package MathMethods;

public class Rational {
    private int numerator;
    private int denominator;

    // Constructor
    public Rational(int numerator, int denominator) {
        if (denominator == 0) {
            throw new IllegalArgumentException("Denominator cannot be zero");
        }
        this.numerator = numerator;
        this.denominator = denominator;
        simplify();
    }

    // GCD helper for simplification
    private int gcd(int a, int b) {
        a = Math.abs(a);
        b = Math.abs(b);
        while (b != 0) {
            int temp = b;
            b = a % b;
            a = temp;
        }
        return a;
    }

    // Simplify the fraction
    private void simplify() {
        int gcd = gcd(numerator, denominator);
        numerator /= gcd;
        denominator /= gcd;

        // Keep denominator positive
        if (denominator < 0) {
            numerator = -numerator;
            denominator = -denominator;
        }
    }

    // ✅ COMPLETED - Instance method: this + other
    public Rational add(Rational other) {
        int newNumerator = this.numerator * other.denominator + other.numerator * this.denominator;
        int newDenominator = this.denominator * other.denominator;
        return new Rational(newNumerator, newDenominator);
    }

    // ✅ COMPLETED - Static method: r1 + r2
    public static Rational add(Rational r1, Rational r2) {
        return r1.add(r2);
    }

    // TODO: Instance method - this - other
    // Formula: a/b - c/d = (a*d - c*b) / (b*d)
    public Rational subtract(Rational other) {
        // YOUR CODE HERE
        return null; // Remove this line when implemented
    }

    // TODO: Static method - r1 - r2
    public static Rational subtract(Rational r1, Rational r2) {
        // YOUR CODE HERE
        return null; // Remove this line when implemented
    }

    // TODO: Instance method - this * other
    // Formula: (a/b) * (c/d) = (a*c) / (b*d)
    public Rational multiply(Rational other) {
        // YOUR CODE HERE
        return null; // Remove this line when implemented
    }

    // TODO: Static method - r1 * r2
    public static Rational multiply(Rational r1, Rational r2) {
        // YOUR CODE HERE
        return null; // Remove this line when implemented
    }

    // TODO: Instance method - this / other
    // Formula: (a/b) ÷ (c/d) = (a*d) / (b*c)
    public Rational divide(Rational other) {
        // YOUR CODE HERE
        // HINT: Division is multiplication by reciprocal
        // Don't forget to check if other.numerator is zero!
        return null; // Remove this line when implemented
    }

    // TODO: Static method - r1 / r2
    public static Rational divide(Rational r1, Rational r2) {
        // YOUR CODE HERE
        return null; // Remove this line when implemented
    }

    // ✅ PROVIDED - String representation
    @Override
    public String toString() {
        if (denominator == 1) {
            return numerator + "";
        }
        return numerator + "/" + denominator;
    }

    // ✅ PROVIDED - Decimal value
    public double toDouble() {
        return (double) numerator / denominator;
    }
}