import SwiftUI

/// Compact player bar with transport, shuffle/repeat, cursor mode, track info, time, volume, skin.
struct PlayerView: View {
    @Environment(PlayerViewModel.self) private var playerVM
    @EnvironmentObject private var theme: AppTheme

    var body: some View {
        VStack(spacing: 0) {
            // Waveform display (clickable for seek)
            WaveformDisplay()

            // Separator between waveform and slider
            if !playerVM.waveformSamples.isEmpty {
                Rectangle()
                    .fill(theme.waveformSeparator)
                    .frame(height: 10)
            }

            // Thin seek slider below the waveform
            SeekSlider()

            HStack(spacing: 0) {
                TransportButtons()

                divider()

                ShuffleRepeatButtons()

                divider()

                CursorModeButton()

                divider()

                TrackInfoStrip()

                Spacer(minLength: 4)

                // Now Playing button
                if playerVM.currentTrack != nil {
                    NowPlayingButton()
                    divider()
                }

                TimeDisplay()

                divider()

                VolumeControl()

                divider()

                SettingsButton()
            }
            .padding(.horizontal, 10)
            .padding(.vertical, 5)
            .frame(height: 52)
        }
        .background(.bar)
    }

    private func divider() -> some View {
        Divider()
            .frame(height: 28)
            .padding(.horizontal, 7)
    }
}

// MARK: - Waveform Display (visual, clickable for seek)

private struct WaveformDisplay: View {
    @Environment(PlayerViewModel.self) private var playerVM
    @EnvironmentObject private var theme: AppTheme
    @State private var isDragging = false
    @State private var dragProgress: Double = 0

    var body: some View {
        if !playerVM.waveformSamples.isEmpty {
            GeometryReader { geo in
                let progress = isDragging ? dragProgress : playerVM.progress
                let samples = playerVM.waveformSamples

                    Canvas { context, size in
                    let midY = size.height / 2
                    let count = samples.count
                    guard count > 0 else { return }

                    let playedIndex = Int(progress * Double(count))

                    for (index, sample) in samples.enumerated() {
                        let x = CGFloat(index) / CGFloat(count) * size.width
                        let barWidth = max(0.5, size.width / CGFloat(count) - 0.3)

                        let topHeight = CGFloat(sample.max) * midY
                        let bottomHeight = CGFloat(-sample.min) * midY

                        let rect = CGRect(
                            x: x,
                            y: midY - topHeight,
                            width: barWidth,
                            height: topHeight + bottomHeight
                        )

                        let color = index < playedIndex
                            ? theme.primaryText
                            : theme.waveformBackground
                        context.fill(Path(rect), with: .color(color))
                    }

                    // Playhead line
                    let playheadX = progress * size.width
                    var playheadPath = Path()
                    playheadPath.move(to: CGPoint(x: playheadX, y: 0))
                    playheadPath.addLine(to: CGPoint(x: playheadX, y: size.height))
                    context.stroke(playheadPath, with: .color(theme.accent), lineWidth: 1.5)
                }
                .contentShape(Rectangle())
                .gesture(
                    DragGesture(minimumDistance: 0)
                        .onChanged { value in
                            isDragging = true
                            dragProgress = max(0, min(1, value.location.x / geo.size.width))
                        }
                        .onEnded { value in
                            let prog = max(0, min(1, value.location.x / geo.size.width))
                            playerVM.seekToProgress(prog)
                            isDragging = false
                        }
                )
            }
            .frame(height: 32)
        }
    }
}

// MARK: - Seek Slider (thin progress bar)

private struct SeekSlider: View {
    @Environment(PlayerViewModel.self) private var playerVM
    @EnvironmentObject private var theme: AppTheme
    @State private var isDragging = false
    @State private var dragProgress: Double = 0

    var body: some View {
        GeometryReader { geo in
            let progress = isDragging ? dragProgress : playerVM.progress

