feat: Refactor OpenAIModelProvider to improve streaming response

This commit refactors the OpenAIModelProvider class to improve the streaming response when generating chat completions with OpenAI. It updates the messages array to include the system prompt and user message, and removes unnecessary comments. This change aims to enhance the overall performance and reliability of the streaming response feature.

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

llm-server/src/model/openai-model-provider.ts

@@ -35,17 +35,18 @@ export class OpenAIModelProvider extends ModelProvider {
     // Get the system prompt based on the model
     const systemPrompt = systemPrompts['codefox-basic']?.systemPrompt || '';
 
-    // Prepare the messages array, including system prompt if available
-    const messages: ChatCompletionMessageParam[] = systemPrompt
-      ? [{ role: 'system', content: systemPrompt }]
-      : [{ role: role as 'user' | 'system' | 'assistant', content: message }];
+    const messages: ChatCompletionMessageParam[] = [
+      { role: 'system', content: systemPrompt },
+      { role: role as 'user' | 'system' | 'assistant', content: message },
+    ];
 
     try {
       const stream = await this.openai.chat.completions.create({
         model,
         messages,
         stream: true,
       });
+
       let chunkCount = 0;
       for await (const chunk of stream) {
         const content = chunk.choices[0]?.delta?.content || '';
@@ -55,6 +56,7 @@ export class OpenAIModelProvider extends ModelProvider {
           res.write(`data: ${JSON.stringify(chunk)}\n\n`);
         }
       }
+
       const endTime = Date.now();
       this.logger.log(
         `Response generation completed. Total chunks: ${chunkCount}`,
@@ -73,20 +75,18 @@ export class OpenAIModelProvider extends ModelProvider {
 
   async getModelTagsResponse(res: Response): Promise<void> {
     this.logger.log('Fetching available models from OpenAI...');
-    // Set SSE headers
     res.writeHead(200, {
       'Content-Type': 'text/event-stream',
       'Cache-Control': 'no-cache',
       Connection: 'keep-alive',
     });
+
     try {
       const startTime = Date.now();
       const models = await this.openai.models.list();
-
       const response = {
-        models: models, // Wrap the models in the required structure
+        models: models,
       };
-
       const endTime = Date.now();
       this.logger.log(
         `Model fetching completed. Total models: ${models.data.length}`,