import SwiftUI
import Combine

struct TapToPayView: View {
    let account: BankAccount
    let onDismiss: () -> Void

    @State private var viewModel: TapToPayViewModel

    init(account: BankAccount, onDismiss: @escaping () -> Void) {
        self.account = account
        self.onDismiss = onDismiss
        self._viewModel = State(wrappedValue: TapToPayViewModel(account: account))
    }

    var body: some View {
        ZStack {
            Color(.systemBackground).ignoresSafeArea()

            VStack(spacing: 0) {
                // Drag indicator
                Capsule()
                    .fill(Color(.systemFill))
                    .frame(width: 36, height: 5)
                    .padding(.top, 12)

                Spacer()

                // Card display
                cardView
                    .padding(.horizontal, 24)

                Spacer().frame(height: 20)

                // NFC animation area
                nfcAnimationArea
                    .frame(height: 200)

                Spacer().frame(height: 16)

                // Status text
                statusText
                    .padding(.horizontal, 32)

                Spacer()

                Divider()

                // Cancel / Retry button
                VStack(spacing: 12) {
                    if viewModel.phase == .error {
                        Button(action: {
                            Task { await viewModel.armToken() }
                        }) {
                            Label("Retry", systemImage: "arrow.clockwise")
                                .font(.body.weight(.medium))
                                .frame(maxWidth: .infinity)
                                .padding(.vertical, 12)
                        }
                        .tint(.blue)
                    }

                    Button(action: {
                        viewModel.cancel()
                        onDismiss()
                    }) {
                        Text("Cancel")
                            .font(.body.weight(.medium))
                            .frame(maxWidth: .infinity)
                            .padding(.vertical, 12)
                            .overlay(
                                RoundedRectangle(cornerRadius: 10)
                                    .stroke(Color(.systemFill), lineWidth: 1)
                            )
                    }
                    .foregroundStyle(.secondary)
                }
                .padding(.horizontal, 24)
                .padding(.top, 12)
                .padding(.bottom, max(24, 0))
            }
        }
        .task {
            await viewModel.armToken()
        }
    }

    // MARK: - Card View

    private var cardView: some View {
        VStack(spacing: 0) {
            ZStack(alignment: .bottomLeading) {
                if let name = cardImageName, UIImage(named: name) != nil {
                    Image(name)
                        .resizable()
                        .scaledToFit()
                        .frame(height: 200)
                        .clipped()
                } else {
                    Rectangle()
                        .fill(cardGradient)
                        .frame(height: 200)
                }

                LinearGradient(
                    stops: [
                        .init(color: .clear,              location: 0.35),
                        .init(color: .black.opacity(0.65), location: 1.0)
                    ],
                    startPoint: .top, endPoint: .bottom
                )

                VStack(alignment: .leading, spacing: 2) {
                    Text(account.accountBriefName.uppercased())
                        .font(.caption.weight(.bold))
                        .foregroundStyle(.white)
                        .shadow(color: .black.opacity(0.5), radius: 3, x: 1, y: 1)
                    Text(maskedNumber)
                        .font(.caption2)
                        .foregroundStyle(.white.opacity(0.85))
                        .fontDesign(.monospaced)
                }
                .padding(12)
            }
            .clipShape(RoundedRectangle(cornerRadius: 16))
            .shadow(color: .black.opacity(0.12), radius: 4, x: 0, y: 2)
        }
    }

    // MARK: - NFC Animation

    private var nfcAnimationArea: some View {
        NfcRingsAnimation()
            .allowsHitTesting(false)
    }

    // MARK: - Status Text

    @ViewBuilder
    private var statusText: some View {
        switch viewModel.phase {
        case .loading:
            VStack(spacing: 12) {
                ProgressView()
                    .scaleEffect(1.2)
                Text("Fetching payment token...")
                    .font(.subheadline)
                    .foregroundStyle(.secondary)
            }
        case .ready:
            VStack(spacing: 8) {
                Image(systemName: "checkmark.circle.fill")
                    .font(.system(size: 28))
                    .foregroundStyle(.green)
                Text("Ready to Tap")
                    .font(.headline)
                Text("Hold your phone near the terminal")
                    .font(.subheadline)
                    .foregroundStyle(.secondary)
            }
        case .error:
            VStack(spacing: 8) {
                Image(systemName: "exclamationmark.triangle.fill")
                    .font(.system(size: 28))
                    .foregroundStyle(.orange)
                Text("Failed to arm token")
                    .font(.headline)
                if let msg = viewModel.errorMessage {
                    Text(msg)
                        .font(.caption)
                        .foregroundStyle(.secondary)
                        .multilineTextAlignment(.center)
                }
            }
        }
    }

