import WidgetKit
import SwiftUI

// MARK: - Models

struct SymbolThumb: Codable, Identifiable, Sendable {
    var id: String { symbol }
    let symbol: String
    let open: Double
    let high: Double
    let low: Double
    let close: Double
    let chg: Double
    let change: Double
    let volume: Double
    let turnover: Double
    let quoteCurrencyName: String
    let baseCurrency: String
    let quoteCurrency: String

    var isPositive: Bool { chg >= 0 }

    var changePercent: String {
        String(format: "%+.2f%%", chg * 100)
    }

    var priceFormatted: String {
        let fmt = NumberFormatter()
        fmt.numberStyle = .decimal
        fmt.minimumFractionDigits = 2
        if close >= 1000 {
            fmt.maximumFractionDigits = 2
        } else if close >= 1 {
            fmt.maximumFractionDigits = 4
        } else {
            fmt.maximumFractionDigits = 6
        }
        return fmt.string(from: NSNumber(value: close)) ?? String(format: "%.2f", close)
    }
}

// MARK: - API

struct RapiraAPI {
    static let url = URL(string: "https://api.rapira.net/market/symbol-thumb")!

    static func fetch() async throws -> [SymbolThumb] {
        let (data, _) = try await URLSession.shared.data(from: url)
        return try JSONDecoder().decode([SymbolThumb].self, from: data)
    }

    static func fetchIcon(for currency: String) async -> Data? {
        guard let url = URL(string: "https://cdn.rapira.net/media/crypto/\(currency).svg") else { return nil }
        return try? await URLSession.shared.data(from: url).0
    }

    static func fetchIcons(for currencies: [String]) async -> [String: Data] {
        await withTaskGroup(of: (String, Data?).self) { group in
            for cur in Set(currencies) {
                group.addTask { (cur, await fetchIcon(for: cur)) }
            }
            var result: [String: Data] = [:]
            for await (cur, data) in group {
                if let data { result[cur] = data }
            }
            return result
        }
    }
}

// MARK: - Entry

struct CryptoEntry: TimelineEntry {
    let date: Date
    let symbols: [SymbolThumb]
    let selectedPairs: [String]
    let icons: [String: Data]

    var filtered: [SymbolThumb] {
        let order = Dictionary(uniqueKeysWithValues: selectedPairs.enumerated().map { ($1, $0) })
        return symbols
            .filter { selectedPairs.contains($0.symbol) }
            .sorted { (order[$0.symbol] ?? 99) < (order[$1.symbol] ?? 99) }
    }
}

// MARK: - Provider

struct CryptoProvider: TimelineProvider {
    func placeholder(in context: Context) -> CryptoEntry {
        CryptoEntry(date: .now, symbols: Self.mock, selectedPairs: ["BTC/USDT", "ETH/USDT", "SOL/USDT"], icons: [:])
    }

    func getSnapshot(in context: Context, completion: @escaping (CryptoEntry) -> Void) {
        Task {
            let symbols = (try? await RapiraAPI.fetch()) ?? Self.mock
            let pairs = loadPairs()
            let filtered = symbols.filter { pairs.contains($0.symbol) }
            let icons = await RapiraAPI.fetchIcons(for: filtered.map(\.quoteCurrency))
            completion(CryptoEntry(date: .now, symbols: symbols, selectedPairs: pairs, icons: icons))
        }
    }

    func getTimeline(in context: Context, completion: @escaping (Timeline<CryptoEntry>) -> Void) {
        Task {
            let symbols = (try? await RapiraAPI.fetch()) ?? Self.mock
            let pairs = loadPairs()
            let filtered = symbols.filter { pairs.contains($0.symbol) }
            let icons = await RapiraAPI.fetchIcons(for: filtered.map(\.quoteCurrency))
            let entry = CryptoEntry(date: .now, symbols: symbols, selectedPairs: pairs, icons: icons)
            let next = Calendar.current.date(byAdding: .minute, value: 5, to: .now)!
            completion(Timeline(entries: [entry], policy: .after(next)))
        }
    }

    private func loadPairs() -> [String] {
        UserDefaults(suiteName: "group.robonen.rapira-market-widget.crypto")?
            .stringArray(forKey: "selectedPairs") ?? ["BTC/USDT", "ETH/USDT", "SOL/USDT"]
    }

