from typing import List, Optional, Union
from pydantic import BaseModel

class Message(BaseModel):
    role: str
    content: Union[str, List[dict]]  # Allowing for both text and complex structures like images

class ChatRequest(BaseModel):
    model: str
    messages: List[Message]
    stream: Optional[bool] = False
    temperature: Optional[float] = 0.7
    top_p: Optional[float] = 0.9
    max_tokens: Optional[int] = 8192