import AppKit
import SwiftUI

@MainActor
final class PlayerModel: ObservableObject {
    static let shared = PlayerModel()

    @Published private(set) var state = PlayerState()
    @Published private(set) var fileName: String?
    @Published private(set) var fileIcon: NSImage?
    @Published private(set) var commandError: String?
    @Published private(set) var pendingRevision: UInt64?
    @Published var seekPosition = 0.0
    @Published var isSeeking = false
    @Published private(set) var volume = 1.0
    @Published private(set) var controlsVisible = true
    @Published private(set) var isFullScreen = false
    @Published private(set) var isOnTop = false

    let videoView: NSView?
    private var handle: OpaquePointer?
    private var timer: Timer?
    private weak var window: NSWindow?
    private var hideDeadline: ContinuousClock.Instant?
    private var controlsHovered = false
    private var titleHovered = false
    private var controlsDragging = false
    private var windowActive = true
    private var lastAudibleVolume = 1.0
    private var needsVideoFit = false
    private var seekPending = false

    private init() {
        let player = player_create()
        handle = player
        if let player, let view = player_macos_make_video_view(player) {
            videoView = Unmanaged<NSView>.fromOpaque(view).takeRetainedValue()
            state = player_get_state(player)
            volume = Double(player_get_volume(player))
        } else {
            videoView = nil
            commandError = "Could not create the media player."
        }
        timer = Timer.scheduledTimer(withTimeInterval: 0.05, repeats: true) { [weak self] _ in
            MainActor.assumeIsolated { self?.poll() }
        }
    }

    var isBusy: Bool { pendingRevision != nil || state.status == PLAYER_OPENING }
    var canTogglePlayback: Bool {
        handle != nil && !isBusy &&
            (state.status == PLAYER_PAUSED || state.status == PLAYER_PLAYING || state.status == PLAYER_ENDED)
    }
    var canSeek: Bool { canTogglePlayback && state.duration.isFinite && state.duration > 0 }
    var canOpen: Bool { handle != nil && !isBusy }
    var canClose: Bool { handle != nil && !isBusy && state.status != PLAYER_EMPTY }
    var canSetVolume: Bool { handle != nil && !isBusy && state.has_audio && state.status != PLAYER_ERROR }
    var duration: Double { state.duration.isFinite ? max(0, state.duration) : 0 }
    var errorText: String? {
        if let commandError { return commandError }
        guard state.status == PLAYER_ERROR else { return nil }
        var error = state.error
        return withUnsafeBytes(of: &error) { bytes in
            let message = String(decoding: bytes.prefix { $0 != 0 }, as: UTF8.self)
            return message.isEmpty ? "An unknown playback error occurred." : message
        }
    }

    func openPanel() {
        guard canOpen else { return }
        revealControls()
        let panel = NSOpenPanel()
        panel.canChooseFiles = true
        panel.canChooseDirectories = false
        panel.allowsMultipleSelection = false
        panel.prompt = "Open"
        guard panel.runModal() == .OK, let url = panel.url else { return }
        open(url)
    }

    func open(_ url: URL) {
        guard canOpen, let handle else { return }
        guard url.isFileURL else {
            commandError = "Only local media files are supported."
            revealControls()
            return
        }
        let revision = player_get_state(handle).revision
        let accepted = url.withUnsafeFileSystemRepresentation { path in
            guard let path else { return false }
            return player_open(handle, path)
        }
        guard accepted else {
            commandError = "Could not queue the file to open. Please try again."
            return
        }
        // Open is always paused; never queue play against the previous file.
        pendingRevision = revision
        fileName = url.lastPathComponent
        fileIcon = NSWorkspace.shared.icon(forFile: url.path)
        needsVideoFit = true
        commandError = nil
        isSeeking = false
        seekPending = false
        seekPosition = 0
        window?.representedURL = url
        window?.title = url.lastPathComponent
        revealControls()
    }

    func togglePlayback() {
        guard let handle, canTogglePlayback else { return }
        let accepted = state.status == PLAYER_PLAYING ? player_pause(handle) : player_play(handle)
        commandError = accepted ? nil : "Could not queue playback. Please try again."
        revealControls()
    }

