import Defaults
import Foundation
import SDWebImageSwiftUI
import SwiftUI

struct PlayerControls: View {
    static let animation = Animation.easeInOut(duration: 0.2)

    private var player: PlayerModel { .shared }
    private var thumbnails: ThumbnailsModel { .shared }

    @ObservedObject private var model = PlayerControlsModel.shared

    #if os(iOS)
        @Environment(\.verticalSizeClass) private var verticalSizeClass
        @ObservedObject private var safeAreaModel = SafeAreaModel.shared
    #elseif os(tvOS)
        enum Field: Hashable {
            case seekOSD
            case play
            case backward
            case forward
            case settings
            case close
        }

        @FocusState private var focusedField: Field?
    #endif

    @Default(.playerControlsLayout) private var regularPlayerControlsLayout
    @Default(.fullScreenPlayerControlsLayout) private var fullScreenPlayerControlsLayout
    @Default(.buttonBackwardSeekDuration) private var buttonBackwardSeekDuration
    @Default(.buttonForwardSeekDuration) private var buttonForwardSeekDuration

    #if os(iOS)
        @Default(.playerControlsLockOrientationEnabled) private var playerControlsLockOrientationEnabled
    #endif
    @Default(.playerControlsSettingsEnabled) private var playerControlsSettingsEnabled
    @Default(.playerControlsCloseEnabled) private var playerControlsCloseEnabled
    @Default(.playerControlsRestartEnabled) private var playerControlsRestartEnabled
    @Default(.playerControlsAdvanceToNextEnabled) private var playerControlsAdvanceToNextEnabled
    @Default(.playerControlsPlaybackModeEnabled) private var playerControlsPlaybackModeEnabled
    @Default(.playerControlsMusicModeEnabled) private var playerControlsMusicModeEnabled

    @Default(.avPlayerUsesSystemControls) private var avPlayerUsesSystemControls

    private let controlsOverlayModel = ControlOverlaysModel.shared
    private var navigation = NavigationModel.shared

    var playerControlsLayout: PlayerControlsLayout {
        player.playingFullScreen ? fullScreenPlayerControlsLayout : regularPlayerControlsLayout
    }

    var showControls: Bool {
        player.activeBackend == .mpv || !avPlayerUsesSystemControls || player.musicMode
    }

    var body: some View {
        ZStack(alignment: .topLeading) {
            if showControls {
                Seek()
                    .zIndex(4)
                    .transition(.opacity)
                    .frame(maxWidth: .infinity, alignment: .topLeading)
                #if os(tvOS)
                    .focused($focusedField, equals: .seekOSD)
                    .onChange(of: player.seek.lastSeekTime) { _ in
                        if !model.presentingControls {
                            focusedField = .seekOSD
                        }
                    }
                #else
                    .offset(y: 2)
                #endif
            }

            VStack {
                ZStack {
                    VStack(spacing: 0) {
                        ZStack {
                            OpeningStream()
                            NetworkState()
                        }

                        Spacer()
                    }
                    .offset(y: playerControlsLayout.osdVerticalOffset + 5)

                    if showControls {
                        Section {
                            #if !os(tvOS)
                                HStack {
                                    seekBackwardButton
                                    Spacer()
                                    togglePlayButton
                                    Spacer()
                                    seekForwardButton
                                }
                                .font(.system(size: playerControlsLayout.bigButtonFontSize))
                            #endif

                            ZStack(alignment: .bottom) {
                                VStack(spacing: 4) {
                                    #if !os(tvOS)
                                        buttonsBar

                                        HStack {
                                            if !player.currentVideo.isNil, player.playingFullScreen {
                                                Button {
                                                    withAnimation(Self.animation) {
                                                        model.presentingDetailsOverlay = true
                                                    }
                                                } label: {
                                                    ControlsBar(fullScreen: $model.presentingDetailsOverlay, expansionState: .constant(.full), presentingControls: false, detailsTogglePlayer: false, detailsToggleFullScreen: false)
                                                        .clipShape(RoundedRectangle(cornerRadius: 4))
                                                        .frame(maxWidth: 300, alignment: .leading)
                                                }
                                                .buttonStyle(.plain)
                                            }
                                            Spacer()
                                        }
                                    #endif

