Added support for Baichuan LLM (#934)

### What problem does this PR solve?

- Added support for Baichuan LLM

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

Co-authored-by: 海贼宅 <stu_xyx@163.com>

rag/llm/chat_model.py

@@ -95,6 +95,84 @@ class DeepSeekChat(Base):
         super().__init__(key, model_name, base_url)
 
 
+class BaiChuanChat(Base):
+    def __init__(self, key, model_name="Baichuan3-Turbo", base_url="https://api.baichuan-ai.com/v1"):
+        if not base_url:
+            base_url = "https://api.baichuan-ai.com/v1"
+        super().__init__(key, model_name, base_url)
+
+    @staticmethod
+    def _format_params(params):
+        return {
+            "temperature": params.get("temperature", 0.3),
+            "max_tokens": params.get("max_tokens", 2048),
+            "top_p": params.get("top_p", 0.85),
+        }
+
+    def chat(self, system, history, gen_conf):
+        if system:
+            history.insert(0, {"role": "system", "content": system})
+        try:
+            response = self.client.chat.completions.create(
+                model=self.model_name,
+                messages=history,
+                extra_body={
+                    "tools": [{
+                        "type": "web_search",
+                        "web_search": {
+                            "enable": True,
+                            "search_mode": "performance_first"
+                        }
+                    }]
+                },
+                **self._format_params(gen_conf))
+            ans = response.choices[0].message.content.strip()
+            if response.choices[0].finish_reason == "length":
+                ans += "...\nFor the content length reason, it stopped, continue?" if is_english(
+                    [ans]) else "······\n由于长度的原因，回答被截断了，要继续吗？"
+            return ans, response.usage.total_tokens
+        except openai.APIError as e:
+            return "**ERROR**: " + str(e), 0
+
+    def chat_streamly(self, system, history, gen_conf):
+        if system:
+            history.insert(0, {"role": "system", "content": system})
+        ans = ""
+        total_tokens = 0
+        try:
+            response = self.client.chat.completions.create(
+                model=self.model_name,
+                messages=history,
+                extra_body={
+                    "tools": [{
+                        "type": "web_search",
+                        "web_search": {
+                            "enable": True,
+                            "search_mode": "performance_first"
+                        }
+                    }]
+                },
+                stream=True,
+                **self._format_params(gen_conf))
+            for resp in response:
+                if resp.choices[0].finish_reason == "stop":
+                    if not resp.choices[0].delta.content:
+                        continue
+                    total_tokens = resp.usage.get('total_tokens', 0)
+                if not resp.choices[0].delta.content:
+                    continue
+                ans += resp.choices[0].delta.content
+                if resp.choices[0].finish_reason == "length":
+                    ans += "...\nFor the content length reason, it stopped, continue?" if is_english(
+                        [ans]) else "······\n由于长度的原因，回答被截断了，要继续吗？"
+                yield ans
+
+        except Exception as e:
+            yield ans + "\n**ERROR**: " + str(e)
+
+        yield total_tokens
+
+
 class QWenChat(Base):
     def __init__(self, key, model_name=Generation.Models.qwen_turbo, **kwargs):
         import dashscope