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

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

    public class MoveEpisodeFiles : IMoveEpisodeFiles
    {
        private readonly IEpisodeService _episodeService;
        private readonly IBuildFileNames _buildFileNames;
        private readonly IEventAggregator _eventAggregator;
        private readonly IDiskProvider _diskProvider;
        private readonly Logger _logger;

        public MoveEpisodeFiles(IEpisodeService episodeService,
                                IBuildFileNames buildFileNames,
                                IEventAggregator eventAggregator,
                                IDiskProvider diskProvider,
                                Logger logger)
        {
            _episodeService = episodeService;
            _buildFileNames = buildFileNames;
            _eventAggregator = eventAggregator;
            _diskProvider = diskProvider;
            _logger = logger;
        }

        public string 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));
            MoveFile(episodeFile, series, filePath);

            return filePath;
        }

        public string 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));
            MoveFile(episodeFile, localEpisode.Series, filePath);
            
            return filePath;
        }

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

            _diskProvider.CreateFolder(new FileInfo(destinationFilename).DirectoryName);

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

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

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

                    _logger.Trace("Setting last write time on season folder: {0}", seasonFolder);
                    _diskProvider.SetFolderWriteTime(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 (UnauthorizedAccessException ex)
                {
                    _logger.Debug("Unable to apply folder permissions to: ", destinationFilename);
                    _logger.TraceException(ex.Message, ex);
                }
            }
        }
    }
}