using Microsoft.EntityFrameworkCore;
using StopShopping.EF;
using StopShopping.Services.Models.Req;
using StopShopping.Services.Models.Resp;

namespace StopShopping.Services.Implementions;

public class ProductService : IProductService
{
    public ProductService(
        StopShoppingContext dbContext,
        IClaimsService claimsService,
        IFileService fileService,
        ISerialNoGenerator serialNoGenerator)
    {
        _dbContext = dbContext;
        _claimsService = claimsService;
        _fileService = fileService;
        _serilNoGenerator = serialNoGenerator;
    }

    private readonly StopShoppingContext _dbContext;
    private readonly IClaimsService _claimsService;
    private readonly IFileService _fileService;
    private readonly ISerialNoGenerator _serilNoGenerator;

    public ApiResponse<ProductInfo> Detail(ProductIdParams model)
    {
        var detail = _dbContext.Products
            .AsNoTracking()
            .Where(p => p.Id == model.ProductId && !p.Deleted)
            .Include(p => p.Category)
            .Select(Cast<ProductInfo>)
            .FirstOrDefault();
        if (null == detail)
            return new ApiResponse<ProductInfo>().Failed("商品已不存在，请刷新重试");

        return new ApiResponse<ProductInfo>(detail);
    }

    public async Task<ApiResponse<PagedResult<Product>>> SearchAsync(ProductSearchParms model)
    {
        var userId = _claimsService.GetCurrentUserId();
        var qry = _dbContext.Products
            .AsNoTracking()
            .Include(p => p.Category)
            .Where(p => !p.Deleted);
        if (userId.HasValue)
            qry = qry.Where(p => p.UserId == userId);
        if (model.CategoryId > 0)
        {
            var categoryPath = (await _dbContext.Categories
                .FirstOrDefaultAsync(c1 => c1.Id == model.CategoryId))
                ?.Path ?? "";

            qry = qry.Where(p =>
                _dbContext.Categories
                    .Where(c => c.Path.StartsWith(categoryPath))
                    .Select(c => c.Id)
                    .Contains(p.CategoryId));
        }
        if (!string.IsNullOrWhiteSpace(model.Keyword))
            qry = qry.Where(p =>
                p.Name.Contains(model.Keyword)
                || (p.Description != null && p.Description.Contains(model.Keyword)));

        var orderedQry = WithOrderBys(qry, model.OrderBys);

        var result = await orderedQry!
            .Select(Cast<Product>)
            .ToAsyncEnumerable()
            .ToPagedAsync(model.PageIndex, model.PageSize);

        return new ApiResponse<PagedResult<Product>>(result);
    }

    public async Task<ApiResponse> EditAsync(EditProductParams model)
    {
        var userId = _claimsService.GetCurrentUserId()!.Value;

        EF.Models.Product? product = null;
        if (model.Id > 0)
        {
            product = await _dbContext.Products
                .FirstOrDefaultAsync(p =>
                    p.Id == model.Id.Value
                    && p.UserId == userId
                    && !p.Deleted);
            if (null == product)
                return ApiResponse.Failed("商品已不存在，请刷新重试");
        }
        else
        {
            product = new()
            {
                SerialNo = _serilNoGenerator.GenerateProductNo(),
                UserId = userId,
                Logo = string.IsNullOrWhiteSpace(model.LogoName)
                    ? Consts.DEFAULT_PRODUCT
                    : model.LogoName
            };
            await _dbContext.Products.AddAsync(product);
        }
        product.CategoryId = model.CategoryId;
        product.Description = model.Description;
        product.Detail = model.Detail;
        product.MinimumUnit = model.MinimumUnit ?? "";
        product.Name = model.Name ?? "";
        product.UnitPrice = model.UnitPrice;

        await _dbContext.SaveChangesAsync();

        return ApiResponse.Succed();
    }

    public async Task<ApiResponse> DeleteAsync(ProductIdParams model)
    {
        var userId = _claimsService.GetCurrentUserId()!.Value;
        var product = await _dbContext.Products
            .FirstOrDefaultAsync(p =>
                p.Id == model.ProductId
                && p.UserId == userId
                && !p.Deleted);
        if (null == product)
            return ApiResponse.Failed("此商品已不存在，请刷新重试");

        product.Deleted = true;
        await _dbContext.SaveChangesAsync();

        return ApiResponse.Succed();
    }

    #region private methods

    private IOrderedQueryable<EF.Models.Product>? WithOrderBys(IQueryable<EF.Models.Product> qry, IEnumerable<ProductOrderBys> orderBys)
    {
        IOrderedQueryable<EF.Models.Product>? orderedQry = null;
        foreach (var orderby in orderBys)
        {
            if (null == orderedQry)
                orderedQry = orderby switch
                {
                    ProductOrderBys.CreateTime => qry.OrderBy(p => p.CreateTime),
                    ProductOrderBys.CreateTimeDesc => qry.OrderByDescending(p => p.CreateTime),
                    ProductOrderBys.Category => qry.OrderBy(p => p.Category),
                    ProductOrderBys.CategoryDesc => qry.OrderByDescending(p => p.Category),
                    ProductOrderBys.SoldAmount => qry.OrderBy(p => p.SoldAmount),
                    ProductOrderBys.SoldAmountDesc => qry.OrderByDescending(p => p.SoldAmount),
                    _ => qry.OrderBy(p => p.CreateTime),
                };
            else
                orderedQry = orderby switch
                {
                    ProductOrderBys.CreateTime => orderedQry.ThenBy(p => p.CreateTime),
                    ProductOrderBys.CreateTimeDesc => orderedQry.ThenByDescending(p => p.CreateTime),
                    ProductOrderBys.Category => orderedQry.ThenBy(p => p.Category),
                    ProductOrderBys.CategoryDesc => orderedQry.ThenByDescending(p => p.Category),
                    ProductOrderBys.SoldAmount => orderedQry.ThenBy(p => p.SoldAmount),
                    ProductOrderBys.SoldAmountDesc => orderedQry.ThenByDescending(p => p.SoldAmount),
                    _ => orderedQry.ThenBy(p => p.CreateTime),
                };
        }
        return orderedQry;
    }

    private T Cast<T>(EF.Models.Product product)
        where T : Product, new()
    {
        var result = new T
        {
            CategoryName = product.Category.Name,
            CreateTime = product.CreateTime.ToFormatted(),
            Description = product.Description,
            Id = product.Id,
            LogoUrl = _fileService.GetFileUrl(Models.UploadScences.Product, product.Logo),
            MinimumUnit = product.MinimumUnit,
            Name = product.Name,
            UnitPrice = product.UnitPrice,
            SoldAmount = product.SoldAmount,
        };
        if (result is ProductInfo)
        {
            (result as ProductInfo)!.CategoryId = product.CategoryId;
            (result as ProductInfo)!.Detail = product.Detail;
        }

        return result;
    }

    #endregion
}