let devices = [
  TerminalDevice.companion.create(id: "BRI12345", ipAddress: "192.168.1.10"),
  TerminalDevice.companion.create(id: "BRI67890", ipAddress: "192.168.1.11")
]

TerminalH2H.shared.registerDevices(
  devices: devices,
  restart: true // restart to apply the refreshed device list immediately
)

# Example: Create a payment session
curl -X POST 'https://terminal-dev.xendit.co/v1/terminal/sessions' \
  -u 'API_KEY:' \
  -H 'Content-Type: application/json' \
  -H 'Idempotency-key: unique-session-123' \
  -d '{
    "terminal_id": "TERMINAL_ID",
    "amount": 10000,
    "currency": "IDR",
    "external_id": "payment-123",
    "payment_method": "card"
  }'

TerminalH2H.shared.setOperationTimeout(minutes: 5) // default value is 5 minutes

// Set provider-specific timeouts
TerminalH2H.shared.setOperationTimeout(type: TimeoutType.card, minutes: 10)
TerminalH2H.shared.setOperationTimeout(type: TimeoutType.qr, minutes: 10)

let device = TerminalDevice.companion.create(id: "BRI12345", ipAddress: "192.168.1.10")

TerminalH2H.shared.observeConnection(device: device) { state in
  // Handle connection state transitions
}

TerminalH2H.shared.observeError { device, error in
  // Use device?.id to correlate errors with specific terminals
}

struct TerminalError {
    let code: ErrorCode
    let message: String
}

func handleTerminalError(_ error: TerminalError?) {
  guard let error = error else { return }

  switch error.code {
  case ErrorCode.authenticationFailed:
    // Verify API key and <a href="#finding-terminal-information">terminal ID</a>
    print("Authentication failed: \(error.message)")
    // Show user-friendly message and retry with correct credentials
        
  case ErrorCode.terminalBusy:
    // Terminal is processing another transaction
    print("Terminal busy: \(error.message)")
    // Wait and retry after a delay
    retryAfterDelay(5.0) // 5 seconds
        
  case ErrorCode.failedToConnect, ErrorCode.notConnected:
    // Network connectivity issues
    print("Connection failed: \(error.message)")
    // Check network connection and terminal <a href="#finding-terminal-information">IP address</a>
    checkNetworkConnectivity()

  case ErrorCode.declinedByReader:
    // Terminal rejected the card tap/insert
    print("Declined by reader: \(error.message)")
    promptCustomerToRetry()

  case ErrorCode.paymentUnpaid:
    // Payment still pending on the terminal
    print("Payment unpaid: \(error.message)")
    confirmStatusWithBackend()

  case ErrorCode.timeout:
    // Gateway timed out while waiting for terminal response
    print("Command timeout: \(error.message)")
    TerminalH2H.shared.restart(terminalID: nil)

  case ErrorCode.duplicated:
    // Duplicate command detected by the gateway
    print("Duplicate command detected: \(error.message)")
    regenerateOrderID()
        
  case ErrorCode.keyInvalid, ErrorCode.invalidCredential:
    // Credential issues
    print("Invalid credentials: \(error.message)")
    // Rotate or refresh API credentials
    refreshCredentials()
        
  case ErrorCode.encryptionFailed:
    // Encryption key issues
    print("Encryption failed: \(error.message)")
    // Re-initialize SDK with correct encryption keys
    reinitializeSDK()

  case ErrorCode.cancelled:
    // Operator cancelled the command on the terminal
    print("Operation cancelled: \(error.message)")
    notifyCashier()
        
  default:
    // Log and escalate unknown errors
    print("Unknown error: \(error.message)")
    // Report to monitoring system
    reportError(error)
  }
}