import SwiftUI
import WidgetKit

// MARK: - Shared widget theme (slate background + brand orange)

enum WidgetTheme {
    static let background = Color(red: 0.224, green: 0.255, blue: 0.310) // dark slate
    static let accent     = Color(red: 0.93,  green: 0.42,  blue: 0.20)  // brand orange
    static let text       = Color.white
    static let textDim    = Color.white.opacity(0.55)
    static let textFaint  = Color.white.opacity(0.4)
}

// MARK: - Vertical-bar progress (comb / equalizer style)

struct BarGrid: View {
    let progress: Double          // 0…1
    let color: Color
    var count: Int = 64
    var gap: CGFloat = 3

    var body: some View {
        GeometryReader { geo in
            let totalGap = gap * CGFloat(count - 1)
            let barW = max(1.5, (geo.size.width - totalGap) / CGFloat(count))
            let filled = Int((progress * Double(count)).rounded())
            HStack(spacing: gap) {
                ForEach(0..<count, id: \.self) { i in
                    RoundedRectangle(cornerRadius: barW / 2)
                        .fill(i < filled ? color : color.opacity(0.22))
                        .frame(width: barW)
                }
            }
            .frame(height: geo.size.height, alignment: .center)
        }
    }
}

// MARK: - Dot-grid progress (day / week / month / year)

enum TimePeriod { case day, week, month, year }

struct ProgressDotView: View {
    let period: TimePeriod
    let accent: Color
    @Environment(\.widgetFamily) private var family

    private var label: String {
        switch period {
        case .day:   let f = DateFormatter(); f.dateFormat = "EEEE d"; return f.string(from: Date())
        case .week:  return "This week"
        case .month: let f = DateFormatter(); f.dateFormat = "MMMM"; return f.string(from: Date())
        case .year:  let f = DateFormatter(); f.dateFormat = "yyyy"; return f.string(from: Date())
        }
    }

    private var progress: Double {
        let cal = Calendar.current; let now = Date()
        switch period {
        case .day:
            let sod = cal.startOfDay(for: now)
            return (now.timeIntervalSince(sod)) / 86400
        case .week:
            let comps = cal.dateComponents([.weekday], from: now)
            let wd = (comps.weekday ?? 1) - 1
            let secIntoDay = now.timeIntervalSince(cal.startOfDay(for: now))
            return (Double(wd) * 86400 + secIntoDay) / (7 * 86400)
        case .month:
            let range = cal.range(of: .day, in: .month, for: now)!
            let day   = cal.component(.day, from: now) - 1
            let secIntoDay = now.timeIntervalSince(cal.startOfDay(for: now))
            return (Double(day) * 86400 + secIntoDay) / (Double(range.count) * 86400)
        case .year:
            let start = cal.date(from: cal.dateComponents([.year], from: now))!
            let end   = cal.date(byAdding: .year, value: 1, to: start)!
            return now.timeIntervalSince(start) / end.timeIntervalSince(start)
        }
    }

    private var subLabel: String {
        let pct = Int(progress * 100)
        return "\(pct)%"
    }

    var body: some View {
        let isMedium = family == .systemMedium
        VStack(alignment: .leading, spacing: isMedium ? 10 : 6) {
            HStack(alignment: .firstTextBaseline) {
                Text(label)
                    .font(.system(size: isMedium ? 22 : 14, weight: .bold))
                    .foregroundColor(.white)
                    .lineLimit(1)
                Spacer()
                Text(subLabel)
                    .font(.system(size: isMedium ? 22 : 13, weight: .bold))
                    .foregroundColor(Color(white: 0.5))
            }
            DotGrid(total: 100, filled: Int(progress * 100), color: accent)
        }
        .padding(.horizontal, isMedium ? 4 : 0)
        .containerBackground(.black, for: .widget)
    }
}

// MARK: - Tasks completed today

struct TasksCompleteView: View {
    @Environment(\.widgetFamily) private var family
    private let teal = Color(red: 0.48, green: 0.87, blue: 0.80)

    private var stats: (done: Int, total: Int) { todayTaskCompletion() }
    private var percent: Int {
        let s = stats
        guard s.total > 0 else { return 0 }
        return Int((Double(s.done) / Double(s.total) * 100).rounded())
    }

    var body: some View {
        let s = stats
        let isMedium = family == .systemMedium
        VStack(alignment: .leading, spacing: isMedium ? 10 : 6) {
            HStack(alignment: .firstTextBaseline) {
                Text("Today's Tasks")
                    .font(.system(size: isMedium ? 22 : 14, weight: .bold))
                    .foregroundColor(.white)
                    .lineLimit(1)
                Spacer()
                Text("\(percent)%")
                    .font(.system(size: isMedium ? 22 : 13, weight: .bold))
                    .foregroundColor(Color(white: 0.5))
            }
            if s.total == 0 {
                Spacer(minLength: 0)
                Text("No tasks due today")
                    .font(.system(size: 12))
                    .foregroundColor(Color(white: 0.5))
                Spacer(minLength: 0)
            } else {
                Text("\(s.done) of \(s.total) done")
                    .font(.system(size: 12))
                    .foregroundColor(teal)
                Spacer(minLength: 2)
                DotGrid(total: s.total, filled: s.done, color: teal)
            }
        }
        .padding(.horizontal, isMedium ? 4 : 0)
        .containerBackground(.black, for: .widget)
    }
}

