import SwiftUI

// MARK: - Rotary Knob

/// A hardware-inspired rotary knob control. Drag vertically to adjust value.
struct RotaryKnobView: View {
    @Binding var value: Float  // 0...1
    var label: String = ""
    var size: CGFloat = 48
    var accentColor: Color = Color(red: 0, green: 0.83, blue: 1.0)

    @State private var isDragging = false
    @State private var dragStartValue: Float = 0

    // Knob rotates from -135deg to +135deg (270deg total range)
    private var rotationAngle: Double {
        Double(value) * 270 - 135
    }

    var body: some View {
        VStack(spacing: 4) {
            ZStack {
                // Outer ring — brushed metal
                Circle()
                    .fill(
                        AngularGradient(
                            colors: [
                                Color(white: 0.25), Color(white: 0.35),
                                Color(white: 0.20), Color(white: 0.30),
                                Color(white: 0.25),
                            ],
                            center: .center
                        )
                    )
                    .frame(width: size, height: size)

                // Value arc
                Circle()
                    .trim(from: 0, to: CGFloat(value) * 0.75)
                    .rotation(.degrees(135))
                    .stroke(
                        accentColor,
                        style: StrokeStyle(lineWidth: 3, lineCap: .round)
                    )
                    .frame(width: size + 6, height: size + 6)
                    .shadow(color: accentColor.opacity(0.6), radius: 4)

                // Inner circle — darker center
                Circle()
                    .fill(
                        RadialGradient(
                            colors: [Color(white: 0.18), Color(white: 0.12)],
                            center: .center,
                            startRadius: 0,
                            endRadius: size * 0.35
                        )
                    )
                    .frame(width: size * 0.7, height: size * 0.7)

                // Position indicator line
                Rectangle()
                    .fill(accentColor)
                    .frame(width: 2, height: size * 0.25)
                    .offset(y: -size * 0.2)
                    .rotationEffect(.degrees(rotationAngle))
                    .shadow(color: accentColor.opacity(0.8), radius: 2)
            }
            .gesture(
                DragGesture(minimumDistance: 1)
                    .onChanged { gesture in
                        if !isDragging {
                            isDragging = true
                            dragStartValue = value
                        }
                        // Vertical drag: up = increase, down = decrease
                        let delta = Float(-gesture.translation.height / 150)
                        value = max(0, min(1, dragStartValue + delta))
                    }
                    .onEnded { _ in isDragging = false }
            )

            if !label.isEmpty {
                Text(label)
                    .font(.system(size: 9, weight: .bold, design: .monospaced))
                    .foregroundStyle(Color(white: 0.5))
            }
        }
    }
}

// MARK: - VU Meter

/// Vertical LED-strip level meter. Green → Yellow → Red.
struct VUMeterView: View {
    var level: Float  // 0...1
    var segmentCount: Int = 12
    var width: CGFloat = 8
    var height: CGFloat = 60

    var body: some View {
        VStack(spacing: 1.5) {
            ForEach((0..<segmentCount).reversed(), id: \.self) { index in
                let threshold = Float(index) / Float(segmentCount)
                let isLit = level > threshold
                let color = segmentColor(index: index)

                RoundedRectangle(cornerRadius: 1)
                    .fill(isLit ? color : color.opacity(0.15))
                    .frame(width: width, height: max(2, height / CGFloat(segmentCount) - 1.5))
                    .shadow(color: isLit ? color.opacity(0.5) : .clear, radius: 2)
            }
        }
    }

    private func segmentColor(index: Int) -> Color {
        let ratio = Float(index) / Float(segmentCount)
        if ratio >= 0.83 { return Color(red: 1.0, green: 0.1, blue: 0.1) }      // Red
        if ratio >= 0.66 { return Color(red: 1.0, green: 0.8, blue: 0.0) }      // Yellow
        return Color(red: 0.0, green: 0.85, blue: 0.4)                            // Green
    }
}

