package io.swtc.proccessing;

import java.util.stream.IntStream;

public class DenoiseProccessor {

    public int[] process(int[] srcPixels, int width, int height, float strength) {
        if (strength <= 0) return srcPixels;

        int[] dstPixels = new int[srcPixels.length];
        int[] tempPixels = new int[srcPixels.length];

        int radius = (int) (strength / 100f * 2) + 1;

        // Pass 1: Horizontal
        IntStream.range(0, height).parallel().forEach(y ->
            blurLine(srcPixels, tempPixels, width, height, y, radius, true)
        );

        // Pass 2: Vertical
        IntStream.range(0, width).parallel().forEach(x ->
            blurLine(tempPixels, dstPixels, width, height, x, radius, false)
        );

        return dstPixels;
    }

    private void blurLine(int[] src, int[] dest, int w, int h, int lineIndex, int radius, boolean horizontal) {
        int length = horizontal ? w : h;
        int limit = length - 1;

        for (int i = 0; i < length; i++) {
            long rSum = 0, gSum = 0, bSum = 0;
            int count = 0;
            int start = Math.max(0, i - radius);
            int end = Math.min(limit, i + radius);

            for (int k = start; k <= end; k++) {
                int idx = horizontal ? (lineIndex * w + k) : (k * w + lineIndex);
                int rgb = src[idx];
                rSum += (rgb >> 16) & 0xFF;
                gSum += (rgb >> 8) & 0xFF;
                bSum += rgb & 0xFF;
                count++;
            }

            int targetIdx = horizontal ? (lineIndex * w + i) : (i * w + lineIndex);
            dest[targetIdx] = ((int)(rSum/count) << 16) | ((int)(gSum/count) << 8) | (int)(bSum/count);
        }
    }
}