bindings.go : add DetectedLanguage to go bindings (#2947)

Adding in DetectedLanguage(), a function to retrieve the detected
language that's populated by processing audio. Also adding in a unit
test to test the success.

Co-authored-by: Amanda Der Bedrosian <aderbedrosian@sdl.com>

bindings/go/pkg/whisper/context.go

@@ -71,6 +71,10 @@ func (context *context) Language() string {
 	return whisper.Whisper_lang_str(context.params.Language())
 }
 
+func (context *context) DetectedLanguage() string {
+	return whisper.Whisper_lang_str(context.model.ctx.Whisper_full_lang_id())
+}
+
 // Set translate flag
 func (context *context) SetTranslate(v bool) {
 	context.params.SetTranslate(v)

bindings/go/pkg/whisper/context_test.go

@@ -91,3 +91,34 @@ func TestProcess(t *testing.T) {
 	err = context.Process(data, nil, nil, nil)
 	assert.NoError(err)
 }
+
+func TestDetectedLanguage(t *testing.T) {
+	assert := assert.New(t)
+
+	fh, err := os.Open(SamplePath)
+	assert.NoError(err)
+	defer fh.Close()
+
+	// Decode the WAV file - load the full buffer
+	dec := wav.NewDecoder(fh)
+	buf, err := dec.FullPCMBuffer()
+	assert.NoError(err)
+	assert.Equal(uint16(1), dec.NumChans)
+
+	data := buf.AsFloat32Buffer().Data
+
+	model, err := whisper.New(ModelPath)
+	assert.NoError(err)
+	assert.NotNil(model)
+	defer model.Close()
+
+	context, err := model.NewContext()
+	assert.NoError(err)
+
+	err = context.Process(data, nil, nil, nil)
+	assert.NoError(err)
+
+	expectedLanguage := "en"
+	actualLanguage := context.DetectedLanguage()
+	assert.Equal(expectedLanguage, actualLanguage)
+}

bindings/go/pkg/whisper/interface.go

@@ -41,6 +41,7 @@ type Context interface {
 	SetTranslate(bool)        // Set translate flag
 	IsMultilingual() bool     // Return true if the model is multilingual.
 	Language() string         // Get language
+	DetectedLanguage() string // Get detected language
 
 	SetOffset(time.Duration)          // Set offset
 	SetDuration(time.Duration)        // Set duration