add deepgram streaming adapter with reconnection logic

internal/transcriber/adapter_deepgram.go

@@ -0,0 +1,406 @@
+package transcriber
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"log"
+	"net/http"
+	"net/url"
+	"sync"
+	"time"
+
+	"github.com/gorilla/websocket"
+	"github.com/leonardotrapani/hyprvoice/internal/language"
+	"github.com/leonardotrapani/hyprvoice/internal/provider"
+)
+
+// DeepgramAdapter implements StreamingAdapter for Deepgram real-time transcription
+type DeepgramAdapter struct {
+	endpoint  *provider.EndpointConfig
+	apiKey    string
+	model     string
+	language  string
+	conn      *websocket.Conn
+	resultsCh chan TranscriptionResult
+	mu        sync.Mutex
+	ctx       context.Context
+	cancel    context.CancelFunc
+	wg        sync.WaitGroup
+	started   bool
+
+	// reconnection config
+	maxRetries  int
+	retryDelays []time.Duration
+}
+
+// Deepgram WebSocket response types (incoming)
+type deepgramWSResponse struct {
+	Type        string            `json:"type"`
+	Channel     *deepgramChannel  `json:"channel,omitempty"`
+	Metadata    *deepgramMetadata `json:"metadata,omitempty"`
+	Error       *deepgramError    `json:"error,omitempty"`
+	ChannelIdx  []int             `json:"channel_index,omitempty"`
+	Duration    float64           `json:"duration,omitempty"`
+	Start       float64           `json:"start,omitempty"`
+	IsFinal     bool              `json:"is_final,omitempty"`
+	SpeechFinal bool              `json:"speech_final,omitempty"`
+}
+
+type deepgramChannel struct {
+	Alternatives []deepgramAlternative `json:"alternatives,omitempty"`
+}
+
+type deepgramAlternative struct {
+	Transcript string  `json:"transcript"`
+	Confidence float64 `json:"confidence"`
+}
+
+type deepgramMetadata struct {
+	RequestID string `json:"request_id"`
+	ModelInfo struct {
+		Name    string `json:"name"`
+		Version string `json:"version"`
+	} `json:"model_info"`
+}
+
+type deepgramError struct {
+	Type        string `json:"type"`
+	Message     string `json:"message"`
+	Description string `json:"description,omitempty"`
+}
+
+// NewDeepgramAdapter creates a new streaming adapter for Deepgram
+// endpoint: the WebSocket endpoint config (e.g., wss://api.deepgram.com, /v1/listen)
+// apiKey: Deepgram API key
+// model: model ID (e.g., "nova-3")
+// lang: canonical language code (will be converted to provider format)
+func NewDeepgramAdapter(endpoint *provider.EndpointConfig, apiKey, model, lang string) *DeepgramAdapter {
+	return &DeepgramAdapter{
+		endpoint:    endpoint,
+		apiKey:      apiKey,
+		model:       model,
+		language:    lang,
+		resultsCh:   make(chan TranscriptionResult, 100),
+		maxRetries:  3,
+		retryDelays: defaultRetryDelays,
+	}
+}
+
+// Start initiates the WebSocket connection to Deepgram
+func (a *DeepgramAdapter) Start(ctx context.Context, lang string) error {
+	a.mu.Lock()
+	defer a.mu.Unlock()
+
+	if a.started {
+		return fmt.Errorf("adapter already started")
+	}
+
+	// use lang param if provided, otherwise use constructor lang
+	if lang != "" {
+		a.language = lang
+	}
+
+	// create cancelable context
+	a.ctx, a.cancel = context.WithCancel(ctx)
+
+	// connect to WebSocket
+	if err := a.connectLocked(); err != nil {
+		return err
+	}
+	a.started = true
+
+	// start reader goroutine
+	a.wg.Add(1)
+	go a.readLoop()
+
+	log.Printf("deepgram: connected, model=%s, language=%s", a.model, a.language)
+	return nil
+}
+
+// connectLocked establishes WebSocket connection. Must be called with mu held.
