Kavita/API/Controllers/ReaderController.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using API.Data;
using API.Data.Repositories;
using API.DTOs;
using API.DTOs.Reader;
using API.Entities;
using API.Entities.Enums;
using API.Extensions;
using API.Services;
using API.Services.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;

namespace API.Controllers
{
    /// <summary>
    /// For all things regarding reading, mainly focusing on non-Book related entities
    /// </summary>
    public class ReaderController : BaseApiController
    {
        private readonly ICacheService _cacheService;
        private readonly IUnitOfWork _unitOfWork;
        private readonly ILogger<ReaderController> _logger;
        private readonly IReaderService _readerService;
        private readonly IDirectoryService _directoryService;
        private readonly ICleanupService _cleanupService;

        /// <inheritdoc />
        public ReaderController(ICacheService cacheService,
            IUnitOfWork unitOfWork, ILogger<ReaderController> logger,
            IReaderService readerService, IDirectoryService directoryService,
            ICleanupService cleanupService)
        {
            _cacheService = cacheService;
            _unitOfWork = unitOfWork;
            _logger = logger;
            _readerService = readerService;
            _directoryService = directoryService;
            _cleanupService = cleanupService;
        }

        /// <summary>
        /// Returns an image for a given chapter. Side effect: This will cache the chapter images for reading.
        /// </summary>
        /// <param name="chapterId"></param>
        /// <param name="page"></param>
        /// <returns></returns>
        [HttpGet("image")]
        public async Task<ActionResult> GetImage(int chapterId, int page)
        {
            if (page < 0) page = 0;
            var chapter = await _cacheService.Ensure(chapterId);
            if (chapter == null) return BadRequest("There was an issue finding image file for reading");

            try
            {
                var path = _cacheService.GetCachedPagePath(chapter, page);
                if (string.IsNullOrEmpty(path) || !System.IO.File.Exists(path)) return BadRequest($"No such image for page {page}");
                var format = Path.GetExtension(path).Replace(".", "");

                return PhysicalFile(path, "image/" + format, Path.GetFileName(path));
            }
            catch (Exception)
            {
                _cacheService.CleanupChapters(new []{ chapterId });
                throw;
            }
        }

        /// <summary>
        /// Returns various information about a Chapter. Side effect: This will cache the chapter images for reading.
        /// </summary>
        /// <param name="chapterId"></param>
        /// <returns></returns>
        [HttpGet("chapter-info")]
        public async Task<ActionResult<ChapterInfoDto>> GetChapterInfo(int chapterId)
        {
            var chapter = await _cacheService.Ensure(chapterId);
            if (chapter == null) return BadRequest("Could not find Chapter");

            var dto = await _unitOfWork.ChapterRepository.GetChapterInfoDtoAsync(chapterId);
            if (dto == null) return BadRequest("Please perform a scan on this series or library and try again");
            var mangaFile = (await _unitOfWork.ChapterRepository.GetFilesForChapterAsync(chapterId)).First();

            return Ok(new ChapterInfoDto()
            {
                ChapterNumber =  dto.ChapterNumber,
                VolumeNumber = dto.VolumeNumber,
                VolumeId = dto.VolumeId,
                FileName = Path.GetFileName(mangaFile.FilePath),
                SeriesName = dto.SeriesName,
                SeriesFormat = dto.SeriesFormat,
                SeriesId = dto.SeriesId,
                LibraryId = dto.LibraryId,
                IsSpecial = dto.IsSpecial,
                Pages = dto.Pages,
                ChapterTitle = dto.ChapterTitle ?? string.Empty
            });
        }


        [HttpPost("mark-read")]
        public async Task<ActionResult> MarkRead(MarkReadDto markReadDto)
        {
            var user = await _unitOfWork.UserRepository.GetUserByUsernameAsync(User.GetUsername(), AppUserIncludes.Progress);
            var volumes = await _unitOfWork.VolumeRepository.GetVolumes(markReadDto.SeriesId);
            user.Progresses ??= new List<AppUserProgress>();
            foreach (var volume in volumes)
            {
                _readerService.MarkChaptersAsRead(user, markReadDto.SeriesId, volume.Chapters);
            }

