package MyGeometryLib;

import org.jetbrains.annotations.Contract;

public class Segment {
    private Vector begin;
    private Vector end;

    Segment(Vector begin, Vector end) {
        this.begin = begin;
        this.end = end;
    }

    @Contract(pure = true)
    private Vector getStart() {
        return begin;
    }

    @Contract(pure = true)
    private Vector getEnd() {
        return end;
    }

    double length() {
        return (this.end.sub(this.begin)).len();
    }

    double distanceTo(Vector point) {
        double lengthFirstSide = (point.sub(begin)).len();
        double lengthSecondeSide = (point.sub(end)).len();
        double lengthLastSide = (end.sub(begin)).len();

        if (lengthLastSide == 0.0) {
            return (end.sub(begin)).sub(point).len();
        }

        double halfPerimeter = (lengthFirstSide + lengthSecondeSide + lengthLastSide) / 2;
        return (2*Math.sqrt(halfPerimeter*(halfPerimeter - lengthFirstSide)*(halfPerimeter - lengthSecondeSide)*(halfPerimeter - lengthLastSide))/lengthLastSide);
    }

    @Override
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }

        if (obj == null || obj.getClass() != this.getClass()) {
            return false;
        }

        Segment segment = (Segment) obj;

        return this.begin.equals(segment.begin) &&
                this.end.equals(segment.end) &&
                (this.end.sub(this.begin)).len() == segment.length();
    }
}