+func (a *DeepgramAdapter) connectLocked() error {
+	wsURL, err := a.buildURL()
+	if err != nil {
+		return fmt.Errorf("build websocket url: %w", err)
+	}
+
+	headers := http.Header{}
+	headers.Set("Authorization", "Token "+a.apiKey)
+
+	log.Printf("deepgram: connecting to %s", wsURL)
+	conn, resp, err := websocket.DefaultDialer.DialContext(a.ctx, wsURL, headers)
+	if err != nil {
+		if resp != nil {
+			log.Printf("deepgram: dial failed with status %d", resp.StatusCode)
+		}
+		return fmt.Errorf("websocket dial: %w", err)
+	}
+	a.conn = conn
+	return nil
+}
+
+// reconnect attempts to re-establish the WebSocket connection with exponential backoff.
+// Returns true if reconnection succeeded.
+func (a *DeepgramAdapter) reconnect() bool {
+	for attempt := 0; attempt < a.maxRetries; attempt++ {
+		// check if context cancelled
+		select {
+		case <-a.ctx.Done():
+			return false
+		default:
+		}
+
+		// wait before retry (skip wait on first attempt)
+		if attempt > 0 {
+			delay := a.retryDelays[attempt-1]
+			if attempt-1 >= len(a.retryDelays) {
+				delay = a.retryDelays[len(a.retryDelays)-1]
+			}
+			log.Printf("deepgram: reconnect attempt %d/%d after %v", attempt+1, a.maxRetries, delay)
+
+			select {
+			case <-a.ctx.Done():
+				return false
+			case <-time.After(delay):
+			}
+		} else {
+			log.Printf("deepgram: reconnect attempt %d/%d", attempt+1, a.maxRetries)
+		}
+
+		a.mu.Lock()
+		// close old connection if exists
+		if a.conn != nil {
+			a.conn.Close()
+			a.conn = nil
+		}
+
+		err := a.connectLocked()
+		a.mu.Unlock()
+
+		if err == nil {
+			log.Printf("deepgram: reconnected successfully")
+			// notify caller of brief interruption
+			select {
+			case a.resultsCh <- TranscriptionResult{Error: fmt.Errorf("connection interrupted, reconnected"), IsFinal: false}:
+			default:
+			}
+			return true
+		}
+
+		log.Printf("deepgram: reconnect failed: %v", err)
+	}
+
+	return false
+}
+
+// buildURL constructs the WebSocket URL with query parameters
+func (a *DeepgramAdapter) buildURL() (string, error) {
+	// parse base URL and path
+	baseURL := a.endpoint.BaseURL + a.endpoint.Path
+
+	u, err := url.Parse(baseURL)
+	if err != nil {
+		return "", fmt.Errorf("parse base url: %w", err)
+	}
+
+	// add query parameters
+	q := u.Query()
+	q.Set("model", a.model)
+	q.Set("encoding", "linear16") // 16-bit linear PCM
+	q.Set("sample_rate", "16000") // 16kHz
+	q.Set("channels", "1")        // mono
+
+	// enable interim results
+	q.Set("interim_results", "true")
+	// enable smart formatting for better output
+	q.Set("smart_format", "true")
+	// enable punctuation
+	q.Set("punctuate", "true")
+
+	// add language if specified
+	providerLang := language.ToProviderFormat(a.language, "deepgram")
+	if providerLang != "" {
+		q.Set("language", providerLang)
+	}
+
+	u.RawQuery = q.Encode()
+	return u.String(), nil
+}
+
+// readLoop reads messages from the WebSocket and sends results to the channel
+func (a *DeepgramAdapter) readLoop() {
+	defer a.wg.Done()
+	defer close(a.resultsCh)
+
+	for {
+		select {
+		case <-a.ctx.Done():
+			return
+		default:
+		}
+
+		a.mu.Lock()
+		conn := a.conn
+		a.mu.Unlock()
+
+		if conn == nil {
+			// no connection, try to reconnect
+			if !a.reconnect() {
+				a.resultsCh <- TranscriptionResult{Error: fmt.Errorf("connection lost, reconnection failed after %d attempts", a.maxRetries)}
