import java.awt.*;
import java.util.*;
import java.io.*;

/**
 * Write a description of class VectorField here.
 *
 * @author (your name)
 * @version (a version number or a date)
 */
public class VectorField
{

    private ArrayList<Polygon> polys = new ArrayList<Polygon>();
    private static final int[] AX_COLOUR = new int[]{127,127,127};
    private int[] arrowColour;

    /**
     * construct0r
     */
    public VectorField(double[][][] coeffs, int[] colour)
    {
        int x,y,i,j;
        double[] current = new double[2];

        arrowColour = colour;   //for reuse later or something idk
        //spawn a shitload of arrows
        for(x=-10; x<=10; x+=2)
            for(y=-10; y<=10; y+=2)
            {
                current[0]=0;current[1]=0;
                for(i=0; i<coeffs.length; i++)
                    for(j=0; j<coeffs[i].length; j++)
                    {
                        current[0]+=coeffs[i][j][0]*Math.pow((double)x,i)*Math.pow((double)y,j);
                        current[1]-=coeffs[i][j][1]*Math.pow((double)x,i)*Math.pow((double)y,j);
                    }
                polys.add(makeArrow(new int[]{320+25*x-(int)(0.5*(current[0]+1)),320-25*y-(int)(0.5*(current[1]+1))},current, colour));
            }

        //draw axes
        ArrayList<Point> yAxis = new ArrayList<Point>(2);
        yAxis.add(new Point(new int[]{320,30}));
        yAxis.add(new Point(new int[]{320,610}));
        polys.add(new Polygon(yAxis, AX_COLOUR, true));

        ArrayList<Point> xAxis = new ArrayList<Point>(2);
        xAxis.add(new Point(new int[]{30,320}));
        xAxis.add(new Point(new int[]{610,320}));
        polys.add(new Polygon(xAxis, AX_COLOUR, true));

    }

    /**
     * default colour constructor
     */
    public VectorField(double[][][] coeffs)
    {
        this(coeffs, new int[]{0,0,0});
    }

    /**
     * Makes an arrow
     */
    public static Polygon makeArrow(int[] offset, double[] length, int[] colour)
    {
        ArrayList<Point> arrow = new ArrayList<Point>(5);
        int[] p0 = new int[]{offset[0],offset[1]};
        int[] p1 = new int[]{offset[0]+(int)(length[0]+0.5),offset[1]+(int)(length[1]+0.5)};
        int[] p2 = new int[]{offset[0]+(int)(0.75*length[0]+0.125*length[1]+0.5),offset[1]+(int)(0.75*length[1]-0.125*length[0]+0.5)};
        int[] p3 = p1;
        int[] p4 = new int[]{offset[0]+(int)(0.75*length[0]-0.125*length[1]+0.5),offset[1]+(int)(0.75*length[1]+0.125*length[0]+0.5)};

        arrow.add(new Point(p0));
        arrow.add(new Point(p1));
        arrow.add(new Point(p2));
        arrow.add(new Point(p3));
        arrow.add(new Point(p4));

        return new Polygon(arrow, colour, false);
    }

    /**
     * can't you even think of a colour
     */
    public static Polygon makeArrow(int[] offset, double[] length)
    {
        return makeArrow(offset, length, new int[]{0,0,0});
    }

    /**
     * Draws
     */
    public void draw(Canvas canvas)
    {
        for(int i=0;i<polys.size();i++)
            polys.get(i).draw(canvas);
    }

    /**
     * Returns a picture of this vector field.
     */
    public Picture toPicture()
    {
        return new Picture(polys);
    }

    /**
     * outputs dis shit to a file
     */
    public void write(String filespec) throws IOException
    {


        File f = new File(filespec);
        f.createNewFile();
        PrintWriter out = new PrintWriter(f);

        out.println("[ placeholder title ]");


        //axes hack

        out.println("c "+AX_COLOUR[0]+" "+AX_COLOUR[1]+" "+AX_COLOUR[2]+" "+
                  polys.get(polys.size()-2).getPoints().get(0).getPosition()[0]+" "+
                  polys.get(polys.size()-2).getPoints().get(0).getPosition()[1]+" "+
                  polys.get(polys.size()-2).getPoints().get(1).getPosition()[0]+" "+
                  polys.get(polys.size()-2).getPoints().get(1).getPosition()[1]);
        out.println("c "+AX_COLOUR[0]+" "+AX_COLOUR[1]+" "+AX_COLOUR[2]+" "+
                  polys.get(polys.size()-1).getPoints().get(0).getPosition()[0]+" "+
                  polys.get(polys.size()-1).getPoints().get(0).getPosition()[1]+" "+
                  polys.get(polys.size()-1).getPoints().get(1).getPosition()[0]+" "+
                  polys.get(polys.size()-1).getPoints().get(1).getPosition()[1]);


        //arrowz
        int s = polys.size()-2;   //leave axes off
        int sp,i,j;
        for (i=0; i<s; i++)
        {
            sp = polys.get(i).getPoints().size();
            out.print("C "+arrowColour[0]+" "+arrowColour[1]+" "+arrowColour[2]+" ");
            for(j = 0;j<sp;j++)
                out.print(polys.get(i).getPoints().get(j).getPosition()[0]+" "+polys.get(i).getPoints().get(j).getPosition()[1]+" ");
            out.println(); //for readability
        }

        out.close();
    }
}