using ErrorOr;
using Mediator;
using Microsoft.EntityFrameworkCore;
using Musify.Application.Contracts;
using Musify.Application.Shared;
using Musify.Application.Tracks.Responses;
using X.PagedList;
using X.PagedList.EF;

namespace Musify.Application.Likes
{
    public record GetLikedTracksQuery(
        long UserId,
        int PageNumber,
        int PageSize)
        : IQuery<ErrorOr<PaginatedResponse<TrackApplicationResponse>>>;

    public class GetLikedTracksQueryHandler(IDatabase database)
        : IQueryHandler<GetLikedTracksQuery, ErrorOr<PaginatedResponse<TrackApplicationResponse>>>
    {
        public async ValueTask<ErrorOr<PaginatedResponse<TrackApplicationResponse>>> Handle(GetLikedTracksQuery request, CancellationToken cancellationToken)
        {
            var likesQuery = database.TrackLikes
                .AsNoTracking()
                .Include(like => like.Track.Owner)
                .Where(like => like.UserId == request.UserId);

            var totalCount = await likesQuery.CountAsync(cancellationToken);

            var pagedEntities = await likesQuery
                .OrderByDescending(like => like.CreatedAt)
                .Select(like => new { like.Track, ListensCount = like.Track.ListeningHistories.Count })
                .ToPagedListAsync(request.PageNumber, request.PageSize, totalCount, cancellationToken);

            var pagedTracks = new StaticPagedList<TrackApplicationResponse>(
                pagedEntities.Select(x => TrackApplicationResponse.FromEntity(x.Track, x.ListensCount)),
                pagedEntities.PageNumber, pagedEntities.PageSize, pagedEntities.TotalItemCount);

            return PaginatedResponse<TrackApplicationResponse>.FromPagedList(pagedTracks);
        }
    }
}