from datetime import datetime
from typing import List, Optional
from pydantic import BaseModel, Field
import uuid

class Message(BaseModel):
    role: str
    content: str

class Conversation(BaseModel):
    id: str = Field(default_factory=lambda: str(uuid.uuid4()))
    user_id: str
    messages: List[Message] = Field(default_factory=list)
    created_at: datetime = Field(default_factory=datetime.utcnow)
    updated_at: datetime = Field(default_factory=datetime.utcnow)

    def add_message(self, role: str, content: str):
        self.messages.append(Message(role=role, content=content))
        self.updated_at = datetime.utcnow()

    def to_dict(self):
        return {
            "id": self.id,
            "user_id": self.user_id,
            "messages": [msg.model_dump() for msg in self.messages],
            "created_at": self.created_at.isoformat(),
            "updated_at": self.updated_at.isoformat(),
        }

    @classmethod
    def from_dict(cls, data: dict):
        data["messages"] = [Message(**msg) for msg in data["messages"]]
        return cls(**data)