using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

using Knot.Modules.Relations.Domain;
using Knot.Shared.Kernel;
using Microsoft.EntityFrameworkCore;

using Knot.Modules.Relations.Application.Abstractions;
namespace Knot.Modules.Relations.Application.Friends;

public record GetIncomingRequestsQuery(Guid UserId) : IQuery<List<FriendRequestDto>>;

internal sealed class GetIncomingRequestsQueryHandler : IQueryHandler<GetIncomingRequestsQuery, List<FriendRequestDto>>
{
    private readonly IRelationsDbContext _context;
    private readonly IUserRepository _userRepository;

    public GetIncomingRequestsQueryHandler(IRelationsDbContext context, IUserRepository userRepository)
    {
        _context = context;
        _userRepository = userRepository;
    }

    public async Task<Result<List<FriendRequestDto>>> Handle(GetIncomingRequestsQuery request, CancellationToken cancellationToken)
    {
        var friendships = await _context.Friendships
            .Where(f => f.FriendId == request.UserId && f.Status == FriendshipStatus.Pending)
            .ToListAsync(cancellationToken);

        var requestsList = new List<FriendRequestDto>();
        foreach (var fs in friendships)
        {
            var user = await _userRepository.GetByIdAsync(fs.UserId, cancellationToken);
            if (user == null)
            {
                continue;
            }

            requestsList.Add(new FriendRequestDto(
                fs.Id,
                new FriendUserDto(user.Id, user.Username, user.DisplayName, user.Avatar),
                fs.CreatedAt
            ));
        }
        return Result.Success(requestsList);
    }
}