package whisper

import (
    "fmt"
    "os"
    "path/filepath"

    "go-whisper-api/config"

    "github.com/ggerganov/whisper.cpp/bindings/go/pkg/whisper"
    "github.com/go-audio/wav"
)

// LoadPCM16Mono reads 16 kHz mono WAV into float32 samples (for diarization).
func LoadPCM16Mono(path string) ([]float32, error) {
    return loadPCM16Mono(path)
}

func loadPCM16Mono(path string) ([]float32, error) {
    fh, err := os.Open(path)
    if err != nil {
        return nil, err
    }
    defer fh.Close()
    dec := wav.NewDecoder(fh)
    buf, err := dec.FullPCMBuffer()
    if err != nil {
        return nil, err
    }
    if dec.SampleRate != whisper.SampleRate {
        return nil, fmt.Errorf("unsupported sample rate: %d", dec.SampleRate)
    }
    if dec.NumChans != 1 {
        return nil, fmt.Errorf("unsupported number of channels: %d", dec.NumChans)
    }
    return buf.AsFloat32Buffer().Data, nil
}

func prepareAudioPCM(sourcePath string) (data []float32, cleanup func(), err error) {
    cleanup = func() {}
    if data, err = loadPCM16Mono(sourcePath); err == nil {
        return data, cleanup, nil
    }
    dir, err := config.MkdirTemp("go-whisper-api-whisper-*")
    if err != nil {
        return nil, nil, err
    }
    cleanup = func() { os.RemoveAll(dir) }
    converted := filepath.Join(dir, "converted.wav")
    if err := AudioToWav(sourcePath, converted); err != nil {
        cleanup()
        return nil, nil, err
    }
    data, err = loadPCM16Mono(converted)
    if err != nil {
        cleanup()
        return nil, nil, err
    }
    return data, cleanup, nil
}