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


class ChatMessage(BaseModel):
    role: str
    content: str
    timestamp: Optional[datetime] = None


class ChatRequest(BaseModel):
    message: str
    session_id: Optional[str] = None
    use_history: bool = True
    use_rag: bool = True


class ChatResponse(BaseModel):
    response: str
    sources: Optional[List[dict]] = []
    session_id: str
    timestamp: datetime = Field(default_factory=datetime.utcnow)


class DocumentUpload(BaseModel):
    filename: str
    content_type: str
    size: int


class DocumentResponse(BaseModel):
    id: str
    filename: str
    status: str
    created_at: datetime
    chunk_count: Optional[int] = 0


class HealthResponse(BaseModel):
    status: str
    timestamp: datetime = Field(default_factory=datetime.utcnow)
    services: dict


class ErrorResponse(BaseModel):
    error: str
    detail: Optional[str] = None
    timestamp: datetime = Field(default_factory=datetime.utcnow)