                                    Spacer()

                                    if playerControlsLayout.displaysTitleLine {
                                        VStack(alignment: .leading) {
                                            Text(player.videoForDisplay?.displayTitle ?? "Not Playing")
                                                .shadow(radius: 10)
                                                .font(.system(size: playerControlsLayout.titleLineFontSize).bold())
                                                .lineLimit(1)

                                            Text(player.currentVideo?.displayAuthor ?? "")
                                                .fontWeight(.semibold)
                                                .shadow(radius: 10)
                                                .foregroundColor(.init(white: 0.8))
                                                .font(.system(size: playerControlsLayout.authorLineFontSize))
                                                .lineLimit(1)
                                        }
                                        .foregroundColor(.white)
                                        .frame(maxWidth: .infinity, alignment: .leading)
                                        .offset(y: -40)
                                    }

                                    timeline
                                        .padding(.bottom, 2)
                                }
                                .zIndex(1)
                                .padding(.top, 2)
                                .transition(.opacity)

                                HStack(spacing: playerControlsLayout.buttonsSpacing) {
                                    #if os(tvOS)
                                        togglePlayButton
                                        seekBackwardButton
                                        seekForwardButton
                                    #endif
                                    if playerControlsRestartEnabled {
                                        restartVideoButton
                                    }
                                    if playerControlsAdvanceToNextEnabled {
                                        advanceToNextItemButton
                                    }
                                    Spacer()
                                    #if os(tvOS)
                                        if playerControlsSettingsEnabled {
                                            settingsButton
                                        }
                                    #endif
                                    if playerControlsPlaybackModeEnabled {
                                        playbackModeButton
                                    }
                                    #if os(tvOS)
                                        closeVideoButton
                                    #else
                                        if playerControlsMusicModeEnabled {
                                            musicModeButton
                                        }
                                    #endif
                                }
                                .zIndex(0)
                                #if os(tvOS)
                                    .offset(y: -playerControlsLayout.timelineHeight - 30)
                                #else
                                    .offset(y: -playerControlsLayout.timelineHeight - 5)
                                #endif
                            }
                        }
                        .opacity(model.presentingControls && !player.availableStreams.isEmpty ? 1 : 0)
                    }
                }
            }
            .frame(maxWidth: .infinity)
            #if os(tvOS)
                .onChange(of: model.presentingControls) { newValue in
                    if newValue {
                        focusedField = .play
                    } else {
                        focusedField = nil
                    }
                }
                .onChange(of: focusedField) { _ in model.resetTimer() }
            #else
                .background(PlayerGestures())
                .background(controlsBackground)
            #endif

            if model.presentingDetailsOverlay {
                Section {
                    VideoDetailsOverlay()
                        .frame(maxWidth: detailsWidth, maxHeight: detailsHeight)
                        .transition(.opacity)
                }
                .frame(maxHeight: .infinity, alignment: .top)
            }
        }
        .onChange(of: model.presentingOverlays) { newValue in
            if newValue {
                model.hide()
            }
        }
        #if os(tvOS)
        .onReceive(model.reporter) { value in
            guard player.presentingPlayer else { return }
            if value == "swipe down", !model.presentingControls, !model.presentingOverlays {
                withAnimation(Self.animation) {
                    controlsOverlayModel.hide()
                }
            } else {
                model.show()
            }
            model.resetTimer()
        }
        #endif
    }

    var detailsWidth: Double {
        guard player.playerSize.width.isFinite else { return 200 }
        return [player.playerSize.width, 600].min()!
    }

    var detailsHeight: Double {
        guard player.playerSize.height.isFinite else { return 200 }
        var inset = 0.0
        #if os(iOS)
            inset = safeAreaModel.safeArea.bottom
        #endif
        return [player.playerSize.height - inset, 500].min()!
    }

