTrackingAreas();
                buttons.zoom.updateTrackingAreas();
            }
        }
    }

    fn capture_traffic_light_frames(&self) -> Option<TrafficLightFrames> {
        let buttons = self.traffic_light_buttons()?;
        let titlebar_container = Self::titlebar_container(&buttons.close)?;

        Some(TrafficLightFrames {
            titlebar: titlebar_container.frame(),
            close: buttons.close.frame(),
            minimize: buttons.minimize.frame(),
            zoom: buttons.zoom.frame(),
        })
    }

    fn native_window(&self) -> &NSWindow {
        // SAFETY: `MacWindow::open` initializes this pointer with an `NSWindow` or `NSPanel` instance.
        // Both types can be borrowed as `NSWindow`.
        unsafe { &*self.native_window.cast::<NSWindow>() }
    }

    fn traffic_light_buttons(&self) -> Option<TrafficLightButtons> {
        let window = self.native_window();
        Some(TrafficLightButtons {
            close: window.standardWindowButton(NSWindowButton::CloseButton)?,
            minimize: window.standardWindowButton(NSWindowButton::MiniaturizeButton)?,
            zoom: window.standardWindowButton(NSWindowButton::ZoomButton)?,
        })
    }

    fn titlebar_container(close_button: &NSButton) -> Option<Retained<NSView>> {
        // SAFETY: `close_button` comes from AppKit's `standardWindowButton(_:)`.
        // Although `superview` is unsafe, objc2 returns each result as `Retained<NSView>`.
        unsafe {
            let button_container = close_button.superview()?;
            button_container.superview()
        }
    }

    fn restore_traffic_light(&mut self) {
        if let Some(frames) = self.traffic_light_frames.take() {
            let Some(buttons) = self.traffic_light_buttons() else {
                return;
            };
            let Some(titlebar_container) = Self::titlebar_container(&buttons.close) else {
                return;
            };

            buttons.close.setFrame(frames.close);
            buttons.minimize.setFrame(frames.minimize);
            buttons.zoom.setFrame(frames.zoom);
            titlebar_container.setFrame(frames.titlebar);

            titlebar_container.updateTrackingAreas();
            buttons.close.updateTrackingAreas();
            buttons.minimize.updateTrackingAreas();
            buttons.zoom.updateTrackingAreas();
        }
    }

    /// `window_state` is the handle this state lives in; a Metal link holds it
    /// weakly to deliver frames.
    fn start_display_link(&mut self, window_state: &Rc<Mutex<MacWindowState>>) {
        self.stop_display_link();
        if !self
            .native_window()
            .occlusionState()
            .contains(NSWindowOcclusionState::Visible)
        {
            return;
        }
        match &mut self.frame_source {
            FrameSource::Metal(metal_frames) => {
                let Some(layer) = self.renderer.layer() else {
                    return;
                };
                let main_thread =
                    crate::main_thread_marker().expect("macOS windows require the main thread");
                let window_state = Rc::downgrade(window_state);
                let source = MetalFrameSource::new(layer, main_thread, move |update| {
                    if let Some(window_state) = window_state.upgrade() {
                        metal_frame(&window_state, update);
                    }
                });
                if let Some(source) = source {
                    metal_frames.replace(Some(source));
                    self.renderer.set_display_link_attached(true);
                }
            }
            FrameSource::DisplayLink(frame_source) => {
                let screen: *mut AnyObject = unsafe { msg_send![self.native_window, screen] };
                let Some(display_id) = display_id_for_screen(screen) else {
                    // AppKit can temporarily report no screen while displays are being reconfigured.
                    return;
                };
                let data = self.native_view.as_ptr() as *mut c_void;
                frame_source
                    .get_or_insert_with(|| WindowFrameSource::new(data, step))
                    .start(display_id)
                    .log_err();
            }
        }
    }

    fn stop_display_link(&mut self) {
        match &mut self.frame_source {
            FrameSource::Metal(metal_frames) => {
                if metal_frames.is_attached() {
                    // Detach the link rather than pause it, so that a synchronous
                    // draw can use the layer's `nextDrawable`.
                    metal_frames.replace(None);
                    self.renderer.set_display_link_attached(false);
                }
            }
            FrameSource::DisplayLink(Some(frame_source)) => frame_source.stop(),
            FrameSource::DisplayLink(None) => {}
        }
    }

    fn is_maximized(&self) -> bool {
        fn rect_to_size(rect: NSRect) -> Size<Pixels> {
            let NSSize { width, height } = rect.size;
            size(width.into(), height.into())
        }

        let bounds = self.bounds();
        let screen_frame = self
            .native_window()
            .screen()
            .map_or_default(|screen| screen.visibleFrame());
        bounds.size == rect_to_size(screen_frame)
    }

    fn is_fullscreen(&self) -> bool {
        self.native_window()
            .styleMask()
            .contains(NSWindowStyleMask::FullScreen)
    }

    fn toggle_simple_fullscreen(&mut self) -> Option<SimpleFullscreenPlan> {
        // If the window is in native fullscreen, simple fullscreen would conflict
        // with AppKit's own fullscreen handling, so ignore the request.
        if self.is_fullscreen() {
            return None;
        }

        if let Some(saved) = self.simple_fullscreen_state.take() {
            Some(SimpleFullscreenPlan::Exit(saved))
        } else {
            let screen = self.native_window().screen()?;
            let screen_frame = screen.frame();
            let bounds = self.bounds();

            self.simple_fullscreen_state = Some(SimpleFullscreenState {
                frame: self.native_window().frame(),
                bounds,
                style_mask: self.native_window().styleMask(),
            });

            Some(SimpleFullscreenPlan::Enter { screen_frame })
        }
    }

    fn bounds(&self) -> Bounds<Pixels> {
        let mut window_frame = self.native_window().frame();
        let Some(screen) = self.native_window().screen() else {
            return Bounds::new(point(px(0.), px(0.)), gpui::DEFAULT_WINDOW_SIZE);
        };
        let screen_frame = screen.frame();

        // Flip the y coordinate to be top-left origin
        window_frame.origin.y =
            screen_frame.size.height - window_frame.origin.y - window_frame.size.height;

        Bounds::new(
            point(
                px((window_frame.origin.x - screen_frame.origin.x) as f32),
                px((window_frame.origin.y + screen_frame.origin.y) as f32),
            ),
            size(
                px(window_frame.size.width as f32),
                px(window_frame.size.height as f32),
            ),
        )
    }

    fn content_size(&self) -> Size<Pixels> {
        let NSSize { width, height } = self
            .native_window()
            .contentView()
            .map_or_default(|view| view.frame().size);
        size(px(width as f32), px(height as f32))
    }

    fn scale_factor(&self) -> f32 {
        get_scale_factor(self.native_window)
    }

    fn window_bounds(&self) -> WindowBounds {
        if self.is_fullscreen() {
            WindowBounds::Fullscreen(self.fullscreen_restore_bounds)
        } else if let Some(state) = &self.simple_fullscreen_state {
            WindowBounds::Windowed(state.bounds)
        } else {
            WindowBounds::Windowed(self.bounds())
        }
    }
}

pub(crate) struct MacWindow(
    Rc<Mutex<MacWindowState>>,
    MainThreadMarker,
    /// The Metal link's frame waker, kept outside the lock so waking never
    /// waits on it. `None` when a `CVDisplayLink` paces frames.
    Option<Rc<MetalFrames>>,
);

impl MacWindow {
    pub fn open(
        handle: AnyWindowHandle,
        WindowParams {
            bounds,
            titlebar,
            kind,
            is_movable,
            app_owns_titlebar_drag,
            is_resizable,
            is_minimizable,
            focus,
            show,
            display_id,
            window_min_size,
            tabbing_identifier,
            use_display_p3,
            ..
        }: WindowParams,
        cursor_visible: Arc<AtomicBool>,
        foreground_executor: ForegroundExecutor,
        background_executor: BackgroundExecutor,
        renderer_context: renderer::Context,
        marker: MainThreadMarker,
    ) -> Result<Self> {
        autoreleasepool(|_| unsafe {
            let renderer = renderer::new_renderer(renderer_context, false, use_display_p3)?;
            let allows_automatic_window_tabbing = tabbing_identifier.is_some();
            if allows_automatic_window_tabbing {
                let () = msg_send![class!(NSWindow), setAllowsAutomaticWindowTabbing: Bool::YES];
            } else {
                let () = msg_send![class!(NSWindow), setAllowsAutomaticWindowTabbing: Bool::NO];
            }

            let mut style_mask;
            if let Some(titlebar) = titlebar.as_ref() {
                style_mask = NSWindowStyleMask::Closable | NSWindowStyleMask::Titled;

                if is_resizable {
                    style_mask |= NSWindowStyleMask::Resizable;
                }

                if is_minimizable {
                    style_mask |= NSWindowStyleMask::Miniaturizable;
                }

                if titlebar.appears_transparent {
                    style_mask |= NSWindowStyleMask::FullSizeContentView;
                }
            } else {
                style_mask = NSWindowStyleMask::Titled | NSWindowStyleMask::FullSizeContentView;
            }

            let native_window: *mut AnyObject = match kind {
                WindowKind::Normal => {
                    msg_send![WINDOW_CLASS, alloc]
                }
                // `AnchoredPopup` is rejected in `MacPlatform::open_window`, grouped here only
                // for exhaustiveness.
                WindowKind::PopUp | WindowKind::AnchoredPopup(_) => {
                    style_mask |= NSWindowStyleMask::NonactivatingPanel;
                    msg_send![PANEL_CLASS, alloc]
                }
                WindowKind::Floating | WindowKind::Dialog => {
                    msg_send![PANEL_CLASS, alloc]
                }
            };

            let display = display_id
                .and_then(MacDisplay::find_by_id)
                .unwrap_or_else(MacDisplay::primary);

            let mut target_screen = None;
            let screens = NSScreen::screens(marker);
            for screen in screens.iter() {
                if display_id_for_screen(Retained::as_ptr(&screen).cast_mut().cast())
                    == Some(display.0)
                {
                    target_screen = Some(screen);
                }
            }
            let target_screen = target_screen.or_else(|| NSScreen::mainScreen(marker));
            let screen_frame = target_screen
                .as_ref()
                .map_or_default(|screen| screen.frame());

            let window_rect = NSRect::new(
                NSPoint::new(
                    screen_frame.origin.x + bounds.origin.x.as_f32() as f64,
                    screen_frame.origin.y
                        + (display.bounds().size.height - bounds.origin.y).as_f32() as f64,
                ),
                NSSize::new(
                    bounds.size.width.as_f32() as f64,
                    bounds.size.height.as_f32() as f64,
                ),
            );

            let native_window: *mut AnyObject = msg_send![
                native_window,
                initWithContentRect: window_rect,
                styleMask: style_mask,
                backing: NSBackingStoreType::Buffered,
                defer: Bool::NO,
                screen: target_screen.as_deref()
            ];
            assert!(!native_window.is_null());
            #[expect(
                deprecated,
                reason = "File-drop decoding expects a property-list array of paths; replacing NSFilenamesPboardType requires migrating both registration and decoding to file URLs"
            )]
            let () = msg_send![
                native_window,
                registerForDraggedTypes:
                    &*NSArray::from_slice(&[NSFilenamesPboardType])
            ];
            let () = msg_send![
                native_window,
                setReleasedWhenClosed: Bool::NO
            ];

            let content_view: *mut AnyObject = msg_send![native_window, contentView];
            let native_view: *mut AnyObject = msg_send![VIEW_CLASS, alloc];
            let content_bounds: NSRect = msg_send![content_view, bounds];
            let native_view: *mut AnyObject = msg_send![native_view, initWithFrame: content_bounds];
            assert!(!native_view.is_null());

            let metal_frames = MetalFrameSource::is_available().then(Rc::<MetalFrames>::default);
            let state = Rc::new(Mutex::new(MacWindowState {
                handle,
                foreground_executor,
                background_executor,
                native_window,
                native_view: NonNull::new_unchecked(native_view),
                blurred_view: None,
                background_appearance: WindowBackgroundAppearance::Opaque,
                cursor_style: CursorStyle::Arrow,
                cursor_visible,
                frame_source: match &metal_frames {
                    Some(metal_frames) => FrameSource::Metal(metal_frames.clone()),
                    None => FrameSource::DisplayLink(None),
                },
                renderer,
                request_frame_callback: None,
                event_callback: None,
                activate_callback: None,
                visibility_callback: None,
                last_visibility: None,
                resize_callback: None,
                moved_callback: None,
                display_changed_callback: None,
                should_close_callback: None,
                close_callback: None,
                appearance_changed_callback: None,
                input_handler: None,
                last_key_equivalent: None,
                last_left_mouse_down_event: None,
                synthetic_drag_counter: 0,
                traffic_light_position: titlebar
                    .as_ref()
                    .and_then(|titlebar| titlebar.traffic_light_position),
                traffic_light_frames: None,
                pre_fullscreen_traffic_light_frames: None,
                transparent_titlebar: titlebar
                    .as_ref()
                    .is_none_or(|titlebar| titlebar.appears_transparent),
                previous_modifiers_changed_event: None,
                keystroke_for_do_command: None,
                do_command_handled: None,
                external_files_dragged: false,
                first_mouse: false,
                app_owns_titlebar_drag,
                fullscreen_restore_bounds: Bounds::default(),
                is_exiting_fullscreen: false,
                simple_fullscreen_state: None,
                move_tab_to_new_window_callback: None,
                merge_all_windows_callback: None,
                select_next_tab_callback: None,
                select_previous_tab_callback: None,
                toggle_tab_bar_callback: None,
                activated_least_once: false,
                color_status: gpui::WindowColorStatus::new(
                    gpui::WindowColorMode::Default,
                    gpui::WindowColorMode::Default,
                    true,
                    None,
                    None,
                ),
                color_profile_dirty: true,
                closed: Arc::new(AtomicBool::new(false)),
                accesskit_adapter: None,
                sheet_parent: None,
            }));
            let mut window = Self(state, marker, metal_frames);

            (*native_window)
                .class()
                .instance_variable(WINDOW_STATE_IVAR)
                .expect("GPUI window state ivar")
                .load_ptr::<*mut c_void>(&*native_window)
                .write(Rc::into_raw(window.0.clone()).cast_mut().cast());
            let _: () = msg_send![native_window, setDelegate: native_window];
            (*native_view)
                .class()
                .instance_variable(WINDOW_STATE_IVAR)
                .expect("GPUI view state ivar")
                .load_ptr::<*mut c_void>(&*native_view)
                .write(Rc::into_raw(window.0.clone()).cast_mut().cast());

            if let Some(title) = titlebar
                .as_ref()
                .and_then(|t| t.title.as_ref().map(AsRef::as_ref))
            {
                window.set_title(title);
            }

            let _: () = msg_send![native_window, setMovable: is_movable.to_objc()];

            if let Some(window_min_size) = window_min_size {
                let _: () = msg_send![native_window, setContentMinSize: NSSize {
                    width: window_min_size.width.to_f64(),
                    height: window_min_size.height.to_f64(),
                }];
            }

            if titlebar.is_none_or(|titlebar| titlebar.appears_transparent) {
                let _: () = msg_send![native_window, setTitlebarAppearsTransparent: Bool::YES];
                let _: () =
                    msg_send![native_window, setTitleVisibility: NSWindowTitleVisibility::Hidden];
            }

            let _: () = msg_send![native_view, setAutoresizingMask: NSAutoresizingMaskOptions::ViewWidthSizable
                    | NSAutoresizingMaskOptions::ViewHeightSizable];
            let _: () = msg_send![native_view, setWantsBestResolutionOpenGLSurface: Bool::YES];

