from pydantic import BaseModel
from typing import Optional
from datetime import datetime


class SessionCreate(BaseModel):
    """Schema for creating a session."""
    title: Optional[str] = "New Conversation"


class SessionUpdate(BaseModel):
    """Schema for updating a session."""
    title: Optional[str] = None


class SessionResponse(BaseModel):
    """Schema for session response."""
    id: str
    user_id: Optional[str]
    title: str
    summary: Optional[str]
    created_at: datetime
    updated_at: datetime
    message_count: Optional[int] = 0
    
    class Config:
        from_attributes = True


class SessionListResponse(BaseModel):
    """Schema for session list response."""
    sessions: list[SessionResponse]
    total: int