    @ViewBuilder var controlsBackground: some View {
        ZStack {
            if player.musicMode,
               let url = controlsBackgroundURL
            {
                ThumbnailView(url: url)
                    .frame(maxWidth: .infinity, maxHeight: .infinity)
                    .transition(.opacity)
                    .animation(.default)
            } else if player.videoForDisplay == nil {
                Color.black
            }
        }
    }

    var controlsBackgroundURL: URL? {
        if let video = player.videoForDisplay,
           let url = thumbnails.best(video).url
        {
            return url
        }

        return nil
    }

    var timeline: some View {
        TimelineView(context: .player).foregroundColor(.primary)
    }

    private var hidePlayerButton: some View {
        button("Hide", systemImage: "chevron.down") {
            player.hide()
        }

        #if !os(tvOS)
        .keyboardShortcut(.cancelAction)
        #endif
    }

    private var playbackStatus: String {
        if player.live {
            return "LIVE"
        }

        guard !player.isLoadingVideo else {
            return "loading..."
        }

        let videoLengthAtRate = (player.currentVideo?.length ?? 0) / Double(player.currentRate)
        let remainingSeconds = videoLengthAtRate - (player.time?.seconds ?? 0)

        if remainingSeconds < 60 {
            return "less than a minute"
        }

        let timeFinishAt = Date().addingTimeInterval(remainingSeconds)

        return "ends at \(formattedTimeFinishAt(timeFinishAt))"
    }

    private func formattedTimeFinishAt(_ date: Date) -> String {
        let dateFormatter = DateFormatter()

        dateFormatter.dateStyle = .none
        dateFormatter.timeStyle = .short

        return dateFormatter.string(from: date)
    }

    var buttonsBar: some View {
        HStack(spacing: playerControlsLayout.buttonsSpacing) {
            fullscreenButton

            pipButton
            #if os(iOS)
                if playerControlsLockOrientationEnabled {
                    lockOrientationButton
                }
            #endif

            Spacer()

            if playerControlsSettingsEnabled {
                settingsButton
            }

            if playerControlsCloseEnabled {
                closeVideoButton
            }
        }
    }

    var fullscreenButton: some View {
        button(
            "Fullscreen",
            systemImage: player.fullscreenImage
        ) {
            player.toggleFullscreen(player.playingFullScreen, showControls: false)
        }
        #if !os(tvOS)
        .keyboardShortcut(player.playingFullScreen ? .cancelAction : .defaultAction)
        #endif
    }

    private var settingsButton: some View {
        button("settings", systemImage: "gearshape") {
            withAnimation(Self.animation) {
                #if os(tvOS)
                    controlsOverlayModel.toggle()
                #else
                    navigation.presentingPlaybackSettings = true
                #endif
            }
        }
        #if os(tvOS)
        .focused($focusedField, equals: .settings)
        #endif
    }

    private var closeVideoButton: some View {
        button("Close", systemImage: "xmark") {
            player.closeCurrentItem()
        }
        #if os(tvOS)
        .focused($focusedField, equals: .close)
        #endif
    }

    private var musicModeButton: some View {
        button("Music Mode", systemImage: "music.note", active: player.musicMode, action: player.toggleMusicMode)
    }

    private var pipButton: some View {
        button("PiP", systemImage: player.pipImage, action: player.togglePiPAction)
            .disabled(!player.pipPossible)
    }

    #if os(iOS)
        private var lockOrientationButton: some View {
            button("Lock Rotation", systemImage: player.lockOrientationImage, active: !player.lockedOrientation.isNil, action: player.lockOrientationAction)
        }
    #endif

    var playbackModeButton: some View {
        button("Playback Mode", systemImage: player.playbackMode.systemImage) {
            player.playbackMode = player.playbackMode.next()
            model.objectWillChange.send()
        }
    }

    var seekBackwardButton: some View {
        var foregroundColor: Color?
        var fontSize: Double?
        var size: Double?
        #if !os(tvOS)
            foregroundColor = .white
            fontSize = playerControlsLayout.bigButtonFontSize
            size = playerControlsLayout.bigButtonSize
        #endif

        let interval = TimeInterval(buttonBackwardSeekDuration) ?? 10

        return button(
            "Seek Backward",
            systemImage: Constants.seekIcon("backward", interval),
            fontSize: fontSize, size: size, cornerRadius: 5, background: false, foregroundColor: foregroundColor
        ) {
            player.backend.seek(relative: .secondsInDefaultTimescale(-interval), seekType: .userInteracted)
        }
        .disabled(player.liveStreamInAVPlayer)
        #if os(tvOS)
            .focused($focusedField, equals: .backward)
        #else
            .keyboardShortcut("k", modifiers: [])
            .keyboardShortcut(KeyEquivalent.leftArrow, modifiers: [])
        #endif
    }

