优化目录结构

service.py

@@ -4,19 +4,22 @@ from typing import Any
 
 from openai import APIError, AsyncOpenAI
 
-from models import (
+from domain import (
     AssistantMessage,
-    FinalAssistantMessage,
     Message,
-    SendMessageResponse,
     Session,
-    SessionHistoryResponse,
-    TokenUsage,
     ToolCall,
     ToolFunctionCall,
     ToolMessage,
     UserMessage,
 )
+from schemas import (
+    CreateSessionResponse,
+    FinalAssistantMessage,
+    SendMessageResponse,
+    SessionHistoryResponse,
+    TokenUsage,
+)
 from storage import JsonSessionStorage
 from tools import ToolRegistry
 
@@ -31,6 +34,7 @@ class ChatService:
         storage: JsonSessionStorage,
         client: AsyncOpenAI,
         model: str,
+        default_system_prompt: str = "You are a helpful assistant.",
         tool_registry: ToolRegistry | None = None,
         max_tool_rounds: int = 5,
         max_tool_calls_per_turn: int = 10,
@@ -40,11 +44,24 @@ class ChatService:
         self.storage = storage
         self.client = client
         self.model = model
+        self.default_system_prompt = default_system_prompt
         self.tool_registry = tool_registry or ToolRegistry()
         self.max_tool_rounds = max_tool_rounds
         self.max_tool_calls_per_turn = max_tool_calls_per_turn
         self._locks: dict[str, asyncio.Lock] = {}
 
+    async def create_session(
+        self, system_prompt: str | None = None
+    ) -> CreateSessionResponse:
+        session = await self.storage.create(
+            system_prompt or self.default_system_prompt
+        )
+        return CreateSessionResponse(
+            session_id=session.session_id,
+            system_prompt=session.system_prompt,
+            created_at=session.created_at,
+        )
+
     async def generate_response(
         self, session_id: str, content: str
     ) -> SendMessageResponse: