littleshop/LittleShop/Services/ISilverPayService.cs

using LittleShop.Enums;

namespace LittleShop.Services;

public interface ISilverPayService
{
    /// <summary>
    /// Create a new payment order in SilverPAY
    /// </summary>
    /// <param name="externalId">External order ID (LittleShop order ID)</param>
    /// <param name="amount">Amount in fiat currency (GBP)</param>
    /// <param name="currency">Cryptocurrency to accept</param>
    /// <param name="description">Optional order description</param>
    /// <param name="webhookUrl">Optional webhook URL for payment notifications</param>
    /// <returns>SilverPAY order details including payment address</returns>
    Task<SilverPayOrderResponse> CreateOrderAsync(
        string externalId,
        decimal amount,
        CryptoCurrency currency,
        string? description = null,
        string? webhookUrl = null);

    /// <summary>
    /// Get the status of a SilverPAY order
    /// </summary>
    /// <param name="orderId">SilverPAY order ID</param>
    /// <returns>Order status and payment details</returns>
    Task<SilverPayOrderResponse?> GetOrderStatusAsync(string orderId);

    /// <summary>
    /// Validate webhook signature from SilverPAY
    /// </summary>
    /// <param name="payload">Webhook payload</param>
    /// <param name="signature">Webhook signature header</param>
    /// <returns>True if signature is valid</returns>
    Task<bool> ValidateWebhookAsync(string payload, string signature);

    /// <summary>
    /// Get current exchange rate for crypto to fiat
    /// </summary>
    /// <param name="cryptoCurrency">Cryptocurrency symbol</param>
    /// <param name="fiatCurrency">Fiat currency (GBP, USD, EUR)</param>
    /// <returns>Current exchange rate</returns>
    Task<decimal?> GetExchangeRateAsync(string cryptoCurrency, string fiatCurrency = "GBP");

    /// <summary>
    /// Get list of supported cryptocurrencies from SilverPAY
    /// </summary>
    /// <returns>List of supported currency codes</returns>
    Task<List<string>> GetSupportedCurrenciesAsync();
}

/// <summary>
/// Response from SilverPAY order creation/status
/// </summary>
public class SilverPayOrderResponse
{
    public string Id { get; set; } = string.Empty;
    public string ExternalId { get; set; } = string.Empty;
    public decimal Amount { get; set; }
    public string Currency { get; set; } = string.Empty;
    public string PaymentAddress { get; set; } = string.Empty;
    public string Status { get; set; } = string.Empty;
    public DateTime CreatedAt { get; set; }
    public DateTime ExpiresAt { get; set; }
    public DateTime? PaidAt { get; set; }
    public Dictionary<string, object>? PaymentDetails { get; set; }

    // Additional fields for crypto amounts
    public decimal? CryptoAmount { get; set; }
    public string? TransactionHash { get; set; }
    public int? Confirmations { get; set; }
}

/// <summary>
/// Webhook notification from SilverPAY
/// </summary>
public class SilverPayWebhookNotification
{
    public string OrderId { get; set; } = string.Empty;
    public string ExternalId { get; set; } = string.Empty;
    public string Status { get; set; } = string.Empty;
    public string Address { get; set; } = string.Empty;
    public string? TxHash { get; set; }
    public decimal Amount { get; set; }
    public int Confirmations { get; set; }
    public int? BlockHeight { get; set; }
    public DateTime Timestamp { get; set; }
}