// ── Timer Live Activity ───────────────────────────────────────
// Dynamic Island + Lock Screen Live Activity for active timer countdown

import SwiftUI
import WidgetKit
import ActivityKit

// MARK: - Live Activity Widget

struct TimerLiveActivity: Widget {
    var body: some WidgetConfiguration {
        ActivityConfiguration(for: TimerActivityAttributes.self) { context in
            // Lock Screen Live Activity
            lockScreenView(context: context)
        } dynamicIsland: { context in
            DynamicIsland {
                // Expanded regions
                DynamicIslandExpandedRegion(.leading) {
                    expandedLeading(context: context)
                }
                DynamicIslandExpandedRegion(.trailing) {
                    expandedTrailing(context: context)
                }
                DynamicIslandExpandedRegion(.center) {
                    expandedCenter(context: context)
                }
                DynamicIslandExpandedRegion(.bottom) {
                    expandedBottom(context: context)
                }
            } compactLeading: {
                // Compact leading — urgency dot + label
                HStack(spacing: 4) {
                    Circle()
                        .fill(colorFromHex(context.state.urgencyHex))
                        .frame(width: 8, height: 8)
                    Text(context.attributes.timerLabel)
                        .font(.system(size: 12, weight: .medium))
                        .lineLimit(1)
                        .frame(maxWidth: 60)
                }
            } compactTrailing: {
                // Compact trailing — countdown
                Text(context.state.targetTime, style: .timer)
                    .font(.system(size: 12, weight: .bold, design: .monospaced))
                    .foregroundStyle(colorFromHex(context.state.urgencyHex))
                    .frame(minWidth: 40)
                    .multilineTextAlignment(.trailing)
            } minimal: {
                // Minimal — just countdown
                Text(context.state.targetTime, style: .timer)
                    .font(.system(size: 11, weight: .bold, design: .monospaced))
                    .multilineTextAlignment(.center)
            }
        }
    }

    // MARK: - Lock Screen View

    @ViewBuilder
    private func lockScreenView(context: ActivityViewContext<TimerActivityAttributes>) -> some View {
        let urgencyColor = colorFromHex(context.state.urgencyHex)

        VStack(spacing: 8) {
            HStack {
                // Urgency indicator + label
                HStack(spacing: 6) {
                    Circle()
                        .fill(urgencyColor)
                        .frame(width: 10, height: 10)
                    Text(context.attributes.timerLabel)
                        .font(.system(size: 15, weight: .semibold))
                        .foregroundStyle(.white)
                }

                Spacer()

                // Pomodoro round indicator
                if let round = context.state.pomodoroRound,
                   let total = context.state.pomodoroTotal {
                    Text(context.state.isBreak ? "Break" : "Round \(round)/\(total)")
                        .font(.system(size: 12, weight: .medium))
                        .foregroundStyle(.white.opacity(0.7))
                        .padding(.horizontal, 8)
                        .padding(.vertical, 3)
                        .background(urgencyColor.opacity(0.3))
                        .clipShape(Capsule())
                }
            }

            HStack(alignment: .bottom) {
                // Large countdown
                Text(context.state.targetTime, style: .timer)
                    .font(.system(size: 36, weight: .bold, design: .monospaced))
                    .foregroundStyle(.white)
                    .contentTransition(.numericText())

                Spacer()

                // Target time
                VStack(alignment: .trailing, spacing: 2) {
                    Text("fires at")
                        .font(.system(size: 10))
                        .foregroundStyle(.white.opacity(0.5))
                    Text(context.state.targetTime, style: .time)
                        .font(.system(size: 14, weight: .medium))
                        .foregroundStyle(.white.opacity(0.8))
                }
            }

            // Urgency progress bar
            GeometryReader { geo in
                ZStack(alignment: .leading) {
                    RoundedRectangle(cornerRadius: 2)
                        .fill(.white.opacity(0.15))
                        .frame(height: 3)
                    RoundedRectangle(cornerRadius: 2)
                        .fill(urgencyColor)
                        .frame(width: max(0, geo.size.width * progressFraction(context.state)), height: 3)
                }
            }
            .frame(height: 3)
        }
        .padding(16)
        .activityBackgroundTint(Color.black.opacity(0.85))
        .activitySystemActionForegroundColor(.white)
    }

    // MARK: - Dynamic Island Expanded Views

    @ViewBuilder
    private func expandedLeading(context: ActivityViewContext<TimerActivityAttributes>) -> some View {
        VStack(alignment: .leading, spacing: 2) {
            Text(context.attributes.timerLabel)
                .font(.system(size: 14, weight: .semibold))
                .lineLimit(1)
            if let round = context.state.pomodoroRound,
               let total = context.state.pomodoroTotal {
                Text(context.state.isBreak ? "Break" : "Round \(round)/\(total)")
                    .font(.system(size: 11))
                    .foregroundStyle(.secondary)
            }
        }
    }

    @ViewBuilder
    private func expandedTrailing(context: ActivityViewContext<TimerActivityAttributes>) -> some View {
        Text(context.state.targetTime, style: .timer)
            .font(.system(size: 20, weight: .bold, design: .monospaced))
            .foregroundStyle(colorFromHex(context.state.urgencyHex))
            .contentTransition(.numericText())
            .multilineTextAlignment(.trailing)
    }

    @ViewBuilder
    private func expandedCenter(context: ActivityViewContext<TimerActivityAttributes>) -> some View {
        EmptyView()
    }

    @ViewBuilder
    private func expandedBottom(context: ActivityViewContext<TimerActivityAttributes>) -> some View {
        HStack(spacing: 16) {
            // Fires at
            HStack(spacing: 4) {
                Image(systemName: "bell.fill")
                    .font(.system(size: 10))
                    .foregroundStyle(.secondary)
                Text(context.state.targetTime, style: .time)
                    .font(.system(size: 12, weight: .medium))
                    .foregroundStyle(.secondary)
            }

            Spacer()

            // Type indicator
            HStack(spacing: 4) {
                Image(systemName: typeIcon(context.attributes.timerType))
                    .font(.system(size: 10))
                    .foregroundStyle(.secondary)
                Text(context.attributes.timerType.capitalized)
                    .font(.system(size: 12, weight: .medium))
                    .foregroundStyle(.secondary)
            }
        }
    }

    // MARK: - Helpers

    private func progressFraction(_ state: TimerActivityAttributes.ContentState) -> CGFloat {
        let remaining = state.targetTime.timeIntervalSinceNow
        let total = max(1, TimeInterval(state.remainingSeconds))
        let fraction = 1.0 - (remaining / total)
        return CGFloat(min(1, max(0, fraction)))
    }

    private func colorFromHex(_ hex: String) -> Color {
        switch hex {
        case "#FF4757": return Color(red: 1.0, green: 0.28, blue: 0.34)
        case "#FF9F43": return Color(red: 1.0, green: 0.62, blue: 0.26)
        case "#FECA57": return Color(red: 0.99, green: 0.79, blue: 0.34)
        case "#2ED573": return Color(red: 0.18, green: 0.84, blue: 0.45)
        case "#A5B1C7": return Color(red: 0.65, green: 0.69, blue: 0.78)
        default:        return Color(red: 0.36, green: 0.55, blue: 0.93) // accent
        }
    }

    private func typeIcon(_ type: String) -> String {
        switch type {
        case "alarm": return "alarm.fill"
        case "countdown": return "timer"
        case "pomodoro": return "target"
        case "event": return "calendar"
        default: return "clock"
        }
    }
}