package mic

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

	"tea.chunkbyte.com/kato/go-worm/lib/config"
)

type fileRecorder struct {
	path    string
	f       *os.File
	written int64
}

func openRecorder(name string) (*fileRecorder, error) {
	dir, err := Dir()
	if err != nil {
		return nil, err
	}
	if err := os.MkdirAll(dir, 0o700); err != nil {
		return nil, err
	}
	path := filepath.Join(dir, filepath.Base(name))
	f, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0o600)
	if err != nil {
		return nil, err
	}
	hdr := make([]byte, wavHeaderSize)
	writeWAVHeader(hdr, 0)
	if _, err := f.Write(hdr); err != nil {
		_ = f.Close()
		return nil, err
	}
	return &fileRecorder{path: path, f: f}, nil
}

func (r *fileRecorder) Write(pcm []byte) error {
	if len(pcm) == 0 {
		return nil
	}
	if r.written+int64(len(pcm)) > config.MaxUploadSize {
		return fmt.Errorf("recording exceeds %d bytes", config.MaxUploadSize)
	}
	n, err := r.f.Write(pcm)
	r.written += int64(n)
	return err
}

func (r *fileRecorder) Close() (int64, error) {
	if r.f == nil {
		return 0, nil
	}
	hdr := make([]byte, wavHeaderSize)
	writeWAVHeader(hdr, int(r.written))
	if _, err := r.f.Seek(0, 0); err != nil {
		_ = r.f.Close()
		r.f = nil
		return r.written, err
	}
	if _, err := r.f.Write(hdr); err != nil {
		_ = r.f.Close()
		r.f = nil
		return r.written, err
	}
	err := r.f.Close()
	r.f = nil
	return r.written, err
}

func (r *fileRecorder) basename() string {
	return filepath.Base(r.path)
}