from datetime import datetime
from typing import Optional
from pydantic import BaseModel, Field, ConfigDict


class CalculationBase(BaseModel):
    operation: str = Field(
        ...,
        description="Mathematical operation: add, subtract, multiply, divide, or square_root",
    )
    first_number: float = Field(..., description="First operand")
    second_number: Optional[float] = Field(
        None, description="Second operand (not required for square_root)"
    )


class CalculationCreate(CalculationBase):
    pass


class CalculationResponse(CalculationBase):
    id: int
    result: float
    created_at: datetime

    model_config = ConfigDict(from_attributes=True)