// MARK: - LED Display

/// Seven-segment-style glowing text display for BPM, time, key.
struct LEDDisplay: View {
    let text: String
    var fontSize: CGFloat = 16
    var color: Color = Color(red: 0, green: 0.83, blue: 1.0)
    var alignment: Alignment = .center

    var body: some View {
        Text(text)
            .font(.system(size: fontSize, weight: .bold, design: .monospaced))
            .foregroundStyle(color)
            .shadow(color: color.opacity(0.7), radius: 4)
            .shadow(color: color.opacity(0.3), radius: 8)
            .frame(maxWidth: .infinity, alignment: alignment)
            .padding(.horizontal, 6)
            .padding(.vertical, 3)
            .background(
                RoundedRectangle(cornerRadius: 4)
                    .fill(Color(white: 0.05))
                    .overlay(
                        RoundedRectangle(cornerRadius: 4)
                            .stroke(Color(white: 0.15), lineWidth: 0.5)
                    )
            )
    }
}

// MARK: - DJ Transport Button

/// Hardware-inspired raised button for transport controls.
struct DJTransportButton: View {
    let icon: String
    var size: ButtonSize = .regular
    var isActive: Bool = false
    var accentColor: Color = Color(red: 0, green: 0.83, blue: 1.0)
    let action: () -> Void

    enum ButtonSize {
        case small, regular, large

        var dimension: CGFloat {
            switch self {
            case .small: 28
            case .regular: 36
            case .large: 52
            }
        }

        var iconSize: CGFloat {
            switch self {
            case .small: 12
            case .regular: 16
            case .large: 24
            }
        }
    }

    @State private var isPressed = false

    var body: some View {
        Button(action: action) {
            Image(systemName: icon)
                .font(.system(size: size.iconSize, weight: .semibold))
                .foregroundStyle(isActive ? accentColor : Color(white: 0.7))
                .frame(width: size.dimension, height: size.dimension)
                .background(
                    ZStack {
                        // Base
                        RoundedRectangle(cornerRadius: size.dimension * 0.2)
                            .fill(
                                LinearGradient(
                                    colors: isPressed
                                        ? [Color(white: 0.12), Color(white: 0.16)]
                                        : [Color(white: 0.22), Color(white: 0.14)],
                                    startPoint: .top,
                                    endPoint: .bottom
                                )
                            )

                        // Border
                        RoundedRectangle(cornerRadius: size.dimension * 0.2)
                            .stroke(
                                LinearGradient(
                                    colors: [Color(white: 0.3), Color(white: 0.1)],
                                    startPoint: .top,
                                    endPoint: .bottom
                                ),
                                lineWidth: 1
                            )
                    }
                )
                .shadow(
                    color: isActive ? accentColor.opacity(0.3) : .clear,
                    radius: 4
                )
                .shadow(
                    color: Color.black.opacity(isPressed ? 0 : 0.5),
                    radius: isPressed ? 0 : 2,
                    y: isPressed ? 0 : 2
                )
                .scaleEffect(isPressed ? 0.95 : 1.0)
                .animation(.easeOut(duration: 0.1), value: isPressed)
        }
        .buttonStyle(.plain)
        .onLongPressGesture(minimumDuration: .infinity, pressing: { pressing in
            isPressed = pressing
        }, perform: {})
    }
}

// MARK: - Fader

/// Vertical fader for EQ bands. Drag to adjust.
struct FaderView: View {
    @Binding var value: Float  // -1...1 for EQ, or 0...1 for volume
    var label: String = ""
    var range: ClosedRange<Float> = -1...1
    var height: CGFloat = 80
    var accentColor: Color = Color(red: 0, green: 0.83, blue: 1.0)

    @State private var isDragging = false
    @State private var dragStartValue: Float = 0

    private var normalizedValue: CGFloat {
        CGFloat((value - range.lowerBound) / (range.upperBound - range.lowerBound))
    }

    var body: some View {
        VStack(spacing: 4) {
            ZStack(alignment: .bottom) {
                // Track groove
                RoundedRectangle(cornerRadius: 2)
                    .fill(Color(white: 0.08))
                    .frame(width: 6, height: height)
                    .overlay(
                        RoundedRectangle(cornerRadius: 2)
                            .stroke(Color(white: 0.2), lineWidth: 0.5)
                    )

                // Value fill
                RoundedRectangle(cornerRadius: 2)
                    .fill(accentColor.opacity(0.5))
                    .frame(width: 6, height: height * normalizedValue)

