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

namespace StopShopping.Services.Implementions;

public class RequestService : IRequestService
{
    public RequestService(
        StopShoppingContext dbContext,
        IClaimsService claimsService,
        ISerialNoGenerator serialNoGenerator)
    {
        _dbContext = dbContext;
        _claimService = claimsService;
        _serialNoGenerator = serialNoGenerator;
    }

    private readonly StopShoppingContext _dbContext;
    private readonly IClaimsService _claimService;
    private readonly ISerialNoGenerator _serialNoGenerator;

    public async Task<ApiResponse> PublishRequestAsync(CreateRequestParams model)
    {
        var serialNo = _serialNoGenerator.GenerateRequestNo();
        var userId = _claimService.GetCurrentUserId()!.Value;

        EF.Models.Request req = new()
        {
            CategoryId = model.CategoryId,
            Deadline = DateOnly.Parse(model.Deadline),
            Description = model.Description,
            Name = model.Name,
            PublisherId = userId,
            SerialNo = serialNo,
            Status = (short)RequestStatus.Publish,
        };

        await _dbContext.Requests.AddAsync(req);
        await _dbContext.SaveChangesAsync();

        return ApiResponse.Succed();
    }

    public async Task<ApiResponse<PagedResult<Request>>> SearchAsync(RequestSearchParams model)
    {
        return await DoSearchAsync(model, null);
    }

    public async Task<ApiResponse<PagedResult<Request>>> RequestOrderSearchAsync(RequestSearchWithStatusParams model)
    {
        return await DoSearchAsync(model, UserRoles.Buyer);
    }

    public async Task<ApiResponse<PagedResult<Request>>> ReplyOrderSearchAsync(RequestSearchWithStatusParams model)
    {
        return await DoSearchAsync(model, UserRoles.Seller);
    }

    public async Task<ApiResponse> DeleteRequestAsync(RequestIdParams model)
    {
        var userId = _claimService.GetCurrentUserId()!.Value;

        var request = await _dbContext.Requests
            .Include(r => r.Replies)
            .Where(r => r.Id == model.RequestId && !r.Deleted)
            .FirstOrDefaultAsync();

        if (null == request)
            return ApiResponse.Failed("此需求已不存在，请刷新重试");

        var status = (RequestStatus)request.Status;
        if (status.CanDelete())
            return ApiResponse.Failed("此需求状态已改变，请刷新重试");

        request.Deleted = true;
        request.Status = (short)RequestStatus.Completed;

        foreach (var reply in request.Replies)
        {
            reply.Rejected = true;
        }

        await _dbContext.SaveChangesAsync();

        return ApiResponse.Succed();
    }

    private async Task<ApiResponse<PagedResult<Request>>> DoSearchAsync<T>(T model, UserRoles? userRoles)
        where T : RequestSearchParams, new()
    {
        var qry = _dbContext.Requests
            .AsNoTracking()
            .Where(q => !q.Deleted);

        if (model is RequestSearchWithStatusParams statusParams)
        {
            if (statusParams.Status != RequestStatus.All)
                qry = qry.Where(q => q.Status == (short)statusParams.Status);
        }
        else
        {
            qry = qry.Where(q => q.Status == (short)RequestStatus.Publish
                || q.Status == (short)RequestStatus.Replied);
        }

        if (model.CategoryId > 0)
        {
            string categoryPath = $"/{model.CategoryId.Value}/";
            qry = qry.Where(q =>
                _dbContext.Categories
                    .Where(c => c.Path.StartsWith(categoryPath) && !c.Deleted)
                    .Select(c => c.Id)
                    .Contains(q.CategoryId));
        }
        if (!string.IsNullOrEmpty(model.Keyword))
        {
            qry = qry.Where(q =>
                q.Name.Contains(model.Keyword)
                || (q.Description != null && q.Description.Contains(model.Keyword))
                || q.SerialNo.Contains(model.Keyword));
        }

        if (userRoles.HasValue)
        {
            var userId = _claimService.GetCurrentUserId()!.Value;
            qry = userRoles.Value switch
            {
                UserRoles.Seller => qry.Where(q => q.Replies.Any(r => r.UserId == userId)),
                UserRoles.Buyer => qry.Where(q => q.PublisherId == userId),
                _ => qry
            };
        }

        var firstOrderBy = model.OrderBys!.First();
        var included = qry
                .Include(r => r.Publisher).AsNoTracking()
                .Include(r => r.Category).AsNoTracking()
                .Select(r => new
                {
                    ReplyAmount = r.Replies.Count,
                    r
                });

        var ordered = firstOrderBy switch
        {
            RequestOrderBys.PublishTime => included.OrderBy(q => q.r.PublishTime),
            RequestOrderBys.PublishTimeDesc => included.OrderByDescending(q => q.r.PublishTime),
            RequestOrderBys.CategoryId => included.OrderBy(q => q.r.CategoryId),
            RequestOrderBys.CategoryIdDesc => included.OrderByDescending(q => q.r.CategoryId),
            RequestOrderBys.ReplyAmount => included.OrderBy(q => q.ReplyAmount),
            RequestOrderBys.ReplyAmountDesc => included.OrderByDescending(q => q.ReplyAmount),
            _ => included.OrderBy(q => q.r.PublishTime)
        };

        foreach (var orderBy in model.OrderBys!.Skip(1))
        {
            ordered = orderBy switch
            {
                RequestOrderBys.PublishTime => ordered!.ThenBy(q => q.r.PublishTime),
                RequestOrderBys.PublishTimeDesc => ordered!.ThenByDescending(q => q.r.PublishTime),
                RequestOrderBys.CategoryId => ordered!.ThenBy(q => q.r.CategoryId),
                RequestOrderBys.CategoryIdDesc => ordered!.ThenByDescending(q => q.r.CategoryId),
                RequestOrderBys.ReplyAmount => ordered!.ThenBy(q => q.ReplyAmount),
                RequestOrderBys.ReplyAmountDesc => ordered!.ThenByDescending(q => q.ReplyAmount),
                _ => ordered!.ThenBy(q => q.r.PublishTime)
            };
        }

        var paged = await ordered.Select(r => new Request
        {
            CategoryId = r.r.Category.Id,
            CategoryName = r.r.Category.Name,
            Deadline = r.r.Deadline.ToFormatted(),
            Description = r.r.Description,
            Id = r.r.Id,
            Name = r.r.Name,
            Publisher = r.r.Publisher.NickName,
            PublishTime = r.r.PublishTime.ToFormatted(),
            ReplyAmount = r.ReplyAmount,
            SerialNo = r.r.SerialNo,
            Status = (RequestStatus)r.r.Status,

        }).ToAsyncEnumerable().ToPagedAsync(model.PageIndex, model.PageSize);

        return new ApiResponse<PagedResult<Request>>(paged);
    }
}