+				return
+			}
+			continue
+		}
+
+		_, message, err := conn.ReadMessage()
+		if err != nil {
+			// check if context was cancelled (normal shutdown)
+			select {
+			case <-a.ctx.Done():
+				return
+			default:
+			}
+
+			// attempt reconnection
+			log.Printf("deepgram: read error: %v, attempting reconnection", err)
+			if !a.reconnect() {
+				a.resultsCh <- TranscriptionResult{Error: fmt.Errorf("websocket read: %w, reconnection failed", err)}
+				return
+			}
+			continue
+		}
+
+		// parse message
+		var resp deepgramWSResponse
+		if err := json.Unmarshal(message, &resp); err != nil {
+			log.Printf("deepgram: parse error: %v", err)
+			continue
+		}
+
+		// handle different message types
+		switch resp.Type {
+		case "Metadata":
+			if resp.Metadata != nil {
+				log.Printf("deepgram: session started, request_id=%s, model=%s",
+					resp.Metadata.RequestID, resp.Metadata.ModelInfo.Name)
+			}
+
+		case "Results":
+			// transcription result
+			if resp.Channel != nil && len(resp.Channel.Alternatives) > 0 {
+				transcript := resp.Channel.Alternatives[0].Transcript
+				if transcript != "" {
+					isFinal := resp.IsFinal || resp.SpeechFinal
+					if isFinal {
+						log.Printf("deepgram: final: %q", transcript)
+					}
+					a.resultsCh <- TranscriptionResult{Text: transcript, IsFinal: isFinal}
+				}
+			}
+
+		case "Error":
+			if resp.Error != nil {
+				errMsg := resp.Error.Message
+				if resp.Error.Description != "" {
+					errMsg = fmt.Sprintf("%s: %s", errMsg, resp.Error.Description)
+				}
+				log.Printf("deepgram: error: %s", errMsg)
+				a.resultsCh <- TranscriptionResult{Error: fmt.Errorf("deepgram: %s", errMsg)}
+			}
+
+		case "UtteranceEnd":
+			log.Printf("deepgram: utterance end detected")
+
+		case "SpeechStarted":
+			log.Printf("deepgram: speech started")
+
+		default:
+			log.Printf("deepgram: unknown message type: %s", resp.Type)
+		}
+	}
+}
+
+// SendChunk sends audio data to the WebSocket
+// Deepgram expects raw binary audio data, not base64 encoded
+func (a *DeepgramAdapter) SendChunk(audio []byte) error {
+	a.mu.Lock()
+	if !a.started {
+		a.mu.Unlock()
+		return fmt.Errorf("adapter not started")
+	}
+	conn := a.conn
+	a.mu.Unlock()
+
+	// check context
+	select {
+	case <-a.ctx.Done():
+		return a.ctx.Err()
+	default:
+	}
+
+	if conn == nil {
+		return fmt.Errorf("no connection")
+	}
+
+	// send raw binary audio (not base64)
+	a.mu.Lock()
+	err := a.conn.WriteMessage(websocket.BinaryMessage, audio)
+	a.mu.Unlock()
+
+	if err != nil {
+		// attempt reconnection
+		log.Printf("deepgram: write error: %v, attempting reconnection", err)
+		if a.reconnect() {
+			// retry the chunk after reconnection
+			a.mu.Lock()
+			err = a.conn.WriteMessage(websocket.BinaryMessage, audio)
+			a.mu.Unlock()
+			if err == nil {
+				return nil
+			}
+		}
+		return fmt.Errorf("websocket write: %w", err)
+	}
+
+	return nil
+}
+
+// Results returns the channel for receiving transcription results
+func (a *DeepgramAdapter) Results() <-chan TranscriptionResult {
+	return a.resultsCh
+}
+
+// Close gracefully closes the WebSocket connection
+func (a *DeepgramAdapter) Close() error {
+	a.mu.Lock()
+
+	if !a.started {
+		a.mu.Unlock()
+		return nil
+	}
+
+	// cancel context first to signal reader to stop
+	if a.cancel != nil {
