using System;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Net.Mime;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
using TagLib;
using File = System.IO.File;

// ReSharper disable InconsistentNaming

namespace BatchProcess
{
    internal class Program
    {
        private static void Main(string[] args)
        {
            Console.WriteLine("Batch Processor");
            Console.WriteLine();

            var skipPause = false;
            if (args.Length > 0 && args[0].ToLower() == "--no-pause")
            {
                skipPause = true;
                args = args.Skip(1).ToArray();
            }

            try
            {
                RealMain(args);
            }
            catch (Exception e)
            {
                Console.WriteLine($"ERROR:{e}");
            }

            Console.WriteLine();

            if (skipPause) return;
            Console.Write("Press ENTER to exit...");
            Console.ReadLine();
        }

        private const string OP_DIR_EMB_COVER_MP3 = "embcover_mp3_jpg_dir";
        private const string OP_DIR_EMB_COVER_M4A = "embcover_m4a_jpg_dir";
        private const string OP_EMB_COVER = "embcover";
        private const string OP_COPY = "copy";
        private const string OP_EMB_COVER_IF_NOT_EMBEDDED = "embcover_if_not_embedded";
        private const string OP_EMB_COVER_IF_NOT_EMBEDDED_COVER_DOT_JPG = "embcover_if_not_embedded_cover_jpg";
        private const string OP_EMB_LRC = "emblrc";
        private const string OP_CONVERT_FLAC_TO_AAC = "convert_flac_to_aac";
        private const string OP_CONVERT_LIB_FLAC_TO_AAC = "convert_lib_flac_to_aac";
        private const string OP_CONVERT_LIB_FLAC_TO_AAC_IN_DIR = "convert_lib_flac_to_aac_in_dir";

        private static void RealMain(string[] args)
        {
            if (0 == args.Length)
            {
                Console.WriteLine($"Usage: {Path.GetFileName(AppDomain.CurrentDomain.FriendlyName)} <op> [args...]");
                Console.WriteLine($"Prefix ops:");
                Console.WriteLine($" *  --no-pause");
                Console.WriteLine($"        Disable enter key to exit");
                Console.WriteLine($"Available ops:");
                Console.WriteLine($" *  {OP_COPY} <sourcePath> <targetPath>");
                Console.WriteLine($"        Copy tags from source to target (replace)");
                Console.WriteLine($"        Note: Only standard tags and front cover");
                Console.WriteLine($" *  {OP_EMB_LRC} <inputPath> <lrcPath> <outputPath>");
                Console.WriteLine($"        Embed lyrics into file(utf8)");
                Console.WriteLine($" *  {OP_EMB_COVER}|{OP_EMB_COVER_IF_NOT_EMBEDDED} <inputPath> <coverPath> [outputPath] [mime-type]");
                Console.WriteLine($"        Embed cover into file, default mine-type is {MediaTypeNames.Image.Jpeg}");
                Console.WriteLine($" *  {OP_EMB_COVER_IF_NOT_EMBEDDED_COVER_DOT_JPG} <inputPath>");
                Console.WriteLine($"        Embed cover into file if not embedded, same folder cover.jpg");
                Console.WriteLine($" *  {OP_DIR_EMB_COVER_MP3} <inputDir> <outputDir>");
                Console.WriteLine($"        Lookup dir, embed same file name jpg/jpeg into mp3");
                Console.WriteLine($"        Embed abc.jpg or abc.jpeg into abc.mp3 and save a copy to output dir.");
                Console.WriteLine($" *  {OP_DIR_EMB_COVER_M4A} <inputDir> <outputDir>");
                Console.WriteLine($"        Lookup dir, embed same file name jpg/jpeg into m4a");
                Console.WriteLine($"        Embed abc.jpg or abc.jpeg into abc.m4a and save a copy to output dir.");
                Console.WriteLine($" *  {OP_CONVERT_FLAC_TO_AAC} <inputPath> <outputPath> [q value]");
                Console.WriteLine($"        Convert to aac and copy tags to output, default q is 1.0");
                Console.WriteLine($" *  {OP_CONVERT_LIB_FLAC_TO_AAC} <inputDir> <outputDir> [q value]");
                Console.WriteLine($"        Convert to aac and copy tags to output, default q is 1.0");
                Console.WriteLine($"        inputDir/Album/Track.flac -> outputDir/Album/Track.m4a");
                Console.WriteLine($"        Also copy inputDir/Album/cover.jpg to outDir/Album/cover.jpg if found");
                Console.WriteLine($" *  {OP_CONVERT_LIB_FLAC_TO_AAC_IN_DIR} <libDir> [q value]");
                Console.WriteLine($"        Convert to aac and copy tags to output, default q is 1.0");
                Console.WriteLine($"        libDir/Album/Track.flac -> libDir/Album/AAC_Q1.00/Track.m4a");
                Console.WriteLine($"");
                Console.WriteLine($" +  More on demand");
                return;
            }

            var op = args[0];

