using Fengling.Backend.Infrastructure;

namespace Fengling.Backend.Web.Application.Queries.MarketingCodes;

/// <summary>
/// 营销码DTO
/// </summary>
public record MarketingCodeDto
{
    public Guid Id { get; init; }
    public string Code { get; init; } = string.Empty;
    public string BatchNo { get; init; } = string.Empty;
    public Guid ProductId { get; init; }
    public string ProductName { get; init; } = string.Empty;
    public Guid? CategoryId { get; init; }
    public string? CategoryName { get; init; }
    public bool IsUsed { get; init; }
    public Guid? UsedByMemberId { get; init; }
    public DateTime? UsedAt { get; init; }
    public DateTime? ExpiryDate { get; init; }
    public DateTime CreatedAt { get; init; }
}

/// <summary>
/// 批次信息DTO
/// </summary>
public record MarketingCodeBatchDto
{
    public string BatchNo { get; init; } = string.Empty;
    public Guid ProductId { get; init; }
    public string ProductName { get; init; } = string.Empty;
    public Guid? CategoryId { get; init; }
    public string? CategoryName { get; init; }
    public int TotalCount { get; init; }
    public int UsedCount { get; init; }
    public DateTime CreatedAt { get; init; }
    public DateTime? ExpiryDate { get; init; }
}

/// <summary>
/// 查询营销码列表
/// </summary>
public record GetMarketingCodesQuery(
    string? BatchNo = null,
    Guid? ProductId = null,
    bool? IsUsed = null,
    DateTime? StartDate = null,
    DateTime? EndDate = null,
    int Page = 1,
    int PageSize = 20) : IQuery<PagedResult<MarketingCodeDto>>;

public class GetMarketingCodesQueryHandler(ApplicationDbContext dbContext)
    : IQueryHandler<GetMarketingCodesQuery, PagedResult<MarketingCodeDto>>
{
    public async Task<PagedResult<MarketingCodeDto>> Handle(GetMarketingCodesQuery request, CancellationToken cancellationToken)
    {
        var query = dbContext.MarketingCodes.AsQueryable();

        // 按批次号筛选
        if (!string.IsNullOrWhiteSpace(request.BatchNo))
        {
            query = query.Where(x => x.BatchNo == request.BatchNo);
        }

        // 按产品ID筛选
        if (request.ProductId.HasValue)
        {
            query = query.Where(x => x.ProductInfo.ProductId == request.ProductId.Value);
        }

        // 按使用状态筛选
        if (request.IsUsed.HasValue)
        {
            query = query.Where(x => x.IsUsed == request.IsUsed.Value);
        }

        // 按创建时间范围筛选
        if (request.StartDate.HasValue)
        {
            query = query.Where(x => x.CreatedAt >= request.StartDate.Value);
        }

        if (request.EndDate.HasValue)
        {
            // EndDate包含当天整天
            var endOfDay = request.EndDate.Value.Date.AddDays(1);
            query = query.Where(x => x.CreatedAt < endOfDay);
        }

        // 获取总数
        var totalCount = await query.CountAsync(cancellationToken);
        
        // 分页查询
        var marketingCodes = await query
            .OrderByDescending(x => x.CreatedAt)
            .Skip((request.Page - 1) * request.PageSize)
            .Take(request.PageSize)
            .Select(x => new MarketingCodeDto
            {
                Id = x.Id.Id,
                Code = x.Code,
                BatchNo = x.BatchNo,
                ProductId = x.ProductInfo.ProductId,
                ProductName = x.ProductInfo.ProductName,
                CategoryId = x.ProductInfo.CategoryId,
                CategoryName = x.ProductInfo.CategoryName,
                IsUsed = x.IsUsed,
                UsedByMemberId = x.UsedByMemberId,
                UsedAt = x.UsedAt,
                ExpiryDate = x.ExpiryDate,
                CreatedAt = x.CreatedAt
            })
            .ToListAsync(cancellationToken);

        return new PagedResult<MarketingCodeDto>(
            marketingCodes,
            totalCount,
            request.Page,
            request.PageSize);
    }
}

/// <summary>
/// 查询所有批次列表
/// </summary>
public record GetMarketingCodeBatchesQuery : IQuery<List<MarketingCodeBatchDto>>;

public class GetMarketingCodeBatchesQueryHandler(ApplicationDbContext dbContext)
    : IQueryHandler<GetMarketingCodeBatchesQuery, List<MarketingCodeBatchDto>>
{
    public async Task<List<MarketingCodeBatchDto>> Handle(GetMarketingCodeBatchesQuery request, CancellationToken cancellationToken)
    {
        var batches = await dbContext.MarketingCodes
            .GroupBy(x => new
            {
                x.BatchNo,
                x.ProductInfo.ProductId,
                x.ProductInfo.ProductName,
                x.ProductInfo.CategoryId,
                x.ProductInfo.CategoryName,
                x.ExpiryDate
            })
            .Select(g => new MarketingCodeBatchDto
            {
                BatchNo = g.Key.BatchNo,
                ProductId = g.Key.ProductId,
                ProductName = g.Key.ProductName,
                CategoryId = g.Key.CategoryId,
                CategoryName = g.Key.CategoryName,
                TotalCount = g.Count(),
                UsedCount = g.Count(x => x.IsUsed),
                CreatedAt = g.Min(x => x.CreatedAt),
                ExpiryDate = g.Key.ExpiryDate
            })
            .OrderByDescending(x => x.CreatedAt)
            .ToListAsync(cancellationToken);

        return batches;
    }
}