            ZStack(alignment: .leading) {
                // Background track
                Rectangle()
                    .fill(theme.seekbarBackground)

                // Filled portion — matches volume slider color (accent)
                Rectangle()
                    .fill(theme.accent)
                    .frame(width: max(0, progress * geo.size.width))
            }
            .contentShape(Rectangle())
            .gesture(
                DragGesture(minimumDistance: 0)
                    .onChanged { value in
                        isDragging = true
                        dragProgress = max(0, min(1, value.location.x / geo.size.width))
                    }
                    .onEnded { value in
                        let prog = max(0, min(1, value.location.x / geo.size.width))
                        playerVM.seekToProgress(prog)
                        isDragging = false
                    }
            )
        }
        .frame(height: 4)
    }
}

// MARK: - Transport Buttons

private struct TransportButtons: View {
    @Environment(PlayerViewModel.self) private var playerVM

    var body: some View {
        HStack(spacing: 5) {
            btn("stop.fill", help: "Stop") { playerVM.stop() }
            btn("backward.end.fill", help: "Previous Track") { playerVM.playPrevious() }
            btn(playerVM.isPlaying ? "pause.fill" : "play.fill", help: playerVM.isPlaying ? "Pause (Space)" : "Play (Space)") { playerVM.togglePlayPause() }
            btn("forward.end.fill", help: "Next Track") { playerVM.playNext() }
        }
    }

    private func btn(_ icon: String, help: String, action: @escaping () -> Void) -> some View {
        Button(action: action) {
            Image(systemName: icon)
                .font(.system(size: 20))
                .frame(width: 40, height: 40)
                .contentShape(Rectangle())
        }
        .buttonStyle(.plain)
        .disabled(playerVM.currentTrack == nil)
        .help(help)
    }
}

// MARK: - Shuffle & Repeat

private struct ShuffleRepeatButtons: View {
    @Environment(PlayerViewModel.self) private var playerVM
    @EnvironmentObject private var theme: AppTheme

    var body: some View {
        HStack(spacing: 4) {
            Button {
                playerVM.shuffleEnabled.toggle()
            } label: {
                Image(systemName: "shuffle")
                    .font(.system(size: 17))
                    .frame(width: 36, height: 36)
                    .foregroundStyle(playerVM.shuffleEnabled ? theme.accent : theme.tertiaryText)
                    .contentShape(Rectangle())
            }
            .buttonStyle(.plain)
            .help(playerVM.shuffleEnabled ? "Shuffle: On" : "Shuffle: Off")

            Button {
                switch playerVM.repeatMode {
                case .off: playerVM.repeatMode = .all
                case .all: playerVM.repeatMode = .one
                case .one: playerVM.repeatMode = .off
                }
            } label: {
                Image(systemName: playerVM.repeatMode == .one ? "repeat.1" : "repeat")
                    .font(.system(size: 17))
                    .frame(width: 36, height: 36)
                    .foregroundStyle(playerVM.repeatMode != .off ? theme.accent : theme.tertiaryText)
                    .contentShape(Rectangle())
            }
            .buttonStyle(.plain)
            .help("Repeat: \(playerVM.repeatMode.rawValue)")
        }
    }
}

// MARK: - Cursor Mode Toggle

private struct CursorModeButton: View {
    @EnvironmentObject private var theme: AppTheme
    @ObservedObject private var viewConfig = PlaylistViewConfig.shared