    static let mock: [SymbolThumb] = [
        SymbolThumb(symbol: "BTC/USDT", open: 71000, high: 71381.5, low: 68894.5,
                    close: 70324, chg: 0.0234, change: 1676, volume: 223.9,
                    turnover: 41930552, quoteCurrencyName: "Bitcoin",
                    baseCurrency: "USDT", quoteCurrency: "BTC"),
        SymbolThumb(symbol: "ETH/USDT", open: 2152.9, high: 2177.4, low: 2105,
                    close: 2143.5, chg: -0.00446, change: -9.4, volume: 27226,
                    turnover: 119347435, quoteCurrencyName: "Ethereum",
                    baseCurrency: "USDT", quoteCurrency: "ETH"),
        SymbolThumb(symbol: "SOL/USDT", open: 91.77, high: 92.29, low: 88.3,
                    close: 90.08, chg: -0.01913, change: -1.69, volume: 349968,
                    turnover: 71024390, quoteCurrencyName: "Solana",
                    baseCurrency: "USDT", quoteCurrency: "SOL"),
        SymbolThumb(symbol: "TON/USDT", open: 1.31, high: 1.35, low: 1.29,
                    close: 1.3382, chg: 0.0223, change: 0.0282, volume: 5200000,
                    turnover: 6958640, quoteCurrencyName: "Toncoin",
                    baseCurrency: "USDT", quoteCurrency: "TON"),
    ]
}

// MARK: - Theme

private enum Theme {
    static let bgTop = Color(red: 0.08, green: 0.12, blue: 0.32)
    static let bgBottom = Color(red: 0.03, green: 0.05, blue: 0.18)
    static let label = Color(red: 0.45, green: 0.65, blue: 1.0)
    static let positive = Color(red: 0.05, green: 0.82, blue: 0.42)
    static let negative = Color(red: 1.0, green: 0.30, blue: 0.30)
    static let divider = Color.white.opacity(0.08)

    static var bgGradient: LinearGradient {
        LinearGradient(
            colors: [bgTop, bgBottom],
            startPoint: .top,
            endPoint: .bottom
        )
    }
}

// MARK: - Coin Icon (Widget — uses prefetched Data)

private struct WidgetCoinIcon: View {
    let symbol: String
    let data: Data?
    let size: CGFloat

    var body: some View {
        if let data, let img = NSImage(data: data) {
            Image(nsImage: img)
                .resizable()
                .aspectRatio(contentMode: .fit)
                .frame(width: size, height: size)
                .clipShape(Circle())
        } else {
            ZStack {
                Circle()
                    .fill(
                        LinearGradient(
                            colors: [coinColor(symbol), coinColor(symbol).opacity(0.7)],
                            startPoint: .topLeading,
                            endPoint: .bottomTrailing
                        )
                    )
                Text(String(symbol.prefix(1)))
                    .font(.system(size: size * 0.42, weight: .bold, design: .rounded))
                    .foregroundStyle(.white)
            }
            .frame(width: size, height: size)
        }
    }
}

private func coinColor(_ s: String) -> Color {
    switch s {
    case "BTC": return .orange
    case "ETH": return Color(red: 0.39, green: 0.49, blue: 0.94)
    case "SOL": return Color(red: 0.56, green: 0.25, blue: 0.95)
    case "BNB": return Color(red: 0.96, green: 0.72, blue: 0.04)
    case "XRP": return Color(red: 0.14, green: 0.14, blue: 0.14)
    case "TON": return Color(red: 0.04, green: 0.65, blue: 0.93)
    default: return Color(red: 0.55, green: 0.55, blue: 0.60)
    }
}

// MARK: - Crypto Row

private struct CryptoRow: View {
    let symbol: SymbolThumb
    let iconData: Data?
    let compact: Bool

    var body: some View {
        HStack(spacing: compact ? 8 : 10) {
            WidgetCoinIcon(symbol: symbol.quoteCurrency, data: iconData, size: compact ? 26 : 30)

            VStack(alignment: .leading, spacing: 1) {
                HStack(spacing: 2) {
                    Text(symbol.quoteCurrency)
                        .fontWeight(.bold)
                    Text("/")
                        .foregroundStyle(.white.opacity(0.35))
                    Text(symbol.baseCurrency)
                        .fontWeight(.medium)
                        .foregroundStyle(.white.opacity(0.55))
                }
                .font(.system(size: compact ? 12 : 13))
                .foregroundStyle(.white)

                Text(symbol.quoteCurrencyName)
                    .font(.system(size: compact ? 9 : 10))
                    .foregroundStyle(.white.opacity(0.4))
                    .lineLimit(1)
            }

            Spacer(minLength: 4)