    func finishSeeking() {
        isSeeking = false
        guard let handle, canSeek else { return }
        let position = min(max(0, seekPosition), duration)
        let accepted = player_seek(handle, position)
        if accepted { seekPending = true }
        commandError = accepted ? nil : "Could not queue the seek. Please try again."
        revealControls()
    }

    func closeFile() {
        guard let handle, canClose else { return }
        guard player_close(handle) else {
            commandError = "Could not queue closing the file. Please try again."
            return
        }
        fileName = nil
        fileIcon = nil
        needsVideoFit = false
        window?.aspectRatio = .zero
        commandError = nil
        isSeeking = false
        seekPending = false
        window?.representedURL = nil
        window?.title = "Player"
        revealControls()
    }

    func seekRelative(_ seconds: Double) {
        guard canSeek, let handle else { return }
        let target = min(max(0, (seekPending ? seekPosition : state.position) + seconds), duration)
        let accepted = player_seek(handle, target)
        if accepted {
            seekPosition = target
            seekPending = true
        }
        commandError = accepted ? nil : "Could not queue the seek. Please try again."
        revealControls()
    }

    func setVolume(_ value: Double) {
        guard let handle else { return }
        if player_set_volume(handle, Float(value)) {
            volume = Double(player_get_volume(handle))
            if volume > 0 { lastAudibleVolume = volume }
        }
        revealControls()
    }

    func toggleMute() {
        guard canSetVolume else { return }
        setVolume(volume == 0 ? lastAudibleVolume : 0)
    }

    func attachWindow(_ window: NSWindow) {
        self.window = window
        window.title = fileName ?? "Player"
        updateWindowState()
        fitVideoWindow()
    }

    func updateWindowState() {
        guard let window else { return }
        isFullScreen = window.styleMask.contains(.fullScreen)
        windowActive = window.isKeyWindow
        window.level = isOnTop && !isFullScreen ? .floating : .normal
        if !isFullScreen { fitVideoWindow() }
        revealControls()
    }

    func toggleFullScreen() {
        window?.toggleFullScreen(nil)
        revealControls()
    }

    func toggleOnTop() {
        guard !isFullScreen else { return }
        isOnTop.toggle()
        window?.level = isOnTop ? .floating : .normal
        revealControls()
    }

    func setControlsHovered(_ hovered: Bool) {
        guard controlsHovered != hovered else { return }
        controlsHovered = hovered
        revealControls()
    }

    func setTitleHovered(_ hovered: Bool) {
        guard titleHovered != hovered else { return }
        titleHovered = hovered
        revealControls()
    }

    func setControlsDragging(_ dragging: Bool) {
        guard controlsDragging != dragging else { return }
        controlsDragging = dragging
        revealControls()
    }

    func hideControls(hideCursor: Bool = true) {
        guard shouldHideControls else { return }
        hideDeadline = nil
        withAnimation(NSWorkspace.shared.accessibilityDisplayShouldReduceMotion ? nil : .easeIn(duration: 0.25)) {
            controlsVisible = false
        }
        NSCursor.setHiddenUntilMouseMoves(hideCursor)
    }

    func beginSeeking() {
        isSeeking = true
        revealControls()
    }

    func revealControls() {
        hideDeadline = nil
        NSCursor.setHiddenUntilMouseMoves(false)
        if !controlsVisible {
            withAnimation(NSWorkspace.shared.accessibilityDisplayShouldReduceMotion ? nil : .easeOut(duration: 0.25)) {
                controlsVisible = true
            }
        }
        guard shouldHideControls else { return }
        hideDeadline = ContinuousClock.now.advanced(by: .milliseconds(2500))
    }

    private var shouldHideControls: Bool {
        canTogglePlayback && state.has_video && fileName != nil &&
            !isSeeking && !seekPending && !controlsHovered && !titleHovered && !controlsDragging &&
            windowActive && errorText == nil &&
            !NSWorkspace.shared.isVoiceOverEnabled
    }

