using GB5Shared.DTO.Framework.Login;

namespace GoodBooks.PAY.PAYBLL.Integration
{
    /// <summary>
    /// Cross-module HTTP client for Sales coupon validation and usage recording.
    /// HTTP-only — never shares Sales assembly.
    /// </summary>
    public interface ISalesCouponService
    {
        /// <summary>
        /// Validates a coupon code for the given order amount.
        /// Returns null if invalid/expired.
        /// </summary>
        Task<CouponValidationResult?> ValidateCouponAsync(
            string couponCode, int customerId, decimal orderAmt, LoginDTO login, CancellationToken ct);

        /// <summary>
        /// Marks a coupon as used after payment success.
        /// Fire-and-forget safe — non-fatal if this fails.
        /// </summary>
        Task RecordCouponUsageAsync(
            string couponCode, int customerId, int payOrderId, LoginDTO login, CancellationToken ct);
    }

    public record CouponValidationResult(
        bool    IsValid,
        string  CouponCode,
        decimal DiscountAmt,
        string? ErrorMessage
    );
}