import java.awt.*;
import java.awt.image.BufferedImage;

public class Triangle{
    public Point2D point1;
    public Point2D point2;
    public Point2D point3;

    private Line LineLong;
    private Line LineA;
    private Line LineB;
    // initialisation variables
    private boolean is_initialised = false;
    private Point2D min;
    private Point2D max;
    // progress variables

    public void invalidate() {
        is_initialised = false;
    }
    public Triangle(Point2D _pA, Point2D _pB, Point2D _pC){
        point1 = _pA;
        point2 = _pB;
        point3 = _pC;
    }
    //  returns int for debug
    public int draw(BufferedImage img){
        long lastMillis;

        if (!is_initialised){initialise();}
        int[] point1;
        int[] point2;
        char currentLine = 'A';

        lastMillis = System.currentTimeMillis();

        point1 = LineLong.nextPix();
        point2 = LineA.nextPix();
        for(int x = min.x+1; x <= max.x; x += 1) {
            while(x-1 == point1[0]) {
                point1 = LineLong.nextPix();
            }
            while(x-1 == point2[0]) {
                if (currentLine == 'A') {
                    try{point2 = LineA.nextPix();}
                    catch (RuntimeException e){
                        currentLine = 'B';
                        point2 = LineB.nextPix();
                    }
                }
                else {
                    point2 = LineB.nextPix();
                }
            }
            // cancel drawing if the x value of the triangle is out of bounds
            if (x >= img.getWidth()) {break;}
            if (x > 0) {
                // check which way to loop
                // TODO - work out a way of not needing to test for this every time
                if (point1[1] < point2[1]) {
                    for (int y = Math.max(point1[1], 0); y <= Math.min(point2[1], img.getHeight() - 1); y += 1) {
                        img.setRGB(x, y, Color.HSBtoRGB(.5f, 1, 1));
                    }
                } else {
                    for (int y = Math.max(point2[1], 0); y <= Math.min(point1[1], img.getHeight() - 1); y += 1) {
                        img.setRGB(x, y, Color.HSBtoRGB(.5f, 1, 1));
                    }
                }
            }
        }
        lastMillis = (System.currentTimeMillis() - lastMillis);
        return (int)lastMillis;
    }
    public void initialise(){
        if (point1 == null || point2 == null || point3 == null){
            throw new NullPointerException();
        }
        min = new Point2D(Math.min(point1.x, Math.min(point2.x, point3.x)), Math.min(point1.y, Math.min(point2.y, point3.y)));
        max = new Point2D(Math.max(point1.x, Math.max(point2.x, point3.x)), Math.max(point1.y, Math.max(point2.y, point3.y)));
        // woo horrible IFs mess.
        // we need to figure out which points touch the edges in order to find which line is the 'full length' edge.
        Point2D realPointA;
        Point2D realPointB;
        Point2D realPointC;
        if (point1.x == min.x) { realPointA = point1;
                if (point2.x == max.x){ realPointB = point2;
                    realPointC = point3;
                } else {
                    realPointB = point3;
                    realPointC = point2;
                }
            }
            else if (point2.x == min.x) { realPointA = point2;
                if (point1.x == max.x) { realPointB = point1;
                    realPointC = point3;
                } else { realPointB = point3;
                    realPointC = point1;
                }
            }
            else {
            realPointA = point3;
                if (point1.x == max.x) { realPointB = point1;
                    realPointC = point2;
                } else { realPointB = point2;
                    realPointC = point1;
                }
            }
        // assign points to lines
        LineLong = new Line(realPointA, realPointB);
        LineA = new Line(realPointA, realPointC);
        LineB = new Line(realPointC, realPointB);

        is_initialised = true;
    }
}