add: encode and sent image function

bot/openai/img2txt.go

@@ -0,0 +1,87 @@
+package openai
+
+import (
+	"bytes"
+	"encoding/base64"
+	"fmt"
+	"image"
+	"image/jpeg"
+	"image/png"
+	"io"
+	"net/http"
+	"strings"
+)
+
+func EncodeImage(img image.Image, format string) (string, error) {
+	switch format {
+	case "jpeg":
+		imgData := new(bytes.Buffer)
+		err := jpeg.Encode(imgData, img, nil)
+		if err != nil {
+			return "", err
+		}
+		imgEnc := base64.StdEncoding.EncodeToString(imgData.Bytes())
+		return string(imgEnc), nil
+
+	case "png":
+		imgData := new(bytes.Buffer)
+		err := png.Encode(imgData, img)
+		if err != nil {
+			return "", err
+		}
+		imgEnc := base64.StdEncoding.EncodeToString(imgData.Bytes())
+		return string(imgEnc), nil
+
+	default:
+		return "", fmt.Errorf("unsupported image format: %s", format)
+	}
+}
+
+func (c *Gpt4Vision) Img2Txt(img image.Image, format string) (string, error) {
+	base64Image, err := EncodeImage(img, format)
+	if err != nil {
+		return "", err
+	}
+
+	body := fmt.Sprintf(`{
+		"model": "gpt-4-turbo",
+		"messages": [
+		  {
+			"role": "user",
+			"content": [
+			  {
+				"type": "text",
+				"text": "What's in this image?"
+			  },
+			  {
+				"type": "image_url",
+				"image_url": {
+				  "url": "data:image/%s;base64,%s"
+				}
+			  }
+			]
+		  }
+		],
+		"max_tokens": 300
+	}`, format, base64Image)
+
+	req, err := http.NewRequest(http.MethodPost, c.endpoint.String(), strings.NewReader(body))
+	if err != nil {
+		return "", err
+	}
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Authorization", "Bearer "+c.apiKey)
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+
+	respBody, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return "", err
+	}
+
+	return string(respBody), nil
+}