    var body: some View {
        Button {
            // Toggle between the two modes (always keep at least one on)
            if viewConfig.cursorFollowsPlayback {
                viewConfig.cursorFollowsPlayback = false
                viewConfig.playbackFollowsCursor = true
            } else {
                viewConfig.cursorFollowsPlayback = true
                viewConfig.playbackFollowsCursor = false
            }
        } label: {
            // Both arrows point right (= playback direction)
            // Line position = cursor:  |→  vs  →|
            Group {
                if viewConfig.cursorFollowsPlayback {
                    // |→  (cursor behind, playback pulls cursor forward)
                    Image(systemName: "arrow.right.to.line")
                        .scaleEffect(x: -1, y: 1)
                } else {
                    // →|  (cursor ahead, playback goes to where cursor points)
                    Image(systemName: "arrow.right.to.line")
                }
            }
            .font(.system(size: 17))
                .frame(width: 36, height: 36)
                .foregroundStyle(theme.accent)
                .contentShape(Rectangle())
        }
        .buttonStyle(.plain)
        .help(viewConfig.cursorFollowsPlayback ? "Cursor follows playback (click to switch)" : "Playback follows cursor (click to switch)")
    }
}

// MARK: - Track Info Strip

private struct TrackInfoStrip: View {
    @Environment(PlayerViewModel.self) private var playerVM
    @EnvironmentObject private var theme: AppTheme

    var body: some View {
        if let track = playerVM.currentTrack {
            HStack(spacing: 5) {
                if playerVM.isPlaying {
                    Image(systemName: "speaker.wave.2.fill")
                        .font(.system(size: 10))
                        .foregroundStyle(theme.playingHighlight)
                }

                Text(trackDescription(track))
                    .font(.system(size: theme.dataFontSize))
                    .lineLimit(1)
                    .truncationMode(.tail)
                    .foregroundStyle(theme.primaryText)
            }
        } else {
            Text("Stopped")
                .font(.system(size: theme.dataFontSize))
                .foregroundStyle(theme.tertiaryText)
        }
    }

    private func trackDescription(_ track: Track) -> String {
        var parts: [String] = []
        if !track.artist.isEmpty { parts.append(track.artist) }
        parts.append(track.title)
        if !track.album.isEmpty { parts.append("[\(track.album)]") }
        return parts.joined(separator: " - ")
    }
}

// MARK: - Time Display

private struct TimeDisplay: View {
    @Environment(PlayerViewModel.self) private var playerVM
    @EnvironmentObject private var theme: AppTheme

    var body: some View {
        if playerVM.currentTrack != nil {
            Text("\(playerVM.currentTimeFormatted) / \(playerVM.durationFormatted)")
                .font(.system(size: 14, design: .monospaced))
                .foregroundStyle(theme.secondaryText)
                .fixedSize()
        }
    }
}

// MARK: - Volume Control

private struct VolumeControl: View {
    @Environment(PlayerViewModel.self) private var playerVM
    @EnvironmentObject private var theme: AppTheme

    var body: some View {
        @Bindable var vm = playerVM

        HStack(spacing: 4) {
            Image(systemName: "speaker.fill")
                .font(.system(size: 10))
                .foregroundStyle(theme.secondaryText)

            Slider(value: $vm.volume, in: 0...1)
                .frame(width: 70)
                .controlSize(.small)
                .tint(theme.accent)
        }
        .help("Volume: \(Int(playerVM.volume * 100))%")
    }
}

// MARK: - Settings Button

private struct SettingsButton: View {
    @EnvironmentObject private var theme: AppTheme
    @Environment(\.openSettings) private var openSettings

    var body: some View {
        Button {
            openSettings()
        } label: {
            Image(systemName: "gearshape")
                .font(.system(size: 14))
                .foregroundStyle(theme.secondaryText)
                .frame(width: 30, height: 30)
                .contentShape(Rectangle())
        }
        .buttonStyle(.plain)
        .help("Settings (⌘,)")
    }
}

// MARK: - Now Playing Button

private struct NowPlayingButton: View {
    @EnvironmentObject private var theme: AppTheme

    var body: some View {
        Button {
            NotificationCenter.default.post(name: .toggleNowPlaying, object: nil)
        } label: {
            Image(systemName: "text.below.photo")
                .font(.system(size: 14))
                .frame(width: 30, height: 30)
                .foregroundStyle(theme.secondaryText)
                .contentShape(Rectangle())
        }
        .buttonStyle(.plain)
        .help("Now Playing (⇧⌘P)")
    }
}