            _unitOfWork.UserRepository.Update(user);

            if (await _unitOfWork.CommitAsync())
            {
                return Ok();
            }


            return BadRequest("There was an issue saving progress");
        }


        /// <summary>
        /// Marks a Series as Unread (progress)
        /// </summary>
        /// <param name="markReadDto"></param>
        /// <returns></returns>
        [HttpPost("mark-unread")]
        public async Task<ActionResult> MarkUnread(MarkReadDto markReadDto)
        {
            var user = await _unitOfWork.UserRepository.GetUserByUsernameAsync(User.GetUsername(), AppUserIncludes.Progress);
            var volumes = await _unitOfWork.VolumeRepository.GetVolumes(markReadDto.SeriesId);
            user.Progresses ??= new List<AppUserProgress>();
            foreach (var volume in volumes)
            {
                _readerService.MarkChaptersAsUnread(user, markReadDto.SeriesId, volume.Chapters);
            }

            _unitOfWork.UserRepository.Update(user);

            if (await _unitOfWork.CommitAsync())
            {
                return Ok();
            }


            return BadRequest("There was an issue saving progress");
        }

        /// <summary>
        /// Marks all chapters within a volume as unread
        /// </summary>
        /// <param name="markVolumeReadDto"></param>
        /// <returns></returns>
        [HttpPost("mark-volume-unread")]
        public async Task<ActionResult> MarkVolumeAsUnread(MarkVolumeReadDto markVolumeReadDto)
        {
            var user = await _unitOfWork.UserRepository.GetUserByUsernameAsync(User.GetUsername(), AppUserIncludes.Progress);

            var chapters = await _unitOfWork.ChapterRepository.GetChaptersAsync(markVolumeReadDto.VolumeId);
            _readerService.MarkChaptersAsUnread(user, markVolumeReadDto.SeriesId, chapters);

            _unitOfWork.UserRepository.Update(user);

            if (await _unitOfWork.CommitAsync())
            {
                return Ok();
            }

            return BadRequest("Could not save progress");
        }

        /// <summary>
        /// Marks all chapters within a volume as Read
        /// </summary>
        /// <param name="markVolumeReadDto"></param>
        /// <returns></returns>
        [HttpPost("mark-volume-read")]
        public async Task<ActionResult> MarkVolumeAsRead(MarkVolumeReadDto markVolumeReadDto)
        {
            var user = await _unitOfWork.UserRepository.GetUserByUsernameAsync(User.GetUsername(), AppUserIncludes.Progress);

            var chapters = await _unitOfWork.ChapterRepository.GetChaptersAsync(markVolumeReadDto.VolumeId);
            _readerService.MarkChaptersAsRead(user, markVolumeReadDto.SeriesId, chapters);

            _unitOfWork.UserRepository.Update(user);

            if (await _unitOfWork.CommitAsync())
            {
                return Ok();
            }

            return BadRequest("Could not save progress");
        }


        /// <summary>
        /// Marks all chapters within a list of volumes as Read. All volumes must belong to the same Series.
        /// </summary>
        /// <param name="dto"></param>
        /// <returns></returns>
        [HttpPost("mark-multiple-read")]
        public async Task<ActionResult> MarkMultipleAsRead(MarkVolumesReadDto dto)
        {
            var user = await _unitOfWork.UserRepository.GetUserByUsernameAsync(User.GetUsername(), AppUserIncludes.Progress);
            user.Progresses ??= new List<AppUserProgress>();

            var chapterIds = await _unitOfWork.VolumeRepository.GetChapterIdsByVolumeIds(dto.VolumeIds);
            foreach (var chapterId in dto.ChapterIds)
            {
                chapterIds.Add(chapterId);
            }
            var chapters = await _unitOfWork.ChapterRepository.GetChaptersByIdsAsync(chapterIds);
            _readerService.MarkChaptersAsRead(user, dto.SeriesId, chapters);

            _unitOfWork.UserRepository.Update(user);

            if (await _unitOfWork.CommitAsync())
            {
                return Ok();
            }

            return BadRequest("Could not save progress");
        }

        /// <summary>
        /// Marks all chapters within a list of volumes as Unread. All volumes must belong to the same Series.
        /// </summary>
        /// <param name="dto"></param>
        /// <returns></returns>
        [HttpPost("mark-multiple-unread")]
        public async Task<ActionResult> MarkMultipleAsUnread(MarkVolumesReadDto dto)
        {
            var user = await _unitOfWork.UserRepository.GetUserByUsernameAsync(User.GetUsername(), AppUserIncludes.Progress);
            user.Progresses ??= new List<AppUserProgress>();

            var chapterIds = await _unitOfWork.VolumeRepository.GetChapterIdsByVolumeIds(dto.VolumeIds);
            foreach (var chapterId in dto.ChapterIds)
            {
                chapterIds.Add(chapterId);
            }
            var chapters = await _unitOfWork.ChapterRepository.GetChaptersByIdsAsync(chapterIds);
            _readerService.MarkChaptersAsUnread(user, dto.SeriesId, chapters);