            // From winit crate: On Mojave, views automatically become layer-backed shortly after
            // being added to a native_window. Changing the layer-backedness of a view breaks the
            // association between the view and its associated OpenGL context. To work around this,
            // on we explicitly make the view layer-backed up front so that AppKit doesn't do it
            // itself and break the association with its context.
            let _: () = msg_send![native_view, setWantsLayer: Bool::YES];
            let _: () = msg_send![
            native_view,
            setLayerContentsRedrawPolicy: NSViewLayerContentsRedrawPolicy::DuringViewResize
            ];

            let native_view: *mut AnyObject = msg_send![native_view, autorelease];
            let _: () = msg_send![content_view, addSubview: native_view];
            let _: Bool = msg_send![native_window, makeFirstResponder: native_view];

            let app: *mut AnyObject = msg_send![class!(NSApplication), sharedApplication];
            let main_window: *mut AnyObject = msg_send![app, mainWindow];
            let mut sheet_parent = None;

            // SAFETY: This is the live GPUIView (an NSView subclass) added to the
            // content view above, and window creation runs on the main thread.
            let tracking_view = &*native_view.cast::<NSView>();

            match kind {
                WindowKind::Normal | WindowKind::Floating => {
                    if kind == WindowKind::Floating {
                        // Let the window float keep above normal windows.
                        let _: () = msg_send![native_window, setLevel: NSFloatingWindowLevel];
                        let _: () = msg_send![native_window, setAcceptsMouseMovedEvents: Bool::YES];
                    } else {
                        let _: () = msg_send![native_window, setLevel: NSNormalWindowLevel];
                        let _: () = msg_send![native_window, setAcceptsMouseMovedEvents: Bool::NO];
                        add_mouse_tracking_area(tracking_view);
                    }

                    if let Some(tabbing_identifier) = tabbing_identifier {
                        let tabbing_id = ns_string(tabbing_identifier.as_str());
                        let _: () = msg_send![native_window, setTabbingIdentifier: tabbing_id];
                    } else {
                        let _: () = msg_send![native_window, setTabbingIdentifier:ptr::null_mut::<AnyObject>()];
                    }
                }
                // `AnchoredPopup` is rejected in `MacPlatform::open_window`, grouped here only
                // for exhaustiveness.
                WindowKind::PopUp | WindowKind::AnchoredPopup(_) => {
                    add_mouse_tracking_area(tracking_view);

                    let _: () = msg_send![native_window, setLevel: NSPopUpWindowLevel];
                    let _: () = msg_send![
                        native_window,
                        setAnimationBehavior: NSWindowAnimationBehavior::UtilityWindow
                    ];
                    let _: () = msg_send![native_window, setCollectionBehavior: NSWindowCollectionBehavior::CanJoinAllSpaces
                            | NSWindowCollectionBehavior::FullScreenAuxiliary];
                }
                WindowKind::Dialog => {
                    if !main_window.is_null() {
                        let parent = {
                            let active_sheet: *mut AnyObject =
                                msg_send![main_window, attachedSheet];
                            if active_sheet.is_null() {
                                main_window
                            } else {
                                active_sheet
                            }
                        };
                        let _: () = msg_send![parent, beginSheet: native_window, completionHandler: None::<&block2::Block<dyn Fn(NSInteger)>>];
                        sheet_parent = Some(parent);
                    }
                }
            }

            if allows_automatic_window_tabbing
                && !main_window.is_null()
                && main_window != native_window
            {
                let main_window_is_fullscreen = (&*main_window.cast::<NSWindow>())
                    .styleMask()
                    .contains(NSWindowStyleMask::FullScreen);
                let user_tabbing_preference = Self::get_user_tabbing_preference()
                    .unwrap_or(UserTabbingPreference::InFullScreen);
                let should_add_as_tab = user_tabbing_preference == UserTabbingPreference::Always
                    || user_tabbing_preference == UserTabbingPreference::InFullScreen
                        && main_window_is_fullscreen;

                if should_add_as_tab {
                    let main_window_can_tab: Bool =
                        msg_send![main_window, respondsToSelector: sel!(addTabbedWindow:ordered:)];
                    let main_window_visible: Bool = msg_send![main_window, isVisible];

                    if main_window_can_tab == Bool::YES && main_window_visible == Bool::YES {
                        let _: () = msg_send![main_window, addTabbedWindow: native_window, ordered: NSWindowOrderingMode::Above];

                        // Ensure the window is visible immediately after adding the tab, since the tab bar is updated with a new entry at this point.
                        // Note: Calling orderFront here can break fullscreen mode (makes fullscreen windows exit fullscreen), so only do this if the main window is not fullscreen.
                        if !main_window_is_fullscreen {
                            let _: () =
                                msg_send![native_window, orderFront: ptr::null_mut::<AnyObject>()];
                        }
                    }
                }
            }

            if focus && show {
                let _: () =
                    msg_send![native_window, makeKeyAndOrderFront: ptr::null_mut::<AnyObject>()];
            } else if show {
                let _: () = msg_send![native_window, orderFront: ptr::null_mut::<AnyObject>()];
            }

            // Set the initial position of the window to the specified origin.
            // Although we already specified the position using `initWithContentRect_styleMask_backing_defer_screen_`,
            // the window position might be incorrect if the main screen (the screen that contains the window that has focus)
            //  is different from the primary screen.
            let _: () = msg_send![native_window, setFrameTopLeftPoint: window_rect.origin];
            {
                let mut window_state = window.0.lock();
                window_state.move_traffic_light();
                window_state.sheet_parent = sheet_parent;
            }

            Ok(window)
        })
    }

    pub fn active_window() -> Option<AnyWindowHandle> {
        unsafe {
            let app: *mut AnyObject = msg_send![class!(NSApplication), sharedApplication];
            let main_window: *mut AnyObject = msg_send![app, mainWindow];
            if main_window.is_null() {
                return None;
            }

            if msg_send![main_window, isKindOfClass: WINDOW_CLASS] {
                let handle = get_window_state(&*main_window).lock().handle;
                Some(handle)
            } else {
                None
            }
        }
    }

    pub fn ordered_windows() -> Vec<AnyWindowHandle> {
        unsafe {
            let app: *mut AnyObject = msg_send![class!(NSApplication), sharedApplication];
            let windows: *mut AnyObject = msg_send![app, orderedWindows];
            let count: NSUInteger = msg_send![windows, count];

            let mut window_handles = Vec::new();
            for i in 0..count {
                let window: *mut AnyObject = msg_send![windows, objectAtIndex:i];
                if msg_send![window, isKindOfClass: WINDOW_CLASS] {
                    let handle = get_window_state(&*window).lock().handle;
                    window_handles.push(handle);
                }
            }

            window_handles
        }
    }

    pub fn get_user_tabbing_preference() -> Option<UserTabbingPreference> {
        unsafe {
            let defaults: *mut AnyObject = msg_send![class!(NSUserDefaults), standardUserDefaults];
            let domain = ns_string("NSGlobalDomain");
            let key = ns_string("AppleWindowTabbingMode");

            let dict: *mut AnyObject = msg_send![defaults, persistentDomainForName: domain];
            let value: *mut AnyObject = if !dict.is_null() {
                msg_send![dict, objectForKey: key]
            } else {
                ptr::null_mut::<AnyObject>()
            };

            let value_str = if !value.is_null() {
                CStr::from_ptr(msg_send![value, UTF8String]).to_string_lossy()
            } else {
                "".into()
            };

            match value_str.as_ref() {
                "manual" => Some(UserTabbingPreference::Never),
                "always" => Some(UserTabbingPreference::Always),
                _ => Some(UserTabbingPreference::InFullScreen),
            }
        }
    }
}

impl Drop for MacWindow {
    fn drop(&mut self) {
        let mut this = self.0.lock();
        // `accesskit_macos::SubclassingAdapter::for_window` strong-retains the
        // window's content view, and that content view keeps the `GPUIView` it
        // hosts alive. Together with the `Rc<Mutex<MacWindowState>>` parked in
        // both views' `windowState` ivar, that forms
        // `MacWindowState -> adapter -> content view -> GPUIView -> MacWindowState`,
        // a cycle the delegate/`frame_source` teardown below cannot break. Drop
        // the adapter here so the native view, its `CAMetalLayer` and the
        // renderer's command queue are actually released with the window.
        drop(this.accesskit_adapter.take());
        this.renderer.destroy();
        let window = this.native_window;
        let sheet_parent = this.sheet_parent.take();
        match &mut this.frame_source {
            FrameSource::Metal(metal_frames) => metal_frames.replace(None),
            FrameSource::DisplayLink(frame_source) => drop(frame_source.take()),
        }
        unsafe {
            let _: () = msg_send![this.native_window, setDelegate: ptr::null_mut::<AnyObject>()];
        }
        this.input_handler.take();
        // A delivery task queued by `report_visibility` may still run after the
        // GPUI window is gone; without a callback it has nothing to notify.
        this.visibility_callback.take();
        this.foreground_executor
            .spawn(async move {
                unsafe {
                    if let Some(parent) = sheet_parent {
                        let _: () = msg_send![parent, endSheet: window];
                    }
                    let _: () = msg_send![window, close];
                    let _: *mut AnyObject = msg_send![window, autorelease];
                }
            })
            .detach();
    }
}

/// Calls `f` if the window is not closed.
///
/// This should be used when spawning foreground tasks interacting with the
/// window, as some messages will end hard faulting if dispatched to no longer
/// valid window handles.
fn if_window_not_closed(closed: Arc<AtomicBool>, f: impl FnOnce()) {
    if !closed.load(Ordering::Acquire) {
        f();
    }
}

// Read display evidence only at negotiation/frame boundaries. The public getter
// remains a cheap cached snapshot; ColorSync still owns physical display mapping.
fn color_status_for_window(state: &MacWindowState) -> gpui::WindowColorStatus {
    let renderer = state.renderer.color_status();
    let evidence = state
        .native_window()
        .screen()
        .and_then(|screen| screen.colorSpace())
        .and_then(|space| space.CGColorSpace())
        .map(|space| space.is_wide_gamut_rgb());
    gpui::WindowColorStatus::new(
        renderer.requested(),
        renderer.effective(),
        renderer.supports_wide_gamut_sdr(),
        evidence,
        renderer.fallback(),
    )
}

impl PlatformWindow for MacWindow {
    fn set_color_mode(
        &mut self,
        mode: gpui::WindowColorMode,
    ) -> anyhow::Result<gpui::WindowColorStatus> {
        let mut state = self.0.lock();
        state.renderer.set_color_mode(mode)?;
        state.color_status = color_status_for_window(&state);
        state.color_profile_dirty = false;
        Ok(state.color_status)
    }

    fn color_status(&self) -> gpui::WindowColorStatus {
        self.0.lock().color_status
    }

    fn prepare_frame(&self) -> bool {
        let mut state = self.0.lock();
        if !state.color_profile_dirty {
            return false;
        }
        state.color_status = color_status_for_window(&state);
        state.color_profile_dirty = false;
        true
    }

    fn bounds(&self) -> Bounds<Pixels> {
        self.0.as_ref().lock().bounds()
    }

    fn window_bounds(&self) -> WindowBounds {
        self.0.as_ref().lock().window_bounds()
    }

    fn is_maximized(&self) -> bool {
        self.0.as_ref().lock().is_maximized()
    }

    fn content_size(&self) -> Size<Pixels> {
        self.0.as_ref().lock().content_size()
    }

    fn resize(&mut self, size: Size<Pixels>) {
        let this = self.0.lock();
        let window = this.native_window;
        let closed = this.closed.clone();
        this.foreground_executor
            .spawn(async move {
                if_window_not_closed(closed, || unsafe {
                    let _: () = msg_send![window, setContentSize: NSSize {
                        width: size.width.as_f32() as f64,
                        height: size.height.as_f32() as f64,
                    }];
                })
            })
            .detach();
    }

    fn merge_all_windows(&self) {
        let native_window = self.0.lock().native_window;
        extern "C" fn merge_windows_async(context: *mut std::ffi::c_void) {
            unsafe {
                let native_window = context as *mut AnyObject;
                let _: () = msg_send![native_window, mergeAllWindows:ptr::null_mut::<AnyObject>()];
            }
        }

        unsafe {
            DispatchQueue::main()
                .exec_async_f(native_window as *mut std::ffi::c_void, merge_windows_async);
        }
    }

    fn move_tab_to_new_window(&self) {
        let native_window = self.0.lock().native_window;
        extern "C" fn move_tab_async(context: *mut std::ffi::c_void) {
            unsafe {
                let native_window = context as *mut AnyObject;
                let _: () =
                    msg_send![native_window, moveTabToNewWindow:ptr::null_mut::<AnyObject>()];
                let _: () =
                    msg_send![native_window, makeKeyAndOrderFront: ptr::null_mut::<AnyObject>()];
            }
        }

        unsafe {
            DispatchQueue::main()
                .exec_async_f(native_window as *mut std::ffi::c_void, move_tab_async);
        }
    }

    fn toggle_window_tab_overview(&self) {
        let native_window = self.0.lock().native_window;
        unsafe {
            let _: () = msg_send![native_window, toggleTabOverview:ptr::null_mut::<AnyObject>()];
        }
    }

    fn set_tabbing_identifier(&self, tabbing_identifier: Option<String>) {
        let native_window = self.0.lock().native_window;
        unsafe {
            let allows_automatic_window_tabbing = tabbing_identifier.is_some();
            if allows_automatic_window_tabbing {
                let () = msg_send![class!(NSWindow), setAllowsAutomaticWindowTabbing: Bool::YES];
            } else {
                let () = msg_send![class!(NSWindow), setAllowsAutomaticWindowTabbing: Bool::NO];
            }

            if let Some(tabbing_identifier) = tabbing_identifier {
                let tabbing_id = ns_string(tabbing_identifier.as_str());
                let _: () = msg_send![native_window, setTabbingIdentifier: tabbing_id];
            } else {
                let _: () =
                    msg_send![native_window, setTabbingIdentifier:ptr::null_mut::<AnyObject>()];
            }
        }
    }

    fn native_window_state(&self) -> Option<Vec<u8>> {
        let native_window = {
            let state = self.0.lock();
            if state.is_fullscreen() || state.simple_fullscreen_state.is_some() {
                return None;
            }
            state.native_window
        };
        // SAFETY: `native_window` is a live `NSWindow` retained by this window's state, and the
        // selectors below are AppKit/Foundation methods sent with their documented signatures. The
        // archived bytes are copied into an owned `Vec` before the objects we allocated are
        // released, so no pointer into Objective-C memory escapes this block.
        unsafe {
            let archiver: *mut AnyObject = msg_send![class!(NSKeyedArchiver), alloc];
            let archiver: *mut AnyObject =
                msg_send![archiver, initRequiringSecureCoding: Bool::YES];
            if archiver.is_null() {
                log::warn!("failed to create an archiver for the native window state");
                return None;
            }
            let delegate: *mut AnyObject = msg_send![WINDOW_STATE_ARCHIVER_DELEGATE_CLASS, new];
            let _: () = msg_send![archiver, setDelegate: delegate];
            let _: () = msg_send![native_window, encodeRestorableStateWithCoder: archiver];
            let _: () = msg_send![archiver, finishEncoding];
            // The archiver holds a weak reference to its delegate; clear it before the delegate
            // is released below.
            let _: () = msg_send![archiver, setDelegate: ptr::null_mut::<AnyObject>()];

            let data: *mut AnyObject = msg_send![archiver, encodedData];
            let bytes: *const c_void = if data.is_null() {
                ptr::null()
            } else {
                msg_send![data, bytes]
            };
            let state = if bytes.is_null() {
                log::warn!("the archiver produced no data for the native window state");
                None
            } else {
                let length: NSUInteger = msg_send![data, length];
                Some(std::slice::from_raw_parts(bytes.cast::<u8>(), length).to_vec())
            };

            let _: () = msg_send![delegate, release];
            let _: () = msg_send![archiver, release];
            state
        }
    }

    fn restore_native_window_state(&self, state: &[u8]) {
        if state.is_empty() {
            return;
        }
        let native_window = self.0.lock().native_window;
        // SAFETY: `native_window` is a live `NSWindow` retained by this window's state. The NSData,
        // NSKeyedUnarchiver and `restoreStateWithCoder:` selectors are sent with their documented
        // signatures, and the `NSData` only borrows `state` for the duration of this synchronous
        // call (it is consumed before `state` could be freed).
        unsafe {
            let data: *mut AnyObject = msg_send![
                class!(NSData),
                dataWithBytes: state.as_ptr().cast::<c_void>(),
                length: state.len()
            ];
            if data.is_null() {
                log::warn!(
                    "failed to wrap {} bytes of native window state",
                    state.len()
                );
                return;
            }

