package uebung02.rationals;

public class Rational {
    private final int num, denom;


    Rational(int num, int denom) {
        if (denom == 0) {
            throw new IllegalArgumentException("Zahl darf nicht 0 sein!");
        } else {
            int gcd = gcDivider(num, denom);

            if (denom < 0) {
                this.num = -num / gcd;
                this.denom = -denom / gcd;
            } else {
                this.num = num / gcd;
                this.denom = denom / gcd;
            }
        }
    }

    Rational (int num) {
        this(num, 1);
    }

    private int gcDivider(int x, int y) {
        //return x == 0 ? y : gcDivider(y % x, x);
        if (x == 0) {
            return y;
        } else {
            return gcDivider(y % x, x);
        }
    }

    public int getNum() {
        return num;
    }

    public int getDenom() {
        return denom;
    }

    public Rational add(Rational other) {
        return new Rational(num * other.getDenom() + denom * other.getNum(),
        denom * other.getDenom());
    }

    public Rational add(int i) {
        return add(new Rational(i));
    }

    public Rational sub(Rational r) {
        return new Rational(num * r.denom - denom * r.num, denom * r.denom);
    }

    public Rational sub(int i) {
        return this.sub(new Rational(i));
    }

    public Rational mult(Rational r) {
        return new Rational(num * r.num, denom * r.denom);
    }

    public Rational mult(int i) {
        return mult(new Rational(i));
    }

    public Rational div(Rational r) {
        return new Rational(num * r.denom, denom * r.num);
    }

    public Rational div(int i) {
        return div(new Rational(i));
    }

    @Override
    public String toString() {
        if (denom == 1) {
            return "" + num;
        } else {
            return num + "/" + denom;
        }
    }

    public boolean lessThan(Rational r) {
        return this.sub(r).num < 0;
    }

    public boolean lessThan(int i) {
        return this.sub(i).num < 0;
    }

    public boolean greaterThan(Rational r) {
        return this.sub(r).num > 0;
    }

    public boolean greaterThan(int i) {
        return this.sub(i).num > 0;
    }

    public boolean lessThanOrEqual(Rational r) {
        return this.sub(r).num <= 0;
    }

    public boolean lessThanOrEqual(int i) {
        return this.sub(i).num <= 0;
    }

    public boolean greaterThanOrEqual(Rational r) {
        return this.sub(r).num >= 0;
    }

    public boolean isEqual(Rational r) {
        return this.num == r.num && this.denom == r.denom;
    }

    public boolean isEqual(int i) {
        return this.isEqual(new Rational(i));
    }

}