"""
Bharat Tech Atlas — Chat Pydantic Models
Request/response schemas for the chat API.
"""
from pydantic import BaseModel, Field
from typing import List, Optional, Literal


class ChatMessage(BaseModel):
    role: Literal["system", "user", "assistant"] = "user"
    content: str = Field(..., min_length=1, max_length=2000)


class ChatRequest(BaseModel):
    messages: List[ChatMessage] = Field(..., min_length=1, max_length=20)
    stream: bool = False


class ChatResponse(BaseModel):
    role: Literal["assistant"] = "assistant"
    content: str
    model: str
    sources: List[str] = []
    safety: dict = {}