    // MARK: - Helpers

    private var maskedNumber: String {
        let raw = account.accountNumber
        guard raw.count >= 4 else { return raw }
        return "•••• \(String(raw.suffix(4)))"
    }

    private var cardImageName: String? {
        switch account.bank {
        case "BML": return "card_bml_\(bmlAsset(account.productCode))"
        case "MIB": return mibCardImageName(account.productCode)
        default:    return nil
        }
    }

    private func bmlAsset(_ code: String) -> String {
        switch code {
        case "C8201","C8001","C8009":                                      return "master_prepaid"
        case "C8205","C8005","C8008":                                      return "master_prepaid_travel"
        case "C3007","C3017","C3097","C3095","C3077","C3177":              return "amex_debit_green"
        case "C3003","C3013","C3053","C3023","C3033","C3052":              return "amex_debit_gold"
        case "C3009","C3019","C3029","C3099","C3088","C3188":              return "amex_credit_gold"
        case "C3001","C3011","C3050","C3051","C3031":                      return "amex_credit_green"
        case "C3005","C3015","C3055","C3054":                              return "amex_platinum"
        case "C1003","C1013","C1083","C1084","C1103","C1113","C1183","C1184": return "visa_gold"
        case "C1007","C1027","C1097","C1107","C1197","C1077","C1177":     return "visa_debit"
        case "C1020","C1021":                                              return "visa_debit_platinum"
        case "C8020","C8022":                                              return "master_gold"
        case "C8902","C8907","C8909","C8912","C8992","C8996","C8997","C8982","C8983": return "master_islamic"
        case "C8101":                                                      return "master_masveriyaa"
        case "C8102":                                                      return "master_odiveriyaa"
        case "C8010","C8011":                                              return "master_platinum"
        case "C8040","C8044":                                              return "master_world"
        case "C8030","C8033":                                              return "master_business_debit"
        case "C8901","C8991","C8980","C8981":                             return "master_passport"
        case "C1090","C1130","C1033","C1133":                             return "visa_corporate"
        case "C8905","C8995":                                              return "visa_credit"
        case "C1001","C1011","C1082","C1081","C1101","C1111","C1181","C1182": return "visa_debit_generic"
        case "C1005","C1006","C1030","C1089":                             return "visa_debit_islamic"
        case "C1017":                                                      return "visa_infinite"
        case "C1009","C1019","C1085","C1086","C1109","C1119","C1185","C1186": return "visa_platinum"
        case "C1050","C1051","C1087","C1088","C1150","C1151","C1187","C1188",
             "C1040","C1041","C1047","C1048","C1140","C1141","C1147","C1148": return "visa_student_black"
        case "C8925","C8926":                                              return "visa_student_blue"
        case "C1071","C1073","C1061","C1063","C1161","C1163":             return "master"
        case "C1070","C1072","C1059","C1062","C1159","C1162":             return "master_prepaid_business"
        default:                                                           return "defaultcard"
        }
    }

    private func mibCardImageName(_ cardType: String) -> String? {
        switch cardType {
        case "51":  return "card_mib_faisa_card"
        case "53":  return "card_mib_visa_black_platinum"
        case "57":  return "card_mib_visa_blue_everyday"
        case "70":  return "card_mib_visa_business"
        case "701": return "card_mib_visa_bingaa_mvr"
        case "702": return "card_mib_visa_bingaa_usd"
        default:    return nil
        }
    }

    private var cardGradient: LinearGradient {
        switch account.bank {
        case "BML": return LinearGradient(
            colors: [Color(red: 0.1, green: 0.3, blue: 0.7),
                     Color(red: 0.05, green: 0.15, blue: 0.4)],
            startPoint: .topLeading, endPoint: .bottomTrailing)
        default: return LinearGradient(
            colors: [Color(red: 0.15, green: 0.5, blue: 0.25),
                     Color(red: 0.05, green: 0.3, blue: 0.15)],
            startPoint: .topLeading, endPoint: .bottomTrailing)
        }
    }
}