            _unitOfWork.UserRepository.Update(user);

            if (await _unitOfWork.CommitAsync())
            {
                return Ok();
            }

            return BadRequest("Could not save progress");
        }

        /// <summary>
        /// Marks all chapters within a list of series as Read.
        /// </summary>
        /// <param name="dto"></param>
        /// <returns></returns>
        [HttpPost("mark-multiple-series-read")]
        public async Task<ActionResult> MarkMultipleSeriesAsRead(MarkMultipleSeriesAsReadDto dto)
        {
            var user = await _unitOfWork.UserRepository.GetUserByUsernameAsync(User.GetUsername(), AppUserIncludes.Progress);
            user.Progresses ??= new List<AppUserProgress>();

            var volumes = await _unitOfWork.VolumeRepository.GetVolumesForSeriesAsync(dto.SeriesIds.ToArray(), true);
            foreach (var volume in volumes)
            {
                _readerService.MarkChaptersAsRead(user, volume.SeriesId, volume.Chapters);
            }

            _unitOfWork.UserRepository.Update(user);

            if (await _unitOfWork.CommitAsync())
            {
                return Ok();
            }

            return BadRequest("Could not save progress");
        }

        /// <summary>
        /// Marks all chapters within a list of series as Unread.
        /// </summary>
        /// <param name="dto"></param>
        /// <returns></returns>
        [HttpPost("mark-multiple-series-unread")]
        public async Task<ActionResult> MarkMultipleSeriesAsUnread(MarkMultipleSeriesAsReadDto dto)
        {
            var user = await _unitOfWork.UserRepository.GetUserByUsernameAsync(User.GetUsername(), AppUserIncludes.Progress);
            user.Progresses ??= new List<AppUserProgress>();

            var volumes = await _unitOfWork.VolumeRepository.GetVolumesForSeriesAsync(dto.SeriesIds.ToArray(), true);
            foreach (var volume in volumes)
            {
                _readerService.MarkChaptersAsUnread(user, volume.SeriesId, volume.Chapters);
            }

            _unitOfWork.UserRepository.Update(user);

            if (await _unitOfWork.CommitAsync())
            {
                return Ok();
            }

            return BadRequest("Could not save progress");
        }

        /// <summary>
        /// Returns Progress (page number) for a chapter for the logged in user
        /// </summary>
        /// <param name="chapterId"></param>
        /// <returns></returns>
        [HttpGet("get-progress")]
        public async Task<ActionResult<ProgressDto>> GetProgress(int chapterId)
        {
            var user = await _unitOfWork.UserRepository.GetUserByUsernameAsync(User.GetUsername(), AppUserIncludes.Progress);
            var progressBookmark = new ProgressDto()
            {
                PageNum = 0,
                ChapterId = chapterId,
                VolumeId = 0,
                SeriesId = 0
            };
            if (user.Progresses == null) return Ok(progressBookmark);
            var progress = user.Progresses.FirstOrDefault(x => x.AppUserId == user.Id && x.ChapterId == chapterId);

            if (progress != null)
            {
                progressBookmark.SeriesId = progress.SeriesId;
                progressBookmark.VolumeId = progress.VolumeId;
                progressBookmark.PageNum = progress.PagesRead;
                progressBookmark.BookScrollId = progress.BookScrollId;
            }
            return Ok(progressBookmark);
        }

