第一次提交

models.py

@@ -0,0 +1,79 @@
+from datetime import datetime
+from typing import Literal
+
+from pydantic import BaseModel, ConfigDict, Field, field_validator, model_validator
+
+
+class Message(BaseModel):
+    role: Literal["user", "assistant"]
+    content: str
+    created_at: datetime
+
+
+class Session(BaseModel):
+    model_config = ConfigDict(extra="forbid")
+
+    session_id: str
+    system_prompt: str
+    created_at: datetime
+    updated_at: datetime
+    messages: list[Message] = Field(default_factory=list)
+
+    @model_validator(mode="before")
+    @classmethod
+    def add_timestamp_to_legacy_messages(cls, data: object) -> object:
+        if not isinstance(data, dict):
+            return data
+
+        fallback = data.get("created_at")
+        messages = data.get("messages")
+        if fallback is not None and isinstance(messages, list):
+            for message in messages:
+                if isinstance(message, dict):
+                    message.setdefault("created_at", fallback)
+        return data
+
+
+class CreateSessionRequest(BaseModel):
+    model_config = ConfigDict(extra="forbid")
+
+    system_prompt: str | None = None
+
+    @field_validator("system_prompt")
+    @classmethod
+    def validate_system_prompt(cls, value: str | None) -> str | None:
+        if value is not None and not value.strip():
+            raise ValueError("system_prompt must not be blank")
+        return value
+
+
+class CreateSessionResponse(BaseModel):
+    session_id: str
+    system_prompt: str
+    created_at: datetime
+
+
+class SendMessageRequest(BaseModel):
+    model_config = ConfigDict(extra="forbid")
+
+    content: str
+    stream: bool = False
+
+    @field_validator("content")
+    @classmethod
+    def validate_content(cls, value: str) -> str:
+        if not value.strip():
+            raise ValueError("content must not be blank")
+        return value
+
+
+class TokenUsage(BaseModel):
+    prompt_tokens: int
+    completion_tokens: int
+    total_tokens: int
+
+
+class SendMessageResponse(BaseModel):
+    session_id: str
+    message: Message
+    usage: TokenUsage | None