using System;
using System.Diagnostics;
using System.IO;

namespace SlamCross.Services;

public static class ConversionService
{
    private static string FfmpegPath => FindFfmpeg();

    private static string FindFfmpeg()
    {
        string[] candidates = ["/usr/bin/ffmpeg", "/usr/local/bin/ffmpeg", "ffmpeg"];
        foreach (var c in candidates)
            if (File.Exists(c)) return c;
        return "ffmpeg";
    }

    public static void ConvertToWav(string inputFile, string outputFile, int sampleRate, int channels)
    {
        var psi = new ProcessStartInfo(FfmpegPath)
        {
            RedirectStandardError = true,
            UseShellExecute = false,
            CreateNoWindow = true
        };
        psi.ArgumentList.Add("-y");
        psi.ArgumentList.Add("-i"); psi.ArgumentList.Add(inputFile);
        psi.ArgumentList.Add("-f"); psi.ArgumentList.Add("wav");
        psi.ArgumentList.Add("-flags"); psi.ArgumentList.Add("bitexact");
        psi.ArgumentList.Add("-map_metadata"); psi.ArgumentList.Add("-1");
        psi.ArgumentList.Add("-vn");
        psi.ArgumentList.Add("-acodec"); psi.ArgumentList.Add("pcm_s16le");
        psi.ArgumentList.Add("-ar"); psi.ArgumentList.Add(sampleRate.ToString());
        psi.ArgumentList.Add("-ac"); psi.ArgumentList.Add(channels.ToString());
        psi.ArgumentList.Add(outputFile);

        using var proc = Process.Start(psi) ?? throw new Exception("Failed to start ffmpeg");
        var err = proc.StandardError.ReadToEnd();
        proc.WaitForExit();
        if (proc.ExitCode != 0)
            throw new Exception($"ffmpeg failed: {err}");
    }
}