            Text(symbol.priceFormatted)
                .font(.system(size: compact ? 13 : 14, weight: .bold, design: .rounded))
                .foregroundStyle(.white)
                .lineLimit(1)
                .minimumScaleFactor(0.6)

            Text(symbol.changePercent)
                .font(.system(size: compact ? 10 : 11, weight: .bold, design: .rounded))
                .foregroundStyle(symbol.isPositive ? Theme.positive : Theme.negative)
                .frame(minWidth: compact ? 48 : 54, alignment: .trailing)
        }
        .padding(.horizontal, compact ? 12 : 14)
        .padding(.vertical, compact ? 6 : 8)
    }
}

// MARK: - Small Widget

struct SmallWidgetView: View {
    let entry: CryptoEntry

    var body: some View {
        if let pair = entry.filtered.first {
            VStack(spacing: 4) {
                Spacer(minLength: 0)

                WidgetCoinIcon(symbol: pair.quoteCurrency, data: entry.icons[pair.quoteCurrency], size: 36)

                HStack(spacing: 2) {
                    Text(pair.quoteCurrency)
                        .fontWeight(.bold)
                    Text("/")
                        .foregroundStyle(.white.opacity(0.35))
                    Text(pair.baseCurrency)
                        .fontWeight(.medium)
                        .foregroundStyle(.white.opacity(0.55))
                }
                .font(.system(size: 13))
                .foregroundStyle(.white)

                Text(pair.priceFormatted)
                    .font(.system(size: 22, weight: .bold, design: .rounded))
                    .foregroundStyle(.white)
                    .minimumScaleFactor(0.5)
                    .lineLimit(1)

                Text(pair.changePercent)
                    .font(.system(size: 13, weight: .bold, design: .rounded))
                    .foregroundStyle(pair.isPositive ? Theme.positive : Theme.negative)

                Spacer(minLength: 0)
            }
            .frame(maxWidth: .infinity)
            .containerBackground(for: .widget) { Theme.bgGradient }
        }
    }
}

// MARK: - Medium Widget

struct MediumWidgetView: View {
    let entry: CryptoEntry

    var body: some View {
        VStack(spacing: 0) {
            let items = Array(entry.filtered.prefix(3))
            ForEach(Array(items.enumerated()), id: \.element.id) { idx, sym in
                CryptoRow(symbol: sym, iconData: entry.icons[sym.quoteCurrency], compact: true)
                if idx < items.count - 1 {
                    Theme.divider.frame(height: 1).padding(.leading, 46)
                }
            }
        }
        .frame(maxHeight: .infinity)
        .containerBackground(for: .widget) { Theme.bgGradient }
    }
}

// MARK: - Large Widget

struct LargeWidgetView: View {
    let entry: CryptoEntry

    var body: some View {
        VStack(spacing: 0) {
            let items = Array(entry.filtered.prefix(6))
            ForEach(Array(items.enumerated()), id: \.element.id) { idx, sym in
                CryptoRow(symbol: sym, iconData: entry.icons[sym.quoteCurrency], compact: false)
                if idx < items.count - 1 {
                    Theme.divider.frame(height: 1).padding(.leading, 54)
                }
            }
            Spacer(minLength: 0)
        }
        .containerBackground(for: .widget) { Theme.bgGradient }
    }
}

// MARK: - Entry View

struct CryptoWidgetEntryView: View {
    var entry: CryptoEntry
    @Environment(\.widgetFamily) private var family

    var body: some View {
        switch family {
        case .systemSmall: SmallWidgetView(entry: entry)
        case .systemMedium: MediumWidgetView(entry: entry)
        case .systemLarge: LargeWidgetView(entry: entry)
        default: MediumWidgetView(entry: entry)
        }
    }
}

// MARK: - Widget

@main
struct CryptoWidget: Widget {
    let kind = "CryptoWidget"

    var body: some WidgetConfiguration {
        StaticConfiguration(kind: kind, provider: CryptoProvider()) { entry in
            CryptoWidgetEntryView(entry: entry)
        }
        .configurationDisplayName("Rapira Crypto")
        .description("Курсы криптовалют в реальном времени")
        .supportedFamilies([.systemSmall, .systemMedium, .systemLarge])
    }
}

// MARK: - Preview

#Preview(as: .systemLarge) {
    CryptoWidget()
} timeline: {
    CryptoEntry(date: .now, symbols: CryptoProvider.mock, selectedPairs: ["BTC/USDT", "ETH/USDT", "SOL/USDT", "TON/USDT"], icons: [:])
}