import SwiftUI
import WidgetKit

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

enum WidgetTheme {
    // Exactly the brand palette: app accent RGB(232,98,42) on the logo's
    // dark RGB(26,29,34) — widgets read as siblings of the app icon.
    static let background = Color(red: 26/255,  green: 29/255, blue: 34/255)
    static let accent     = Color(red: 232/255, green: 98/255, blue: 42/255)
    static let text       = Color.white
    static let textDim    = Color.white.opacity(0.55)
    static let textFaint  = Color.white.opacity(0.4)
}

private extension String {
    func widgetTitleCased() -> String {
        split(separator: " ").map { rawWord in
            let word = String(rawWord)
            guard let first = word.first else { return word }
            if word == word.uppercased(), word.count <= 5 { return word }
            return first.uppercased() + word.dropFirst().lowercased()
        }
        .joined(separator: " ")
    }
}

// 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

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

    private var headerFont: Font {
        switch family {
        case .systemLarge: return .system(.title3, design: .monospaced)
        case .accessoryRectangular: return .system(.caption, design: .monospaced)
        default: return .system(.body, design: .monospaced)
        }
    }

    private var spacing: CGFloat {
        family == .accessoryRectangular ? 4 : 10
    }

    private var horizontalPadding: CGFloat {
        switch family {
        case .systemLarge: return 8
        case .accessoryRectangular: return 0
        default: return 4
        }
    }

    private var isAccessory: Bool { family == .accessoryRectangular }

    // 100 tiny dots are illegible in a lock-screen pill — show a coarse grid there.
    private var dotCount: Int { isAccessory ? 28 : entry.totalDots }

    var body: some View {
        let percent = Int((entry.progress * 100).rounded(.down))
        VStack(alignment: .leading, spacing: spacing) {
            HStack(alignment: .firstTextBaseline) {
                Text(entry.title)
                    .font(headerFont)
                    .foregroundColor(isAccessory ? .primary : .white)
                    .lineLimit(1)
                    .minimumScaleFactor(0.72)
                Spacer()
                Text("\(percent)%")
                    .font(headerFont)
                    .foregroundColor(isAccessory ? .primary.opacity(0.7) : Color(white: 0.5))
                    .lineLimit(1)
            }
            DotGridView(progress: entry.progress, totalDots: dotCount,
                        color: isAccessory ? .primary : accent)
        }
        .padding(.horizontal, horizontalPadding)
        .containerBackground(for: .widget) {
            if isAccessory { AccessoryWidgetBackground() } else { WidgetTheme.background }
        }
    }
}

// MARK: - Reusable circular dot grid

struct DotGridView: View {
    let progress: Double
    var totalDots: Int = 100
    let color: Color
    var gap: CGFloat = 3

    private var filledDots: Int {
        Int((min(1, max(0, progress)) * Double(totalDots)).rounded(.down))
    }

    var body: some View {
        GeometryReader { geo in
            let layout = layout(for: totalDots, in: geo.size)
            let columns = Array(repeating: GridItem(.fixed(layout.size), spacing: gap, alignment: .center),
                                count: layout.cols)
            LazyVGrid(columns: columns, alignment: .center, spacing: gap) {
                ForEach(0..<totalDots, id: \.self) { index in
                    dot(filled: index < filledDots, size: layout.size)
                }
            }
            .frame(width: layout.width, height: layout.height, alignment: .topLeading)
            .frame(maxWidth: .infinity, maxHeight: .infinity, alignment: .top)
        }
    }

    @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)
        }
    }

    private func layout(for count: Int, in size: CGSize) -> (cols: Int, rows: Int, size: CGFloat, width: CGFloat, height: CGFloat) {
        guard count > 0, size.width > 1, size.height > 1 else { return (1, 1, 6, 6, 6) }
        var best = (cols: 1, rows: count, size: CGFloat(0), width: CGFloat(0), height: 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)
            let gridWidth = CGFloat(cols) * s + gap * CGFloat(cols - 1)
            let gridHeight = CGFloat(rows) * s + gap * CGFloat(rows - 1)
            if s > best.size && gridWidth <= size.width && gridHeight <= size.height {
                best = (cols, rows, s, gridWidth, gridHeight)
            }
        }
        return best
    }
}

// MARK: - Event Countdown — Bars style (medium)

struct EventBarsView: View {
    let entry: EventEntry

    var body: some View {
        VStack(alignment: .leading, spacing: 0) {
            HStack(alignment: .firstTextBaseline, spacing: 10) {
                Text(entry.eventName.widgetTitleCased())
                    .font(.system(.body, design: .monospaced))
                    .foregroundColor(WidgetTheme.accent)
                    .lineLimit(1)
                    .minimumScaleFactor(0.78)
                    .layoutPriority(1)
                Button(intent: CycleCountdownUnitIntent()) {
                    Text(entry.fineTimeLeft)
                        .font(.system(.body, design: .monospaced))
                        .foregroundColor(WidgetTheme.textDim)
                        .lineLimit(1)
                        .minimumScaleFactor(0.9)
                }
                .buttonStyle(.plain)
                .fixedSize(horizontal: true, vertical: false)
                .layoutPriority(2)
                Spacer(minLength: 0)
            }
            Spacer(minLength: 8)
            BarGrid(progress: entry.progress, color: WidgetTheme.accent)
                .frame(maxHeight: .infinity)
        }
        .padding(.horizontal, 4).padding(.vertical, 2)
        .containerBackground(WidgetTheme.background, for: .widget)
    }
}

// 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(.caption, design: .monospaced))
                    .lineLimit(1)
                Text(task.timeLeftLabel)
                    .font(.system(.caption2, design: .monospaced))
                    .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(WidgetTheme.accent)
            } 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(WidgetTheme.accent)
            }
            VStack(spacing: 0) {
                if let days = task.daysLeft {
                    Text("\(days)").font(.system(.caption, design: .monospaced))
                    Text("days").font(.system(.caption2, design: .monospaced))
                } else {
                    Image(systemName: "checkmark").font(.system(size: 14))
                }
            }
        }
        .containerBackground(.thinMaterial, for: .widget)
    }
}