Add OpenRouter support and improve logging in chat handler (#601)

- Added OpenRouter API URL handling in `llm_openai.go`.
- Enhanced logging in `chat_main_handler.go` for better debugging:
  - Added detailed config logging.
  - Added pre-request and stream error logging.

api/chat_main_handler.go

@@ -497,7 +497,8 @@ func (h *ChatHandler) chatStream(w http.ResponseWriter, chatSession sqlc_queries
 	}
 
 	config, err := genOpenAIConfig(chatModel)
-	log.Printf("%+v", config)
+	log.Printf("%+v", config.String()) 
+	// print all config details
 	if err != nil {
 		RespondWithError(w, http.StatusInternalServerError, eris.Wrap(err, "gen open ai config").Error(), err)
 		return nil, err
@@ -533,6 +534,7 @@ func (h *ChatHandler) chatStream(w http.ResponseWriter, chatSession sqlc_queries
 		fmt.Fprint(w, string(data))
 		return &models.LLMAnswer{Answer: completion.Choices[0].Message.Content, AnswerId: completion.ID}, nil
 	}
+	log.Print("before request")
 	stream, err := client.CreateChatCompletionStream(ctx, openai_req)
 
 	if err != nil {
@@ -566,6 +568,7 @@ func (h *ChatHandler) chatStream(w http.ResponseWriter, chatSession sqlc_queries
 	for {
 		rawLine, err := stream.RecvRaw()
 		if err != nil {
+			log.Printf("stream error: %+v", err)
 			if errors.Is(err, io.EOF) {
 				// send the last message
 				if len(answer) > 0 {

api/llm_openai.go

@@ -91,6 +91,16 @@ func getModelBaseUrl(apiUrl string) (string, error) {
 	if apiUrl == "https://dashscope.aliyuncs.com/compatible-mode/v1/chat/completions" {
 		return "https://dashscope.aliyuncs.com/compatible-mode/v1", nil
 	}
+	// open router
+	// https://openrouter.ai/api/v1
+	if strings.Contains(apiUrl, "openrouter") {
+		// keep the url until /v1
+		slashIndex := strings.Index(apiUrl, "/v1")
+		if slashIndex > 0 {
+			return apiUrl[:slashIndex] + "/v1", nil
+		}
+		return apiUrl, nil
+	}
 	parsedUrl, err := url.Parse(apiUrl)
 	if err != nil {
 		return "", err