    private func fitVideoWindow() {
        guard needsVideoFit, canTogglePlayback, let window, !isFullScreen else { return }
        needsVideoFit = false
        let aspect = state.video_aspect_ratio
        guard state.has_video, aspect.isFinite, aspect > 0 else {
            window.aspectRatio = .zero
            return
        }
        let screen = (window.screen ?? NSScreen.main)?.visibleFrame ?? window.frame
        let width = min(window.frame.width, screen.width, screen.height * aspect)
        let size = NSSize(width: width, height: width / aspect)
        // ponytail: extreme ratios retain letterboxing; compact controls if exact fitting is needed.
        guard size.width >= window.minSize.width, size.height >= window.minSize.height else {
            window.aspectRatio = .zero
            return
        }
        window.aspectRatio = NSSize(width: aspect, height: 1)
        let frame = NSRect(
            x: min(max(window.frame.midX - size.width / 2, screen.minX), screen.maxX - size.width),
            y: min(max(window.frame.midY - size.height / 2, screen.minY), screen.maxY - size.height),
            width: size.width, height: size.height)
        window.setFrame(frame, display: true)
    }

    private func poll() {
        guard let handle else { return }
        applyState(player_get_state(handle))
    }

    func applyState(_ next: PlayerState) {
        if let revision = pendingRevision {
            guard next.revision != revision, next.status != PLAYER_OPENING else { return }
            pendingRevision = nil
        }
        let statusChanged = state.status != next.status
        state = next
        if !next.seek_pending || next.status == PLAYER_ERROR { seekPending = false }
        if !isSeeking && !seekPending {
            seekPosition = min(max(0, next.position.isFinite ? next.position : 0), duration)
        }
        fitVideoWindow()
        if statusChanged { revealControls() }
        if let hideDeadline, ContinuousClock.now >= hideDeadline { hideControls() }
    }

    func shutdown() {
        timer?.invalidate()
        timer = nil
        hideDeadline = nil
        NSCursor.setHiddenUntilMouseMoves(false)
        guard let player = handle else { return }
        handle = nil
        player_destroy(player)
    }
}

@MainActor
private struct PlayerGlass: NSViewRepresentable {
    var titlebar = false

    func makeNSView(context: Context) -> NSVisualEffectView {
        let view = NSVisualEffectView()
        view.blendingMode = .withinWindow
        view.state = .active
        view.appearance = NSAppearance(named: .vibrantDark)
        view.material = titlebar ? .titlebar : .hudWindow
        return view
    }

    func updateNSView(_ view: NSVisualEffectView, context: Context) {}
}

@MainActor
private struct PlaybackSlider: NSViewRepresentable {
    @Binding var value: Double
    let range: ClosedRange<Double>
    var volume = false
    var enabled = true
    var onEditingChanged: (Bool) -> Void = { _ in }

    func makeCoordinator() -> Coordinator { Coordinator(self) }

    func makeNSView(context: Context) -> Slider {
        let slider = Slider()
        let cell = Cell()
        cell.volume = volume
        slider.cell = cell
        slider.isContinuous = true
        slider.target = context.coordinator
        slider.action = #selector(Coordinator.changed(_:))
        return slider
    }

    func updateNSView(_ slider: Slider, context: Context) {
        context.coordinator.parent = self
        slider.minValue = range.lowerBound
        slider.maxValue = range.upperBound
        slider.doubleValue = value
        slider.isEnabled = enabled
        slider.editingChanged = onEditingChanged
        slider.setAccessibilityLabel(volume ? "Volume" : "Playback Position")
    }