+		a.cancel()
+	}
+
+	// get conn ref while holding lock
+	conn := a.conn
+
+	a.started = false
+	a.mu.Unlock()
+
+	// close websocket outside of lock (readLoop may be blocked on read)
+	if conn != nil {
+		// send close frame (best effort)
+		_ = conn.WriteMessage(websocket.CloseMessage, websocket.FormatCloseMessage(websocket.CloseNormalClosure, ""))
+		conn.Close()
+	}
+
+	// wait for reader to finish
+	a.wg.Wait()
+
+	log.Printf("deepgram: closed")
+	return nil
+}

internal/transcriber/adapter_deepgram_test.go

@@ -0,0 +1,434 @@
+package transcriber
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/gorilla/websocket"
+	"github.com/leonardotrapani/hyprvoice/internal/provider"
+)
+
+func TestDeepgramAdapter_ImplementsStreamingAdapter(t *testing.T) {
+	var _ StreamingAdapter = (*DeepgramAdapter)(nil)
+}
+
+func TestDeepgramAdapter_Creation(t *testing.T) {
+	endpoint := &provider.EndpointConfig{
+		BaseURL: "wss://api.deepgram.com",
+		Path:    "/v1/listen",
+	}
+	adapter := NewDeepgramAdapter(endpoint, "test-api-key", "nova-3", "en")
+
+	if adapter.apiKey != "test-api-key" {
+		t.Errorf("apiKey = %q, want %q", adapter.apiKey, "test-api-key")
+	}
+	if adapter.model != "nova-3" {
+		t.Errorf("model = %q, want %q", adapter.model, "nova-3")
+	}
+	if adapter.language != "en" {
+		t.Errorf("language = %q, want %q", adapter.language, "en")
+	}
+	if adapter.maxRetries != 3 {
+		t.Errorf("maxRetries = %d, want %d", adapter.maxRetries, 3)
+	}
+}
+
+func TestDeepgramAdapter_BuildURL(t *testing.T) {
+	tests := []struct {
+		name     string
+		model    string
+		language string
+		wantURL  []string // URL must contain all these substrings
+	}{
+		{
+			name:     "english",
+			model:    "nova-3",
+			language: "en",
+			wantURL:  []string{"model=nova-3", "language=en-US", "encoding=linear16", "sample_rate=16000"},
+		},
+		{
+			name:     "spanish",
+			model:    "nova-2",
+			language: "es",
+			wantURL:  []string{"model=nova-2", "language=es", "encoding=linear16"},
+		},
+		{
+			name:     "auto-detect",
+			model:    "nova-3",
+			language: "",
+			wantURL:  []string{"model=nova-3", "encoding=linear16"},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			endpoint := &provider.EndpointConfig{
+				BaseURL: "wss://api.deepgram.com",
+				Path:    "/v1/listen",
+			}
+			adapter := NewDeepgramAdapter(endpoint, "test-key", tt.model, tt.language)
+
+			url, err := adapter.buildURL()
+			if err != nil {
+				t.Fatalf("buildURL() error = %v", err)
+			}
+
+			for _, want := range tt.wantURL {
+				if !strings.Contains(url, want) {
+					t.Errorf("buildURL() = %q, want to contain %q", url, want)
+				}
+			}
+		})
+	}
+}
+
+func TestDeepgramAdapter_SendChunkNotStarted(t *testing.T) {
+	endpoint := &provider.EndpointConfig{
+		BaseURL: "wss://api.deepgram.com",
+		Path:    "/v1/listen",
+	}
+	adapter := NewDeepgramAdapter(endpoint, "test-key", "nova-3", "en")
+
+	err := adapter.SendChunk([]byte("audio data"))
+	if err == nil {
+		t.Error("SendChunk() should return error when adapter not started")
+	}
+	if !strings.Contains(err.Error(), "not started") {
+		t.Errorf("error should mention 'not started', got: %v", err)
+	}
+}
+
+func TestDeepgramAdapter_CloseNotStarted(t *testing.T) {
+	endpoint := &provider.EndpointConfig{
+		BaseURL: "wss://api.deepgram.com",
+		Path:    "/v1/listen",
