using MediatR;
using TakeoutSaaS.Application.App.Stores;
using TakeoutSaaS.Application.App.Stores.Dto;
using TakeoutSaaS.Application.App.Stores.Queries;
using TakeoutSaaS.Domain.Stores.Entities;
using TakeoutSaaS.Domain.Stores.Repositories;
using TakeoutSaaS.Shared.Abstractions.Constants;
using TakeoutSaaS.Shared.Abstractions.Exceptions;

namespace TakeoutSaaS.Application.App.Stores.Handlers;

/// <summary>
/// 获取门店费用配置处理器。
/// </summary>
public sealed class GetStoreFeeQueryHandler(
    IStoreRepository storeRepository)
    : IRequestHandler<GetStoreFeeQuery, StoreFeeDto?>
{
    /// <inheritdoc />
    public async Task<StoreFeeDto?> Handle(GetStoreFeeQuery request, CancellationToken cancellationToken)
    {
        // 1. 校验门店存在
        var store = await storeRepository.FindByIdAsync(request.StoreId, null, cancellationToken);
        if (store is null)
        {
            throw new BusinessException(ErrorCodes.NotFound, "门店不存在");
        }

        // 2. (空行后) 查询费用配置
        var fee = await storeRepository.GetStoreFeeAsync(request.StoreId, null, cancellationToken);
        if (fee is null)
        {
            var fallback = new StoreFee
            {
                StoreId = request.StoreId,
                MinimumOrderAmount = 0m,
                BaseDeliveryFee = 0m,
                PackagingFeeMode = Domain.Stores.Enums.PackagingFeeMode.Fixed,
                OrderPackagingFeeMode = Domain.Stores.Enums.OrderPackagingFeeMode.Fixed,
                FixedPackagingFee = 0m
            };
            return StoreMapping.ToDto(fallback);
        }

        // 3. (空行后) 返回结果
        return StoreMapping.ToDto(fee);
    }
}