using DeepDrftContent.FileDatabase.Models;

namespace DeepDrftContent.Processors;

/// <summary>
/// Dispatches an audio file to the correct format processor by extension. The single seam through
/// which <see cref="TrackContentService"/> processes uploads, so callers depend on one abstraction
/// rather than three concrete processors.
/// </summary>
public class AudioProcessorRouter
{
    private readonly AudioProcessor _wavProcessor;
    private readonly Mp3AudioProcessor _mp3Processor;
    private readonly FlacAudioProcessor _flacProcessor;

    public AudioProcessorRouter(
        AudioProcessor wavProcessor,
        Mp3AudioProcessor mp3Processor,
        FlacAudioProcessor flacProcessor)
    {
        _wavProcessor = wavProcessor;
        _mp3Processor = mp3Processor;
        _flacProcessor = flacProcessor;
    }

    /// <summary>
    /// Processes <paramref name="filePath"/> with the processor matching its extension, returning a
    /// <see cref="ProcessedAudio"/> store plan (extracted metadata plus a streamed writer for the
    /// canonical vault bytes). Throws <see cref="ArgumentException"/> for unsupported extensions.
    /// </summary>
    public async Task<ProcessedAudio?> ProcessAudioFileAsync(string filePath, CancellationToken cancellationToken = default)
    {
        var ext = Path.GetExtension(filePath).ToLowerInvariant();
        return ext switch
        {
            ".wav" => await _wavProcessor.ProcessWavFileAsync(filePath, cancellationToken),
            ".mp3" => await _mp3Processor.ProcessMp3FileAsync(filePath, cancellationToken),
            ".flac" => await _flacProcessor.ProcessFlacFileAsync(filePath, cancellationToken),
            _ => throw new ArgumentException($"Unsupported audio format: {ext}", nameof(filePath)),
        };
    }
}