+	}
+	adapter := NewDeepgramAdapter(endpoint, "test-key", "nova-3", "en")
+
+	// closing not-started adapter should not error
+	err := adapter.Close()
+	if err != nil {
+		t.Errorf("Close() error = %v, want nil", err)
+	}
+}
+
+// mockDeepgramServer creates a mock WebSocket server for testing
+func mockDeepgramServer(t *testing.T, handler func(*websocket.Conn)) *httptest.Server {
+	upgrader := websocket.Upgrader{}
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// verify auth header
+		auth := r.Header.Get("Authorization")
+		if !strings.HasPrefix(auth, "Token ") {
+			http.Error(w, "Unauthorized", http.StatusUnauthorized)
+			return
+		}
+
+		conn, err := upgrader.Upgrade(w, r, nil)
+		if err != nil {
+			t.Logf("upgrade error: %v", err)
+			return
+		}
+		defer conn.Close()
+
+		handler(conn)
+	}))
+	return server
+}
+
+func TestDeepgramAdapter_StartAndClose(t *testing.T) {
+	server := mockDeepgramServer(t, func(conn *websocket.Conn) {
+		// send metadata response
+		metadata := deepgramWSResponse{
+			Type: "Metadata",
+			Metadata: &deepgramMetadata{
+				RequestID: "test-123",
+			},
+		}
+		metadata.Metadata.ModelInfo.Name = "nova-3"
+		if err := conn.WriteJSON(metadata); err != nil {
+			t.Logf("write metadata error: %v", err)
+			return
+		}
+
+		// wait for close
+		for {
+			_, _, err := conn.ReadMessage()
+			if err != nil {
+				break
+			}
+		}
+	})
+	defer server.Close()
+
+	// convert http URL to ws URL
+	wsURL := "ws" + strings.TrimPrefix(server.URL, "http")
+	endpoint := &provider.EndpointConfig{
+		BaseURL: wsURL,
+		Path:    "",
+	}
+
+	adapter := NewDeepgramAdapter(endpoint, "test-api-key", "nova-3", "en")
+
+	ctx := context.Background()
+	if err := adapter.Start(ctx, ""); err != nil {
+		t.Fatalf("Start() error = %v", err)
+	}
+
+	// verify can't start twice
+	if err := adapter.Start(ctx, ""); err == nil {
+		t.Error("Start() should return error when already started")
+	}
+
+	// close
+	if err := adapter.Close(); err != nil {
+		t.Errorf("Close() error = %v", err)
+	}
+}
+
+func TestDeepgramAdapter_ReceivesResults(t *testing.T) {
+	var wg sync.WaitGroup
+	wg.Add(1)
+
+	server := mockDeepgramServer(t, func(conn *websocket.Conn) {
+		defer wg.Done()
+
+		// send metadata
+		metadata := deepgramWSResponse{Type: "Metadata", Metadata: &deepgramMetadata{RequestID: "test-123"}}
+		_ = conn.WriteJSON(metadata)
+
+		// send interim result
+		interim := deepgramWSResponse{
+			Type:    "Results",
+			IsFinal: false,
+			Channel: &deepgramChannel{
+				Alternatives: []deepgramAlternative{{Transcript: "hello", Confidence: 0.95}},
+			},
+		}
+		_ = conn.WriteJSON(interim)
+
+		// send final result
+		final := deepgramWSResponse{
+			Type:    "Results",
+			IsFinal: true,
+			Channel: &deepgramChannel{
+				Alternatives: []deepgramAlternative{{Transcript: "hello world", Confidence: 0.98}},
+			},
+		}
+		_ = conn.WriteJSON(final)
+
+		// wait briefly then close
+		time.Sleep(50 * time.Millisecond)
+	})
+	defer server.Close()
+
+	wsURL := "ws" + strings.TrimPrefix(server.URL, "http")
+	endpoint := &provider.EndpointConfig{BaseURL: wsURL, Path: ""}
+	adapter := NewDeepgramAdapter(endpoint, "test-api-key", "nova-3", "en")
+
+	ctx := context.Background()
+	if err := adapter.Start(ctx, ""); err != nil {
+		t.Fatalf("Start() error = %v", err)
+	}
+
+	// collect results
