from pydantic import BaseModel, Field
from typing import Optional

class DogBase(BaseModel):
    name: str = Field(..., description="Dog's name")
    breed: str = Field(..., description="Dog's breed")
    age: int = Field(..., gt=0, description="Dog's age in years")
    owner_id: Optional[str] = Field(None, description="ID of the dog's owner")

    class Config:
        schema_extra = {
            "example": {
                "name": "Buddy",
                "breed": "Labrador",
                "age": 5,
                "owner_id": "123e4567-e89b-12d3-a456-426614174000"
            }
        }

class DogCreate(DogBase):
    pass

class DogResponse(DogBase):
    id: int

    class Config:
        orm_mode = True