            // On macOS < 15 the `NSWindowRestoresWorkspaceAtLaunch` user default controls whether
            // the window is restored to its original Space. On macOS 15+ that default is broken
            // (FB15644170), and the `_windowRestorationOptions` override on our unarchiver subclass
            // handles it instead.
            if !is_macos_version_at_least(NSOperatingSystemVersion {
                majorVersion: 15,
                minorVersion: 0,
                patchVersion: 0,
            }) {
                RESTORES_WORKSPACE_AT_LAUNCH_DEFAULT.call_once(|| {
                    let defaults: *mut AnyObject =
                        msg_send![class!(NSUserDefaults), standardUserDefaults];
                    let key = ns_string("NSWindowRestoresWorkspaceAtLaunch");
                    let yes_value: *mut AnyObject =
                        msg_send![class!(NSNumber), numberWithBool: Bool::YES];
                    let dict: *mut AnyObject = msg_send![
                        class!(NSDictionary),
                        dictionaryWithObject: yes_value,
                        forKey: key
                    ];
                    let _: () = msg_send![defaults, registerDefaults: dict];
                });
            }

            let unarchiver: *mut AnyObject = msg_send![WINDOW_STATE_UNARCHIVER_CLASS, alloc];
            let mut error: *mut AnyObject = ptr::null_mut::<AnyObject>();
            let unarchiver: *mut AnyObject =
                msg_send![unarchiver, initForReadingFromData: data, error: &mut error];
            if unarchiver.is_null() {
                log::warn!(
                    "failed to unarchive the native window state: {}",
                    ns_error_description(error)
                );
                return;
            }
            let _: () = msg_send![native_window, restoreStateWithCoder: unarchiver];
            let error: *mut AnyObject = msg_send![unarchiver, error];
            if !error.is_null() {
                log::warn!(
                    "failed to restore the native window state: {}",
                    ns_error_description(error)
                );
            }
            let _: () = msg_send![unarchiver, release];
        }
    }

    fn set_traffic_light_position(&self, position: Point<Pixels>) {
        let mut state = self.0.lock();
        state.traffic_light_position = Some(position);
        state.move_traffic_light();
    }

    fn scale_factor(&self) -> f32 {
        self.0.as_ref().lock().scale_factor()
    }

    fn appearance(&self) -> WindowAppearance {
        unsafe {
            let appearance: Option<Retained<NSAppearance>> =
                msg_send![self.0.lock().native_window, effectiveAppearance];
            crate::window_appearance::window_appearance_from_native(appearance.as_deref())
        }
    }

    fn display(&self) -> Option<Rc<dyn PlatformDisplay>> {
        let screen: *mut AnyObject = unsafe { msg_send![self.0.lock().native_window, screen] };
        let display_id = display_id_for_screen(screen)?;
        Some(Rc::new(MacDisplay(display_id)))
    }

    fn mouse_position(&self) -> Point<Pixels> {
        let position = self
            .0
            .lock()
            .native_window()
            .mouseLocationOutsideOfEventStream();
        convert_mouse_position(position, self.content_size().height)
    }

    fn modifiers(&self) -> Modifiers {
        unsafe {
            let modifiers: NSEventModifierFlags = msg_send![class!(NSEvent), modifierFlags];

            let control = modifiers.contains(NSEventModifierFlags::Control);
            let alt = modifiers.contains(NSEventModifierFlags::Option);
            let shift = modifiers.contains(NSEventModifierFlags::Shift);
            let command = modifiers.contains(NSEventModifierFlags::Command);
            let function = modifiers.contains(NSEventModifierFlags::Function);

            Modifiers {
                control,
                alt,
                shift,
                platform: command,
                function,
            }
        }
    }

    fn capslock(&self) -> Capslock {
        unsafe {
            let modifiers: NSEventModifierFlags = msg_send![class!(NSEvent), modifierFlags];

            Capslock {
                on: modifiers.contains(NSEventModifierFlags::CapsLock),
            }
        }
    }

    fn set_input_handler(&mut self, input_handler: PlatformInputHandler) {
        self.0.as_ref().lock().input_handler = Some(input_handler);
    }

    fn take_input_handler(&mut self) -> Option<PlatformInputHandler> {
        self.0.as_ref().lock().input_handler.take()
    }

    fn prompt(
        &self,
        level: PromptLevel,
        msg: &str,
        detail: Option<&str>,
        answers: &[PromptButton],
    ) -> Option<oneshot::Receiver<usize>> {
        // NSAlert's first button keeps Return and Cancel keeps Escape, but the keyboard
        // focus (and therefore Space) defaults to Cancel, leaving the middle button of
        // prompts like "Save / Don't Save / Cancel" unreachable from the keyboard. Move
        // the initial focus onto the last non-cancel, non-default button instead.
        let initial_focus_ix = answers
            .iter()
            .enumerate()
            .rev()
            .find(|(_, label)| !label.is_cancel())
            .map(|(ix, _)| ix)
            .filter(|&ix| ix > 0);

        let alert = NSAlert::new(self.1);
        alert.setAlertStyle(match level {
            PromptLevel::Critical => NSAlertStyle::Critical,
            PromptLevel::Warning => NSAlertStyle::Warning,
            PromptLevel::Info => NSAlertStyle::Informational,
        });
        let message = NSString::from_str(msg);
        alert.setMessageText(message.as_ref());

        if let Some(detail) = detail {
            let detail_text = NSString::from_str(detail);
            alert.setInformativeText(detail_text.as_ref());
        }

        let mut initial_focus_button: Option<Retained<NSButton>> = None;
        for (ix, answer) in answers.iter().enumerate() {
            let title = NSString::from_str(answer.label());
            let button = alert.addButtonWithTitle(&title);
            button.setTag(ix as NSInteger);

            if answer.is_cancel() {
                if let Some(key) = core::char::from_u32(crate::events::ESCAPE_KEY as u32) {
                    let key = NSString::from_str(&key.to_string());
                    button.setKeyEquivalent(&key);
                }
            } else if Some(ix) == initial_focus_ix {
                initial_focus_button = Some(button);
            }
        }

        if let Some(button) = initial_focus_button {
            alert.window().setInitialFirstResponder(Some(&button));
        }

        let (done_tx, done_rx) = oneshot::channel();
        let done_tx = Cell::new(Some(done_tx));

        let block = RcBlock::new(move |answer: NSInteger| {
            if let Some(done_tx) = done_tx.take() {
                let _ = done_tx.send(answer.try_into().unwrap());
            }
        });

        let lock = self.0.lock();
        let native_window = lock.native_window;
        let closed = lock.closed.clone();
        let executor = lock.foreground_executor.clone();
        executor
            .spawn(async move {
                if !closed.load(Ordering::Acquire) {
                    let sheet_window: &NSWindow = unsafe { &*(native_window as *const NSWindow) };

                    alert.beginSheetModalForWindow_completionHandler(sheet_window, Some(&block));
                }
            })
            .detach();

        Some(done_rx)
    }

    fn activate(&self) {
        let lock = self.0.lock();
        let window = lock.native_window;
        let view = lock.native_view.as_ptr();
        let closed = lock.closed.clone();
        let executor = lock.foreground_executor.clone();
        executor
            .spawn(async move {
                if !closed.load(Ordering::Acquire) {
                    let window = unsafe { &*window.cast::<NSWindow>() };
                    if !window.isVisible() {
                        let view = unsafe { &*view.cast::<NSView>() };
                        view.setNeedsDisplay(true);
                    }
                    window.makeKeyAndOrderFront(None);
                }
            })
            .detach();
    }

    fn request_attention(&self) {
        if self.is_active() {
            return;
        }

        let executor = self.0.lock().foreground_executor.clone();
        executor
            .spawn(async move {
                unsafe {
                    let app: *mut AnyObject = msg_send![class!(NSApplication), sharedApplication];
                    let _: NSInteger = msg_send![app, requestUserAttention: NSRequestUserAttentionType::InformationalRequest];
                }
            })
            .detach();
    }

    fn is_active(&self) -> bool {
        self.0.lock().native_window().isKeyWindow()
    }

    fn visibility(&self) -> WindowVisibility {
        visibility(&self.0.lock())
    }

    // is_hovered is unused on macOS. See Window::is_window_hovered.
    fn is_hovered(&self) -> bool {
        false
    }

    fn set_title(&mut self, title: &str) {
        unsafe {
            let app: *mut AnyObject = msg_send![class!(NSApplication), sharedApplication];
            let window = self.0.lock().native_window;
            let title = ns_string(title);
            let _: () = msg_send![app, changeWindowsItem:window, title:title, filename:false];
            let _: () = msg_send![window, setTitle: title];
            self.0.lock().move_traffic_light();
        }
    }

    fn get_title(&self) -> String {
        unsafe {
            let title: *mut AnyObject = msg_send![self.0.lock().native_window, title];
            if title.is_null() {
                "".to_string()
            } else {
                title.to_str().to_string()
            }
        }
    }

    fn set_app_id(&mut self, _app_id: &str) {}

    fn set_background_appearance(&self, background_appearance: WindowBackgroundAppearance) {
        let mut this = self.0.as_ref().lock();
        // Existing setter is infallible. Preserve the last valid opaque window
        // rather than creating an unsupported partially configured wide window.
        if background_appearance != WindowBackgroundAppearance::Opaque
            && this.renderer.color_status().requested() == gpui::WindowColorMode::WideGamutSdr
        {
            log::warn!("disable wide-gamut SDR before enabling a transparent window");
            return;
        }
        this.background_appearance = background_appearance;

        let opaque = background_appearance == WindowBackgroundAppearance::Opaque;
        this.renderer.update_transparency(!opaque);

        unsafe {
            let _: () = msg_send![this.native_window, setOpaque: opaque.to_objc()];
            let background_color = if opaque {
                NSColor::colorWithSRGBRed_green_blue_alpha(0f64, 0f64, 0f64, 1f64)
            } else {
                // Not using `+[NSColor clearColor]` to avoid broken shadow.
                NSColor::colorWithSRGBRed_green_blue_alpha(0f64, 0f64, 0f64, 0.0001)
            };
            let _: () = msg_send![this.native_window, setBackgroundColor: &*background_color];

            if background_appearance != WindowBackgroundAppearance::Blurred {
                if let Some(blur_view) = this.blurred_view {
                    let _: () = msg_send![blur_view, removeFromSuperview];
                    this.blurred_view = None;
                }
            } else if this.blurred_view.is_none() {
                let content_view: *mut AnyObject = msg_send![this.native_window, contentView];
                let frame: NSRect = msg_send![content_view, bounds];
                let blur_view: *mut AnyObject = msg_send![BLURRED_VIEW_CLASS, alloc];
                let blur_view: *mut AnyObject = msg_send![blur_view, initWithFrame: frame];
                let _: () = msg_send![blur_view, setAutoresizingMask: NSAutoresizingMaskOptions::ViewWidthSizable
                        | NSAutoresizingMaskOptions::ViewHeightSizable];

                let _: () = msg_send![
                    content_view,
                    addSubview: blur_view,
                    positioned: NSWindowOrderingMode::Below,
                    relativeTo: ptr::null_mut::<AnyObject>()
                ];
                this.blurred_view = Some(msg_send![blur_view, autorelease]);
            }
        }
    }

    fn background_appearance(&self) -> WindowBackgroundAppearance {
        self.0.as_ref().lock().background_appearance
    }

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

    fn set_edited(&mut self, edited: bool) {
        unsafe {
            let window = self.0.lock().native_window;
            msg_send![window, setDocumentEdited: edited.to_objc()]
        }

        // Changing the document edited state resets the traffic light position,
        // so we have to move it again.
        self.0.lock().move_traffic_light();
    }

    fn set_document_path(&self, path: Option<&std::path::Path>) {
        unsafe {
            let window = self.0.lock().native_window;
            let filename = path.map_or(ns_string(""), |p| ns_string(&p.to_string_lossy()));
            let _: () = msg_send![window, setRepresentedFilename: filename];
        }

        // Changing the document path state resets the traffic light position,
        // so we have to move it again.
        self.0.lock().move_traffic_light();
    }

    fn show_character_palette(&self) {
        let this = self.0.lock();
        let window = this.native_window;
        this.foreground_executor
            .spawn(async move {
                unsafe {
                    let app: *mut AnyObject = msg_send![class!(NSApplication), sharedApplication];
                    let _: () = msg_send![app, orderFrontCharacterPalette: window];
                }
            })
            .detach();
    }

    fn minimize(&self) {
        let window = self.0.lock().native_window;
        unsafe {
            let _: () = msg_send![window, miniaturize: ptr::null_mut::<AnyObject>()];
        }
    }

    fn zoom(&self) {
        let this = self.0.lock();
        let window = this.native_window;
        let closed = this.closed.clone();
        this.foreground_executor
            .spawn(async move {
                if_window_not_closed(closed, || unsafe {
                    let _: () = msg_send![window, zoom: ptr::null_mut::<AnyObject>()];
                })
            })
            .detach();
    }

    fn toggle_fullscreen(&self) {
        let this = self.0.lock();
        let window = this.native_window;
        let closed = this.closed.clone();
        this.foreground_executor
            .spawn(async move {
                if_window_not_closed(closed, || unsafe {
                    let _: () = msg_send![window, toggleFullScreen: ptr::null_mut::<AnyObject>()];
                })
            })
            .detach();
    }

    fn toggle_simple_fullscreen(&self) {
        let state = self.0.clone();
        let (foreground_executor, closed) = {
            let this = self.0.lock();
            (this.foreground_executor.clone(), this.closed.clone())
        };
        foreground_executor
            .spawn(async move {
                if_window_not_closed(closed, move || {
                    let (native_window, native_view, plan) = {
                        let mut lock = state.lock();
                        (
                            lock.native_window,
                            lock.native_view.as_ptr(),
                            lock.toggle_simple_fullscreen(),
                        )
                    };
                    if let Some(plan) = plan {
                        unsafe { apply_simple_fullscreen_plan(native_window, native_view, plan) };
                    }
                })
            })
            .detach();
    }

    fn is_simple_fullscreen(&self) -> bool {
        self.0.lock().simple_fullscreen_state.is_some()
    }

    fn is_fullscreen(&self) -> bool {
        let this = self.0.lock();
        let window = this.native_window;

        unsafe {
            (&*window.cast::<NSWindow>())
                .styleMask()
                .contains(NSWindowStyleMask::FullScreen)
        }
    }

    fn on_request_frame(&self, callback: Box<dyn FnMut(RequestFrameOptions)>) {
        self.0.as_ref().lock().request_frame_callback = Some(callback);
    }

    fn on_input(&self, callback: Box<dyn FnMut(PlatformInput) -> gpui::DispatchEventResult>) {
        self.0.as_ref().lock().event_callback = Some(callback);
    }

    fn on_active_status_change(&self, callback: Box<dyn FnMut(bool)>) {
        self.0.as_ref().lock().activate_callback = Some(callback);
    }

    fn on_visibility_change(&self, callback: Box<dyn FnMut(WindowVisibility)>) {
        let mut state = self.0.lock();
        state.last_visibility = Some(visibility(&state));
        state.visibility_callback = Some(callback);
    }

    fn on_hover_status_change(&self, _: Box<dyn FnMut(bool)>) {}

    fn on_resize(&self, callback: Box<dyn FnMut(Size<Pixels>, f32)>) {
        self.0.as_ref().lock().resize_callback = Some(callback);
    }

    fn on_display_changed(&self, callback: Box<dyn FnMut()>) {
        self.0.as_ref().lock().display_changed_callback = Some(callback);
    }

    fn on_moved(&self, callback: Box<dyn FnMut()>) {
        self.0.as_ref().lock().moved_callback = Some(callback);
    }

    fn on_should_close(&self, callback: Box<dyn FnMut() -> bool>) {
        self.0.as_ref().lock().should_close_callback = Some(callback);
    }

    fn on_close(&self, callback: Box<dyn FnOnce()>) {
        self.0.as_ref().lock().close_callback = Some(callback);
    }

    fn on_hit_test_window_control(&self, _callback: Box<dyn FnMut() -> Option<WindowControlArea>>) {
    }

    fn on_appearance_changed(&self, callback: Box<dyn FnMut()>) {
        self.0.lock().appearance_changed_callback = Some(callback);
    }

    fn tabbed_windows(&self) -> Option<Vec<SystemWindowTab>> {
        unsafe {
            let windows: *mut AnyObject = msg_send![self.0.lock().native_window, tabbedWindows];
            if windows.is_null() {
                return None;
            }

            let count: NSUInteger = msg_send![windows, count];
            let mut result = Vec::new();
            for i in 0..count {
                let window: *mut AnyObject = msg_send![windows, objectAtIndex:i];
                if msg_send![window, isKindOfClass: WINDOW_CLASS] {
                    let handle = get_window_state(&*window).lock().handle;
                    let title: *mut AnyObject = msg_send![window, title];
                    let title = SharedString::from(title.to_str().to_string());

                    result.push(SystemWindowTab::new(title, handle));
                }
            }

