using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using static AutoTag.cli.Helpers;
using TagFile = TagLib.File;

namespace AutoTag.cli {
	internal static class AutoTag {
		
		private static void Main(string[] args) {
			if (args.Length != 3 || (args[0] != "albums" && args[0] != "playlists")) {
				Console.WriteLine("Usage: autotag <albums/playlists> <inputfolder> <outputfolder>");
				Environment.Exit(1);
			}
			
			Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);

			var type = args[0] == "albums" ? FolderType.Albums : FolderType.Playlists;
			
			var inputDir = new Folder(args[1], type);
			var outputDir = args[2];

			switch (inputDir.Type) {
				case FolderType.Albums: {
					foreach (var track in Directory.EnumerateFiles(inputDir.Path, "*.*", SearchOption.AllDirectories).Where(IsAllowed)) {
						Console.WriteLine("<- " + track); 
						var tagFile             = TagFile.Create(track);
						if (tagFile.Tag.AlbumArtists.Length == 0)
							tagFile.Tag.AlbumArtists = new[] {tagFile.Tag.Performers[0]};
						var outputFileDirectory = Path.Combine(outputDir, CleanFileName(tagFile.Tag.AlbumArtists[0]), CleanFileName(tagFile.Tag.Album));
						Directory.CreateDirectory(outputFileDirectory);
						var outputFilePath = Path.Combine(outputDir, CleanFileName(tagFile.Tag.AlbumArtists[0]), CleanFileName(tagFile.Tag.Album),
														  CleanFileName($"{tagFile.Tag.Track}. {tagFile.Tag.Performers[0]} - {tagFile.Tag.Title}{Path.GetExtension(track)}"));
						if (tagFile.Tag.Disc != 0 && tagFile.Tag.Disc != 1) {
							outputFilePath = Path.Combine(outputDir, CleanFileName(tagFile.Tag.AlbumArtists[0]), CleanFileName(tagFile.Tag.Album),
															  CleanFileName($"Disc{tagFile.Tag.Disc} - {tagFile.Tag.Track}. {tagFile.Tag.Performers[0]} - {tagFile.Tag.Title}{Path.GetExtension(track)}"));
						}
						
						File.Copy(track, outputFilePath, true);
						var newTagFile = TagFile.Create(outputFilePath);
						newTagFile.Tag.Comment = null;
						newTagFile.Tag.Genres = null;
						newTagFile.Save();
						Console.WriteLine("-> " + outputFilePath);
						Console.WriteLine();
					}

					break;
				}
				case FolderType.Playlists: {
					foreach (var playlist in Directory.GetDirectories(inputDir.Path)) {
						var tracks = Directory.EnumerateFiles(playlist, "*.*", SearchOption.AllDirectories).Where(IsAllowed).OrderBy(s => s, new AlphanumComparator());
						
						uint i = 1;
						var trackCount = tracks.Count();
						var playlistName = Path.GetFileName(playlist);
						
						foreach (var track in tracks) {
							Console.WriteLine("<- " + track);
							var tagFile             = TagFile.Create(track);
							var outputFileDirectory = Path.Combine(outputDir, "Various Artists", CleanFileName(playlistName));
							Directory.CreateDirectory(outputFileDirectory);
							
							var outputFilePath = Path.Combine(outputDir, "Various Artists", CleanFileName(playlistName),
															  CleanFileName((tagFile.Tag.Performers.Length == 0 ? $"{i}. {tagFile.Tag.Title}{Path.GetExtension(track)}" : $"{i}. {tagFile.Tag.Performers[0]} - {tagFile.Tag.Title}{Path.GetExtension(track)}")));
							File.Copy(track, outputFilePath, true);
							var newTagFile = TagFile.Create(outputFilePath);
							newTagFile.Tag.Comment = null;
							newTagFile.Tag.Genres = null;
							newTagFile.Tag.Album = playlistName;
							newTagFile.Tag.Track = i++;
							newTagFile.Tag.TrackCount = (uint) trackCount;
							newTagFile.Tag.AlbumArtists = new[] {"Various Artists"};
							
							newTagFile.Save();
							Console.WriteLine("-> " + outputFilePath);
							Console.WriteLine();
						}
					}

					break;
				}
				default: throw new ArgumentOutOfRangeException();
			}
		}
	}

	internal class Folder {
		public readonly string     Path;
		public readonly FolderType Type;

		public Folder(string path, FolderType type) {
			Path = path;
			Type = type;
		}
	}

	internal enum FolderType {
		Albums,
		Playlists
	}

	internal static class Helpers {
		private static readonly List<string> AllowedFileTypes = new List<string> {".flac", ".opus", ".mp3", ".m4a"};

		internal static bool IsAllowed(string filename) => AllowedFileTypes.Any(filename.EndsWith);

		internal static string CleanFileName(string fileName) {
			return Path.GetInvalidFileNameChars().Aggregate(fileName, (current, c) => current.Replace(c.ToString(), string.Empty))
					   .Replace(":", " -");
			//var tempBytes = Encoding.GetEncoding("ISO-8859-8").GetBytes(str);
			//return Encoding.UTF8.GetString(tempBytes);
		}
	}
}