                // Fader cap
                RoundedRectangle(cornerRadius: 3)
                    .fill(
                        LinearGradient(
                            colors: [Color(white: 0.45), Color(white: 0.25)],
                            startPoint: .top,
                            endPoint: .bottom
                        )
                    )
                    .frame(width: 20, height: 12)
                    .shadow(color: .black.opacity(0.4), radius: 2, y: 1)
                    .offset(y: -height * normalizedValue + 6)
            }
            .frame(width: 20, height: height)
            .gesture(
                DragGesture(minimumDistance: 1)
                    .onChanged { gesture in
                        if !isDragging {
                            isDragging = true
                            dragStartValue = value
                        }
                        let delta = Float(-gesture.translation.height / height)
                            * (range.upperBound - range.lowerBound)
                        value = max(range.lowerBound, min(range.upperBound, dragStartValue + delta))
                    }
                    .onEnded { _ in isDragging = false }
            )

            if !label.isEmpty {
                Text(label)
                    .font(.system(size: 8, weight: .bold, design: .monospaced))
                    .foregroundStyle(Color(white: 0.5))
            }
        }
    }
}

// MARK: - DJ Section Background

/// Textured surface for grouping DJ controls.
struct DJSectionBackground: View {
    var cornerRadius: CGFloat = 8

    var body: some View {
        RoundedRectangle(cornerRadius: cornerRadius)
            .fill(
                LinearGradient(
                    colors: [
                        Color(red: 0.06, green: 0.06, blue: 0.08),
                        Color(red: 0.04, green: 0.04, blue: 0.06),
                    ],
                    startPoint: .top,
                    endPoint: .bottom
                )
            )
            .overlay(
                RoundedRectangle(cornerRadius: cornerRadius)
                    .stroke(
                        LinearGradient(
                            colors: [Color(white: 0.15), Color(white: 0.05)],
                            startPoint: .top,
                            endPoint: .bottom
                        ),
                        lineWidth: 1
                    )
            )
            .shadow(color: .black.opacity(0.5), radius: 4, y: 2)
    }
}

// MARK: - Vinyl Spin Animation

/// Album art with vinyl grooves that spins during playback.
struct VinylSpinView: View {
    let trackTitle: String
    let artworkView: AnyView?
    var isPlaying: Bool
    var size: CGFloat = 120

    @State private var rotation: Double = 0

    var body: some View {
        ZStack {
            // Vinyl disc
            Circle()
                .fill(
                    RadialGradient(
                        colors: [
                            Color(white: 0.08),
                            Color(white: 0.04),
                            Color(white: 0.06),
                            Color(white: 0.03),
                            Color(white: 0.05),
                        ],
                        center: .center,
                        startRadius: size * 0.2,
                        endRadius: size * 0.5
                    )
                )
                .frame(width: size, height: size)

            // Grooves (concentric rings)
            ForEach(0..<6, id: \.self) { ring in
                let ringRadius = size * 0.22 + CGFloat(ring) * (size * 0.045)
                Circle()
                    .stroke(Color(white: 0.1), lineWidth: 0.5)
                    .frame(width: ringRadius * 2, height: ringRadius * 2)
            }

            // Center label (album art or placeholder)
            if let artwork = artworkView {
                artwork
                    .frame(width: size * 0.35, height: size * 0.35)
                    .clipShape(Circle())
            } else {
                Circle()
                    .fill(Color(white: 0.12))
                    .frame(width: size * 0.35, height: size * 0.35)
                    .overlay(
                        Text(String(trackTitle.prefix(2)).uppercased())
                            .font(.system(size: size * 0.08, weight: .bold, design: .monospaced))
                            .foregroundStyle(Color(white: 0.4))
                    )
            }

            // Spindle hole
            Circle()
                .fill(Color(white: 0.02))
                .frame(width: size * 0.05, height: size * 0.05)
        }
        .rotationEffect(.degrees(rotation))
        .onChange(of: isPlaying) { _, playing in
            if playing {
                withAnimation(.linear(duration: 3).repeatForever(autoreverses: false)) {
                    rotation += 360
                }
            } else {
                // Stop smoothly — remove repeating animation
                withAnimation(.easeOut(duration: 0.5)) {
                    // Keep current rotation (no reset)
                }
            }
        }
        .onAppear {
            if isPlaying {
                withAnimation(.linear(duration: 3).repeatForever(autoreverses: false)) {
                    rotation = 360
                }
            }
        }
    }
}