package calculator.model.unaryOperations;

import calculator.model.*;
import calculator.model.mode.*;

public class Sine extends UnaryOperation
{
    public double operateUnary(double operand)
    {
        AngleMode angle = Engine.getMode().getAngle();
        if (Engine.getMode().getInverse())
        {
            // For sine inverse case, the value should be range of -1 to 1.
            if ((operand < -1) || (operand > 1))
            {
                throw new OperationParameterException("Invalid Input For Sine Function");
            }

            double sineInverse = Math.asin(operand);
            if (angle == AngleMode.Degrees)
            {
                sineInverse = Math.toDegrees(sineInverse);
            }

            Engine.getMode().setInverse(false);
            return sineInverse;
        }
        else
        {
            // The sine case
            if (angle == AngleMode.Degrees)
            {
                // The sine function is cyclic. Hence to avoid calculation
                // error because of rounding off, convert the angle to
                // equivalent value < 180 degrees.
                if (Math.abs((operand % 360) / 180) > 1)
                {
                    operand = operand % 180 * -1;
                }
                else
                {
                    operand = operand % 180;
                }

                operand = Math.toRadians(operand);
            }

            return Math.sin(operand);
        }
    }
}