from pydantic import BaseModel, Field
from typing import Optional
from datetime import datetime
from uuid import UUID

# Base schema for Book, used for inheritance
class BookBase(BaseModel):
    title: str = Field(..., description="Book title")
    author: str = Field(..., description="Book author")
    description: Optional[str] = Field(None, description="Book description")

# Schema for creating a new Book
class BookCreate(BookBase):
    pass

# Schema for updating an existing Book (all fields optional)
class BookUpdate(BaseModel):
    title: Optional[str] = Field(None, description="Book title")
    author: Optional[str] = Field(None, description="Book author")
    description: Optional[str] = Field(None, description="Book description")

# Schema for representing a Book in responses
class BookSchema(BookBase):
    id: UUID
    created_at: datetime
    updated_at: datetime

    class Config:
        orm_mode = True
        schema_extra = {
            "example": {
                "id": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
                "title": "The Great Gatsby",
                "author": "F. Scott Fitzgerald",
                "description": "A novel about the American Dream",
                "created_at": "2023-01-01T12:00:00",
                "updated_at": "2023-01-01T12:00:00"
            }
        }