import SwiftUI
import PassKit

struct ContentView: View {
    @StateObject private var handler = PaymentHandler()
    @State private var amount: String = "7.250"

    private var canPay: Bool {
        PKPaymentAuthorizationController.canMakePayments() && (Double(amount) ?? 0) > 0
    }

    var body: some View {
        VStack(spacing: 24) {
            VStack(spacing: 4) {
                Text("TruePay").font(.largeTitle).bold()
                Text("Apple Pay demo").foregroundColor(.secondary)
            }

            HStack {
                Text("Amount")
                Spacer()
                TextField("0.000", text: $amount)
                    .keyboardType(.decimalPad)
                    .multilineTextAlignment(.trailing)
                    .frame(width: 120)
                Text(Config.currencyCode).foregroundColor(.secondary)
            }
            .padding()
            .background(Color(.secondarySystemBackground))
            .cornerRadius(12)

            if canPay {
                ApplePayButton {
                    handler.startPayment(amount: Double(amount) ?? 0)
                }
                .frame(height: 48)
                .cornerRadius(10)
            } else {
                Text("Apple Pay is not available on this device.")
                    .font(.footnote).foregroundColor(.secondary)
            }

            if let status = handler.status {
                Text(status)
                    .font(.callout)
                    .foregroundColor(handler.succeeded ? .green : .red)
                    .multilineTextAlignment(.center)
            }

            Spacer()
        }
        .padding()
    }
}

/// Native PKPaymentButton wrapped for SwiftUI.
struct ApplePayButton: UIViewRepresentable {
    let action: () -> Void

    func makeUIView(context: Context) -> PKPaymentButton {
        let button = PKPaymentButton(paymentButtonType: .buy, paymentButtonStyle: .black)
        button.addTarget(context.coordinator, action: #selector(Coordinator.tapped), for: .touchUpInside)
        return button
    }

    func updateUIView(_ uiView: PKPaymentButton, context: Context) {}

    func makeCoordinator() -> Coordinator { Coordinator(action: action) }

    final class Coordinator: NSObject {
        let action: () -> Void
        init(action: @escaping () -> Void) { self.action = action }
        @objc func tapped() { action() }
    }
}