using System;
using System.IO;
using System.Linq;
using NLog;
using NzbDrone.Common;
using NzbDrone.Common.Disk;
using NzbDrone.Common.EnsureThat;
using NzbDrone.Common.EnvironmentInfo;
using NzbDrone.Core.Configuration;
using NzbDrone.Core.Organizer;
using NzbDrone.Core.Parser.Model;
using NzbDrone.Core.Tv;

namespace NzbDrone.Core.MediaFiles
{
    public interface IMoveEpisodeFiles
    {
        EpisodeFile MoveEpisodeFile(EpisodeFile episodeFile, Series series);
        EpisodeFile MoveEpisodeFile(EpisodeFile episodeFile, LocalEpisode localEpisode);
    }

    public class EpisodeFileMovingService : IMoveEpisodeFiles
    {
        private readonly IEpisodeService _episodeService;
        private readonly IBuildFileNames _buildFileNames;
        private readonly IDiskProvider _diskProvider;
        private readonly IConfigService _configService;
        private readonly Logger _logger;

        public EpisodeFileMovingService(IEpisodeService episodeService,
                                IBuildFileNames buildFileNames,
                                IDiskProvider diskProvider,
                                IConfigService configService,
                                Logger logger)
        {
            _episodeService = episodeService;
            _buildFileNames = buildFileNames;
            _diskProvider = diskProvider;
            _configService = configService;
            _logger = logger;
        }

        public EpisodeFile MoveEpisodeFile(EpisodeFile episodeFile, Series series)
        {
            var episodes = _episodeService.GetEpisodesByFileId(episodeFile.Id);
            var newFileName = _buildFileNames.BuildFilename(episodes, series, episodeFile);
            var filePath = _buildFileNames.BuildFilePath(series, episodes.First().SeasonNumber, newFileName, Path.GetExtension(episodeFile.Path));

            _logger.Trace("Renaming episode file: {0} to {1}", episodeFile, filePath);
            MoveFile(episodeFile, series, filePath);

            return episodeFile;
        }

        public EpisodeFile MoveEpisodeFile(EpisodeFile episodeFile, LocalEpisode localEpisode)
        {
            var newFileName = _buildFileNames.BuildFilename(localEpisode.Episodes, localEpisode.Series, episodeFile);
            var filePath = _buildFileNames.BuildFilePath(localEpisode.Series, localEpisode.SeasonNumber, newFileName, Path.GetExtension(episodeFile.Path));

            _logger.Trace("Moving episode file: {0} to {1}", episodeFile, filePath);
            MoveFile(episodeFile, localEpisode.Series, filePath);
            
            return episodeFile;
        }

        private EpisodeFile MoveFile(EpisodeFile episodeFile, Series series, string destinationFilename)
        {
            Ensure.That(episodeFile, () => episodeFile).IsNotNull();
            Ensure.That(series,() => series).IsNotNull();
            Ensure.That(destinationFilename, () => destinationFilename).IsValidPath();

            if (!_diskProvider.FileExists(episodeFile.Path))
            {
                throw new FileNotFoundException("Episode file path does not exist", episodeFile.Path);
            }

            if (episodeFile.Path.PathEquals(destinationFilename))
            {
                throw new SameFilenameException("File not moved, source and destination are the same", episodeFile.Path);
            }

            var directoryName = new FileInfo(destinationFilename).DirectoryName;

            if (!_diskProvider.FolderExists(directoryName))
            {
                _diskProvider.CreateFolder(directoryName);
                SetFolderPermissions(directoryName);

                if (!directoryName.PathEquals(series.Path))
                {
                    SetFolderPermissions(series.Path);
                }
            }

            _logger.Debug("Moving [{0}] > [{1}]", episodeFile.Path, destinationFilename);
            _diskProvider.MoveFile(episodeFile.Path, destinationFilename);
            episodeFile.Path = destinationFilename;

            try
            {
                _logger.Trace("Setting last write time on series folder: {0}", series.Path);
                _diskProvider.FolderSetLastWriteTimeUtc(series.Path, episodeFile.DateAdded);

                if (series.SeasonFolder)
                {
                    var seasonFolder = Path.GetDirectoryName(destinationFilename);

                    _logger.Trace("Setting last write time on season folder: {0}", seasonFolder);
                    _diskProvider.FolderSetLastWriteTimeUtc(seasonFolder, episodeFile.DateAdded);
                }
            }

            catch (Exception ex)
            {
                _logger.WarnException("Unable to set last write time", ex);
            }

            //We should only run this on Windows
            if (OsInfo.IsWindows)
            {
                //Wrapped in Try/Catch to prevent this from causing issues with remote NAS boxes, the move worked, which is more important.
                try
                {
                    _diskProvider.InheritFolderPermissions(destinationFilename);
                }
                catch (Exception ex)
                {
                    if (ex is UnauthorizedAccessException || ex is InvalidOperationException)
                    {
                        _logger.Debug("Unable to apply folder permissions to: ", destinationFilename);
                        _logger.TraceException(ex.Message, ex);
                    }

                    else
                    {
                        throw;
                    }
                }
            }

            else
            {
                SetPermissions(destinationFilename, _configService.FileChmod);
            }

            return episodeFile;
        }

        private void SetPermissions(string path, string permissions)
        {
            if (!_configService.SetPermissionsLinux)
            {
                return;
            }

            try
            {
                _diskProvider.SetPermissions(path, permissions, _configService.ChownUser, _configService.ChownGroup);
            }

            catch (Exception ex)
            {
                if (ex is UnauthorizedAccessException || ex is InvalidOperationException)
                {
                    _logger.Debug("Unable to apply permissions to: ", path);
                    _logger.TraceException(ex.Message, ex);
                }
                else
                {
                    throw;
                }
            }
        }

        private void SetFolderPermissions(string path)
        {
            SetPermissions(path, _configService.FolderChmod);
        }
    }
}