            Some(result)
        }
    }

    fn tab_bar_visible(&self) -> bool {
        unsafe {
            let tab_group: *mut AnyObject = msg_send![self.0.lock().native_window, tabGroup];
            if tab_group.is_null() {
                false
            } else {
                let tab_bar_visible: Bool = msg_send![tab_group, isTabBarVisible];
                tab_bar_visible == Bool::YES
            }
        }
    }

    fn on_move_tab_to_new_window(&self, callback: Box<dyn FnMut()>) {
        self.0.as_ref().lock().move_tab_to_new_window_callback = Some(callback);
    }

    fn on_merge_all_windows(&self, callback: Box<dyn FnMut()>) {
        self.0.as_ref().lock().merge_all_windows_callback = Some(callback);
    }

    fn on_select_next_tab(&self, callback: Box<dyn FnMut()>) {
        self.0.as_ref().lock().select_next_tab_callback = Some(callback);
    }

    fn on_select_previous_tab(&self, callback: Box<dyn FnMut()>) {
        self.0.as_ref().lock().select_previous_tab_callback = Some(callback);
    }

    fn on_toggle_tab_bar(&self, callback: Box<dyn FnMut()>) {
        self.0.as_ref().lock().toggle_tab_bar_callback = Some(callback);
    }

    fn draw(&self, scene: &gpui::Scene) {
        let mut this = self.0.lock();
        this.renderer.draw(scene);
    }

    #[cfg(any(test, feature = "test-support"))]
    fn submit_scene_for_validation(&self, scene: &gpui::Scene) -> anyhow::Result<()> {
        let mut this = self.0.lock();
        let drawable = this
            .renderer
            .layer()
            .ok_or_else(|| anyhow::anyhow!("window has no native layer"))?
            .drawableSize();
        let extent = gpui::size(
            gpui::DevicePixels(drawable.width.ceil() as i32),
            gpui::DevicePixels(drawable.height.ceil() as i32),
        );
        this.renderer.render_scene(scene, extent)
    }

    // GPUI calls this without waking the frame waker when a window only needs
    // a present, so a paused Metal link must resume here too.
    fn schedule_frame(&self) {
        if let Some(metal_frames) = &self.2 {
            metal_frames.wake();
        }
    }

    fn frame_waker(&self) -> Option<Rc<dyn Fn()>> {
        let metal_frames = Rc::downgrade(self.2.as_ref()?);
        Some(Rc::new(move || {
            if let Some(metal_frames) = metal_frames.upgrade() {
                metal_frames.wake();
            }
        }))
    }

    fn sprite_atlas(&self) -> Arc<dyn PlatformAtlas> {
        self.0.lock().renderer.sprite_atlas().clone()
    }

    fn gpu_specs(&self) -> Option<gpui::GpuSpecs> {
        None
    }

    fn update_ime_position(&self, _bounds: Bounds<Pixels>) {
        let executor = self.0.lock().foreground_executor.clone();
        executor
            .spawn(async move {
                unsafe {
                    let input_context: *mut AnyObject =
                        msg_send![class!(NSTextInputContext), currentInputContext];
                    if input_context.is_null() {
                        return;
                    }
                    let _: () = msg_send![input_context, invalidateCharacterCoordinates];
                }
            })
            .detach()
    }

    fn titlebar_double_click(&self, is_resizable: bool, is_minimizable: bool) {
        let this = self.0.lock();
        if this.simple_fullscreen_state.is_some() {
            return;
        }
        let window = this.native_window;
        let closed = this.closed.clone();
        this.foreground_executor
            .spawn(async move {
                if_window_not_closed(closed, || {
                    unsafe {
                        let defaults: *mut AnyObject = msg_send![class!(NSUserDefaults), standardUserDefaults];
                        let domain = ns_string("NSGlobalDomain");
                        let key = ns_string("AppleActionOnDoubleClick");

                        let dict: *mut AnyObject = msg_send![defaults, persistentDomainForName: domain];
                        let action: *mut AnyObject = if !dict.is_null() {
                            msg_send![dict, objectForKey: key]
                        } else {
                            ptr::null_mut::<AnyObject>()
                        };

                        let action_str = if !action.is_null() {
                            CStr::from_ptr(msg_send![action, UTF8String]).to_string_lossy()
                        } else {
                            "".into()
                        };

                        match action_str.as_ref() {
                            "None" => {
                                // "Do Nothing" selected, so do no action
                            }
                            "Minimize" => {
                                if is_minimizable {
                                    let _: () = msg_send![window, miniaturize: ptr::null_mut::<AnyObject>()];
                                }
                            }
                            "Maximize" => {
                                if is_resizable {
                                    let _: () = msg_send![window, zoom: ptr::null_mut::<AnyObject>()];
                                }
                            }
                            "Fill" => {
                                if is_resizable {
                                    // Unlike `zoom:`, AppKit's private Fill action honors the system's
                                    // "Tiled windows have margins" setting.
                                    let responds_to_zoom_fill: Bool =
                                        msg_send![window, respondsToSelector: sel!(_zoomFill:)];
                                    if responds_to_zoom_fill == Bool::YES {
                                        let _: () = msg_send![window, _zoomFill: ptr::null_mut::<AnyObject>()];
                                    } else {
                                        let _: () = msg_send![window, zoom: ptr::null_mut::<AnyObject>()];
                                    }
                                }
                            }
                            _ => {
                                if is_resizable {
                                    let _: () = msg_send![window, zoom: ptr::null_mut::<AnyObject>()];
                                }
                            }
                        }
                    }
                })
            })
            .detach();
    }

    fn start_window_move(&self) {
        let this = self.0.lock();
        if this.simple_fullscreen_state.is_some() {
            return;
        }
        let window = this.native_window;

        unsafe {
            let app: *mut AnyObject = msg_send![class!(NSApplication), sharedApplication];
            let event: *mut AnyObject = msg_send![app, currentEvent];
            let _: () = msg_send![window, performWindowDragWithEvent: event];
        }
    }

    fn can_start_external_drag(&self) -> bool {
        true
    }

    fn start_external_drag(&self, payload: &ExternalDragPayload) -> bool {
        let ExternalDragPayload::Files(paths) = payload;
        if paths.entries().is_empty() {
            log::warn!("start_external_drag declined: no paths");
            return false;
        }

        let (native_view, native_window, last_left_mouse_down_event) = {
            let state = self.0.lock();
            (
                state.native_view.as_ptr(),
                state.native_window,
                state.last_left_mouse_down_event.clone(),
            )
        };

        let Some(last_left_mouse_down_event) = last_left_mouse_down_event else {
            log::warn!("start_external_drag declined: no retained left mouse down event");
            return false;
        };

        // SAFETY: This method runs on the AppKit/foreground path during drag initiation. The
        // native view/window are retained by MacWindowState, copied out under a short lock above,
        // and all pointers passed to Objective-C remain valid for their respective calls.
        unsafe {
            let event: *mut AnyObject = Retained::as_ptr(&last_left_mouse_down_event)
                .cast_mut()
                .cast();
            let dragging_items: *mut AnyObject = msg_send![class!(NSMutableArray), array];
            // AppKit keeps this frame's distance from the event's location as the drag image's
            // offset from the cursor, so it has to stay anchored on `event`.
            let location: NSPoint = msg_send![event, locationInWindow];
            let frame = NSRect::new(
                NSPoint::new(location.x - 16., location.y - 16.),
                NSSize::new(32., 32.),
            );

            for (path, is_directory) in paths.entries() {
                // Preserve non-UTF-8 paths
                let Ok(path_bytes) = CString::new(path.as_os_str().as_bytes()) else {
                    log::warn!("start_external_drag skipped path containing an interior nul byte");
                    continue;
                };

                let path_bytes = NonNull::new_unchecked(path_bytes.as_ptr().cast_mut());
                let url = NSURL::fileURLWithFileSystemRepresentation_isDirectory_relativeToURL(
                    path_bytes,
                    *is_directory,
                    None,
                );

                let pasteboard_writer = ProtocolObject::<dyn NSPasteboardWriting>::from_ref(&*url);
                let item = NSDraggingItem::initWithPasteboardWriter(
                    NSDraggingItem::alloc(),
                    pasteboard_writer,
                );

                // Resolve drag images lazily via `imageComponentsProvider` (Apple's
                // recommendation for large item counts), and by file *type* rather than
                // `iconForFile:`, which can synchronously hit LaunchServices, network
                // mounts, or iCloud for every selected path and beachball drag startup.
                let is_directory = *is_directory;
                let extension = path
                    .extension()
                    .and_then(|extension| extension.to_str())
                    .map(String::from);
                let provider = RcBlock::new(move || {
                    let component = NSDraggingImageComponent::draggingImageComponentWithKey(
                        NSDraggingImageComponentIconKey,
                    );
                    let workspace = NSWorkspace::sharedWorkspace();
                    let content_type = if is_directory {
                        UTTypeFolder.retain()
                    } else {
                        extension
                            .as_ref()
                            .and_then(|extension| {
                                UTType::typeWithFilenameExtension(&NSString::from_str(extension))
                            })
                            .unwrap_or_else(|| UTTypeData.retain())
                    };
                    let icon = workspace.iconForContentType(&content_type);
                    component.setContents(Some(&icon));
                    // Component frames are relative to the item's dragging frame.
                    component.setFrame(NSRect::new(NSPoint::new(0., 0.), NSSize::new(32., 32.)));
                    let components = NSArray::from_slice(&[&*component]);
                    NonNull::new_unchecked(Retained::autorelease_return(components))
                });
                item.setDraggingFrame(frame);
                item.setImageComponentsProvider(Some(&provider));
                let _: () = msg_send![dragging_items, addObject: Retained::as_ptr(&item)];
            }

            let count: NSUInteger = msg_send![dragging_items, count];
            if count == 0 {
                log::warn!("start_external_drag declined: no dragging items");
                return false;
            }

            let session: *mut AnyObject = msg_send![
                native_view,
                beginDraggingSessionWithItems: dragging_items,
                event: event,
                source: native_window
            ];

            let started = !session.is_null();
            if started {
                self.0.lock().synthetic_drag_counter += 1;
            }
            log::debug!(
                "start_external_drag completed: started={}, item_count={}",
                started,
                count
            );
            started
        }
    }

    fn play_system_bell(&self) {
        NSBeep()
    }

    #[cfg(any(test, feature = "test-support"))]
    fn render_to_linear_p3(&self, scene: &gpui::Scene) -> Result<gpui::LinearP3Image> {
        self.0.lock().renderer.render_to_linear_p3(scene)
    }

    #[cfg(any(test, feature = "test-support"))]
    fn render_to_image(&self, scene: &gpui::Scene) -> Result<RgbaImage> {
        let mut this = self.0.lock();
        this.renderer.render_to_image(scene)
    }

    fn a11y_init(&self, callbacks: gpui::A11yCallbacks) {
        let mut lock = self.0.lock();

        let activation_handler = A11yActivationHandler {
            callback: callbacks.activation,
        };
        let action_handler = A11yActionHandler(callbacks.action);

        let adapter = unsafe {
            accesskit_macos::SubclassingAdapter::for_window(
                lock.native_window as *mut c_void,
                activation_handler,
                action_handler,
            )
        };

        lock.accesskit_adapter = Some(adapter);
    }

    fn a11y_tree_update(&self, tree_update: accesskit::TreeUpdate) {
        let events = {
            let mut lock = self.0.lock();
            lock.accesskit_adapter
                .as_mut()
                .and_then(|adapter| adapter.update_if_active(|| tree_update))
        };
        if let Some(events) = events {
            events.raise();
        }
    }

    fn a11y_update_window_bounds(&self) {
        // macOS handles window bounds tracking automatically via NSAccessibility.
    }
}

struct A11yActivationHandler {
    callback: Box<dyn Fn() -> Option<accesskit::TreeUpdate> + Send + 'static>,
}

impl accesskit::ActivationHandler for A11yActivationHandler {
    fn request_initial_tree(&mut self) -> Option<accesskit::TreeUpdate> {
        (self.callback)()
    }
}

struct A11yActionHandler(Box<dyn Fn(accesskit::ActionRequest) + Send + 'static>);

impl accesskit::ActionHandler for A11yActionHandler {
    fn do_action(&mut self, request: accesskit::ActionRequest) {
        (self.0)(request);
    }
}

impl rwh::HasWindowHandle for MacWindow {
    fn window_handle(&self) -> Result<rwh::WindowHandle<'_>, rwh::HandleError> {
        // SAFETY: The AppKitWindowHandle is a wrapper around a pointer to an NSView
        unsafe {
            Ok(rwh::WindowHandle::borrow_raw(rwh::RawWindowHandle::AppKit(
                rwh::AppKitWindowHandle::new(self.0.lock().native_view.cast()),
            )))
        }
    }
}

impl rwh::HasDisplayHandle for MacWindow {
    fn display_handle(&self) -> Result<rwh::DisplayHandle<'_>, rwh::HandleError> {
        Ok(rwh::DisplayHandle::appkit())
    }
}

fn get_scale_factor(native_window: *mut AnyObject) -> f32 {
    let factor = unsafe {
        let screen: *mut AnyObject = msg_send![native_window, screen];
        if screen.is_null() {
            return 2.0;
        }
        (&*screen.cast::<NSScreen>()).backingScaleFactor() as f32
    };

    // We are not certain what triggers this, but it seems that sometimes
    // this method would return 0 (https://github.com/zed-industries/zed/issues/6412)
    // It seems most likely that this would happen if the window has no screen
    // (if it is off-screen), though we'd expect to see viewDidChangeBackingProperties before
    // it was rendered for real.
    // Regardless, attempt to avoid the issue here.
    if factor == 0.0 { 2. } else { factor }
}