        /// <summary>
        /// Save page against Chapter for logged in user
        /// </summary>
        /// <param name="progressDto"></param>
        /// <returns></returns>
        [HttpPost("progress")]
        public async Task<ActionResult> BookmarkProgress(ProgressDto progressDto)
        {
            var user = await _unitOfWork.UserRepository.GetUserByUsernameAsync(User.GetUsername());

            if (await _readerService.SaveReadingProgress(progressDto, user.Id)) return Ok(true);

            return BadRequest("Could not save progress");
        }

        /// <summary>
        /// Continue point is the chapter which you should start reading again from. If there is no progress on a series, then the first chapter will be returned (non-special unless only specials).
        /// Otherwise, loop through the chapters and volumes in order to find the next chapter which has progress.
        /// </summary>
        /// <returns></returns>
        [HttpGet("continue-point")]
        public async Task<ActionResult<ChapterDto>> GetContinuePoint(int seriesId)
        {
            var userId = await _unitOfWork.UserRepository.GetUserIdByUsernameAsync(User.GetUsername());

            return Ok(await _readerService.GetContinuePoint(seriesId, userId));
        }

        /// <summary>
        /// Returns if the user has reading progress on the Series
        /// </summary>
        /// <param name="seriesId"></param>
        /// <returns></returns>
        [HttpGet("has-progress")]
        public async Task<ActionResult<ChapterDto>> HasProgress(int seriesId)
        {
            var userId = await _unitOfWork.UserRepository.GetUserIdByUsernameAsync(User.GetUsername());
            return Ok(await _unitOfWork.AppUserProgressRepository.HasAnyProgressOnSeriesAsync(seriesId, userId));
        }

        /// <summary>
        /// Marks every chapter that is sorted below the passed number as Read. This will not mark any specials as read.
        /// </summary>
        /// <remarks>This is built for Tachiyomi and is not expected to be called by any other place</remarks>
        /// <returns></returns>
        [HttpPost("mark-chapter-until-as-read")]
        public async Task<ActionResult<bool>> MarkChaptersUntilAsRead(int seriesId, float chapterNumber)
        {
            var user = await _unitOfWork.UserRepository.GetUserByUsernameAsync(User.GetUsername(), AppUserIncludes.Progress);
            user.Progresses ??= new List<AppUserProgress>();

            var volumes = await _unitOfWork.VolumeRepository.GetVolumesForSeriesAsync(new List<int>() { seriesId }, true);
            foreach (var volume in volumes.OrderBy(v => v.Number))
            {
                var chapters = volume.Chapters.OrderBy(c => float.Parse(c.Number)).Where(c => !c.IsSpecial && Parser.Parser.MaximumNumberFromRange(c.Range) <= chapterNumber);
                _readerService.MarkChaptersAsRead(user, volume.SeriesId, chapters);
            }

            _unitOfWork.UserRepository.Update(user);

            if (!_unitOfWork.HasChanges()) return Ok(true);
            if (await _unitOfWork.CommitAsync()) return Ok(true);

            await _unitOfWork.RollbackAsync();
            return Ok(false);
        }

        /// <summary>
        /// Marks every chapter that is sorted below the passed number as Read. This will not mark any specials as read.
        /// </summary>
        /// <remarks>This is built for Tachiyomi and is not expected to be called by any other place</remarks>
        /// <returns></returns>
        [HttpPost("mark-chapter-until-as-read")]
        public async Task<ActionResult<bool>> MarkChaptersUntilAsRead(int seriesId, float chapterNumber)
        {
            var user = await _unitOfWork.UserRepository.GetUserByUsernameAsync(User.GetUsername(), AppUserIncludes.Progress);
            user.Progresses ??= new List<AppUserProgress>();

            var volumes = await _unitOfWork.VolumeRepository.GetVolumesForSeriesAsync(new List<int>() { seriesId }, true);
            foreach (var volume in volumes.OrderBy(v => v.Number))
            {
                var chapters = volume.Chapters.OrderBy(c => float.Parse(c.Number)).Where(c => !c.IsSpecial && Parser.Parser.MaximumNumberFromRange(c.Range) <= chapterNumber);
                _readerService.MarkChaptersAsRead(user, volume.SeriesId, chapters);
            }

            _unitOfWork.UserRepository.Update(user);

            if (!_unitOfWork.HasChanges()) return Ok(true);
            if (await _unitOfWork.CommitAsync()) return Ok(true);

            await _unitOfWork.RollbackAsync();
            return Ok(false);
        }

        /// <summary>
        /// Returns a list of bookmarked pages for a given Chapter
        /// </summary>
        /// <param name="chapterId"></param>
        /// <returns></returns>
        [HttpGet("get-bookmarks")]
        public async Task<ActionResult<IEnumerable<BookmarkDto>>> GetBookmarks(int chapterId)
        {
            var user = await _unitOfWork.UserRepository.GetUserByUsernameAsync(User.GetUsername(), AppUserIncludes.Bookmarks);
            if (user.Bookmarks == null) return Ok(Array.Empty<BookmarkDto>());
            return Ok(await _unitOfWork.UserRepository.GetBookmarkDtosForChapter(user.Id, chapterId));
        }