            Console.WriteLine($"OP:{op}");

            var argsToOp = args.Skip(1).ToArray();

            switch (op.ToLower())
            {
                default: throw new ArgumentException($"No recognizable op:{op}");
                case OP_DIR_EMB_COVER_MP3: EmbJpegCoverDir(argsToOp, "*.mp3"); break;
                case OP_DIR_EMB_COVER_M4A: EmbJpegCoverDir(argsToOp, "*.m4a"); break;
                case OP_EMB_COVER: EmbCover(argsToOp, true); break;
                case OP_EMB_COVER_IF_NOT_EMBEDDED: EmbCover(argsToOp, false); break;
                case OP_EMB_LRC: EmbLrc(argsToOp); break;
                case OP_COPY: CopyTag(argsToOp); break;
                case OP_EMB_COVER_IF_NOT_EMBEDDED_COVER_DOT_JPG:
                    if (argsToOp.Length != 1) throw new ArgumentException("args need 1");
                    // ReSharper disable once AssignNullToNotNullAttribute
                    var argsMod = new[] { argsToOp[0], Path.Combine(Path.GetDirectoryName(argsToOp[0]), "cover.jpg") };
                    EmbCover(argsMod, false);
                    break;

                case OP_CONVERT_FLAC_TO_AAC: ConvertFlacToAac(argsToOp); break;
                case OP_CONVERT_LIB_FLAC_TO_AAC: ConvertLibFlacToAac(argsToOp); break;
                case OP_CONVERT_LIB_FLAC_TO_AAC_IN_DIR: ConvertLibFlacToAacInDir(argsToOp); break;
            }
        }

        // impl

        private static void ConvertLibFlacToAacInDir(string[] args)
        {
            if (args.Length < 1) throw new ArgumentException("args least need 1");
            var libDir = args[0];

            if (false == Directory.Exists(libDir)) throw new DirectoryNotFoundException($"lib dir `{libDir}' not found.");

            var q = args.Length > 1 && float.TryParse(args[1], out var tq) && tq is >= 0 and <= 1
                ? tq
                : 1.0;

            foreach (var albDir in Directory.GetDirectories(libDir))
            {
                var outAlbDir = Path.Combine(albDir, $"AAC_Q{q:N2}");

                if (false == Directory.Exists(outAlbDir))
                {
                    Console.WriteLine($"Create dir:{outAlbDir}");
                    Directory.CreateDirectory(outAlbDir);
                }

                foreach (var flacPath in Directory.GetFiles(albDir, "*.flac"))
                {
                    var outM4APath = Path.Combine(outAlbDir, Path.ChangeExtension(Path.GetFileName(flacPath), ".m4a"));
                    Console.WriteLine(
                        ConvertFlacToAac(new[] {flacPath, outM4APath, $"{q}"}) 
                            ? $"Convert OK. -> {outM4APath}" 
                            : $"Exist, Skipped. {outM4APath}"
                    );
                }
            }
        }

        private static void ConvertLibFlacToAac(string[] args)
        {
            if (args.Length < 2) throw new ArgumentException("args least need 2");
            var inDir = args[0];
            var outDir = args[1];

            if (false == Directory.Exists(inDir)) throw new DirectoryNotFoundException($"input dir `{inDir}' not found.");
            if (false == Directory.Exists(outDir)) throw new DirectoryNotFoundException($"output dir `{inDir}' not found.");

            var q = args.Length > 2 && float.TryParse(args[2], out var tq) && tq is >= 0 and <= 1
                ? tq
                : 1.0;

            foreach (var albDir in Directory.GetDirectories(inDir))
            {
                var albDirName = Path.GetFileName(albDir);
                var outAlbDir = Path.Combine(outDir, albDirName);
                if (false == Directory.Exists(outAlbDir))
                {
                    Console.WriteLine($"Create dir:{outAlbDir}");
                    Directory.CreateDirectory(outAlbDir);
                }