/// Returns whether `window` is one of GPUI's managed windows.
unsafe fn is_gpui_window(window: *mut AnyObject) -> bool {
    unsafe {
        msg_send![window, isKindOfClass: WINDOW_CLASS]
            || msg_send![window, isKindOfClass: PANEL_CLASS]
    }
}

unsafe fn get_window_state(object: &AnyObject) -> Rc<Mutex<MacWindowState>> {
    unsafe {
        let raw = *object
            .class()
            .instance_variable(WINDOW_STATE_IVAR)
            .expect("GPUI window state ivar")
            .load::<*mut c_void>(object);
        let rc1 = Rc::from_raw(raw as *mut Mutex<MacWindowState>);
        let rc2 = rc1.clone();
        mem::forget(rc1);
        rc2
    }
}

unsafe fn drop_window_state(object: &AnyObject) {
    unsafe {
        let raw = *object
            .class()
            .instance_variable(WINDOW_STATE_IVAR)
            .expect("GPUI window state ivar")
            .load::<*mut c_void>(object);
        Rc::from_raw(raw as *mut Mutex<MacWindowState>);
    }
}

extern "C" fn yes(_: &AnyObject, _: Sel) -> Bool {
    Bool::YES
}

extern "C" fn dealloc_window(this: &AnyObject, _: Sel) {
    unsafe {
        drop_window_state(this);
        let _: () = msg_send![super(this, class!(NSWindow)), dealloc];
    }
}

extern "C" fn dealloc_view(this: &AnyObject, _: Sel) {
    unsafe {
        drop_window_state(this);
        let _: () = msg_send![super(this, class!(NSView)), dealloc];
    }
}

fn add_mouse_tracking_area(native_view: &NSView) {
    let options = NSTrackingAreaOptions::MouseEnteredAndExited
        | NSTrackingAreaOptions::MouseMoved
        // Track even when another application is active so visible
        // windows can respond to hover without being focused.
        | NSTrackingAreaOptions::ActiveAlways
        | NSTrackingAreaOptions::InVisibleRect;

    // SAFETY: NSView provides the tracking-event callbacks, and the owner is
    // the same view that retains the tracking area. No user info is supplied.
    let tracking_area = unsafe {
        NSTrackingArea::initWithRect_options_owner_userInfo(
            NSTrackingArea::alloc(),
            NSRect::ZERO,
            options,
            Some(native_view),
            None,
        )
    };
    native_view.addTrackingArea(&tracking_area);
}

extern "C" fn reset_cursor_rects(this: &AnyObject, _: Sel) {
    // SAFETY: AppKit invokes cursor-rect updates on the main thread for GPUIView instances,
    // whose WINDOW_STATE_IVAR is initialized when the view is created. The cursor registered
    // below is a valid NSCursor.
    unsafe {
        let _: () = msg_send![super(this, class!(NSView)), resetCursorRects];

        let window_state = get_window_state(this);
        let cursor_style = window_state.lock().cursor_style;

        let cursor: *mut AnyObject = match cursor_style {
            CursorStyle::Arrow => msg_send![class!(NSCursor), arrowCursor],
            CursorStyle::IBeam => msg_send![class!(NSCursor), IBeamCursor],
            CursorStyle::Crosshair => msg_send![class!(NSCursor), crosshairCursor],
            CursorStyle::ClosedHand => msg_send![class!(NSCursor), closedHandCursor],
            CursorStyle::OpenHand => msg_send![class!(NSCursor), openHandCursor],
            CursorStyle::PointingHand => msg_send![class!(NSCursor), pointingHandCursor],
            CursorStyle::ResizeLeftRight => msg_send![class!(NSCursor), resizeLeftRightCursor],
            CursorStyle::ResizeUpDown => msg_send![class!(NSCursor), resizeUpDownCursor],
            CursorStyle::ResizeLeft => msg_send![class!(NSCursor), resizeLeftCursor],
            CursorStyle::ResizeRight => msg_send![class!(NSCursor), resizeRightCursor],
            CursorStyle::ResizeColumn => msg_send![class!(NSCursor), resizeLeftRightCursor],
            CursorStyle::ResizeRow => msg_send![class!(NSCursor), resizeUpDownCursor],
            CursorStyle::ResizeUp => msg_send![class!(NSCursor), resizeUpCursor],
            CursorStyle::ResizeDown => msg_send![class!(NSCursor), resizeDownCursor],

            // Undocumented, private class methods:
            // https://stackoverflow.com/questions/27242353/cocoa-predefined-resize-mouse-cursor
            CursorStyle::ResizeUpLeftDownRight => {
                msg_send![class!(NSCursor), _windowResizeNorthWestSouthEastCursor]
            }
            CursorStyle::ResizeUpRightDownLeft => {
                msg_send![class!(NSCursor), _windowResizeNorthEastSouthWestCursor]
            }

            CursorStyle::IBeamCursorForVerticalLayout => {
                msg_send![class!(NSCursor), IBeamCursorForVerticalLayout]
            }
            CursorStyle::OperationNotAllowed => {
                msg_send![class!(NSCursor), operationNotAllowedCursor]
            }
            CursorStyle::DragLink => msg_send![class!(NSCursor), dragLinkCursor],
            CursorStyle::DragCopy => msg_send![class!(NSCursor), dragCopyCursor],
            CursorStyle::ContextualMenu => msg_send![class!(NSCursor), contextualMenuCursor],
        };

        let bounds: NSRect = msg_send![this, bounds];
        let _: () = msg_send![this, addCursorRect: bounds, cursor: cursor];
    }
}

extern "C" fn handle_key_equivalent(
    this: &AnyObject,
    _: Sel,
    native_event: *mut AnyObject,
) -> Bool {
    handle_key_event(this, native_event, true)
}

extern "C" fn handle_key_down(this: &AnyObject, _: Sel, native_event: *mut AnyObject) {
    handle_key_event(this, native_event, false);
}

extern "C" fn handle_key_up(this: &AnyObject, _: Sel, native_event: *mut AnyObject) {
    handle_key_event(this, native_event, false);
}

// Things to test if you're modifying this method:
//  U.S. layout:
//   - The IME consumes characters like 'j' and 'k', which makes paging through `less` in
//     the terminal behave incorrectly by default. This behavior should be patched by our
//     IME integration
//   - `alt-t` should open the tasks menu
//   - In vim mode, this keybinding should work:
//     ```
//        {
//          "context": "Editor && vim_mode == insert",
//          "bindings": {"j j": "vim::NormalBefore"}
//        }
//     ```
//     and typing 'j k' in insert mode with this keybinding should insert the two characters
//  Brazilian layout:
//   - `" space` should create an unmarked quote
//   - `" backspace` should delete the marked quote
//   - `" "`should create an unmarked quote and a second marked quote
//   - `" up` should insert a quote, unmark it, and move up one line
//   - `" cmd-down` should insert a quote, unmark it, and move to the end of the file
//   - `cmd-ctrl-space` and clicking on an emoji should type it
//  Czech (QWERTY) layout:
//   - in vim mode `option-4`  should go to end of line (same as $)
//  Japanese (Romaji) layout:
//   - type `a i left down up enter enter` should create an unmarked text "愛"
//   - In vim mode with `jj` bound to `vim::NormalBefore` in insert mode, typing 'j i' with
//     Japanese IME should produce "じ" (ji), not "jい"

/// Returns true if the current keyboard input source is a composition-based IME
/// (e.g. Japanese Hiragana, Korean, Chinese Pinyin) that produces non-ASCII output.
///
/// This checks two properties:
/// 1. The source type is `kTISTypeKeyboardInputMode` (an IME input mode, not a plain
///    keyboard layout). This excludes non-ASCII layouts like Armenian and Ukrainian
///    that map keys directly without composition.
/// 2. The source is not ASCII-capable, which excludes modes like Japanese Romaji that
///    produce ASCII characters and should allow multi-stroke keybindings like `jj`.
unsafe fn is_ime_input_source_active() -> bool {
    unsafe {
        let source = TISCopyCurrentKeyboardInputSource();
        if source.is_null() {
            return false;
        }

        let source_type =
            TISGetInputSourceProperty(source, kTISPropertyInputSourceType as *const c_void);
        let is_input_mode = !source_type.is_null()
            && CFEqual(
                source_type as CFTypeRef,
                kTISTypeKeyboardInputMode as CFTypeRef,
            ) != 0;

        let is_ascii = TISGetInputSourceProperty(
            source,
            kTISPropertyInputSourceIsASCIICapable as *const c_void,
        );
        let is_ascii_capable = !is_ascii.is_null() && CFBooleanGetValue(is_ascii as CFBooleanRef);

        CFRelease(source as CFTypeRef);

        is_input_mode && !is_ascii_capable
    }
}

extern "C" fn handle_key_event(
    this: &AnyObject,
    native_event: *mut AnyObject,
    key_equivalent: bool,
) -> Bool {
    let window_state = unsafe { get_window_state(this) };
    let mut lock = window_state.as_ref().lock();

    let window_height = lock.content_size().height;
    let event = unsafe { platform_input_from_native(native_event, Some(window_height)) };

    let Some(event) = event else {
        return Bool::NO;
    };

    let run_callback = |event: PlatformInput| -> Bool {
        let mut callback = window_state.as_ref().lock().event_callback.take();
        let handled: Bool = if let Some(callback) = callback.as_mut() {
            (!callback(event).propagate).to_objc()
        } else {
            Bool::NO
        };
        window_state.as_ref().lock().event_callback = callback;
        handled
    };

    match event {
        PlatformInput::KeyDown(key_down_event) => {
            // For certain keystrokes, macOS will first dispatch a "key equivalent" event.
            // If that event isn't handled, it will then dispatch a "key down" event. GPUI
            // makes no distinction between these two types of events, so we need to ignore
            // the "key down" event if we've already just processed its "key equivalent" version.
            if key_equivalent {
                lock.last_key_equivalent = Some(key_down_event.clone());
            } else if lock.last_key_equivalent.take().as_ref() == Some(&key_down_event) {
                return Bool::NO;
            }

            drop(lock);

            let is_composing =
                with_input_handler(this, |input_handler| input_handler.marked_text_range())
                    .flatten()
                    .is_some();

            // If we're composing, send the key to the input handler first;
            // otherwise we only send to the input handler if we don't have a matching binding.
            // The input handler may call `do_command_by_selector` if it doesn't know how to handle
            // a key. If it does so, it will return YES so we won't send the key twice.
            // We also do this for non-printing keys (like arrow keys and escape) as the IME menu
            // may need them even if there is no marked text;
            // however we skip keys with control or the input handler adds control-characters to the buffer.
            // and keys with function, as the input handler swallows them.
            // and keys with platform (Cmd), so that Cmd+key events (e.g. Cmd+`) are not
            // consumed by the IME on non-QWERTY / dead-key layouts.
            // We also send printable keys to the IME first when an IME input source (e.g. Japanese,
            // Korean, Chinese) is active and the input handler accepts text input. This prevents
            // multi-stroke keybindings like `jj` from intercepting keys that the IME should compose
            // (e.g. typing 'ji' should produce 'じ', not 'jい'). If the IME doesn't handle the key,
            // it calls `doCommandBySelector:` which routes it back to keybinding matching.
            let is_ime_printable_key = !is_composing
                && key_down_event
                    .keystroke
                    .key_char
                    .as_ref()
                    .is_some_and(|key_char| key_char.chars().all(|c| !c.is_control()))
                && !key_down_event.keystroke.modifiers.control
                && !key_down_event.keystroke.modifiers.function
                && !key_down_event.keystroke.modifiers.platform
                && unsafe { is_ime_input_source_active() }
                && with_input_handler(this, |input_handler| {
                    input_handler.query_prefers_ime_for_printable_keys()
                })
                .unwrap_or(false);

            if is_composing
                || is_ime_printable_key
                || (key_down_event.keystroke.key_char.is_none()
                    && !key_down_event.keystroke.modifiers.control
                    && !key_down_event.keystroke.modifiers.function
                    && !key_down_event.keystroke.modifiers.platform)
            {
                {
                    let mut lock = window_state.as_ref().lock();
                    lock.keystroke_for_do_command = Some(key_down_event.keystroke.clone());
                    lock.do_command_handled.take();
                    drop(lock);
                }

                let handled: Bool = unsafe {
                    let input_context: *mut AnyObject = msg_send![this, inputContext];
                    if input_context.is_null() {
                        Bool::NO
                    } else {
                        msg_send![input_context, handleEvent: native_event]
                    }
                };
                window_state.as_ref().lock().keystroke_for_do_command.take();
                if let Some(handled) = window_state.as_ref().lock().do_command_handled.take() {
                    return handled.to_objc();
                } else if handled == Bool::YES {
                    return Bool::YES;
                }

                let handled = run_callback(PlatformInput::KeyDown(key_down_event));
                return handled;
            }

            let handled = run_callback(PlatformInput::KeyDown(key_down_event.clone()));
            if handled == Bool::YES {
                return Bool::YES;
            }

            if key_down_event.is_held
                && let Some(key_char) = key_down_event.keystroke.key_char.as_ref()
            {
                let handled = with_input_handler(this, |input_handler| {
                    if !input_handler.apple_press_and_hold_enabled() {
                        input_handler.replace_text_in_range(None, key_char);
                        return Bool::YES;
                    }
                    Bool::NO
                });
                if handled == Some(Bool::YES) {
                    return Bool::YES;
                }
            }

            // Don't send key equivalents to the input handler if there are key modifiers other
            // than Function key, or macOS shortcuts like cmd-` will stop working.
            if key_equivalent && key_down_event.keystroke.modifiers != Modifiers::function() {
                return Bool::NO;
            }

            unsafe {
                let input_context: *mut AnyObject = msg_send![this, inputContext];
                if input_context.is_null() {
                    Bool::NO
                } else {
                    msg_send![input_context, handleEvent: native_event]
                }
            }
        }

        PlatformInput::KeyUp(_) => {
            drop(lock);
            run_callback(event)
        }

        _ => Bool::NO,
    }
}

extern "C" fn handle_view_event(this: &AnyObject, _: Sel, native_event: *mut AnyObject) {
    let window_state = unsafe { get_window_state(this) };
    let weak_window_state = Rc::downgrade(&window_state);
    let mut lock = window_state.as_ref().lock();
    let window_height = lock.content_size().height;
    let native_event_type: NSEventType = unsafe { msg_send![native_event, type] };
    match native_event_type {
        NSEventType::LeftMouseDown => {
            // AppKit owns `native_event` for the callback; retain it so the drag session can still
            // be started later, once the pointer leaves the window.
            lock.last_left_mouse_down_event = unsafe { Retained::retain(native_event) };
        }
        NSEventType::LeftMouseUp => {
            lock.last_left_mouse_down_event = None;
        }
        _ => {}
    }
    let event = unsafe { platform_input_from_native(native_event, Some(window_height)) };

    if let Some(mut event) = event {
        // AppKit unhides the cursor on the next mouse movement; mirror that here.
        if matches!(
            event,
            PlatformInput::MouseMove(_)
                | PlatformInput::MouseDown(_)
                | PlatformInput::MouseUp(_)
                | PlatformInput::MousePressure(_)
                | PlatformInput::MouseExited(_)
                | PlatformInput::Scroll(_)
                | PlatformInput::Pinch(_)
        ) {
            lock.cursor_visible.store(true, Ordering::Relaxed);
        }

        match &mut event {
            PlatformInput::MouseDown(
                event @ MouseDownEvent {
                    button: MouseButton::Left,
                    modifiers: Modifiers { control: true, .. },
                    ..
                },
            ) => {
                // On mac, a ctrl-left click should be handled as a right click.
                *event = MouseDownEvent {
                    button: MouseButton::Right,
                    modifiers: Modifiers {
                        control: false,
                        ..event.modifiers
                    },
                    click_count: 1,
                    ..*event
                };
            }

            // Handles focusing click.
            PlatformInput::MouseDown(
                event @ MouseDownEvent {
                    button: MouseButton::Left,
                    ..
                },
            ) if (lock.first_mouse) => {
                *event = MouseDownEvent {
                    first_mouse: true,
                    ..*event
                };
                lock.first_mouse = false;
            }

            // Because we map a ctrl-left_down to a right_down -> right_up let's ignore
            // the ctrl-left_up to avoid having a mismatch in button down/up events if the
            // user is still holding ctrl when releasing the left mouse button
            PlatformInput::MouseUp(
                event @ MouseUpEvent {
                    button: MouseButton::Left,
                    modifiers: Modifiers { control: true, .. },
                    ..
                },
            ) => {
                *event = MouseUpEvent {
                    button: MouseButton::Right,
                    modifiers: Modifiers {
                        control: false,
                        ..event.modifiers
                    },
                    click_count: 1,
                    ..*event
                };
            }