        /// <summary>
        /// Returns a list of all bookmarked pages for a User
        /// </summary>
        /// <returns></returns>
        [HttpGet("get-all-bookmarks")]
        public async Task<ActionResult<IEnumerable<BookmarkDto>>> GetAllBookmarks()
        {
            var user = await _unitOfWork.UserRepository.GetUserByUsernameAsync(User.GetUsername(), AppUserIncludes.Bookmarks);
            if (user.Bookmarks == null) return Ok(Array.Empty<BookmarkDto>());
            return Ok(await _unitOfWork.UserRepository.GetAllBookmarkDtos(user.Id));
        }

        /// <summary>
        /// Removes all bookmarks for all chapters linked to a Series
        /// </summary>
        /// <param name="dto"></param>
        /// <returns></returns>
        [HttpPost("remove-bookmarks")]
        public async Task<ActionResult> RemoveBookmarks(RemoveBookmarkForSeriesDto dto)
        {
            var user = await _unitOfWork.UserRepository.GetUserByUsernameAsync(User.GetUsername(), AppUserIncludes.Bookmarks);
            if (user.Bookmarks == null) return Ok("Nothing to remove");
            try
            {
                user.Bookmarks = user.Bookmarks.Where(bmk => bmk.SeriesId != dto.SeriesId).ToList();
                _unitOfWork.UserRepository.Update(user);

                if (await _unitOfWork.CommitAsync())
                {
                    try
                    {
                        await _cleanupService.CleanupBookmarks();
                    }
                    catch (Exception ex)
                    {
                        _logger.LogError(ex, "There was an issue cleaning up old bookmarks");
                    }
                    return Ok();
                }
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "There was an exception when trying to clear bookmarks");
                await _unitOfWork.RollbackAsync();
            }

            return BadRequest("Could not clear bookmarks");

        }

        /// <summary>
        /// Returns all bookmarked pages for a given volume
        /// </summary>
        /// <param name="volumeId"></param>
        /// <returns></returns>
        [HttpGet("get-volume-bookmarks")]
        public async Task<ActionResult<IEnumerable<BookmarkDto>>> GetBookmarksForVolume(int volumeId)
        {
            var user = await _unitOfWork.UserRepository.GetUserByUsernameAsync(User.GetUsername(), AppUserIncludes.Bookmarks);
            if (user.Bookmarks == null) return Ok(Array.Empty<BookmarkDto>());
            return Ok(await _unitOfWork.UserRepository.GetBookmarkDtosForVolume(user.Id, volumeId));
        }

        /// <summary>
        /// Returns all bookmarked pages for a given series
        /// </summary>
        /// <param name="seriesId"></param>
        /// <returns></returns>
        [HttpGet("get-series-bookmarks")]
        public async Task<ActionResult<IEnumerable<BookmarkDto>>> GetBookmarksForSeries(int seriesId)
        {
            var user = await _unitOfWork.UserRepository.GetUserByUsernameAsync(User.GetUsername(), AppUserIncludes.Bookmarks);
            if (user.Bookmarks == null) return Ok(Array.Empty<BookmarkDto>());

            return Ok(await _unitOfWork.UserRepository.GetBookmarkDtosForSeries(user.Id, seriesId));
        }

        /// <summary>
        /// Bookmarks a page against a Chapter
        /// </summary>
        /// <param name="bookmarkDto"></param>
        /// <returns></returns>
        [HttpPost("bookmark")]
        public async Task<ActionResult> BookmarkPage(BookmarkDto bookmarkDto)
        {
            // Don't let user save past total pages.
            bookmarkDto.Page = await _readerService.CapPageToChapter(bookmarkDto.ChapterId, bookmarkDto.Page);

            try
            {
                var user = await _unitOfWork.UserRepository.GetUserByUsernameAsync(User.GetUsername(), AppUserIncludes.Bookmarks);
                var userBookmark =
                    await _unitOfWork.UserRepository.GetBookmarkForPage(bookmarkDto.Page, bookmarkDto.ChapterId, user.Id);

