from datetime import datetime
from typing import Optional

from pydantic import BaseModel, Field


class TodoBase(BaseModel):
    """
    Base schema for Todo items.
    """
    title: str = Field(..., min_length=1, max_length=255)
    description: Optional[str] = None
    completed: bool = False


class TodoCreate(TodoBase):
    """
    Schema for creating a new Todo item.
    """
    pass


class TodoUpdate(BaseModel):
    """
    Schema for updating an existing Todo item.
    """
    title: Optional[str] = Field(None, min_length=1, max_length=255)
    description: Optional[str] = None
    completed: Optional[bool] = None


class TodoInDBBase(TodoBase):
    """
    Base schema for Todo items in the database.
    """
    id: int
    created_at: datetime
    updated_at: datetime

    class Config:
        from_attributes = True


class Todo(TodoInDBBase):
    """
    Schema for returning a Todo item.
    """
    pass