            _ => {}
        };

        match &event {
            PlatformInput::MouseDown(_) => {
                drop(lock);
                unsafe {
                    let input_context: *mut AnyObject = msg_send![this, inputContext];
                    if !input_context.is_null() {
                        let _: Bool = msg_send![input_context, handleEvent: native_event];
                    }
                }
                lock = window_state.as_ref().lock();
            }
            PlatformInput::MouseMove(
                event @ MouseMoveEvent {
                    pressed_button: Some(_),
                    ..
                },
            ) => {
                // Synthetic drag is used for selecting long buffer contents while buffer is being scrolled.
                // External file drag and drop is able to emit its own synthetic mouse events which will conflict
                // with these ones.
                if !lock.external_files_dragged {
                    lock.synthetic_drag_counter += 1;
                    let executor = lock.foreground_executor.clone();
                    executor
                        .spawn(synthetic_drag(
                            weak_window_state,
                            lock.synthetic_drag_counter,
                            event.clone(),
                            lock.background_executor.clone(),
                        ))
                        .detach();
                }
            }

            PlatformInput::MouseUp(MouseUpEvent { .. }) => {
                lock.synthetic_drag_counter += 1;
            }

            PlatformInput::ModifiersChanged(ModifiersChangedEvent {
                modifiers,
                capslock,
            }) => {
                // Only raise modifiers changed event when they have actually changed
                if let Some(PlatformInput::ModifiersChanged(ModifiersChangedEvent {
                    modifiers: prev_modifiers,
                    capslock: prev_capslock,
                })) = &lock.previous_modifiers_changed_event
                    && prev_modifiers == modifiers
                    && prev_capslock == capslock
                {
                    return;
                }

                lock.previous_modifiers_changed_event = Some(event.clone());
            }

            _ => {}
        }

        if let Some(mut callback) = lock.event_callback.take() {
            drop(lock);
            callback(event);
            window_state.lock().event_callback = Some(callback);
        }
    }
}

fn visibility(state: &MacWindowState) -> WindowVisibility {
    let is_visible = state
        .native_window()
        .occlusionState()
        .contains(NSWindowOcclusionState::Visible);
    if is_visible {
        WindowVisibility::Visible
    } else {
        WindowVisibility::Hidden
    }
}

fn report_visibility(window_state: &Rc<Mutex<MacWindowState>>) {
    let state = window_state.lock();
    if state.last_visibility.is_none() {
        return;
    }
    let executor = state.foreground_executor.clone();
    drop(state);

    // AppKit can notify while GPUI is updating a window. Deliver observers
    // after that update completes, as activation notifications do. The state
    // is read at delivery rather than captured here so a burst of
    // notifications collapses to the final value.
    executor
        .spawn({
            let window_state = window_state.clone();
            async move {
                let mut state = window_state.lock();
                let visibility = visibility(&state);
                if state.last_visibility == Some(visibility) {
                    return;
                }
                state.last_visibility = Some(visibility);
                if let Some(mut callback) = state.visibility_callback.take() {
                    drop(state);
                    callback(visibility);
                    window_state.lock().visibility_callback = Some(callback);
                }
            }
        })
        .detach();
}

extern "C" fn window_did_change_occlusion_state(this: &AnyObject, _: Sel, _: *mut AnyObject) {
    let window_state = unsafe { get_window_state(this) };
    let mut lock = window_state.lock();
    if lock
        .native_window()
        .occlusionState()
        .contains(NSWindowOcclusionState::Visible)
    {
        lock.move_traffic_light();
        lock.start_display_link(&window_state);
    } else {
        lock.stop_display_link();
    }
    drop(lock);
    // The only visibility source: AppKit posts this for covering, minimizing,
    // hiding, Space switches, and display sleep alike.
    report_visibility(&window_state);
}

extern "C" fn window_did_resize(this: &AnyObject, _: Sel, _: *mut AnyObject) {
    let window_state = unsafe { get_window_state(this) };
    window_state.as_ref().lock().move_traffic_light();
}

extern "C" fn window_will_enter_fullscreen(this: &AnyObject, _: Sel, _: *mut AnyObject) {
    let window_state = unsafe { get_window_state(this) };
    let mut lock = window_state.as_ref().lock();
    lock.fullscreen_restore_bounds = lock.bounds();
    lock.is_exiting_fullscreen = false;
    lock.pre_fullscreen_traffic_light_frames = lock.traffic_light_frames;
    lock.restore_traffic_light();

    let min_version = NSOperatingSystemVersion {
        majorVersion: 15,
        minorVersion: 3,
        patchVersion: 0,
    };

    if is_macos_version_at_least(min_version) {
        unsafe {
            let _: () = msg_send![lock.native_window, setTitlebarAppearsTransparent: Bool::NO];
        }
    }
}

extern "C" fn window_will_exit_fullscreen(this: &AnyObject, _: Sel, _: *mut AnyObject) {
    let window_state = unsafe { get_window_state(this) };
    let mut lock = window_state.as_ref().lock();
    lock.is_exiting_fullscreen = true;

    let min_version = NSOperatingSystemVersion {
        majorVersion: 15,
        minorVersion: 3,
        patchVersion: 0,
    };

    if is_macos_version_at_least(min_version) && lock.transparent_titlebar {
        unsafe {
            let _: () = msg_send![lock.native_window, setTitlebarAppearsTransparent: Bool::YES];
        }
    }

    lock.move_traffic_light();
}

extern "C" fn window_did_fail_to_exit_fullscreen(this: &AnyObject, _: Sel, _: *mut AnyObject) {
    let window_state = unsafe { get_window_state(this) };
    let mut lock = window_state.as_ref().lock();
    lock.is_exiting_fullscreen = false;
    lock.restore_traffic_light();
}

extern "C" fn window_did_exit_fullscreen(this: &AnyObject, _: Sel, _: *mut AnyObject) {
    // SAFETY: This method is registered only on GPUI window classes, which initialize
    // WINDOW_STATE_IVAR with an Rc<Mutex<MacWindowState>> during window creation.
    let window_state = unsafe { get_window_state(this) };
    let mut lock = window_state.as_ref().lock();
    lock.is_exiting_fullscreen = false;
    // Moving the buttons during the transition captures their fullscreen frames.
    // Keep using the native windowed frames when restoring them on the next entry.
    lock.traffic_light_frames = lock.pre_fullscreen_traffic_light_frames.take();
    lock.move_traffic_light();
}

pub(crate) fn is_macos_version_at_least(version: NSOperatingSystemVersion) -> bool {
    NSProcessInfo::processInfo().isOperatingSystemAtLeastVersion(version)
}

fn ns_error_description(error: *mut AnyObject) -> String {
    if error.is_null() {
        return "unknown error".to_owned();
    }
    unsafe {
        let description: *mut AnyObject = msg_send![error, localizedDescription];
        description.to_str().to_owned()
    }
}

extern "C" fn window_did_move(this: &AnyObject, _: Sel, _: *mut AnyObject) {
    let window_state = unsafe { get_window_state(this) };
    let mut lock = window_state.as_ref().lock();
    if let Some(mut callback) = lock.moved_callback.take() {
        drop(lock);
        callback();
        window_state.lock().moved_callback = Some(callback);
    }
}

// Update the window scale factor and drawable size, and call the resize callback if any.
fn update_window_scale_factor(window_state: &Rc<Mutex<MacWindowState>>) {
    let mut lock = window_state.as_ref().lock();
    let scale_factor = lock.scale_factor();
    let size = lock.content_size();
    let drawable_size = size.to_device_pixels(scale_factor);
    let layer = lock.renderer.layer_ptr().cast::<AnyObject>();
    if !layer.is_null() {
        unsafe {
            let _: () = msg_send![
                layer,
                setContentsScale: scale_factor as f64
            ];
        }
    }

    lock.renderer.update_drawable_size(drawable_size);

    if let Some(mut callback) = lock.resize_callback.take() {
        let content_size = lock.content_size();
        let scale_factor = lock.scale_factor();
        drop(lock);
        callback(content_size, scale_factor);
        window_state.as_ref().lock().resize_callback = Some(callback);
    };
}

extern "C" fn window_did_change_color_profile(this: &AnyObject, _: Sel, _: *mut AnyObject) {
    let state = unsafe { get_window_state(this) };
    let mut state = state.lock();
    state.color_profile_dirty = true;
    unsafe {
        (&*state.native_view.as_ptr().cast::<NSView>()).setNeedsDisplay(true);
    }
}

extern "C" fn window_did_change_screen(this: &AnyObject, _: Sel, _: *mut AnyObject) {
    let window_state = unsafe { get_window_state(this) };
    let mut lock = window_state.as_ref().lock();
    lock.start_display_link(&window_state);
    lock.color_profile_dirty = true;
    unsafe {
        (&*lock.native_view.as_ptr().cast::<NSView>()).setNeedsDisplay(true);
    }
    drop(lock);
    update_window_scale_factor(&window_state);
    report_display_change(&window_state);
}

fn report_display_change(window_state: &Rc<Mutex<MacWindowState>>) {
    let executor = window_state.lock().foreground_executor.clone();
    // AppKit can post screen changes while GPUI is updating a window, e.g.
    // from `setFrame:`, so deliver after that update completes.
    executor
        .spawn({
            let window_state = window_state.clone();
            async move {
                let callback = window_state.lock().display_changed_callback.take();
                if let Some(mut callback) = callback {
                    callback();
                    window_state.lock().display_changed_callback = Some(callback);
                }
            }
        })
        .detach();
}

extern "C" fn window_did_change_key_status(this: &AnyObject, selector: Sel, _: *mut AnyObject) {
    let signal_at = PlatformFrameSignal::capture(scheduler::Instant::now);
    let window_state = unsafe { get_window_state(this) };
    let lock = window_state.lock();
    let is_active = lock.native_window().isKeyWindow();

    // AppKit also unhides the cursor on activation changes, so mirror that here.
    lock.cursor_visible.store(true, Ordering::Relaxed);

    // When opening a pop-up while the application isn't active, Cocoa sends a spurious
    // `windowDidBecomeKey` message to the previous key window even though that window
    // isn't actually key. This causes a bug if the application is later activated while
    // the pop-up is still open, making it impossible to activate the previous key window
    // even if the pop-up gets closed. The only way to activate it again is to de-activate
    // the app and re-activate it, which is a pretty bad UX.
    // The following code detects the spurious event and invokes `resignKeyWindow`:
    // in theory, we're not supposed to invoke this method manually but it balances out
    // the spurious `becomeKeyWindow` event and helps us work around that bug.
    if selector == sel!(windowDidBecomeKey:) && !is_active {
        let native_window = lock.native_window;
        drop(lock);
        unsafe {
            let _: () = msg_send![native_window, resignKeyWindow];
        }
        return;
    }

    let executor = lock.foreground_executor.clone();
    drop(lock);

    let a11y_events = {
        let mut lock = window_state.lock();
        lock.accesskit_adapter
            .as_mut()
            .and_then(|adapter| adapter.update_view_focus_state(is_active))
    };
    if let Some(events) = a11y_events {
        events.raise();
    }

    // When a window becomes active, trigger an immediate synchronous frame request to prevent
    // tab flicker when switching between windows in native tabs mode.
    //
    // This is only done on subsequent activations (not the first) to ensure the initial focus
    // path is properly established. Without this guard, the focus state would remain unset until
    // the first mouse click, causing keybindings to be non-functional.
    if selector == sel!(windowDidBecomeKey:) && is_active {
        let window_state = unsafe { get_window_state(this) };
        let mut lock = window_state.lock();

        if lock.activated_least_once {
            if let Some(mut callback) = lock.request_frame_callback.take() {
                lock.renderer.set_presents_with_transaction(true);
                lock.stop_display_link();
                drop(lock);
                callback(RequestFrameOptions {
                    signal_at,
                    signal_source: FrameRequestSource::NativeCallback,
                    ..Default::default()
                });

                let mut lock = window_state.lock();
                lock.request_frame_callback = Some(callback);
                lock.renderer.set_presents_with_transaction(false);
                lock.start_display_link(&window_state);
            }
        } else {
            lock.activated_least_once = true;
        }
    }

    executor
        .spawn(async move {
            let mut lock = window_state.as_ref().lock();
            if is_active {
                lock.move_traffic_light();
            }

            if let Some(mut callback) = lock.activate_callback.take() {
                drop(lock);
                callback(is_active);
                window_state.lock().activate_callback = Some(callback);
            };
        })
        .detach();
}

extern "C" fn window_should_close(this: &AnyObject, _: Sel, _: *mut AnyObject) -> Bool {
    let window_state = unsafe { get_window_state(this) };
    let mut lock = window_state.as_ref().lock();
    if let Some(mut callback) = lock.should_close_callback.take() {
        drop(lock);
        let should_close = callback();
        window_state.lock().should_close_callback = Some(callback);
        should_close.to_objc()
    } else {
        Bool::YES
    }
}

extern "C" fn close_window(this: &AnyObject, _: Sel) {
    unsafe {
        let (close_callback, simple_fullscreen_state) = {
            let window_state = get_window_state(this);
            let mut lock = window_state.as_ref().lock();
            lock.closed.store(true, Ordering::Release);
            (
                lock.close_callback.take(),
                lock.simple_fullscreen_state.take(),
            )
        };

        if simple_fullscreen_state.is_some() {
            pop_simple_fullscreen_presentation_options();
        }

        if let Some(callback) = close_callback {
            callback();
        }

        let _: () = msg_send![super(this, class!(NSWindow)), close];
    }
}

extern "C" fn make_backing_layer(this: &AnyObject, _: Sel) -> *mut AnyObject {
    let window_state = unsafe { get_window_state(this) };
    let window_state = window_state.as_ref().lock();
    window_state.renderer.layer_ptr() as *mut AnyObject
}

extern "C" fn view_did_change_backing_properties(this: &AnyObject, _: Sel) {
    let window_state = unsafe { get_window_state(this) };
    update_window_scale_factor(&window_state);
}

extern "C" fn set_frame_size(this: &AnyObject, _: Sel, size: NSSize) {
    fn convert(value: NSSize) -> Size<Pixels> {
        Size {
            width: px(value.width as f32),
            height: px(value.height as f32),
        }
    }

    let window_state = unsafe { get_window_state(this) };
    let mut lock = window_state.as_ref().lock();

    let new_size = convert(size);
    let old_size = unsafe {
        let old_frame: NSRect = msg_send![this, frame];
        convert(old_frame.size)
    };

    if old_size == new_size {
        return;
    }

    unsafe {
        let _: () = msg_send![super(this, class!(NSView)), setFrameSize: size];
    }

    let scale_factor = lock.scale_factor();
    let drawable_size = new_size.to_device_pixels(scale_factor);
    lock.renderer.update_drawable_size(drawable_size);

    if let Some(mut callback) = lock.resize_callback.take() {
        let content_size = lock.content_size();
        let scale_factor = lock.scale_factor();
        drop(lock);
        callback(content_size, scale_factor);
        window_state.lock().resize_callback = Some(callback);
    };
}

extern "C" fn display_layer(this: &AnyObject, _: Sel, _: *mut AnyObject) {
    let signal_at = PlatformFrameSignal::capture(scheduler::Instant::now);
    let window_state = unsafe { get_window_state(this) };
    let mut lock = window_state.lock();
    if let Some(mut callback) = lock.request_frame_callback.take() {
        lock.renderer.set_presents_with_transaction(true);
        lock.stop_display_link();
        drop(lock);
        callback(RequestFrameOptions {
            signal_at,
            signal_source: FrameRequestSource::NativeCallback,
            ..Default::default()
        });

        let mut lock = window_state.lock();
        lock.request_frame_callback = Some(callback);
        lock.renderer.set_presents_with_transaction(false);
        lock.start_display_link(&window_state);
    }
}

extern "C" fn step(view: *mut c_void) {
    let view = view as *mut AnyObject;
    let window_state = unsafe { get_window_state(&*view) };
    let mut lock = window_state.lock();

