fengling-risk-control/Fengling.RiskControl.Application/Services/OrderRiskValidationService.cs

using Fengling.RiskControl.Domain.Aggregates.RiskScores;

namespace Fengling.RiskControl.Application.Services;

public class OrderRiskValidationService : IOrderRiskValidationService
{
    private readonly IRiskEvaluationService _riskService;
    private readonly IMemberIntegrationService _memberService;

    public OrderRiskValidationService(
        IRiskEvaluationService riskService,
        IMemberIntegrationService memberService)
    {
        _riskService = riskService;
        _memberService = memberService;
    }

    public async Task<OrderDiscountValidationResult> ValidateDiscountAsync(OrderDiscountValidationRequest request)
    {
        if (request.OriginalAmount <= 0)
        {
            return new OrderDiscountValidationResult
            {
                IsAllowed = false,
                Reason = "订单金额必须大于0",
                MaxDiscountAllowed = 0
            };
        }

        var discountRate = (double)request.DiscountAmount / request.OriginalAmount;

        var riskResult = await _riskService.EvaluateRiskAsync(new RiskEvaluationRequest
        {
            MemberId = request.MemberId,
            EntityType = "order_discount",
            EntityId = request.OrderId,
            ActionType = "apply_discount",
            Context = new Dictionary<string, object>
            {
                ["discountAmount"] = request.DiscountAmount,
                ["originalAmount"] = request.OriginalAmount,
                ["discountRate"] = discountRate,
                ["discountType"] = request.DiscountType
            }
        });

        if (riskResult.Blocked)
        {
            return new OrderDiscountValidationResult
            {
                IsAllowed = false,
                Reason = riskResult.Message,
                MaxDiscountAllowed = 0,
                RiskDetails = riskResult
            };
        }

        var maxDiscount = riskResult.RiskLevel switch
        {
            RiskLevel.Low => request.OriginalAmount / 2,
            RiskLevel.Medium => request.OriginalAmount / 5,
            RiskLevel.High => 0,
            _ => 0
        };

        return new OrderDiscountValidationResult
        {
            IsAllowed = request.DiscountAmount <= maxDiscount,
            Reason = request.DiscountAmount <= maxDiscount ? "折扣申请通过" : $"超过最大允许折扣: {maxDiscount}",
            MaxDiscountAllowed = maxDiscount,
            RiskDetails = riskResult
        };
    }
}