    @MainActor
    final class Coordinator: NSObject {
        var parent: PlaybackSlider
        init(_ parent: PlaybackSlider) { self.parent = parent }
        @objc func changed(_ slider: Slider) {
            if !slider.tracking { parent.onEditingChanged(true) }
            parent.value = slider.doubleValue
            if !slider.tracking { parent.onEditingChanged(false) }
        }
    }

    final class Slider: NSSlider {
        var editingChanged: (Bool) -> Void = { _ in }
        private(set) var tracking = false
        override func mouseDown(with event: NSEvent) {
            guard isEnabled else { return }
            tracking = true
            editingChanged(true)
            super.mouseDown(with: event)
            tracking = false
            editingChanged(false)
        }
    }

    final class Cell: NSSliderCell {
        var volume = false
        override func drawBar(inside rect: NSRect, flipped: Bool) {
            let bar = NSRect(x: rect.minX, y: rect.midY - 1.5, width: rect.width, height: 3)
            NSColor.white.withAlphaComponent(0.12).setFill()
            NSBezierPath(roundedRect: bar, xRadius: 1.5, yRadius: 1.5).fill()
            if volume {
                let fraction = (doubleValue - minValue) / (maxValue - minValue)
                let fill = NSRect(x: bar.minX, y: bar.minY, width: bar.width * fraction, height: bar.height)
                NSColor.systemOrange.withAlphaComponent(0.85).setFill()
                NSBezierPath(roundedRect: fill, xRadius: 1.5, yRadius: 1.5).fill()
            }
        }
        override func drawKnob(_ rect: NSRect) {
            let width: CGFloat = volume ? 16 : 3
            let height: CGFloat = volume ? 12 : 15
            let knob = NSRect(x: rect.midX - width / 2, y: rect.midY - height / 2, width: width, height: height)
            let color = volume ? NSColor(white: isEnabled ? 0.85 : 0.45, alpha: 1)
                               : NSColor.white.withAlphaComponent(isEnabled ? 0.65 : 0.25)
            color.setFill()
            NSBezierPath(roundedRect: knob, xRadius: volume ? 6 : 1, yRadius: volume ? 6 : 1).fill()
        }
    }
}

@MainActor
private struct VideoSurface: NSViewRepresentable {
    let view: NSView

    func makeNSView(context: Context) -> NSView { view }
    func updateNSView(_ nsView: NSView, context: Context) {}
}

@MainActor
private struct PlayerContent: View {
    @ObservedObject var model: PlayerModel
    @State private var showsRemainingTime = false
    @State private var dropTargeted = false
    @State private var controlSize = CGSize(width: 440, height: 68)
    // Relative offsets preserve the dragged position across resize/fullscreen.
    @State private var controlOffset = CGSize.zero
    @State private var dragOrigin = CGSize.zero

    private func time(_ seconds: Double) -> String {
        let value = Int(min(max(0, seconds.isFinite ? seconds : 0), Double(Int.max / 2)))
        let hours = value / 3600
        return hours > 0
            ? String(format: "%d:%02d:%02d", hours, value / 60 % 60, value % 60)
            : String(format: "%02d:%02d", value / 60, value % 60)
    }

    private func iconButton(_ symbol: String, _ label: String, action: @escaping () -> Void) -> some View {
        Button(action: action) {
            Image(systemName: symbol).font(.system(size: 17)).frame(width: 24, height: 24)
        }
        .buttonStyle(.plain)
        .help(label)
        .accessibilityLabel(label)
    }

    private var titlebar: some View {
        HStack(spacing: 4) {
            if let icon = model.fileIcon {
                Image(nsImage: icon).resizable().frame(width: 16, height: 16)
            } else {
                Image(systemName: "play.rectangle.fill").font(.system(size: 14))
            }
            Text(model.fileName ?? "Player")
                .font(.system(size: 13, weight: .semibold))
                .lineLimit(1)
                .truncationMode(.middle)
                .help(model.fileName ?? "Player")
            Spacer(minLength: 12)
            iconButton(model.isOnTop ? "pin.fill" : "pin",
                       model.isOnTop ? "Stop Keeping Window on Top" : "Keep Window on Top", action: model.toggleOnTop)
                .foregroundStyle(.white.opacity(model.isOnTop ? 1 : 0.6))
                .disabled(model.isFullScreen)
        }
        .padding(.leading, model.isFullScreen ? 16 : 86)
        .padding(.trailing, 12)
        .frame(height: 32)
        .foregroundStyle(.white.opacity(0.6))
        .background(PlayerGlass(titlebar: true).allowsHitTesting(false))
        .background(WindowChrome(model: model))
        .onHover(perform: model.setTitleHovered)
        .opacity(model.controlsVisible ? 1 : 0)
        .allowsHitTesting(model.controlsVisible)
        .accessibilityHidden(!model.controlsVisible)
    }