                // We need to get the image
                var chapter = await _cacheService.Ensure(bookmarkDto.ChapterId);
                if (chapter == null) return BadRequest("There was an issue finding image file for reading");
                var path = _cacheService.GetCachedPagePath(chapter, bookmarkDto.Page);
                var fileInfo = new FileInfo(path);

                var bookmarkDirectory =
                    (await _unitOfWork.SettingsRepository.GetSettingAsync(ServerSettingKey.BookmarkDirectory)).Value;
                _directoryService.CopyFileToDirectory(path, Path.Join(bookmarkDirectory,
                    $"{user.Id}", $"{bookmarkDto.SeriesId}", $"{bookmarkDto.ChapterId}"));


               if (userBookmark == null)
               {
                   user.Bookmarks ??= new List<AppUserBookmark>();
                   user.Bookmarks.Add(new AppUserBookmark()
                   {
                       Page = bookmarkDto.Page,
                       VolumeId = bookmarkDto.VolumeId,
                       SeriesId = bookmarkDto.SeriesId,
                       ChapterId = bookmarkDto.ChapterId,
                       FileName = Path.Join($"{user.Id}", $"{bookmarkDto.SeriesId}", $"{bookmarkDto.ChapterId}", fileInfo.Name)

                   });
                   _unitOfWork.UserRepository.Update(user);
               }

               await _unitOfWork.CommitAsync();
            }
            catch (Exception)
            {
               await _unitOfWork.RollbackAsync();
               return BadRequest("Could not save bookmark");
            }

            return Ok();
        }

        /// <summary>
        /// Removes a bookmarked page for a Chapter
        /// </summary>
        /// <param name="bookmarkDto"></param>
        /// <returns></returns>
        [HttpPost("unbookmark")]
        public async Task<ActionResult> UnBookmarkPage(BookmarkDto bookmarkDto)
        {
            var user = await _unitOfWork.UserRepository.GetUserByUsernameAsync(User.GetUsername(), AppUserIncludes.Bookmarks);

            if (user.Bookmarks == null) return Ok();
            try {
                user.Bookmarks = user.Bookmarks.Where(x =>
                    x.ChapterId == bookmarkDto.ChapterId
                    && x.AppUserId == user.Id
                    && x.Page != bookmarkDto.Page).ToList();

                _unitOfWork.UserRepository.Update(user);

                if (await _unitOfWork.CommitAsync())
                {
                    return Ok();
                }
            }
            catch (Exception)
            {
                await _unitOfWork.RollbackAsync();
            }

            return BadRequest("Could not remove bookmark");
        }

        /// <summary>
        /// Returns the next logical chapter from the series.
        /// </summary>
        /// <example>
        /// V1 → V2 → V3 chapter 0 → V3 chapter 10 → SP 01 → SP 02
        /// </example>
        /// <param name="seriesId"></param>
        /// <param name="volumeId"></param>
        /// <param name="currentChapterId"></param>
        /// <returns>chapter id for next manga</returns>
        [HttpGet("next-chapter")]
        public async Task<ActionResult<int>> GetNextChapter(int seriesId, int volumeId, int currentChapterId)
        {
            var userId = await _unitOfWork.UserRepository.GetUserIdByUsernameAsync(User.GetUsername());
            return await _readerService.GetNextChapterIdAsync(seriesId, volumeId, currentChapterId, userId);
        }


        /// <summary>
        /// Returns the previous logical chapter from the series.
        /// </summary>
        /// <example>
        /// V1 ← V2 ← V3 chapter 0 ← V3 chapter 10 ← SP 01 ← SP 02
        /// </example>
        /// <param name="seriesId"></param>
        /// <param name="volumeId"></param>
        /// <param name="currentChapterId"></param>
        /// <returns>chapter id for next manga</returns>
        [HttpGet("prev-chapter")]
        public async Task<ActionResult<int>> GetPreviousChapter(int seriesId, int volumeId, int currentChapterId)
        {
            var userId = await _unitOfWork.UserRepository.GetUserIdByUsernameAsync(User.GetUsername());
            return await _readerService.GetPrevChapterIdAsync(seriesId, volumeId, currentChapterId, userId);
        }

    }
}