feat: persist voice samples to disk, generate VTT, cleanup after analysis

internal/infrastructure/speech/local_voice_file_store.go

@@ -0,0 +1,57 @@
+package speech
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+// LocalVoiceFileStore persists voice sample files on the local filesystem.
+// All files for a sample share a common prefix: {storageDir}/{sampleID}.{ext}
+type LocalVoiceFileStore struct {
+	storageDir string
+}
+
+func NewLocalVoiceFileStore(storageDir string) (*LocalVoiceFileStore, error) {
+	if err := os.MkdirAll(storageDir, 0750); err != nil {
+		return nil, fmt.Errorf("create voice storage dir: %w", err)
+	}
+	return &LocalVoiceFileStore{storageDir: storageDir}, nil
+}
+
+func (s *LocalVoiceFileStore) SaveRaw(_ context.Context, sampleID string, data []byte) (string, error) {
+	path := filepath.Join(s.storageDir, sampleID+".ogg")
+	if err := os.WriteFile(path, data, 0600); err != nil {
+		return "", fmt.Errorf("save raw audio: %w", err)
+	}
+	return path, nil
+}
+
+func (s *LocalVoiceFileStore) SaveConverted(_ context.Context, sampleID string, data []byte) (string, error) {
+	path := filepath.Join(s.storageDir, sampleID+".wav")
+	if err := os.WriteFile(path, data, 0600); err != nil {
+		return "", fmt.Errorf("save converted audio: %w", err)
+	}
+	return path, nil
+}
+
+func (s *LocalVoiceFileStore) SaveVTT(_ context.Context, sampleID string, content string) (string, error) {
+	path := filepath.Join(s.storageDir, sampleID+".vtt")
+	if err := os.WriteFile(path, []byte(content), 0600); err != nil {
+		return "", fmt.Errorf("save vtt: %w", err)
+	}
+	return path, nil
+}
+
+// Cleanup removes all files associated with a sample ID (.ogg, .wav, .vtt).
+// Missing files are silently ignored.
+func (s *LocalVoiceFileStore) Cleanup(_ context.Context, sampleID string) error {
+	for _, ext := range []string{".ogg", ".wav", ".vtt"} {
+		path := filepath.Join(s.storageDir, sampleID+ext)
+		if err := os.Remove(path); err != nil && !os.IsNotExist(err) {
+			return fmt.Errorf("cleanup %s: %w", ext, err)
+		}
+	}
+	return nil
+}