+	var results []TranscriptionResult
+	timeout := time.After(2 * time.Second)
+
+loop:
+	for {
+		select {
+		case result, ok := <-adapter.Results():
+			if !ok {
+				break loop
+			}
+			results = append(results, result)
+			if result.IsFinal {
+				break loop
+			}
+		case <-timeout:
+			t.Fatal("timeout waiting for results")
+		}
+	}
+
+	adapter.Close()
+	wg.Wait()
+
+	// verify results
+	if len(results) < 2 {
+		t.Fatalf("expected at least 2 results, got %d", len(results))
+	}
+
+	// check interim
+	if results[0].Text != "hello" || results[0].IsFinal {
+		t.Errorf("interim result = %+v, want Text='hello', IsFinal=false", results[0])
+	}
+
+	// check final
+	found := false
+	for _, r := range results {
+		if r.Text == "hello world" && r.IsFinal {
+			found = true
+			break
+		}
+	}
+	if !found {
+		t.Errorf("did not find expected final result 'hello world'")
+	}
+}
+
+func TestDeepgramAdapter_SendsRawBinaryAudio(t *testing.T) {
+	receivedAudio := make(chan []byte, 1)
+
+	server := mockDeepgramServer(t, func(conn *websocket.Conn) {
+		// send metadata first
+		metadata := deepgramWSResponse{Type: "Metadata", Metadata: &deepgramMetadata{RequestID: "test-123"}}
+		_ = conn.WriteJSON(metadata)
+
+		// read audio chunk
+		msgType, data, err := conn.ReadMessage()
+		if err != nil {
+			return
+		}
+		if msgType != websocket.BinaryMessage {
+			t.Errorf("expected binary message, got %d", msgType)
+		}
+		receivedAudio <- data
+
+		// keep reading until close
+		for {
+			_, _, err := conn.ReadMessage()
+			if err != nil {
+				break
+			}
+		}
+	})
+	defer server.Close()
+
+	wsURL := "ws" + strings.TrimPrefix(server.URL, "http")
+	endpoint := &provider.EndpointConfig{BaseURL: wsURL, Path: ""}
+	adapter := NewDeepgramAdapter(endpoint, "test-api-key", "nova-3", "en")
+
+	ctx := context.Background()
+	if err := adapter.Start(ctx, ""); err != nil {
+		t.Fatalf("Start() error = %v", err)
+	}
+
+	// send audio chunk
+	testAudio := []byte{0x01, 0x02, 0x03, 0x04}
+	if err := adapter.SendChunk(testAudio); err != nil {
+		t.Errorf("SendChunk() error = %v", err)
+	}
+
+	// verify audio was received
+	select {
+	case audio := <-receivedAudio:
+		if string(audio) != string(testAudio) {
+			t.Errorf("received audio = %v, want %v", audio, testAudio)
+		}
+	case <-time.After(time.Second):
+		t.Error("timeout waiting for audio")
+	}
+
+	adapter.Close()
+}
+
+func TestDeepgramAdapter_HandlesError(t *testing.T) {
+	server := mockDeepgramServer(t, func(conn *websocket.Conn) {
+		// send error
+		errResp := deepgramWSResponse{
+			Type: "Error",
+			Error: &deepgramError{
+				Type:    "AuthError",
+				Message: "Invalid API key",
+			},
+		}
+		data, _ := json.Marshal(errResp)
+		_ = conn.WriteMessage(websocket.TextMessage, data)
+
+		time.Sleep(50 * time.Millisecond)
+	})
+	defer server.Close()
+
+	wsURL := "ws" + strings.TrimPrefix(server.URL, "http")
+	endpoint := &provider.EndpointConfig{BaseURL: wsURL, Path: ""}
+	adapter := NewDeepgramAdapter(endpoint, "test-api-key", "nova-3", "en")
+
+	ctx := context.Background()
+	if err := adapter.Start(ctx, ""); err != nil {
+		t.Fatalf("Start() error = %v", err)
+	}
+
+	// wait for error result
+	select {
+	case result := <-adapter.Results():
+		if result.Error == nil {
+			t.Error("expected error result")
+		}
+		if !strings.Contains(result.Error.Error(), "Invalid API key") {