// MARK: - NFC Rings Animation (SwiftUI port of Android NfcTapAnimationView)

private struct NfcRingsAnimation: View {
    @State private var progress: Double = 0

    var body: some View {
        Canvas { context, size in
            let cx = size.width / 2
            let cy = size.height / 2
            let dp: CGFloat = 1

            let posW: CGFloat = 44 * dp
            let posH: CGFloat = 72 * dp
            let posX = cx - posW / 2

            let phoneW: CGFloat = 52 * dp
            let phoneH: CGFloat = 90 * dp
            let phoneX = cx - phoneW / 2
            let phoneY = cy + 10 * dp

            let posY = cy - 150 * dp
            let gapTop = posY + posH + 4 * dp
            let originY = phoneY
            let maxR = max((originY - gapTop) - 4 * dp, 10)

            // POS terminal body
            context.fill(
                Path(roundedRect: CGRect(x: posX, y: posY, width: posW, height: posH),
                     cornerRadius: 7 * dp),
                with: .color(Color(.systemFill))
            )
            context.stroke(
                Path(roundedRect: CGRect(x: posX, y: posY, width: posW, height: posH),
                     cornerRadius: 7 * dp),
                with: .color(.primary),
                lineWidth: 2.5 * dp
            )

            // POS screen
            context.fill(
                Path(roundedRect: CGRect(x: posX + 4 * dp, y: posY + 6 * dp,
                                         width: posW - 8 * dp, height: posH * 0.45),
                     cornerRadius: 4 * dp),
                with: .color(.blue.opacity(0.3))
            )

            // POS card slot
            let slotY = posY + posH * 0.72
            context.stroke(
                Path { p in
                    p.move(to: CGPoint(x: posX + 6 * dp, y: slotY))
                    p.addLine(to: CGPoint(x: posX + posW - 6 * dp, y: slotY))
                },
                with: .color(.primary),
                lineWidth: 2 * dp
            )

            // Phone body
            context.fill(
                Path(roundedRect: CGRect(x: phoneX, y: phoneY,
                                         width: phoneW, height: phoneH),
                     cornerRadius: 8 * dp),
                with: .color(Color(.systemFill))
            )
            context.stroke(
                Path(roundedRect: CGRect(x: phoneX, y: phoneY,
                                         width: phoneW, height: phoneH),
                     cornerRadius: 8 * dp),
                with: .color(.primary),
                lineWidth: 2.5 * dp
            )

            // Phone screen
            context.fill(
                Path(roundedRect: CGRect(x: phoneX + 4 * dp, y: phoneY + 10 * dp,
                                         width: phoneW - 8 * dp, height: phoneH - 25 * dp),
                     cornerRadius: 4 * dp),
                with: .color(.blue.opacity(0.3))
            )

            // Animated NFC rings
            for i in 0..<3 {
                let p = (progress + CGFloat(i) / 3).truncatingRemainder(dividingBy: 1)
                let r = min(p * maxR + 6 * dp, maxR)
                let alpha = ((1 - p) * 0.8).clamped(to: 0...0.8)
                let ringRect = CGRect(x: cx - r, y: originY - r,
                                      width: r * 2, height: r * 2)

                context.stroke(
                    Path(ellipseIn: ringRect),
                    with: .color(.blue.opacity(alpha)),
                    lineWidth: 3 * dp
                )
            }
        }
        .onReceive(Timer.publish(every: 1.0 / 60, on: .main, in: .common).autoconnect()) { _ in
            progress = Date().timeIntervalSince1970
                .truncatingRemainder(dividingBy: 1.6) / 1.6
        }
    }
}

extension Comparable {
    func clamped(to limits: ClosedRange<Self>) -> Self {
        min(max(self, limits.lowerBound), limits.upperBound)
    }
}

// MARK: - Preview

#Preview {
    TapToPayView(
        account: BankAccount(
            id: "BML_1234_bml_test",
            bank: "BML",
            profileName: "Personal",
            profileType: "BML_DEBIT",
            productCode: "C1007",
            accountNumber: "411111XXXXXX1234",
            accountBriefName: "John Doe",
            currencyName: "MVR",
            accountTypeName: "Visa Debit",
            availableBalance: 5000,
            currentBalance: 5200,
            blockedAmount: 0,
            mvrBalance: nil,
            statusDesc: "Active",
            profileImageHash: nil,
            loginTag: "bml_test",
            profileId: "test_pid",
            internalId: "card_123"
        ),
        onDismiss: {}
    )
}