优化项目结构

src/chat_api/domain/messages.py

@@ -0,0 +1,43 @@
+from datetime import datetime
+from typing import Annotated, Literal
+
+from pydantic import BaseModel, Field
+
+
+class ToolFunctionCall(BaseModel):
+    name: str
+    arguments: str
+
+
+class ToolCall(BaseModel):
+    id: str
+    type: Literal["function"] = "function"
+    function: ToolFunctionCall
+
+
+class UserMessage(BaseModel):
+    role: Literal["user"] = "user"
+    content: str
+    created_at: datetime
+
+
+class AssistantMessage(BaseModel):
+    role: Literal["assistant"] = "assistant"
+    content: str | None = None
+    tool_calls: list[ToolCall] = Field(default_factory=list)
+    created_at: datetime
+
+
+class ToolMessage(BaseModel):
+    role: Literal["tool"] = "tool"
+    content: str
+    tool_call_id: str
+    name: str
+    is_error: bool = False
+    created_at: datetime
+
+
+Message = Annotated[
+    UserMessage | AssistantMessage | ToolMessage,
+    Field(discriminator="role"),
+]