                var coverPath = Path.Combine(albDir, "cover.jpg");
                var destCoverPath = Path.Combine(outAlbDir, "cover.jpg");
                if (File.Exists(coverPath) && false == File.Exists(destCoverPath))
                {
                    Console.WriteLine($"Copy {coverPath}");
                    Console.WriteLine($"  -> {destCoverPath} ");
                    File.Copy(coverPath, destCoverPath);
                }

                foreach (var flacPath in Directory.GetFiles(albDir, "*.flac"))
                {
                    var outM4APath = Path.Combine(outAlbDir, Path.ChangeExtension(Path.GetFileName(flacPath), ".m4a"));
                    if (ConvertFlacToAac(new[] { flacPath, outM4APath, $"{q}" }))
                    {
                        Console.WriteLine($"Convert OK. -> {outM4APath}");
                    }
                    else
                    {
                        Console.WriteLine($"Exist, Skipped. {outM4APath}");
                    }
                }
            }
        }

        private static bool ConvertFlacToAac(string[] args)
        {
            if (args.Length < 2) throw new ArgumentException("args least need 2");
            var pathIn = args[0];
            var pathOutput = args[1];
            var q = args.Length > 2 && float.TryParse(args[2], out var tq) && tq is >= 0 and <= 1
                ? tq
                : 1.0;

            if (false == File.Exists(pathIn)) throw new FileNotFoundException($"sourcePath `{pathIn}' not found.");
            if (File.Exists(pathOutput)) return false;
            if (false == Directory.Exists(Path.GetDirectoryName(pathOutput))) throw new DirectoryNotFoundException($"targetPath dir not found.");

            Console.WriteLine($"Processing   {pathIn}...");

            var flacProcess = new Process
            {
                StartInfo =
                {
                    FileName = "FLAC",
                    Arguments = $"-s -c -d \"{pathIn}\"",
                    RedirectStandardOutput = true,
                    UseShellExecute = false,
                }
            };

            var aacProcess = new Process
            {
                StartInfo =
                {
                    FileName = "NeroAacEnc",
                    Arguments = $"-if - -q {q} -of \"{pathOutput}\"",
                    RedirectStandardInput = true,
                    UseShellExecute = false,
                }
            };

            flacProcess.Start();
            aacProcess.Start();

            var pipe = Task.Factory.StartNew(() =>
            {
                try
                {
                    flacProcess.StandardOutput.BaseStream.CopyTo(aacProcess.StandardInput.BaseStream, 1024 * 512);
                }
                catch
                {
                    //EAT ERROR
                }

                try
                {
                    aacProcess.StandardInput.BaseStream.Close();
                }
                catch
                {
                    //EAT ERROR
                }
            });

            Task.WaitAll(pipe);
            flacProcess.WaitForExit();
            aacProcess.WaitForExit();

            CopyTag(args);
            return true;
        }

        private static void CopyTag(string[] args)
        {
            if (args.Length < 2) throw new ArgumentException("args need 2");
            var pathIn = args[0];
            var pathOutput = args[1];

            if (false == File.Exists(pathIn)) throw new FileNotFoundException($"sourcePath `{pathIn}' not found.");
            if (false == Directory.Exists(Path.GetDirectoryName(pathOutput))) throw new DirectoryNotFoundException($"targetPath dir not found.");
            if (false == File.Exists(pathOutput)) throw new FileNotFoundException($"targetPath `{pathOutput}' not found.");

            using var src = TagLib.File.Create(pathIn);
            var dst = TagLib.File.Create(pathOutput);
            dst.Tag.Clear();
            dst.Save();
            dst.Dispose();
            dst = TagLib.File.Create(pathOutput);
            src.Tag.CopyTo(dst.Tag, true);
            dst.Tag.Pictures = src.Tag.Pictures;
            src.Dispose();
            dst.Save();
            dst.Dispose();
            Console.WriteLine("Tag Copied.");
        }

        private static void EmbCover(string[] args, bool overwrite)
        {
            if (args.Length < 2) throw new ArgumentException("args least need 2");
            var pathIn = args[0];
            var pathCover = args[1];
            var pathOutput = args.Length > 2 ? args[2] : args[0];
            var mimeType = args.Length > 3 ? args[4] : MediaTypeNames.Image.Jpeg;

            if (false == File.Exists(pathIn)) throw new FileNotFoundException($"inputPath `{pathIn}' not found.");
            if (false == File.Exists(pathCover)) throw new FileNotFoundException($"coverPath `{pathCover}' not found.");

