using System.Linq;
using System.Threading.Tasks;
using API.Entities;
using API.Entities.Enums;
using API.Interfaces.Repositories;
using Microsoft.EntityFrameworkCore;

namespace API.Data.Repositories
{
    public class AppUserProgressRepository : IAppUserProgressRepository
    {
        private readonly DataContext _context;

        public AppUserProgressRepository(DataContext context)
        {
            _context = context;
        }

        public void Update(AppUserProgress userProgress)
        {
            _context.Entry(userProgress).State = EntityState.Modified;
        }

        /// <summary>
        /// This will remove any entries that have chapterIds that no longer exists. This will execute the save as well.
        /// </summary>
        public async Task<int> CleanupAbandonedChapters()
        {
            var chapterIds = _context.Chapter.Select(c => c.Id);

            var rowsToRemove = await _context.AppUserProgresses
                .Where(progress => !chapterIds.Contains(progress.ChapterId))
                .ToListAsync();

            var rowsToRemoveBookmarks = await _context.AppUserBookmark
                .Where(progress => !chapterIds.Contains(progress.ChapterId))
                .ToListAsync();

            var rowsToRemoveReadingLists = await _context.ReadingListItem
                .Where(item => !chapterIds.Contains(item.ChapterId))
                .ToListAsync();

            _context.RemoveRange(rowsToRemove);
            _context.RemoveRange(rowsToRemoveBookmarks);
            _context.RemoveRange(rowsToRemoveReadingLists);
            return await _context.SaveChangesAsync() > 0 ? rowsToRemove.Count : 0;
        }

        /// <summary>
        /// Checks if user has any progress against a library of passed type
        /// </summary>
        /// <param name="libraryType"></param>
        /// <param name="userId"></param>
        /// <returns></returns>
        public async Task<bool> UserHasProgress(LibraryType libraryType, int userId)
        {
            var seriesIds = await _context.AppUserProgresses
                .Where(aup => aup.PagesRead > 0 && aup.AppUserId == userId)
                .AsNoTracking()
                .Select(aup => aup.SeriesId)
                .ToListAsync();

            if (seriesIds.Count == 0) return false;

            return await _context.Series
                .Include(s => s.Library)
                .Where(s => seriesIds.Contains(s.Id) && s.Library.Type == libraryType)
                .AsNoTracking()
                .AnyAsync();
        }

        public async Task<AppUserProgress> GetUserProgressAsync(int chapterId, int userId)
        {
            return await _context.AppUserProgresses
                .Where(p => p.ChapterId == chapterId && p.AppUserId == userId)
                .SingleOrDefaultAsync();
        }
    }
}