package mm.structures;

import java.util.Random;

/**
 * Square matrix (n x n) of m (colorCount) colors.
 */
public class ColorField extends Matrix {

    private int n, colorCount;
    private int[][] neighbourMask;
    private ColorPixel[] colors;

    /**
     * Initialize mm.structures.ColorField as n x n matrix using given colors array as colors.
     *
     * @param n      - Dimension of matrix.
     * @param colors - Colors to be used in field.
     */
    public ColorField(int n, ColorPixel[] colors) {
        super(n);
        init(colors, true);
    }

    private ColorField(int n, ColorPixel[] colors, int[][] neighbourMask) {
        super(n);
        this.neighbourMask = neighbourMask;
        init(colors, false);
    }

    /**
     * Initialize mm.structures.ColorField as n x n matrix using given colors array as colors.
     *
     * @param array  - Array representing the field matrix.
     * @param colors - Colors to be used in field.
     */
    private ColorField(int[][] array, ColorPixel[] colors) {
        super(array);
        colors = colors != null ? colors : new ColorPixel[0];
        init(colors, true);
    }

    /**
     * Initialize colors array and color map (array of ints representing colors).
     * @param colors - Colors to be used in field.
     */
    private void init(ColorPixel[] colors, boolean calculateNeighbourMask) {
        this.n = super.n;
        this.colors = colors;
        this.colorCount = colors.length;
        // Set codes for each color.
        for(int i = 0; i < colorCount; i++) {
            colors[i].setCode(i);
        }
        if(calculateNeighbourMask) {
            // Calculate neighbourMask array in advance, used to improve performance
            //  compared to calculating indices for every `getNeighbours` lookup.
            neighbourMask = new int[super.length][8];
            for (int i = 0, index = 0; i < m; i++) {
                for (int j = 0; j < n; j++, index++) {
                    for (int ii = i - 1, ind = 0; ii <= i + 1; ii++) {
                        for (int jj = j - 1; jj <= j + 1; jj++) {
                            if (ii == i && jj == j) {
                                continue;
                            }
                            neighbourMask[index][ind++] =
                                    ((ii < 0 || ii >= m) || (jj < 0 || jj >= n))
                                            ? -1 : indexOf(ii, jj);
                        }
                    }
                }
            }
        }
    }

    public int getN() {
        return n;
    }

    public int getColorCount() {
        return colorCount;
    }

    public ColorPixel[] getColors() {
        return colors;
    }

    /**
     * Find values of neighbours of (i, j).
     *
     * @param i - mm.structures.Matrix row.
     * @param j - mm.structures.Matrix column.
     * @return - Vector (1x8) of neighbours. If neighbour index is out of bounds, -1 is used as value.
     */
    public int[] getNeighbours(int i, int j) {
        int[] map = neighbourMask[indexOf(i, j)];
        int[] neighbours = new int[8];
        for (int ii = 0; ii < 8; ii++) {
            neighbours[ii] = map[ii] == -1 ? -1 : a[map[ii]];
        }
        return neighbours;
    }

    public static ColorField GenerateField(int n, ColorPixel[] colors) {
        ColorField cf = new ColorField(n, colors);
        Random r = new Random();
        for(int i = 0; i < cf.length; i++) {
            cf.setElement(i, colors[r.nextInt(cf.colorCount)].getCode());
        }
        return cf;
    }
}

@@ -17,16 +17,41 @@
 tures;%0A%0A
+import java.util.Arrays;%0A
 import j
@@ -3041,24 +3041,116 @@
 i, int j) %7B%0A
+        return getNeighbours(indexOf(i, j));%0A    %7D%0A%0A    public int%5B%5D getNeighbours(int i) %7B%0A
         int%5B
@@ -3172,28 +3172,16 @@
 urMask%5Bi
-ndexOf(i, j)
 %5D;%0A     
@@ -3210,24 +3210,53 @@
 new int%5B8%5D;%0A
+        int existsCount = 0;%0A
         for 
@@ -3300,57 +3300,97 @@
     
-neighbours%5Bii
+if(map%5Bii%5D != -1) %7B%0A                neighbours%5BexistsCount++
 %5D = 
+a%5B
 map%5Bii%5D
- == -1 ? -1 : a%5Bmap%5Bii%5D%5D;
+%5D;%0A            %7D
 %0A   
@@ -3415,19 +3415,63 @@
 urn 
-neighbours;
+Arrays.copyOf(neighbours, existsCount);%0A    %7D%0A        %7D
 %0A   

change getNeighbours to return existing only