# Payment Gateway Integration Example
#
# This example demonstrates how to integrate the Payment Gateway
# into your CloudLayer application.

defmodule MyApp.PaymentExample do
  @moduledoc """
  Example module showing how to use the Payment Gateway API.
  """

  @doc """
  Example: Process a payment for a user purchase.
  """
  def process_purchase(user_id, amount, currency \\ "USD") do
    # Check if Payment Gateway is available
    if payment_gateway_available?() do
      case PaymentGatewayApp.start_payment(amount, currency, user_id) do
        {:ok, payment} ->
          # Store payment ID in your database
          # save_payment_record(user_id, payment.id)
          
          {:ok, %{
            payment_id: payment.id,
            status: payment.status,
            message: "Payment initiated successfully"
          }}

        {:error, reason} ->
          {:error, "Payment failed: #{inspect(reason)}"}
      end
    else
      {:error, "Payment Gateway not available"}
    end
  end

  @doc """
  Example: Check payment status and update order.
  """
  def check_payment_and_update_order(payment_id, order_id) do
    if payment_gateway_available?() do
      case PaymentGatewayApp.get_payment_status(payment_id) do
        {:ok, status} ->
          # Update your order based on payment status
          case status.status do
            "completed" ->
              # complete_order(order_id)
              {:ok, "Order completed"}

            "failed" ->
              # cancel_order(order_id)
              {:ok, "Order cancelled"}

            "pending" ->
              {:ok, "Payment still pending"}

            _ ->
              {:ok, "Payment status: #{status.status}"}
          end

        {:error, reason} ->
          {:error, "Failed to check status: #{inspect(reason)}"}
      end
    else
      {:error, "Payment Gateway not available"}
    end
  end

  @doc """
  Example: Webhook handler for payment notifications.
  """
  def handle_payment_webhook(payload) do
    # Verify webhook signature (implement based on your provider)
    # verify_webhook_signature(payload)

    payment_id = payload["payment_id"]
    status = payload["status"]

    # Update your database
    # update_payment_status(payment_id, status)

    # Send notification to user
    # notify_user_payment_status(payment_id, status)

    {:ok, "Webhook processed"}
  end

  # Helper function to check if Payment Gateway is available
  defp payment_gateway_available? do
    Code.ensure_loaded?(PaymentGatewayApp) and
      Application.get_env(:da_product_app, :enable_payment_gateway, false)
  end
end