            Console.WriteLine($"Processing   {pathIn}...");
            Console.WriteLine($"Comver image:{pathCover}");

            if (pathIn != pathOutput) File.Copy(pathIn, pathOutput, true);

            if (EmbedCoverIntoFile(pathOutput, pathCover, mimeType, overwrite))
            {
                //                  12345678901234
                Console.WriteLine($"Saved to:    {pathOutput}");
            }
            else
            {
                Console.WriteLine("Skipped.");
            }
        }

        private static void EmbLrc(string[] args)
        {
            if (args.Length < 3) throw new ArgumentException("args need 2");
            var pathIn = args[0];
            var pathLrc = args[1];
            var pathOutput = args[2];

            if (false == File.Exists(pathIn)) throw new FileNotFoundException($"inputPath `{pathIn}' not found.");
            if (false == File.Exists(pathLrc)) throw new FileNotFoundException($"coverPath `{pathLrc}' not found.");

            Console.WriteLine($"Processing   {pathIn}...");
            Console.WriteLine($"Comver image:{pathLrc}");

            if (pathIn != pathOutput) File.Copy(pathIn, pathOutput);

            EmbedLrcIntoFile(pathOutput, pathLrc);

            //                  12345678901234
            Console.WriteLine($"Saved to:    {pathOutput}");
        }

        private static void EmbJpegCoverDir(string[] args, string pattern)
        {
            if (args.Length != 2) throw new ArgumentException("args need 2");

            var dirIn = args[0];
            var dirOut = args[1];

            if (false == Directory.Exists(dirIn)) throw new DirectoryNotFoundException($"inputDir `{dirIn}' not found.");
            if (false == Directory.Exists(dirOut)) throw new DirectoryNotFoundException($"outputDir `{dirOut} not found.'");

            Console.WriteLine($"Enter directory:{dirIn}");
            var files = Directory.GetFiles(dirIn, pattern);
            if (0 == files.Length)
            {
                Console.WriteLine($"Not result for {pattern}");
            }
            else
            {
                foreach (var file in files)
                {
                    //                  12345678901234
                    Console.WriteLine($"Processing   {file}...");

                    var imgFilePath = Path.ChangeExtension(file, ".jpg");
                    if (false == File.Exists(imgFilePath)) imgFilePath = Path.ChangeExtension(file, ".jpeg");
                    if (false == File.Exists(imgFilePath))
                    {
                        Console.WriteLine("Cover image file not found, Skipped. ***");
                        continue;
                    }

                    //                  12345678901234
                    Console.WriteLine($"Comver image:{imgFilePath}");

                    var destFileName = Path.Combine(dirOut, Path.GetFileName(file));
                    File.Copy(file, destFileName);

                    EmbedCoverIntoFile(destFileName, imgFilePath, MediaTypeNames.Image.Jpeg);

                    //                  12345678901234
                    Console.WriteLine($"Saved to:    {destFileName}");
                }
            }
            Console.WriteLine($"Leave directory:{dirIn}");
        }

        private static bool EmbedCoverIntoFile(string filePath, string coverPath, string mimeType, bool overwrite = true)
        {
            using var mediaFile = TagLib.File.Create(filePath);

            if (!overwrite)
            {
                if (mediaFile.Tag.Pictures.Any(p => p.Type == PictureType.FrontCover)) return false;
            }

            var pic = new Picture //REF: stackoverflow.com/a/30285220/2430943
            {
                Type = PictureType.FrontCover,
                Description = "Cover",
                MimeType = mimeType,
                Data = File.ReadAllBytes(coverPath)
            };
            mediaFile.Tag.Pictures = new IPicture[] { pic };

            mediaFile.Save();
            return true;
        }

        private static void EmbedLrcIntoFile(string filePath, string lrcPath)
        {
            var mediaFile = TagLib.File.Create(filePath);

            mediaFile.Tag.Lyrics = File.ReadAllText(lrcPath, Encoding.UTF8);

            mediaFile.Save();
        }
    }
}