+			t.Errorf("error = %v, want to contain 'Invalid API key'", result.Error)
+		}
+	case <-time.After(time.Second):
+		t.Error("timeout waiting for error")
+	}
+
+	adapter.Close()
+}
+
+func TestDeepgramAdapter_ContextCancellation(t *testing.T) {
+	server := mockDeepgramServer(t, func(conn *websocket.Conn) {
+		// send metadata first so connection is established
+		metadata := deepgramWSResponse{Type: "Metadata", Metadata: &deepgramMetadata{RequestID: "test-123"}}
+		_ = conn.WriteJSON(metadata)
+
+		// just keep connection open until closed
+		for {
+			_, _, err := conn.ReadMessage()
+			if err != nil {
+				break
+			}
+		}
+	})
+	defer server.Close()
+
+	wsURL := "ws" + strings.TrimPrefix(server.URL, "http")
+	endpoint := &provider.EndpointConfig{BaseURL: wsURL, Path: ""}
+	adapter := NewDeepgramAdapter(endpoint, "test-api-key", "nova-3", "en")
+
+	ctx, cancel := context.WithCancel(context.Background())
+	if err := adapter.Start(ctx, ""); err != nil {
+		t.Fatalf("Start() error = %v", err)
+	}
+
+	// cancel context - this should trigger Close() to be called or at least stop SendChunk
+	cancel()
+
+	// SendChunk should return error after context cancelled
+	err := adapter.SendChunk([]byte("test"))
+	if err == nil {
+		// it's ok if first chunk after cancel succeeds - the context cancel is async
+		// but subsequent operations should fail
+	}
+
+	// Close should work even after context cancelled
+	if err := adapter.Close(); err != nil {
+		t.Errorf("Close() error = %v", err)
+	}
+
+	// results channel should be closed after Close()
+	select {
+	case _, ok := <-adapter.Results():
+		if ok {
+			// drain any remaining
+			for range adapter.Results() {
+			}
+		}
+	case <-time.After(2 * time.Second):
+		t.Error("timeout waiting for results channel to close")
+	}
+}

progress.txt

@@ -346,4 +346,17 @@ Started: Sun Feb  1 12:22:47 AM CET 2026
 - DefaultModel(Transcription) returns 'nova-3'
 - Registered in provider.init()
 - Comprehensive test file created: deepgram_test.go
-- All tests passing, typecheck passes
+- All tests passing, typecheck passes
+
+### Task 34: Create Deepgram StreamingAdapter
+- Created `internal/transcriber/adapter_deepgram.go`
+- DeepgramAdapter struct: endpoint, apiKey, model, language, conn, resultsCh, mutex, ctx/cancel, WaitGroup
+- Start(): connects to wss://api.deepgram.com/v1/listen with Authorization: Token header
+- Query params: model, language, encoding=linear16, sample_rate=16000, channels=1, interim_results=true, smart_format=true, punctuate=true
+- Language conversion via language.ToProviderFormat(lang, "deepgram")
+- SendChunk(): sends raw binary audio (websocket.BinaryMessage, not base64 like ElevenLabs)
+- readLoop goroutine: parses Metadata, Results (interim + final), Error, UtteranceEnd, SpeechStarted messages
+- Close(): cancels context, sends close frame, waits for reader goroutine
+- Added reconnection logic (maxRetries=3, exponential backoff 1s, 2s, 4s) matching ElevenLabs pattern
+- Comprehensive tests with mock WebSocket server
+- All tests passing with -race flag, typecheck passes

tasks/prd.jsonc

@@ -806,7 +806,7 @@
 				"Close() terminates cleanly",
 				"Typecheck passes"
 			],
-			"passes": false
+			"passes": true
 		},
 		{
 			"title": "Add reconnection logic to Deepgram StreamingAdapter",