feat: initial commit

internal/application/usecase/handle_voice_message.go

@@ -0,0 +1,80 @@
+package usecase
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+
+	"github.com/paramah/gw_telegram/internal/application/dto"
+	"github.com/paramah/gw_telegram/internal/domain/port"
+)
+
+type HandleVoiceMessage struct {
+	downloader  port.FileDownloader
+	converter   AudioConverter
+	transcriber port.SpeechTranscriber
+	textHandler *HandleTextMessage
+	gateway     port.MessageGateway
+	logger      *slog.Logger
+}
+
+// AudioConverter converts audio between formats (OGG -> WAV etc.)
+type AudioConverter interface {
+	Convert(ctx context.Context, input []byte, fromMime, toMime string) ([]byte, error)
+}
+
+func NewHandleVoiceMessage(
+	downloader port.FileDownloader,
+	converter AudioConverter,
+	transcriber port.SpeechTranscriber,
+	textHandler *HandleTextMessage,
+	gateway port.MessageGateway,
+	logger *slog.Logger,
+) *HandleVoiceMessage {
+	return &HandleVoiceMessage{
+		downloader:  downloader,
+		converter:   converter,
+		transcriber: transcriber,
+		textHandler: textHandler,
+		gateway:     gateway,
+		logger:      logger,
+	}
+}
+
+func (h *HandleVoiceMessage) Execute(ctx context.Context, in dto.IncomingMessageDTO) error {
+	_ = h.gateway.SendTyping(ctx, in.ChatID)
+
+	audioBytes, mimeType, err := h.downloader.Download(ctx, in.VoiceFileID)
+	if err != nil {
+		h.logger.ErrorContext(ctx, "voice download failed", "error", err, "file_id", in.VoiceFileID)
+		_ = h.gateway.SendText(ctx, in.ChatID, "Sorry, I couldn't download the audio message. Please try again.")
+		return fmt.Errorf("handle voice: download: %w", err)
+	}
+
+	// Convert OGG Opus (Telegram default) to WAV for Whisper
+	if mimeType == "audio/ogg" || mimeType == "" {
+		wavBytes, err := h.converter.Convert(ctx, audioBytes, "audio/ogg", "audio/wav")
+		if err != nil {
+			h.logger.WarnContext(ctx, "audio conversion failed, trying raw", "error", err)
+			// fall through with original bytes
+		} else {
+			audioBytes = wavBytes
+			mimeType = "audio/wav"
+		}
+	}
+
+	transcript, err := h.transcriber.Transcribe(ctx, audioBytes, mimeType)
+	if err != nil {
+		h.logger.ErrorContext(ctx, "transcription failed", "error", err)
+		_ = h.gateway.SendText(ctx, in.ChatID, "Sorry, I couldn't understand the voice message. Please try sending text instead.")
+		return fmt.Errorf("handle voice: transcribe: %w", err)
+	}
+
+	h.logger.InfoContext(ctx, "voice transcribed", "user_id", in.UserID, "length", len(transcript))
+
+	textIn := in
+	textIn.Text = transcript
+	textIn.IsVoice = false
+
+	return h.textHandler.Execute(ctx, textIn)
+}