    if let Some(mut callback) = lock.request_frame_callback.take() {
        let signal = match &lock.frame_source {
            FrameSource::DisplayLink(Some(frame_source)) => frame_source.take_signal(),
            _ => None,
        };
        let (signal_at, signal_source) = signal.map_or(
            (None, FrameRequestSource::NativeCallback),
            |(at, source)| (Some(at), source),
        );
        drop(lock);
        callback(RequestFrameOptions {
            signal_at,
            signal_source,
            ..Default::default()
        });
        window_state.lock().request_frame_callback = Some(callback);
    }
}

fn metal_frame(
    window_state: &Rc<Mutex<MacWindowState>>,
    update: &objc2_quartz_core::CAMetalDisplayLinkUpdate,
) {
    let signal_at = PlatformFrameSignal::capture(scheduler::Instant::now);
    let mut lock = window_state.lock();
    let FrameSource::Metal(metal_frames) = &lock.frame_source else {
        return;
    };
    let metal_frames = metal_frames.clone();
    let Some(mut callback) = lock.request_frame_callback.take() else {
        return;
    };
    lock.renderer.set_frame_drawable(Some(update.drawable()));
    drop(lock);
    metal_frames.begin_frame();
    callback(RequestFrameOptions {
        signal_at,
        signal_source: FrameRequestSource::NativeCallback,
        ..Default::default()
    });
    let mut lock = window_state.lock();
    lock.request_frame_callback = Some(callback);
    // A frame with nothing to draw leaves its drawable unused; releasing it
    // lets the link hand it out again.
    let used_drawable = lock.renderer.set_frame_drawable(None).is_none();
    metal_frames.end_frame(used_drawable);
}

extern "C" fn valid_attributes_for_marked_text(_: &AnyObject, _: Sel) -> *mut AnyObject {
    unsafe { msg_send![class!(NSArray), array] }
}

extern "C" fn has_marked_text(this: &AnyObject, _: Sel) -> Bool {
    let has_marked_text_result =
        with_input_handler(this, |input_handler| input_handler.marked_text_range()).flatten();

    has_marked_text_result.is_some().to_objc()
}

extern "C" fn marked_range(this: &AnyObject, _: Sel) -> NSRange {
    let marked_range_result =
        with_input_handler(this, |input_handler| input_handler.marked_text_range()).flatten();

    marked_range_result.map_or(NSRange::invalid(), |range| range.into())
}

extern "C" fn selected_range(this: &AnyObject, _: Sel) -> NSRange {
    let selected_range_result = with_input_handler(this, |input_handler| {
        input_handler.selected_text_range(false)
    })
    .flatten();

    selected_range_result.map_or(NSRange::invalid(), |selection| selection.range.into())
}

extern "C" fn first_rect_for_character_range(
    this: &AnyObject,
    _: Sel,
    range: NSRange,
    _: *mut NSRange,
) -> NSRect {
    let frame = get_frame(this);
    with_input_handler(this, |input_handler| {
        input_handler.bounds_for_range(range.to_range()?)
    })
    .flatten()
    .map_or(
        NSRect::new(NSPoint::new(0., 0.), NSSize::new(0., 0.)),
        |bounds| {
            NSRect::new(
                NSPoint::new(
                    frame.origin.x + bounds.origin.x.as_f32() as f64,
                    frame.origin.y + frame.size.height
                        - bounds.origin.y.as_f32() as f64
                        - bounds.size.height.as_f32() as f64,
                ),
                NSSize::new(
                    bounds.size.width.as_f32() as f64,
                    bounds.size.height.as_f32() as f64,
                ),
            )
        },
    )
}

fn get_frame(this: &AnyObject) -> NSRect {
    unsafe {
        let state = get_window_state(this);
        let lock = state.lock();
        let mut frame = lock.native_window().frame();
        let content_layout_rect: NSRect = msg_send![lock.native_window, contentLayoutRect];
        let style_mask: NSWindowStyleMask = msg_send![lock.native_window, styleMask];
        if !style_mask.contains(NSWindowStyleMask::FullSizeContentView) {
            frame.origin.y -= frame.size.height - content_layout_rect.size.height;
        }
        frame
    }
}

extern "C" fn insert_text(
    this: &AnyObject,
    _: Sel,
    text: *mut AnyObject,
    replacement_range: NSRange,
) {
    unsafe {
        let is_attributed_string: Bool = msg_send![text, isKindOfClass: class!(NSAttributedString)];
        let text: *mut AnyObject = if is_attributed_string == Bool::YES {
            msg_send![text, string]
        } else {
            text
        };

        let text = text.to_str();
        let replacement_range = replacement_range.to_range();
        with_input_handler(this, |input_handler| {
            input_handler.replace_text_in_range(replacement_range, text)
        });
    }
}

extern "C" fn set_marked_text(
    this: &AnyObject,
    _: Sel,
    text: *mut AnyObject,
    selected_range: NSRange,
    replacement_range: NSRange,
) {
    unsafe {
        let is_attributed_string: Bool = msg_send![text, isKindOfClass: class!(NSAttributedString)];
        let text: *mut AnyObject = if is_attributed_string == Bool::YES {
            msg_send![text, string]
        } else {
            text
        };
        let selected_range = selected_range.to_range();
        let replacement_range = replacement_range.to_range();
        let text = text.to_str();
        with_input_handler(this, |input_handler| {
            input_handler.replace_and_mark_text_in_range(replacement_range, text, selected_range)
        });
    }
}
extern "C" fn unmark_text(this: &AnyObject, _: Sel) {
    with_input_handler(this, |input_handler| input_handler.unmark_text());
}

extern "C" fn attributed_substring_for_proposed_range(
    this: &AnyObject,
    _: Sel,
    range: NSRange,
    actual_range: *mut NSRange,
) -> *mut AnyObject {
    with_input_handler(this, |input_handler| {
        let range = range.to_range()?;
        if range.is_empty() {
            return None;
        }
        let mut adjusted: Option<Range<usize>> = None;

        let selected_text = input_handler.text_for_range(range.clone(), &mut adjusted)?;
        unsafe { write_actual_text_range(actual_range, adjusted.unwrap_or(range)) };
        unsafe {
            let string: *mut AnyObject = msg_send![class!(NSAttributedString), alloc];
            let string: *mut AnyObject =
                msg_send![string, initWithString: ns_string(&selected_text)];
            let string: *mut AnyObject = msg_send![string, autorelease];
            Some(string)
        }
    })
    .flatten()
    .unwrap_or(ptr::null_mut::<AnyObject>())
}

/// AppKit's optional NSRange output parameters are borrowed for the callback.
unsafe fn write_actual_text_range(actual_range: *mut NSRange, range: Range<usize>) {
    if !actual_range.is_null() {
        unsafe { actual_range.write(NSRange::from(range)) };
    }
}

// We ignore which selector it asks us to do because the user may have
// bound the shortcut to something else.
extern "C" fn do_command_by_selector(this: &AnyObject, _: Sel, _: Sel) {
    let state = unsafe { get_window_state(this) };
    let mut lock = state.as_ref().lock();
    let keystroke = lock.keystroke_for_do_command.take();
    let mut event_callback = lock.event_callback.take();
    drop(lock);

    if let Some((keystroke, callback)) = keystroke.zip(event_callback.as_mut()) {
        let handled = (callback)(PlatformInput::KeyDown(KeyDownEvent {
            keystroke,
            is_held: false,
            prefer_character_input: false,
        }));
        state.as_ref().lock().do_command_handled = Some(!handled.propagate);
    }

    state.as_ref().lock().event_callback = event_callback;
}

extern "C" fn view_did_change_effective_appearance(this: &AnyObject, _: Sel) {
    unsafe {
        let state = get_window_state(this);
        let appearance_changed_callback = {
            let mut lock = state.as_ref().lock();
            lock.appearance_changed_callback.take()
        };

        if let Some(mut callback) = appearance_changed_callback {
            callback();
            state.lock().appearance_changed_callback = Some(callback);
        }

        // AppKit can relayout the standard traffic light buttons as part of
        // applying a new appearance, so reapply GPUI's custom position.
        state.lock().move_traffic_light();
    }
}

extern "C" fn accepts_first_mouse(this: &AnyObject, _: Sel, _: *mut AnyObject) -> Bool {
    let window_state = unsafe { get_window_state(this) };
    let mut lock = window_state.as_ref().lock();
    lock.first_mouse = true;
    Bool::YES
}

// Reports which region of the view AppKit should treat as app-owned titlebar content
// (rather than a system-owned window-move region). When `app_owns_titlebar_drag` is
// true, we claim the entire view so AppKit neither drags the window from the titlebar
// nor waits to disambiguate double-clicks before delivering titlebar clicks (the macOS
// 27 delay); such windows implement dragging themselves via [`Window::start_window_move`].
// Otherwise we return an empty rect so AppKit's native titlebar dragging keeps working.
// This is independent of `NSWindow.isMovable`, so the Window-menu tiling items stay
// enabled regardless.
extern "C" fn opaque_rect_for_window_move_when_in_titlebar(this: &AnyObject, _: Sel) -> NSRect {
    let zero_rect = NSRect::new(NSPoint::new(0., 0.), NSSize::new(0., 0.));
    let window_state = unsafe { get_window_state(this) };
    let app_owns_titlebar_drag = window_state.as_ref().lock().app_owns_titlebar_drag;
    if app_owns_titlebar_drag {
        unsafe { msg_send![this, bounds] }
    } else {
        zero_rect
    }
}

extern "C" fn character_index_for_point(this: &AnyObject, _: Sel, position: NSPoint) -> NSUInteger {
    let position = screen_point_to_gpui_point(this, position);
    with_input_handler(this, |input_handler| {
        input_handler.character_index_for_point(position)
    })
    .flatten()
    .unwrap_or(NSNotFound as NSUInteger)
}

fn screen_point_to_gpui_point(this: &AnyObject, position: NSPoint) -> Point<Pixels> {
    let frame = get_frame(this);
    let window_x = position.x - frame.origin.x;
    let window_y = frame.size.height - (position.y - frame.origin.y);

    point(px(window_x as f32), px(window_y as f32))
}

fn is_drag_from_this_window(this: &AnyObject, dragging_info: *mut AnyObject) -> bool {
    let source: *mut AnyObject = unsafe { msg_send![dragging_info, draggingSource] };
    std::ptr::eq(source as *const AnyObject, this as *const AnyObject)
}

extern "C" fn dragging_entered(
    this: &AnyObject,
    _: Sel,
    dragging_info: *mut AnyObject,
) -> NSDragOperation {
    let is_source_window = is_drag_from_this_window(this, dragging_info);
    let window_state = unsafe { get_window_state(this) };
    let position = drag_event_position(&window_state, dragging_info);
    let paths = external_paths_from_event(dragging_info);
    if let Some(event) = paths.map(|paths| FileDropEvent::Entered { position, paths })
        && send_file_drop_event(window_state, event)
    {
        if is_source_window {
            return NSDragOperation::Move;
        }
        return NSDragOperation::Copy;
    }
    NSDragOperation::None
}

extern "C" fn dragging_updated(
    this: &AnyObject,
    _: Sel,
    dragging_info: *mut AnyObject,
) -> NSDragOperation {
    let is_source_window = is_drag_from_this_window(this, dragging_info);
    let window_state = unsafe { get_window_state(this) };
    let position = drag_event_position(&window_state, dragging_info);
    if send_file_drop_event(window_state, FileDropEvent::Pending { position }) {
        if is_source_window {
            NSDragOperation::Move
        } else {
            NSDragOperation::Copy
        }
    } else {
        NSDragOperation::None
    }
}

extern "C" fn dragging_exited(this: &AnyObject, _: Sel, _: *mut AnyObject) {
    let window_state = unsafe { get_window_state(this) };
    send_file_drop_event(window_state, FileDropEvent::Exited);
}

extern "C" fn perform_drag_operation(
    this: &AnyObject,
    _: Sel,
    dragging_info: *mut AnyObject,
) -> Bool {
    let window_state = unsafe { get_window_state(this) };
    let position = drag_event_position(&window_state, dragging_info);
    send_file_drop_event(window_state, FileDropEvent::Submit { position }).to_objc()
}

fn external_paths_from_event(dragging_info: *mut AnyObject) -> Option<ExternalPaths> {
    let mut paths = SmallVec::new();
    let pasteboard: *mut AnyObject = unsafe { msg_send![dragging_info, draggingPasteboard] };
    if pasteboard.is_null() {
        return None;
    }
    #[expect(
        deprecated,
        reason = "File-drop decoding expects a property-list array of paths; replacing NSFilenamesPboardType requires migrating both registration and decoding to file URLs"
    )]
    let filenames: *mut NSArray<NSString> =
        unsafe { msg_send![pasteboard, propertyListForType: NSFilenamesPboardType] };
    let filenames = unsafe { filenames.as_ref() }?;
    for file in filenames {
        let path = unsafe {
            let f = file.UTF8String();
            CStr::from_ptr(f).to_string_lossy().into_owned()
        };
        paths.push(PathBuf::from(path))
    }
    Some(ExternalPaths(paths))
}

extern "C" fn conclude_drag_operation(this: &AnyObject, _: Sel, _: *mut AnyObject) {
    let window_state = unsafe { get_window_state(this) };
    send_file_drop_event(window_state, FileDropEvent::Exited);
}

extern "C" fn dragging_session_source_operation_mask(
    _: &AnyObject,
    _: Sel,
    _: *mut AnyObject,
    context: NSDraggingContext,
) -> NSDragOperation {
    let operation = match context {
        NSDraggingContext::OutsideApplication => NSDragOperation::Copy,
        NSDraggingContext::WithinApplication => NSDragOperation::Copy | NSDragOperation::Move,
        _ => NSDragOperation::Copy | NSDragOperation::Move,
    };
    log::debug!(
        "dragging_session_source_operation_mask: context={}, operation={}",
        context.0,
        operation.bits()
    );
    operation
}

extern "C" fn dragging_session_ended(
    this: &AnyObject,
    _: Sel,
    _: *mut AnyObject,
    _: NSPoint,
    operation: NSDragOperation,
) {
    log::debug!("dragging_session_ended operation={}", operation.bits());
    // SAFETY: AppKit invokes this selector on the GPUIWindow instance registered in build_classes,
    // which always has WINDOW_STATE_IVAR initialized to the owning MacWindowState.
    let window_state = unsafe { get_window_state(this) };
    {
        let mut lock = window_state.lock();
        lock.synthetic_drag_counter += 1;
        lock.last_left_mouse_down_event = None;
    }
    send_file_drop_event(window_state, FileDropEvent::Ended);
}

fn synthetic_drag_button_is_pressed(button: Option<MouseButton>, pressed: NSUInteger) -> bool {
    let bit = match button {
        Some(MouseButton::Left) => 0,
        Some(MouseButton::Right) => 1,
        Some(MouseButton::Middle) => 2,
        Some(MouseButton::Navigate(gpui::NavigationDirection::Back)) => 3,
        Some(MouseButton::Navigate(gpui::NavigationDirection::Forward)) => 4,
        None => return false,
    };
    pressed & (1 << bit) != 0
}

async fn synthetic_drag(
    window_state: Weak<Mutex<MacWindowState>>,
    drag_id: usize,
    event: MouseMoveEvent,
    executor: BackgroundExecutor,
) {
    loop {
        executor.timer(Duration::from_millis(16)).await;
        let Some(window_state) = window_state.upgrade() else {
            break;
        };
        let mut lock = window_state.lock();
        if lock.synthetic_drag_counter != drag_id {
            break;
        }
        // Native menu tracking can consume mouse-up, leaving stale drag events replaying.
        // Check whether the original mouse button is still physically pressed before replaying.
        let pressed: NSUInteger = unsafe { msg_send![class!(NSEvent), pressedMouseButtons] };
        if !synthetic_drag_button_is_pressed(event.pressed_button, pressed) {
            lock.synthetic_drag_counter += 1;
            break;
        }
        if let Some(mut callback) = lock.event_callback.take() {
            drop(lock);
            callback(PlatformInput::MouseMove(event.clone()));
            window_state.lock().event_callback = Some(callback);
        }
    }
}