    private var playbackControls: some View {
        VStack(spacing: 8) {
            HStack(spacing: 0) {
                HStack(spacing: 4) {
                    iconButton(model.volume == 0 ? "speaker.slash.fill" : "speaker.wave.2.fill",
                               model.volume == 0 ? "Unmute" : "Mute", action: model.toggleMute)
                    PlaybackSlider(value: Binding(get: { model.volume }, set: model.setVolume),
                                   range: 0...1, volume: true, enabled: model.canSetVolume,
                                   onEditingChanged: model.setControlsDragging)
                        .frame(width: 70, height: 14)
                        .accessibilityLabel("Volume")
                        .accessibilityValue("\(Int((model.volume * 100).rounded())) percent")
                }
                .disabled(!model.canSetVolume)
                .frame(width: 106, alignment: .leading)
                Spacer(minLength: 8)
                HStack(spacing: 24) {
                    iconButton("backward.fill", "Seek Back 5 Seconds") { model.seekRelative(-5) }
                        .disabled(!model.canSeek)
                    Button(action: model.togglePlayback) {
                        Image(systemName: model.state.status == PLAYER_PLAYING ? "pause.fill" : "play.fill")
                            .font(.system(size: 24))
                            .frame(width: 24, height: 24)
                    }
                    .buttonStyle(.plain)
                    .accessibilityLabel(model.state.status == PLAYER_PLAYING ? "Pause" : "Play")
                    .help(model.state.status == PLAYER_PLAYING ? "Pause (Space)" : "Play (Space)")
                    .disabled(!model.canTogglePlayback)
                    iconButton("forward.fill", "Seek Forward 5 Seconds") { model.seekRelative(5) }
                        .disabled(!model.canSeek)
                }
                Spacer(minLength: 8)
                HStack(spacing: 12) {
                    iconButton(model.isFullScreen ? "arrow.down.right.and.arrow.up.left" : "arrow.up.left.and.arrow.down.right",
                               model.isFullScreen ? "Exit Full Screen" : "Enter Full Screen", action: model.toggleFullScreen)
                    Menu {
                        Button("Open File…", action: model.openPanel).disabled(!model.canOpen)
                        Button("Close File", action: model.closeFile).disabled(!model.canClose)
                        Divider()
                        Button(model.isOnTop ? "Stop Keeping Window on Top" : "Keep Window on Top", action: model.toggleOnTop)
                            .disabled(model.isFullScreen)
                    } label: {
                        Image(systemName: "gearshape").font(.system(size: 17)).frame(width: 24, height: 24)
                    }
                    .menuStyle(.borderlessButton)
                    .menuIndicator(.hidden)
                    .fixedSize()
                    .accessibilityLabel("Playback Actions")
                    .help("Playback Actions")
                }
                .frame(width: 106, alignment: .trailing)
            }
            .padding(.horizontal, 16)
            .padding(.top, 14)

            HStack(spacing: 10) {
                Text(time(model.seekPosition)).frame(minWidth: 32, alignment: .trailing)
                PlaybackSlider(value: $model.seekPosition, range: 0...max(model.duration, 0.001),
                               enabled: model.canSeek, onEditingChanged: { editing in
                    if editing { model.beginSeeking() } else { model.finishSeeking() }
                })
                .frame(height: 14)
                .accessibilityLabel("Playback Position")
                .accessibilityValue(time(model.seekPosition))
                Button {
                    showsRemainingTime.toggle()
                    model.revealControls()
                } label: {
                    Text(showsRemainingTime ? "−" + time(model.duration - model.seekPosition) : time(model.duration))
                        .frame(minWidth: 32, alignment: .leading)
                }
                .buttonStyle(.plain)
                .help(showsRemainingTime ? "Show Duration" : "Show Remaining Time")
                .accessibilityLabel(showsRemainingTime ? "Remaining Time" : "Duration")
                .accessibilityValue(time(showsRemainingTime ? model.duration - model.seekPosition : model.duration))
            }
            .font(.system(size: 11).monospacedDigit())
            .padding(.horizontal, 16)
            .padding(.bottom, 8)
        }
        .foregroundStyle(.white.opacity(0.6))
        .onHover(perform: model.setControlsHovered)
    }

