feat: add tts with go-piper (#649)

Signed-off-by: mudler <mudler@localai.io>

api/localai.go

@@ -0,0 +1,78 @@
+package api
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	model "github.com/go-skynet/LocalAI/pkg/model"
+	"github.com/go-skynet/LocalAI/pkg/tts"
+	"github.com/go-skynet/LocalAI/pkg/utils"
+	llama "github.com/go-skynet/go-llama.cpp"
+	"github.com/gofiber/fiber/v2"
+)
+
+type TTSRequest struct {
+	Model string `json:"model" yaml:"model"`
+	Input string `json:"input" yaml:"input"`
+}
+
+func generateUniqueFileName(dir, baseName, ext string) string {
+	counter := 1
+	fileName := baseName + ext
+
+	for {
+		filePath := filepath.Join(dir, fileName)
+		_, err := os.Stat(filePath)
+		if os.IsNotExist(err) {
+			return fileName
+		}
+
+		counter++
+		fileName = fmt.Sprintf("%s_%d%s", baseName, counter, ext)
+	}
+}
+
+func ttsEndpoint(cm *ConfigMerger, o *Option) func(c *fiber.Ctx) error {
+	return func(c *fiber.Ctx) error {
+
+		input := new(TTSRequest)
+		// Get input data from the request body
+		if err := c.BodyParser(input); err != nil {
+			return err
+		}
+
+		piperModel, err := o.loader.BackendLoader(model.PiperBackend, input.Model, []llama.ModelOption{}, uint32(0), o.assetsDestination)
+		if err != nil {
+			return err
+		}
+
+		if piperModel == nil {
+			return fmt.Errorf("could not load piper model")
+		}
+
+		w, ok := piperModel.(*tts.Piper)
+		if !ok {
+			return fmt.Errorf("loader returned non-piper object %+v", w)
+		}
+
+		if err := os.MkdirAll(o.audioDir, 0755); err != nil {
+			return err
+		}
+
+		fileName := generateUniqueFileName(o.audioDir, "piper", ".wav")
+		filePath := filepath.Join(o.audioDir, fileName)
+
+		modelPath := filepath.Join(o.loader.ModelPath, input.Model)
+
+		if err := utils.VerifyPath(modelPath, o.loader.ModelPath); err != nil {
+			return err
+		}
+
+		if err := w.TTS(input.Input, modelPath, filePath); err != nil {
+			return err
+		}
+
+		return c.Download(filePath)
+	}
+}