// ── Timeline View ──────────────────────────────────────────────
// Main screen — vertical timeline showing all active/upcoming timers

import SwiftUI

struct TimelineView: View {
    @EnvironmentObject var store: TimerStore
    @State private var showCreateTimer = false
    @State private var showQuickTimer = false

    var body: some View {
        NavigationStack {
            ZStack {
                CMColors.bg.ignoresSafeArea()

                ScrollView {
                    VStack(spacing: CMSpacing.xl) {
                        // Clock header
                        ClockHeader(now: store.now)

                        // Next up card
                        if let next = store.nextFiringTimer {
                            NextUpCard(timer: next, now: store.now)
                        }

                        // Quick timer bar
                        QuickTimerBar {
                            showQuickTimer = true
                        }

                        // Active timers
                        if store.activeTimers.isEmpty {
                            EmptyTimelineView()
                        } else {
                            TimerListSection(
                                title: "Active",
                                timers: store.activeTimers.sorted { $0.targetTime < $1.targetTime },
                                now: store.now
                            )
                        }

                        // Firing timers overlay check
                        let firingTimers = store.timers.filter { $0.state == .firing }
                        if !firingTimers.isEmpty {
                            // Show inline firing card for non-critical
                            ForEach(firingTimers.filter { $0.urgency != .critical }) { timer in
                                FiringCard(timer: timer)
                            }
                        }

                        // Completed/dismissed (recent)
                        let recentDone = store.timers
                            .filter { [.completed, .dismissed].contains($0.state) }
                            .sorted { ($0.completedAt ?? $0.dismissedAt ?? .distantPast) > ($1.completedAt ?? $1.dismissedAt ?? .distantPast) }
                            .prefix(5)

                        if !recentDone.isEmpty {
                            TimerListSection(
                                title: "Recent",
                                timers: Array(recentDone),
                                now: store.now
                            )
                        }
                    }
                    .padding(.horizontal, CMSpacing.lg)
                    .padding(.bottom, 100)
                }

                // FAB
                VStack {
                    Spacer()
                    HStack {
                        Spacer()
                        Button {
                            HapticEngine.tap()
                            showCreateTimer = true
                        } label: {
                            Image(systemName: "plus")
                                .font(.title2.weight(.semibold))
                                .foregroundStyle(.white)
                                .frame(width: 56, height: 56)
                                .background(CMColors.accent)
                                .clipShape(Circle())
                                .shadow(color: CMShadow.glow, radius: 12)
                        }
                        .padding(.trailing, CMSpacing.xl)
                        .padding(.bottom, CMSpacing.lg)
                    }
                }
            }
            .navigationBarHidden(true)
            .sheet(isPresented: $showCreateTimer) {
                CreateTimerView()
            }
            .sheet(isPresented: $showQuickTimer) {
                QuickTimerSheet()
            }
            .overlay {
                // Full-screen overlay for CRITICAL firing timers
                let criticalFiring = store.timers.first { $0.state == .firing && $0.urgency == .critical }
                if let timer = criticalFiring {
                    AlarmOverlay(timer: timer)
                }
            }
        }
    }
}

// MARK: - Clock Header

struct ClockHeader: View {
    let now: Date

    var body: some View {
        VStack(spacing: CMSpacing.xs) {
            Text(formatTime(now))
                .font(CMFonts.mono(size: 48, weight: .bold))
                .foregroundStyle(CMColors.text)
                .shadow(color: CMColors.accentGlow, radius: 20)

            Text(formatDate(now))
                .font(CMFonts.body(size: 16, weight: .medium))
                .foregroundStyle(CMColors.textSecondary)
        }
        .frame(maxWidth: .infinity)
        .padding(.top, CMSpacing.xl)
        .padding(.bottom, CMSpacing.md)
    }
}

// MARK: - Next Up Card

struct NextUpCard: View {
    let timer: CMTimer
    let now: Date

    var body: some View {
        VStack(alignment: .leading, spacing: CMSpacing.sm) {
            HStack {
                Text("NEXT UP")
                    .font(CMFonts.body(size: 11, weight: .bold))
                    .foregroundStyle(CMColors.textMuted)
                    .tracking(1.5)