    private func controllerPosition(in size: CGSize) -> CGPoint {
        let x = size.width / 2 + controlOffset.width * size.width
        let y = size.height * 0.96 - controlSize.height / 2 + controlOffset.height * size.height
        return CGPoint(
            x: min(max(x, controlSize.width / 2 + 12), size.width - controlSize.width / 2 - 12),
            y: min(max(y, 32 + controlSize.height / 2 + 12), size.height - controlSize.height / 2 - 12)
        )
    }

    var body: some View {
        GeometryReader { geometry in
            ZStack(alignment: .top) {
                Color.black
                if let view = model.videoView {
                    VideoSurface(view: view)
                        .accessibilityLabel("Video")
                        .gesture(
                            TapGesture(count: 2).onEnded { model.toggleFullScreen() }
                                .exclusively(before: TapGesture().onEnded { model.hideControls() })
                        )
                }
                if let error = model.errorText {
                    VStack(spacing: 12) {
                        Image(systemName: "exclamationmark.triangle").font(.system(size: 32)).foregroundStyle(.yellow)
                        Text("Unable to Play").font(.headline)
                        Text(error).font(.callout).multilineTextAlignment(.center).textSelection(.enabled)
                        Button("Open Another File…", action: model.openPanel).disabled(!model.canOpen)
                    }
                    .padding(24)
                    .frame(maxWidth: 420)
                    .background(.regularMaterial, in: RoundedRectangle(cornerRadius: 12))
                    .frame(maxWidth: .infinity, maxHeight: .infinity)
                } else if model.isBusy {
                    VStack(spacing: 12) {
                        ProgressView().controlSize(.large)
                        Text("Opening…").font(.callout).foregroundStyle(.secondary)
                    }
                    .frame(maxWidth: .infinity, maxHeight: .infinity)
                } else if model.fileName == nil {
                    VStack(spacing: 14) {
                        Image(systemName: "play.rectangle").font(.system(size: 56, weight: .ultraLight))
                            .foregroundStyle(.white.opacity(0.65))
                        Text("Player").font(.system(size: 22, weight: .medium))
                        Text("Drop a media file here").font(.callout).foregroundStyle(.secondary)
                        Button("Open File…", action: model.openPanel)
                            .buttonStyle(.bordered).controlSize(.large).disabled(!model.canOpen)
                    }
                    .frame(maxWidth: .infinity, maxHeight: .infinity)
                } else if !model.state.has_video && model.state.has_audio {
                    VStack(spacing: 16) {
                        Image(systemName: "waveform").font(.system(size: 64, weight: .ultraLight))
                        Text(model.fileName ?? "").font(.headline).lineLimit(1)
                    }
                    .foregroundStyle(.secondary)
                    .padding(40)
                    .frame(maxWidth: .infinity, maxHeight: .infinity)
                }