/// Sends the specified FileDropEvent using `PlatformInput::FileDrop` to the window
/// state and updates the window state according to the event passed.
fn send_file_drop_event(
    window_state: Rc<Mutex<MacWindowState>>,
    file_drop_event: FileDropEvent,
) -> bool {
    let external_files_dragged = match file_drop_event {
        FileDropEvent::Entered { .. } => Some(true),
        FileDropEvent::Exited | FileDropEvent::Ended => Some(false),
        _ => None,
    };

    let mut lock = window_state.lock();
    if let Some(mut callback) = lock.event_callback.take() {
        drop(lock);
        callback(PlatformInput::FileDrop(file_drop_event));
        let mut lock = window_state.lock();
        lock.event_callback = Some(callback);
        if let Some(external_files_dragged) = external_files_dragged {
            lock.external_files_dragged = external_files_dragged;
        }
        true
    } else {
        false
    }
}

fn drag_event_position(
    window_state: &Mutex<MacWindowState>,
    dragging_info: *mut AnyObject,
) -> Point<Pixels> {
    let drag_location: NSPoint = unsafe { msg_send![dragging_info, draggingLocation] };
    convert_mouse_position(drag_location, window_state.lock().content_size().height)
}

fn with_input_handler<F, R>(window: &AnyObject, f: F) -> Option<R>
where
    F: FnOnce(&mut PlatformInputHandler) -> R,
{
    let window_state = unsafe { get_window_state(window) };
    let mut lock = window_state.as_ref().lock();
    if let Some(mut input_handler) = lock.input_handler.take() {
        drop(lock);
        let result = f(&mut input_handler);
        window_state.lock().input_handler = Some(input_handler);
        Some(result)
    } else {
        None
    }
}

fn display_id_for_screen(screen: *mut AnyObject) -> Option<CGDirectDisplayID> {
    if screen.is_null() {
        return None;
    }

    unsafe {
        let device_description: *mut AnyObject = msg_send![screen, deviceDescription];
        if device_description.is_null() {
            return None;
        }
        let screen_number_key: *mut AnyObject = ns_string("NSScreenNumber");
        let screen_number: *mut AnyObject =
            msg_send![device_description, objectForKey: screen_number_key];
        if screen_number.is_null() {
            return None;
        }
        let screen_number: NSUInteger = msg_send![screen_number, unsignedIntegerValue];
        Some(screen_number as CGDirectDisplayID)
    }
}

extern "C" fn blurred_view_init_with_frame(
    this: &AnyObject,
    _: Sel,
    frame: NSRect,
) -> *mut AnyObject {
    unsafe {
        let view: *mut AnyObject =
            msg_send![super(this, class!(NSVisualEffectView)), initWithFrame: frame];
        // A window-background material, whose tint and extra saturation
        // `blurred_view_update_layer` strips, leaving only the blur. `Selection`, used before,
        // has no `CABackdropLayer` on macOS 27, so nothing behind the window was blurred. (Setting
        // a material also avoids the deprecated default, `AppearanceBased`.)
        let _: () = msg_send![view, setMaterial: NSVisualEffectMaterial::UnderWindowBackground];
        // The default, but blurring what's behind the window is this view's whole purpose.
        let _: () = msg_send![view, setBlendingMode: NSVisualEffectBlendingMode::BehindWindow];
        let _: () = msg_send![view, setState: NSVisualEffectState::Active];
        view
    }
}

extern "C" fn blurred_view_update_layer(this: &AnyObject, _: Sel) {
    unsafe {
        let _: () = msg_send![super(this, class!(NSVisualEffectView)), updateLayer];
        let layer: *mut AnyObject = msg_send![this, layer];
        if !layer.is_null() {
            remove_layer_background(layer);
        }
    }
}

unsafe fn remove_layer_background(layer: *mut AnyObject) {
    unsafe {
        let _: () = msg_send![layer, setBackgroundColor: None::<&CGColor>];

        let class_name: *mut AnyObject = msg_send![layer, className];
        if msg_send![class_name, isEqualToString: ns_string("CAChameleonLayer")] {
            // Remove the desktop tinting effect.
            let _: () = msg_send![layer, setHidden: Bool::YES];
            return;
        }

        let filters: *mut AnyObject = msg_send![layer, filters];
        if !filters.is_null() {
            // Remove the increased saturation.
            // The effect of a `CAFilter` or `CIFilter` is determined by its name, and the
            // `description` reflects its name and some parameters. Currently `NSVisualEffectView`
            // uses a `CAFilter` named "colorSaturate". If one day they switch to `CIFilter`, the
            // `description` will still contain "Saturat" ("... inputSaturation = ...").
            let test_string: *mut AnyObject = ns_string("Saturat");
            let count: NSUInteger = msg_send![filters, count];
            for i in 0..count {
                let filter: *mut AnyObject = msg_send![filters, objectAtIndex: i];
                let description: *mut AnyObject = msg_send![filter, description];
                let hit: Bool = msg_send![description, containsString: test_string];
                if hit == Bool::NO {
                    continue;
                }

                let all_indices = NSRange {
                    location: 0,
                    length: count,
                };
                let indices: *mut AnyObject = msg_send![class!(NSMutableIndexSet), indexSet];
                let _: () = msg_send![indices, addIndexesInRange: all_indices];
                let _: () = msg_send![indices, removeIndex:i];
                let filtered: *mut AnyObject = msg_send![filters, objectsAtIndexes: indices];
                let _: () = msg_send![layer, setFilters: filtered];
                break;
            }
        }

        let sublayers: *mut AnyObject = msg_send![layer, sublayers];
        if !sublayers.is_null() {
            let count: NSUInteger = msg_send![sublayers, count];
            for i in 0..count {
                let sublayer: *mut AnyObject = msg_send![sublayers, objectAtIndex: i];
                remove_layer_background(sublayer);
            }
        }
    }
}

extern "C" fn add_titlebar_accessory_view_controller(
    this: &AnyObject,
    _: Sel,
    view_controller: *mut AnyObject,
) {
    unsafe {
        let _: () = msg_send![super(this, class!(NSWindow)), addTitlebarAccessoryViewController: view_controller];

        // Hide the native tab bar and set its height to 0, since we render our own.
        let accessory_view: *mut AnyObject = msg_send![view_controller, view];
        let _: () = msg_send![accessory_view, setHidden: Bool::YES];
        let mut frame: NSRect = msg_send![accessory_view, frame];
        frame.size.height = 0.0;
        let _: () = msg_send![accessory_view, setFrame: frame];
    }
}

extern "C" fn move_tab_to_new_window(this: &AnyObject, _: Sel, _: *mut AnyObject) {
    unsafe {
        let _: () = msg_send![super(this, class!(NSWindow)), moveTabToNewWindow:ptr::null_mut::<AnyObject>()];

        let window_state = get_window_state(this);
        let mut lock = window_state.as_ref().lock();
        if let Some(mut callback) = lock.move_tab_to_new_window_callback.take() {
            drop(lock);
            callback();
            window_state.lock().move_tab_to_new_window_callback = Some(callback);
        }
    }
}

extern "C" fn merge_all_windows(this: &AnyObject, _: Sel, _: *mut AnyObject) {
    unsafe {
        let _: () =
            msg_send![super(this, class!(NSWindow)), mergeAllWindows:ptr::null_mut::<AnyObject>()];

        let window_state = get_window_state(this);
        let mut lock = window_state.as_ref().lock();
        if let Some(mut callback) = lock.merge_all_windows_callback.take() {
            drop(lock);
            callback();
            window_state.lock().merge_all_windows_callback = Some(callback);
        }
    }
}

extern "C" fn select_next_tab(this: &AnyObject, _sel: Sel, _id: *mut AnyObject) {
    let window_state = unsafe { get_window_state(this) };
    let mut lock = window_state.as_ref().lock();
    if let Some(mut callback) = lock.select_next_tab_callback.take() {
        drop(lock);
        callback();
        window_state.lock().select_next_tab_callback = Some(callback);
    }
}

extern "C" fn select_previous_tab(this: &AnyObject, _sel: Sel, _id: *mut AnyObject) {
    let window_state = unsafe { get_window_state(this) };
    let mut lock = window_state.as_ref().lock();
    if let Some(mut callback) = lock.select_previous_tab_callback.take() {
        drop(lock);
        callback();
        window_state.lock().select_previous_tab_callback = Some(callback);
    }
}

extern "C" fn toggle_tab_bar(this: &AnyObject, _sel: Sel, _id: *mut AnyObject) {
    unsafe {
        let _: () =
            msg_send![super(this, class!(NSWindow)), toggleTabBar:ptr::null_mut::<AnyObject>()];

        let window_state = get_window_state(this);
        let mut lock = window_state.as_ref().lock();
        lock.move_traffic_light();

        if let Some(mut callback) = lock.toggle_tab_bar_callback.take() {
            drop(lock);
            callback();
            window_state.lock().toggle_tab_bar_callback = Some(callback);
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use objc2::runtime::{AnyClass, AnyProtocol};
    // Compare our dynamic registrations with AppKit's own protocol metadata,
    // independently of the Rust function signatures used to register them.
    #[test]
    fn registered_callbacks_match_system_protocols() {
        use objc2::encode::EncodingBox;
        fn encodings(mut types: &str) -> Vec<EncodingBox> {
            let mut result = Vec::new();
            while !types.is_empty() {
                result.push(EncodingBox::from_start_of_str(&mut types).unwrap());
                types = types.trim_start_matches(|c: char| c.is_ascii_digit() || c == '-');
            }
            result
        }
        for core in [c"NSWindowDelegate", c"NSTextInputClient"] {
            assert!(
                AnyProtocol::get(core).is_some(),
                "{core:?} must be registered to check window callbacks"
            );
        }
        let mut checked = 0;
        for name in [
            c"GPUIView",
            c"GPUIWindow",
            c"GPUIPanel",
            c"GPUIApplicationDelegate",
            c"GPUIWindowStateArchiverDelegate",
        ] {
            let class = AnyClass::get(name).unwrap();
            for method in class.instance_methods().iter() {
                for protocol_name in [
                    c"NSTextInputClient",
                    c"NSWindowDelegate",
                    c"NSDraggingSource",
                    c"NSDraggingDestination",
                    c"NSApplicationDelegate",
                    c"NSMenuDelegate",
                    c"NSMenuItemValidation",
                    c"CALayerDelegate",
                    c"NSKeyedArchiverDelegate",
                ] {
                    // A protocol exists in the runtime only once something in the
                    // process has loaded it, which differs between macOS images.
                    // Check the ones present; the core ones are required below.
                    let Some(protocol) = AnyProtocol::get(protocol_name) else {
                        continue;
                    };
                    for required in [Bool::YES, Bool::NO] {
                        let description = unsafe {
                            objc2::ffi::protocol_getMethodDescription(
                                protocol,
                                method.name(),
                                required,
                                Bool::YES,
                            )
                        };
                        if description.types.is_null() {
                            continue;
                        }
                        let expected = encodings(
                            unsafe { CStr::from_ptr(description.types) }
                                .to_str()
                                .unwrap(),
                        );
                        let actual = encodings(method.return_type().to_str().unwrap());
                        assert_eq!(
                            actual[0],
                            expected[0],
                            "{name:?} {:?}: return encoding",
                            method.name()
                        );
                        assert_eq!(method.arguments_count(), expected.len() - 1);
                        for (index, expected) in expected[1..].iter().enumerate() {
                            let argument = method.argument_type(index).unwrap();
                            let actual = encodings(argument.to_str().unwrap());
                            assert_eq!(
                                &actual[0],
                                expected,
                                "{name:?} {:?}: argument {index}",
                                method.name()
                            );
                        }
                        checked += 1;
                    }
                }
            }
        }
        assert!(checked >= 30, "only checked {checked} callback signatures");
    }

    #[test]
    fn native_attention_signature_matches_appkit() {
        class!(NSApplication)
            .verify_sel::<(NSRequestUserAttentionType,), NSInteger>(sel!(requestUserAttention:))
            .unwrap();
    }

    #[test]
    fn text_input_range_pointer_signatures_match_appkit() {
        let view = unsafe { &*VIEW_CLASS };
        view.verify_sel::<(NSRange, *mut NSRange), NSRect>(
            sel!(firstRectForCharacterRange:actualRange:),
        )
        .unwrap();
        view.verify_sel::<(NSRange, *mut NSRange), *mut AnyObject>(
            sel!(attributedSubstringForProposedRange:actualRange:),
        )
        .unwrap();
    }

    #[test]
    fn optional_actual_text_range_accepts_null_and_reports_range() {
        unsafe { write_actual_text_range(ptr::null_mut(), 2..5) };
        let mut actual = NSRange::invalid();
        unsafe { write_actual_text_range(&mut actual, 2..5) };
        assert_eq!(actual.to_range(), Some(2..5));
    }

    #[test]
    fn layer_background_can_be_cleared_with_objc_checks_enabled() {
        objc2::rc::autoreleasepool(|_| {
            let layer = objc2_quartz_core::CALayer::new();
            unsafe {
                remove_layer_background(Retained::as_ptr(&layer).cast_mut().cast());
            }
            assert!(layer.backgroundColor().is_none());
        });
    }

    #[test]
    fn text_input_class_checks_accept_plain_and_attributed_strings() {
        objc2::rc::autoreleasepool(|_| unsafe {
            let plain = objc2_foundation::NSString::from_str("text");
            let attributed = objc2_foundation::NSAttributedString::initWithString(
                objc2_foundation::NSAttributedString::alloc(),
                &plain,
            );
            let plain_result: Bool = msg_send![&*plain, isKindOfClass: class!(NSAttributedString)];
            let attributed_result: Bool =
                msg_send![&*attributed, isKindOfClass: class!(NSAttributedString)];
            assert!(!plain_result.as_bool());
            assert!(attributed_result.as_bool());
        });
    }

    #[test]
    fn display_id_for_screen_handles_missing_metadata() {
        assert_eq!(display_id_for_screen(ptr::null_mut::<AnyObject>()), None);
        autoreleasepool(|_| unsafe {
            let mut builder = ClassBuilder::new(c"GPUIDisplayIdTestScreen", class!(NSObject))
                .expect("test screen class");
            builder.add_ivar::<*mut AnyObject>(c"deviceDescription");
            builder.add_method(
                sel!(deviceDescription),
                test_screen_device_description as extern "C" fn(_, Sel) -> *mut AnyObject,
            );
            let screen: Retained<AnyObject> = msg_send![builder.register(), new];
            let description = screen
                .class()
                .instance_variable(c"deviceDescription")
                .expect("test screen description ivar")
                .load_ptr::<*mut AnyObject>(&screen);
            let screen = Retained::as_ptr(&screen).cast_mut();
            description.write(ptr::null_mut());
            assert_eq!(display_id_for_screen(screen), None);

            let dictionary: Retained<AnyObject> = msg_send![class!(NSMutableDictionary), new];
            description.write(Retained::as_ptr(&dictionary).cast_mut());
            assert_eq!(display_id_for_screen(screen), None);

            for display_id in [0u32, 42] {
                let number: Retained<AnyObject> =
                    msg_send![class!(NSNumber), numberWithUnsignedInt: display_id];
                let _: () = msg_send![
                    &*dictionary,
                    setObject: &*number,
                    forKey: ns_string("NSScreenNumber")
                ];
                assert_eq!(display_id_for_screen(screen), Some(display_id));
            }
        });
    }

    extern "C" fn test_screen_device_description(screen: &AnyObject, _: Sel) -> *mut AnyObject {
        unsafe {
            *screen
                .class()
                .instance_variable(c"deviceDescription")
                .expect("test screen description ivar")
                .load::<*mut AnyObject>(screen)
        }
    }
}