from pydantic import BaseModel, Field

class CountryBase(BaseModel):
    name: str = Field(..., index=True, unique=True, description="Country name")
    code: str = Field(..., min_length=3, max_length=3, description="Country code (3 characters)")
    population: int = Field(..., gt=0, description="Country population")
    area: int = Field(..., gt=0, description="Country area")

    class Config:
        schema_extra = {
            "example": {
                "name": "United States",
                "code": "USA",
                "population": 329500000,
                "area": 9833520
            }
        }

class CountryCreate(CountryBase):
    pass

class CountryResponse(CountryBase):
    id: int

    class Config:
        orm_mode = True