                Spacer()

                UrgencyBadge(urgency: timer.urgency)
            }

            Text(timer.label)
                .font(CMFonts.body(size: 18, weight: .semibold))
                .foregroundStyle(CMColors.text)

            HStack {
                Image(systemName: "clock")
                    .font(.caption)
                    .foregroundStyle(CMColors.textMuted)

                Text(formatRelativeTime(timer.targetTime, now: now))
                    .font(CMFonts.mono(size: 14, weight: .medium))
                    .foregroundStyle(CMColors.urgencyColor(timer.urgency))

                Spacer()

                Text(formatTime(timer.targetTime))
                    .font(CMFonts.body(size: 14))
                    .foregroundStyle(CMColors.textSecondary)
            }

            // Cascade progress
            if !timer.warnings.isEmpty {
                let firedCount = timer.warnings.filter(\.fired).count
                let total = timer.warnings.count
                CascadeProgressBar(
                    fired: firedCount,
                    total: total,
                    urgency: timer.urgency
                )
            }

            // Time blindness aid
            let remaining = getRemainingSeconds(timer, now: now)
            if let ref = getTimeReference(seconds: remaining) {
                Text(ref)
                    .font(CMFonts.body(size: 12))
                    .foregroundStyle(CMColors.textMuted)
                    .italic()
            }
        }
        .padding(CMSpacing.lg)
        .background(CMColors.surface)
        .overlay(
            RoundedRectangle(cornerRadius: CMRadius.lg)
                .stroke(CMColors.urgencyBorder(timer.urgency), lineWidth: 1)
        )
        .clipShape(RoundedRectangle(cornerRadius: CMRadius.lg))
    }
}

// MARK: - Quick Timer Bar

struct QuickTimerBar: View {
    let onCustom: () -> Void

    @EnvironmentObject var store: TimerStore

    private let presets: [(String, Int)] = [
        ("5m", 5),
        ("15m", 15),
        ("25m", 25),
        ("45m", 45),
        ("1h", 60),
    ]

    var body: some View {
        ScrollView(.horizontal, showsIndicators: false) {
            HStack(spacing: CMSpacing.sm) {
                ForEach(presets, id: \.0) { label, minutes in
                    Button {
                        HapticEngine.tap()
                        let _ = store.addCountdown(CreateCountdownParams(
                            label: "\(label) Timer",
                            durationSeconds: TimeInterval(minutes * 60),
                            cascade: CascadeConfig(preset: .light, intervals: [])
                        ))
                    } label: {
                        Text(label)
                            .font(CMFonts.body(size: 14, weight: .semibold))
                            .foregroundStyle(CMColors.text)
                            .padding(.horizontal, CMSpacing.lg)
                            .padding(.vertical, CMSpacing.sm)
                            .background(CMColors.surface)
                            .clipShape(Capsule())
                            .overlay(
                                Capsule().stroke(CMColors.border, lineWidth: 1)
                            )
                    }
                }

                Button {
                    HapticEngine.tap()
                    onCustom()
                } label: {
                    Image(systemName: "slider.horizontal.3")
                        .font(.body.weight(.semibold))
                        .foregroundStyle(CMColors.accent)
                        .padding(.horizontal, CMSpacing.lg)
                        .padding(.vertical, CMSpacing.sm)
                        .background(CMColors.surface)
                        .clipShape(Capsule())
                        .overlay(
                            Capsule().stroke(CMColors.accent.opacity(0.4), lineWidth: 1)
                        )
                }
            }
        }
    }
}

// MARK: - Empty State

struct EmptyTimelineView: View {
    var body: some View {
        VStack(spacing: CMSpacing.lg) {
            Image(systemName: "timer")
                .font(.system(size: 48))
                .foregroundStyle(CMColors.textMuted)

            Text("No active timers")
                .font(CMFonts.body(size: 18, weight: .semibold))
                .foregroundStyle(CMColors.textSecondary)

            Text("Create your first timer with the + button\nor tap a quick preset above")
                .font(CMFonts.body(size: 14))
                .foregroundStyle(CMColors.textMuted)
                .multilineTextAlignment(.center)
        }
        .padding(.vertical, CMSpacing.xxxl)
    }
}