zf: fix Gemini provider routing and output validation

4 files changed, 53 insertions, 16 deletions

diff --git a/internal/audio/gemini_provider.go b/internal/audio/gemini_provider.go
index 23c4f4b..8d0c517 100644
--- a/internal/audio/gemini_provider.go
+++ b/internal/audio/gemini_provider.go
@@ -206,20 +206,16 @@ func writeGeminiAudioFile(outputFile string, audioData []byte, mimeType string)
 	}
 
 	ext := strings.ToLower(filepath.Ext(outputFile))
-	mimeType = strings.ToLower(mimeType)
-	if ext == ".wav" || (ext == "" && (mimeType == "" || strings.Contains(mimeType, "pcm"))) {
-		encoded, err := encodePCMAsWAV(audioData)
-		if err != nil {
-			return err
-		}
+	if ext != ".wav" {
+		return fmt.Errorf("Gemini TTS only supports .wav output files, got %q", outputFile)
+	}
 
-		if err := os.WriteFile(outputFile, encoded, 0644); err != nil {
-			return fmt.Errorf("failed to write output file: %w", err)
-		}
-		return nil
+	encoded, err := encodePCMAsWAV(audioData)
+	if err != nil {
+		return err
 	}
 
-	if err := os.WriteFile(outputFile, audioData, 0644); err != nil {
+	if err := os.WriteFile(outputFile, encoded, 0644); err != nil {
 		return fmt.Errorf("failed to write output file: %w", err)
 	}
 
diff --git a/internal/audio/gemini_provider_test.go b/internal/audio/gemini_provider_test.go
index 1c04f55..b8ab4c9 100644
--- a/internal/audio/gemini_provider_test.go
+++ b/internal/audio/gemini_provider_test.go
@@ -141,3 +141,21 @@ func TestWriteGeminiAudioFileWritesWAV(t *testing.T) {
 		t.Fatalf("len(output) = %d, want %d", got, want)
 	}
 }
+
+func TestWriteGeminiAudioFileRejectsUnsupportedFormats(t *testing.T) {
+	dir := t.TempDir()
+	outputFile := filepath.Join(dir, "output.mp3")
+
+	err := writeGeminiAudioFile(outputFile, []byte{0x11, 0x22}, "audio/pcm")
+	if err == nil {
+		t.Fatal("writeGeminiAudioFile() expected error for non-wav output")
+	}
+
+	if !strings.Contains(err.Error(), "only supports .wav output files") {
+		t.Fatalf("writeGeminiAudioFile() error = %v, want unsupported-format message", err)
+	}
+
+	if _, statErr := os.Stat(outputFile); !os.IsNotExist(statErr) {
+		t.Fatalf("expected no output file to be written, statErr=%v", statErr)
+	}
+}
diff --git a/internal/audio/provider.go b/internal/audio/provider.go
index a4379f1..7ca4282 100644
--- a/internal/audio/provider.go
+++ b/internal/audio/provider.go
@@ -65,6 +65,11 @@ func NewProvider(config *Config) (Provider, error) {
 			return nil, fmt.Errorf("OpenAI API key is required")
 		}
 		return NewOpenAIProvider(config)
+	case "gemini":
+		if config.GoogleAPIKey == "" {
+			return nil, fmt.Errorf("Google API key is required")
+		}
+		return NewGeminiProvider(config)
 
 	default:
 		return nil, fmt.Errorf("unknown audio provider: %s", config.Provider)
diff --git a/internal/audio/provider_test.go b/internal/audio/provider_test.go
index 97d3e9c..24d2729 100644
--- a/internal/audio/provider_test.go
+++ b/internal/audio/provider_test.go
@@ -54,10 +54,11 @@ func TestDefaultProviderConfig(t *testing.T) {
 
 func TestNewProvider(t *testing.T) {
 	tests := []struct {
-		name    string
-		config  *Config
-		wantErr bool
-		errMsg  string
+		name         string
+		config       *Config
+		wantErr      bool
+		errMsg       string
+		wantProvider string
 	}{
 		{
 			name:    "nil config uses defaults",
@@ -81,17 +82,34 @@ func TestNewProvider(t *testing.T) {
 			wantErr: true,
 			errMsg:  "unknown audio provider: unknown",
 		},
+		{
+			name: "gemini provider with key",
+			config: &Config{
+				Provider:     "gemini",
+				GoogleAPIKey: "test-google-key",
+			},
+			wantErr:      false,
+			wantProvider: "gemini",
+		},
 	}
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			_, err := NewProvider(tt.config)
+			provider, err := NewProvider(tt.config)
 			if (err != nil) != tt.wantErr {
 				t.Errorf("NewProvider() error = %v, wantErr %v", err, tt.wantErr)
 			}
 			if tt.wantErr && err != nil && err.Error() != tt.errMsg {
 				t.Errorf("NewProvider() error = %v, want %v", err.Error(), tt.errMsg)
 			}
+			if !tt.wantErr && tt.wantProvider != "" {
+				if provider == nil {
+					t.Fatalf("NewProvider() returned nil provider")
+				}
+				if provider.Name() != tt.wantProvider {
+					t.Fatalf("NewProvider() Name() = %v, want %v", provider.Name(), tt.wantProvider)
+				}
+			}
 		})
 	}
 }