                titlebar

                if model.canTogglePlayback {
                    playbackControls
                        .frame(width: 440, height: 68)
                        .background {
                            PlayerGlass()
                                .clipShape(RoundedRectangle(cornerRadius: 12))
                                .gesture(DragGesture(minimumDistance: 4).onChanged { value in
                                    model.setControlsDragging(true)
                                    controlOffset = CGSize(width: dragOrigin.width + value.translation.width / geometry.size.width,
                                                           height: dragOrigin.height + value.translation.height / geometry.size.height)
                                }.onEnded { _ in
                                    let position = controllerPosition(in: geometry.size)
                                    controlOffset = CGSize(width: (position.x - geometry.size.width / 2) / geometry.size.width,
                                                           height: (position.y - (geometry.size.height * 0.96 - controlSize.height / 2)) / geometry.size.height)
                                    dragOrigin = controlOffset
                                    model.setControlsDragging(false)
                                })
                        }
                        .scaleEffect(min(1, (geometry.size.width - 32) / 440))
                        .frame(width: min(440, geometry.size.width - 32),
                               height: 68 * min(1, (geometry.size.width - 32) / 440))
                        .onGeometryChange(for: CGSize.self) { $0.size } action: { controlSize = $0 }
                        .position(controllerPosition(in: geometry.size))
                        .opacity(model.controlsVisible ? 1 : 0)
                        .allowsHitTesting(model.controlsVisible)
                        .accessibilityHidden(!model.controlsVisible)
                }
                if dropTargeted {
                    RoundedRectangle(cornerRadius: 10)
                        .strokeBorder(.white.opacity(0.75), lineWidth: 2)
                        .padding(8)
                        .allowsHitTesting(false)
                }
            }
            .dropDestination(for: URL.self) { urls, _ in
                guard model.canOpen, let url = urls.first, url.isFileURL else { return false }
                model.open(url)
                return true
            } isTargeted: {
                dropTargeted = $0
                model.revealControls()
            }
            .onContinuousHover { phase in
                switch phase {
                case .active: break
                case .ended: model.hideControls(hideCursor: false)
                }
            }
        }
        .ignoresSafeArea()
        .frame(minWidth: 400, minHeight: 240)
        .preferredColorScheme(.dark)
    }
}

@MainActor
private struct WindowChrome: NSViewRepresentable {
    @ObservedObject var model: PlayerModel

    func makeNSView(context: Context) -> ChromeView { ChromeView(model: model) }
    func updateNSView(_ view: ChromeView, context: Context) { view.updateButtons() }
    static func dismantleNSView(_ view: ChromeView, coordinator: ()) { view.detach() }

    final class ChromeView: NSView {
        private let model: PlayerModel
        private weak var configuredWindow: NSWindow?
        private var monitor: Any?
        private var observers: [NSObjectProtocol] = []

        init(model: PlayerModel) {
            self.model = model
            super.init(frame: .zero)
        }
        required init?(coder: NSCoder) { nil }

        override func viewDidMoveToWindow() {
            super.viewDidMoveToWindow()
            guard let window else { detach(); return }
            guard window !== configuredWindow else { return }
            detach()
            configuredWindow = window
            window.styleMask.insert(.fullSizeContentView)
            window.titleVisibility = .hidden
            window.titlebarAppearsTransparent = true
            window.backgroundColor = .black
            window.acceptsMouseMovedEvents = true
            window.collectionBehavior.insert(.fullScreenPrimary)
            window.appearance = NSAppearance(named: .darkAqua)
            for name in [NSWindow.didBecomeKeyNotification, NSWindow.didResignKeyNotification,
                         NSWindow.didEnterFullScreenNotification, NSWindow.didExitFullScreenNotification] {
                observers.append(NotificationCenter.default.addObserver(forName: name, object: window, queue: .main) { [weak self] _ in
                    MainActor.assumeIsolated {
                        self?.model.updateWindowState()
                        self?.updateButtons()
                    }
                })
            }
            monitor = NSEvent.addLocalMonitorForEvents(matching: [.mouseMoved, .leftMouseDown, .keyDown]) { [weak self] event in
                let consumed = MainActor.assumeIsolated {
                    guard let self, event.window === self.configuredWindow else { return false }
                    if event.type == .keyDown && event.keyCode == 48 { self.model.revealControls() }
                    if event.type == .mouseMoved || event.type == .leftMouseDown {
                        self.model.revealControls()
                    } else if event.type == .keyDown && !(event.window?.firstResponder is NSSlider) &&
                                !(event.window?.firstResponder is NSTextView) {
                        if event.keyCode == 53 && self.model.isFullScreen {
                            self.model.toggleFullScreen()
                            return true
                        }
                        if event.modifierFlags.intersection([.command, .control, .option]).isEmpty &&
                            event.charactersIgnoringModifiers?.lowercased() == "f" {
                            self.model.toggleFullScreen()
                            return true
                        }
                    }
                    return false
                }
                return consumed ? nil : event
            }
            Task { @MainActor [weak self, weak window] in
                guard let self, let window else { return }
                self.model.attachWindow(window)
                self.updateButtons()
            }
        }