// MARK: - Circular dot grid (event countdown motif)

struct DotGrid: View {
    let total: Int
    let filled: Int
    let color: Color
    var gap: CGFloat = 3

    var body: some View {
        GeometryReader { geo in
            let l = layout(for: total, in: geo.size)
            VStack(spacing: gap) {
                ForEach(0..<l.rows, id: \.self) { row in
                    HStack(spacing: gap) {
                        ForEach(0..<l.cols, id: \.self) { col in
                            let idx = row * l.cols + col
                            if idx < total {
                                dot(filled: idx < filled, size: l.size)
                            } else {
                                Color.clear.frame(width: l.size, height: l.size)
                            }
                        }
                        Spacer(minLength: 0)
                    }
                }
                Spacer(minLength: 0)
            }
        }
    }

    @ViewBuilder
    private func dot(filled: Bool, size: CGFloat) -> some View {
        if filled {
            Circle().fill(color).frame(width: size, height: size)
        } else {
            Circle()
                .strokeBorder(color.opacity(0.55), lineWidth: max(0.8, size * 0.13))
                .frame(width: size, height: size)
        }
    }

    /// Pick the column count that yields the largest uniform circle that still fits
    /// every dot inside the available area — an even grid that fills the widget.
    private func layout(for count: Int, in size: CGSize) -> (cols: Int, rows: Int, size: CGFloat) {
        guard count > 0, size.width > 1, size.height > 1 else { return (1, 1, 6) }
        var best = (cols: 1, rows: count, size: CGFloat(0))
        for cols in 1...count {
            let rows = Int(ceil(Double(count) / Double(cols)))
            let w = (size.width  - gap * CGFloat(cols - 1)) / CGFloat(cols)
            let h = (size.height - gap * CGFloat(rows - 1)) / CGFloat(rows)
            let s = min(w, h)
            if s > best.size { best = (cols, rows, s) }
        }
        return best
    }
}

// MARK: - Event Countdown Widget (small + medium)

struct EventCountdownView: View {
    let entry: EventEntry
    @Environment(\.widgetFamily) var family

    private let teal = Color(red: 0.48, green: 0.87, blue: 0.80)

    private var percent: Int { Int((entry.progress * 100).rounded()) }

    var body: some View {
        Group {
            if family == .systemSmall {
                small
            } else {
                medium
            }
        }
        .containerBackground(.black, for: .widget)
    }

    private var filled: Int { Int(entry.progress * Double(entry.totalDays)) }

    // Wide layout: event name + days-left countdown, then the dot-grid progress.
    private var medium: some View {
        VStack(alignment: .leading, spacing: 10) {
            HStack(alignment: .firstTextBaseline, spacing: 8) {
                Text(LocalizedStringKey(entry.eventName))
                    .font(.system(size: 20, weight: .bold))
                    .foregroundColor(teal)
                    .lineLimit(1)
                Spacer(minLength: 4)
                VStack(alignment: .trailing, spacing: 1) {
                    Button(intent: CycleCountdownUnitIntent()) {
                        Text(entry.timeLeftLabel)
                            .font(.system(size: 14, weight: .semibold))
                            .foregroundColor(Color(white: 0.62))
                            .lineLimit(1)
                    }
                    .buttonStyle(.plain)
                    Text("\(percent)%")
                        .font(.system(size: 11, weight: .bold))
                        .foregroundColor(Color(white: 0.4))
                }
            }
            DotGrid(total: entry.totalDays, filled: filled, color: teal)
        }
        .padding(.horizontal, 4)
    }

    private var small: some View {
        VStack(alignment: .leading, spacing: 6) {
            Text(LocalizedStringKey(entry.eventName))
                .font(.system(size: 14, weight: .bold))
                .foregroundColor(teal)
                .lineLimit(2)
            Button(intent: CycleCountdownUnitIntent()) {
                Text(entry.timeLeftLabel)
                    .font(.system(size: 12, weight: .semibold))
                    .foregroundColor(Color(white: 0.62))
                    .lineLimit(1)
            }
            .buttonStyle(.plain)
            Spacer(minLength: 2)
            DotGrid(total: entry.totalDays, filled: filled, color: teal)
        }
    }
}

// MARK: - Lock Screen Widget (accessoryRectangular)

struct LockScreenRectView: View {
    let task: WidgetTask

    var body: some View {
        HStack(spacing: 10) {
            VStack(alignment: .leading, spacing: 2) {
                Text(task.title)
                    .font(.system(size: 13, weight: .semibold))
                    .lineLimit(1)
                Text(task.timeLeftLabel)
                    .font(.system(size: 11))
                    .foregroundColor(.secondary)
            }
            Spacer()
            if !task.isComplete, let days = task.daysLeft, days <= 365 {
                ProgressView(value: Double(365 - days), total: 365)
                    .progressViewStyle(.circular)
                    .frame(width: 22, height: 22)
                    .tint(.white)
            } else if task.isComplete {
                Image(systemName: "checkmark.circle.fill")
                    .foregroundColor(.green)
            }
        }
        .containerBackground(.thinMaterial, for: .widget)
    }
}

// MARK: - Lock Screen Circular

struct LockScreenCircularView: View {
    let task: WidgetTask

    var body: some View {
        ZStack {
            if !task.isComplete, let days = task.daysLeft, days <= 365 {
                ProgressView(value: Double(365 - days), total: 365)
                    .progressViewStyle(.circular)
                    .tint(.white)
            }
            VStack(spacing: 0) {
                if let days = task.daysLeft {
                    Text("\(days)").font(.system(size: 14, weight: .bold))
                    Text("days").font(.system(size: 7))
                } else {
                    Image(systemName: "checkmark").font(.system(size: 14, weight: .bold))
                }
            }
        }
        .containerBackground(.thinMaterial, for: .widget)
    }
}