# Checkout

Apresentar um pagamento com FaciPayCheckout.start.

`FaciPayCheckout.start(...)` apresenta o checkout (sheet com `WKWebView`) e devolve um
`CheckoutResult`.

```swift
FaciPayCheckout.start(
    from: viewController,
    references: [
        PaymentReference(referenceNumber: "ORD_001", referenceAmount: 5000.0) // AOA
    ],
    createOrder: {
        let response = await MyBackendAPI.createPaymentOrder(amount: 5000.0)
        if let txnId = response.transactionId {
            return .success(merchantTransactionId: txnId)
        } else {
            return .failure(message: "Falha ao criar ordem", cause: response.error)
        }
    },
    completion: { result in
        switch result {
        case .approved(let payment): print("Aprovado:", payment.orderId)
        case .pending(let payment):  print("Pendente:", payment.orderId)
        case .cancelled:             print("Cancelado")
        case .failed(let error):     print("Erro:", error.localizedDescription)
        }
    },
    customerInfo: CustomerInfo(name: "João Silva", phone: "923000000"),
    config: FaciPayConfig(
        language: .portuguese,
        theme: .light,
        defaultPaymentMethod: .mcxExpress,
        referencePaymentLifeSpan: 1440 // minutos
    )
)
```

## SwiftUI (async)

```swift
let result = await FaciPayCheckout.start(
    references: [PaymentReference(referenceNumber: "ORD_001", referenceAmount: 5000.0)],
    createOrder: { .success(merchantTransactionId: try await createOrder()) },
    customerInfo: CustomerInfo(name: "João Silva", phone: "923000000")
)
```

## Parâmetros

<ParamField path="from" type="UIViewController" required>
  O view controller que apresenta o checkout (modo UIKit).
</ParamField>

<ParamField path="references" type="[PaymentReference]" required>
  Itens a pagar. `referenceNumber`, `referenceAmount` (Double, > 0), `referenceQuantity`
  (predefinição 1), `referenceTotalQuantity` (opcional). `totalAmount` é calculado.
</ParamField>

<ParamField path="createOrder" type="() async -> CreateOrderResult" required>
  Cria a ordem no seu backend. `.success(merchantTransactionId:)` ou
  `.failure(message:cause:)`.
</ParamField>

<ParamField path="customerInfo" type="CustomerInfo">
  `name`, `phone` (`244XXXXXXXXX` ou `9XXXXXXXX`), `email` (opcional).
</ParamField>

<ParamField path="config" type="FaciPayConfig">
  `language`, `theme`, `defaultPaymentMethod`, `allowedPaymentMethods`,
  `showUIOfProcessingInfo`, `referencePaymentLifeSpan`, `showAmount`.
</ParamField>

<Card title="Próximo passo: Resultado & erros" icon="arrow-right" href="/pt/ios/callbacks">
  CheckoutResult, PaymentResult e FaciPayError.
</Card>