        func updateButtons() {
            let hidden = !model.controlsVisible || model.isFullScreen
            for button in [NSWindow.ButtonType.closeButton, .miniaturizeButton, .zoomButton] {
                if let view = configuredWindow?.standardWindowButton(button), view.isHidden != hidden {
                    view.isHidden = hidden
                }
            }
        }

        override func mouseDown(with event: NSEvent) { window?.performDrag(with: event) }

        func detach() {
            if let monitor { NSEvent.removeMonitor(monitor) }
            monitor = nil
            observers.forEach(NotificationCenter.default.removeObserver)
            observers.removeAll()
            configuredWindow = nil
        }
    }
}

@MainActor
final class AppDelegate: NSObject, NSApplicationDelegate {
    func applicationDidFinishLaunching(_ notification: Notification) {
        NSApp.setActivationPolicy(.regular)
        NSApp.activate(ignoringOtherApps: true)
    }

    func application(_ application: NSApplication, open urls: [URL]) {
        if let url = urls.first { PlayerModel.shared.open(url) }
    }

    func applicationShouldTerminateAfterLastWindowClosed(_ sender: NSApplication) -> Bool { true }

    func applicationWillTerminate(_ notification: Notification) {
        PlayerModel.shared.shutdown()
    }
}

@main
@MainActor
struct PlayerApp: App {
    @NSApplicationDelegateAdaptor(AppDelegate.self) private var delegate
    @StateObject private var model = PlayerModel.shared

    var body: some Scene {
        Window("\(model.fileName ?? "Player")", id: "player") {
            PlayerContent(model: model)
        }
        .defaultSize(width: 900, height: 560)
        .windowStyle(.hiddenTitleBar)
        .commands {
            CommandGroup(replacing: .newItem) {
                Button("Open File…", action: model.openPanel).keyboardShortcut("o")
                    .disabled(!model.canOpen)
                Button("Close File", action: model.closeFile)
                    .keyboardShortcut("w", modifiers: [.command, .shift])
                    .disabled(!model.canClose)
            }
            CommandMenu("Playback") {
                Button(model.state.status == PLAYER_PLAYING ? "Pause" : "Play", action: model.togglePlayback)
                    .keyboardShortcut(.space, modifiers: []).disabled(!model.canTogglePlayback)
                Button("Seek Back 5 Seconds") { model.seekRelative(-5) }
                    .keyboardShortcut(.leftArrow, modifiers: []).disabled(!model.canSeek)
                Button("Seek Forward 5 Seconds") { model.seekRelative(5) }
                    .keyboardShortcut(.rightArrow, modifiers: []).disabled(!model.canSeek)
                Divider()
                Button("Volume Up") { model.setVolume(min(1, model.volume + 0.05)) }
                    .keyboardShortcut(.upArrow, modifiers: []).disabled(!model.canSetVolume)
                Button("Volume Down") { model.setVolume(max(0, model.volume - 0.05)) }
                    .keyboardShortcut(.downArrow, modifiers: []).disabled(!model.canSetVolume)
                Button(model.volume == 0 ? "Unmute" : "Mute", action: model.toggleMute)
                    .keyboardShortcut("m", modifiers: []).disabled(!model.canSetVolume)
            }
            CommandGroup(after: .windowArrangement) {
                Button(model.isFullScreen ? "Exit Full Screen" : "Enter Full Screen", action: model.toggleFullScreen)
                    .keyboardShortcut("f", modifiers: [.control, .command])
                Button(model.isOnTop ? "Stop Keeping Window on Top" : "Keep Window on Top", action: model.toggleOnTop)
                    .disabled(model.isFullScreen)
            }
        }
    }
}