using System.Diagnostics;
using ReviewProxy.Lib.IO;

namespace ReviewProxy.Lib;

public class FileEncoder : IEncoder
{
    private TempFile tempFile;
    private Stream inputStream;
    private string workDirectory;
    private string outputFilePath;

    public FileEncoder(Stream inputStream, string workDirectory, string outputFilePath)
    {
        this.tempFile = new TempFile();
        this.inputStream = inputStream;

        this.workDirectory = workDirectory;
        this.outputFilePath = outputFilePath;

        this.Init();
    }

    public async ValueTask EncodeAsync()
    {
        Console.WriteLine($"Using {this.tempFile.FilePath}");
        using (var outputStream = this.tempFile.Open())
        {
            await this.inputStream.CopyToAsync(outputStream).ConfigureAwait(false);
        }

        using (var proc = this.CreateEncoder())
        {
            if (proc is null)
            {
                throw new FileNotFoundException("ffmpeg could't execute.");
            }

            await proc.WaitForExitAsync().ConfigureAwait(false);
        }

        this.BundleToZip();
    }

    private void BundleToZip()
    {
        using (var archive = new ZipArchiver(this.outputFilePath, this.workDirectory))
        {
            archive.Compress();
        }
    }

    private void Init()
    {
        if (!Directory.Exists(workDirectory))
        {
            Directory.CreateDirectory(workDirectory);
        }
    }

    private Process? CreateEncoder()
    {
        string tsFilePath = Path.Combine(workDirectory, "a%03d.ts");
        string plFilePath = Path.Combine(workDirectory, "playlist.m3u8");

        var args = $"-i \"{tempFile.FilePath}\" -c:v libx264 -vf scale=-2:720 -movflags faststart -b:v 1000K -r 24 -c:a aac -b:a 64k -y -pix_fmt yuv420p -crf 23 -f segment -segment_format mpegts -segment_time 5 -segment_list \"{plFilePath}\" \"{tsFilePath}\"";
        var startInfo = new ProcessStartInfo()
        {
            FileName = "ffmpeg",
            Arguments = args,
            RedirectStandardInput = true,
        };

        return Process.Start(startInfo);
    }

    public void Dispose()
    {
        inputStream.Dispose();
        tempFile.Dispose();

        if (Directory.Exists(workDirectory))
        {
            Directory.Delete(workDirectory, true);
        }

        if (File.Exists(outputFilePath))
        {
            File.Delete(outputFilePath);
        }
    }
}