    var seekForwardButton: some View {
        var foregroundColor: Color?
        var fontSize: Double?
        var size: Double?
        #if !os(tvOS)
            foregroundColor = .white
            fontSize = playerControlsLayout.bigButtonFontSize
            size = playerControlsLayout.bigButtonSize
        #endif

        let interval = TimeInterval(buttonForwardSeekDuration) ?? 10

        return button(
            "Seek Forward",
            systemImage: Constants.seekIcon("forward", interval),
            fontSize: fontSize, size: size, cornerRadius: 5, background: false, foregroundColor: foregroundColor
        ) {
            player.backend.seek(relative: .secondsInDefaultTimescale(interval), seekType: .userInteracted)
        }
        .disabled(player.liveStreamInAVPlayer)
        #if os(tvOS)
            .focused($focusedField, equals: .forward)
        #else
            .keyboardShortcut("l", modifiers: [])
            .keyboardShortcut(KeyEquivalent.rightArrow, modifiers: [])
        #endif
    }

    private var restartVideoButton: some View {
        button("Restart video", systemImage: "backward.end.fill", cornerRadius: 5, action: player.replayAction)
    }

    private var togglePlayButton: some View {
        var foregroundColor: Color?
        var fontSize: Double?
        var size: Double?
        #if !os(tvOS)
            foregroundColor = .white
            fontSize = playerControlsLayout.bigButtonFontSize
            size = playerControlsLayout.bigButtonSize
        #endif

        return button(
            model.isPlaying ? "Pause" : "Play",
            systemImage: model.isPlaying ? "pause.fill" : "play.fill",
            fontSize: fontSize,
            size: size,
            background: false, foregroundColor: foregroundColor
        ) {
            player.backend.togglePlay()
        }
        #if os(tvOS)
        .focused($focusedField, equals: .play)
        #else
        .keyboardShortcut("p")
        .keyboardShortcut(.space)
        #endif
        .disabled(model.isLoadingVideo)
    }

    private var advanceToNextItemButton: some View {
        button("Next", systemImage: "forward.fill", cornerRadius: 5) {
            player.advanceToNextItem()
        }
        .disabled(!player.isAdvanceToNextItemAvailable)
    }

    func button(
        _ label: String,
        systemImage: String? = nil,
        fontSize: Double? = nil,
        size: Double? = nil,
        width _: Double? = nil,
        height _: Double? = nil,
        cornerRadius: Double = 3,
        background: Bool = false,
        foregroundColor: Color? = nil,
        active: Bool = false,
        action: @escaping () -> Void = {}
    ) -> some View {
        #if os(tvOS)
            let useBackground = false
        #else
            let useBackground = background
        #endif
        return Button {
            action()
            model.resetTimer()
        } label: {
            Group {
                if let image = systemImage {
                    Label(label, systemImage: image)
                        .labelStyle(.iconOnly)
                } else {
                    Label(label, systemImage: "")
                        .labelStyle(.titleOnly)
                }
            }
            .padding()
            .contentShape(Rectangle())
            .shadow(radius: (foregroundColor == .white || !useBackground) ? 3 : 0)
        }
        .font(.system(size: fontSize ?? playerControlsLayout.buttonFontSize))
        .buttonStyle(.plain)
        .foregroundColor(foregroundColor.isNil ? (active ? Color("AppRedColor") : .primary) : foregroundColor)
        .frame(width: size ?? playerControlsLayout.buttonSize, height: size ?? playerControlsLayout.buttonSize)
        .modifier(ControlBackgroundModifier(enabled: useBackground))
        .clipShape(RoundedRectangle(cornerRadius: cornerRadius))
        .environment(\.colorScheme, .dark)
    }
}

struct PlayerControls_Previews: PreviewProvider {
    static var previews: some View {
        ZStack {
            Color.gray

            PlayerControls()
                .injectFixtureEnvironmentObjects()
        }
    }
}