/*
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 */

package ATC;

/**
 *
 * @author zootreeves
 */

public class Triangle {
    // state data for a triangle with vertices a, b, c
    private Coordinate a, b, c;

    // constructs a triangle with the given vertices
    public Triangle(Coordinate newA, Coordinate newB, Coordinate newC) {
        a = newA;
        b = newB;
        c = newC;
    }

    // access each vertex
    public Coordinate getVertexA() {
        return a;
    }
    public Coordinate getVertexB() {
        return b;
    }
    public Coordinate getVertexC() {
        return c;
    }

    // calculate the length of the side opposite vertex a
    public double getSideA() {
        // get the distance between vertices b and c
        double length = b.distance(c);
        return length;
    }

    // calculate the length of the side opposite vertex b
    public double getSideB() {
        // get the distance between vertices a and c
        double length = a.distance(c);
        return length;
    }

    // calculate the length of the side opposite vertex c
    public double getSideC() {
        // get the distance between vertices a and b
        double length = a.distance(b);
        return length;
    }

    // calculate the angle at vertex a
    public double getAngleA() {
        // get the length of each side
        double as = getSideA(), bs = getSideB(), cs = getSideC();
        // apply the law of cosines
        double angle = Math.acos((bs*bs + cs*cs - as*as) / (2*bs*cs));
        return angle;
    }

    // calculate the angle at vertex b
    public double getAngleB() {
        // get the length of each side
        double as = getSideA(), bs = getSideB(), cs = getSideC();
        // apply the law of cosines
        double angle = Math.acos((as*as + cs*cs - bs*bs) / (2*as*cs));
        return angle;
    }

    // calculate the angle at vertex c
    public double getAngleC() {
        // get the length of each side
        double as = getSideA(), bs = getSideB(), cs = getSideC();
        // apply the law of cosines
        double angle = Math.acos((as*as + bs*bs - cs*cs) / (2*as*bs));
        return angle;
    }

    // check whether no side is longer than the other two sides put together
    public boolean isValid()
    {
        // get the length of each side
        double as = getSideA(), bs = getSideB(), cs = getSideC();
        if (as > (bs + cs))
            return false;
        if (bs > (as + cs))
            return false;
        if (cs > (as + bs))
            return false;
        return true;
    }

    // calculate the sum of the lengths of the sides
    public double getPerimeter() {
        // get the length of each side
        double as = getSideA(), bs = getSideB(), cs = getSideC();
        return (as + bs + cs);
    }

    // calculate the signed area
    double getSignedArea() {
        double signedArea = 0.5 * (a.getX() * (b.getY() - c.getY()) +
                                   b.getX() * (c.getY() - a.getY()) +
                                   c.getX() * (a.getY() - b.getY()));
        return signedArea;
    }

    // calculate the absolute area
    public double getArea() {
        return Math.abs(getSignedArea());
    }

    // determine orientation based on the signed area
    public int getOrientation() {
        double signedArea = getSignedArea();
        if (signedArea > 0.0)
            return 1;
        if (signedArea < 0.0)
            return -1;
        return 0;
    }

    // pretty-print the coordinates inside square brackets
    public String toString() {
        return ("["+a+",\n "+b+",\n "+c+"]");
    }

    // do the coordinates of the vertices a, b, c match up in order?
    // note that we are not checking all 6 orderings of a, b, c
    public boolean equals(Object o)
    {
        Triangle triangle = (Triangle) o;
        if (triangle.getVertexA() != a)
            return false;
        if (triangle.getVertexB() != b)
            return false;
        if (triangle.getVertexC() != c)
            return false;
        return true;
    }

    // check whether a given point falls inside the triangle
    public boolean contains(Coordinate p)
    {
        int orientation = (new Triangle(b, c, p)).getOrientation();
        if ((new Triangle(a, b, p)).getOrientation() != orientation)
            return false;
        if (orientation != (new Triangle(b, c, p)).getOrientation())
            return false;
        return true;
    }

}