package com.wasu.cs.utils;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.view.View;

/**
 * Created by chenming on 2016/9/19.
 *
 * @Description: fastblur工具类
 * @email chenming@wasu.com
 */

public class FastBlurUtils {
	private static final String TAG = "FastBlurUtils";
	private static float BLUR_DEGREE = 5f;//模糊程度
	private static int BLUR_RADIUS = 4;//模糊半径

	/**
	 * 获得模糊化的背景图片
	 *
	 * @param activity 获取模糊化的背景activity
	 * @return 模糊化的背景图片
	 */
	public static Bitmap getBlurBackgroundDrawer(Activity activity) {
		Bitmap bmp = takeScreenShot(activity);
		return startBlurBackground(bmp);
	}

	/**
	 * 截屏
	 *
	 * @param activity 截屏的activity
	 * @return 截屏图片
	 */
	private static Bitmap takeScreenShot(Activity activity) {
		View view = activity.getWindow().getDecorView();
		view.setDrawingCacheEnabled(true);
		view.buildDrawingCache();
		//Bitmap b1 = view.getDrawingCache();
		Bitmap b1 = view.getDrawingCache(false);


		// 获取屏幕长和高
		int width = activity.getResources().getDisplayMetrics().widthPixels;
		int height = activity.getResources().getDisplayMetrics().heightPixels;

		Bitmap bmp = Bitmap.createBitmap(b1, 0, 0, width, height);
		view.destroyDrawingCache();
		return bmp;
	}

	private static Bitmap startBlurBackground(Bitmap bkg) {
		long startMs = System.currentTimeMillis();
		//float radius = 4; //模糊程度

		Bitmap overlay = fastblur(small(bkg), (int) BLUR_RADIUS);

		//Log.i(TAG, "blur time:" + (System.currentTimeMillis() - startMs));
		return big(overlay);
	}

	/**
	 * 放大图片
	 *
	 * @param bitmap 需要放大的图片
	 * @return 放大的图片
	 */
	private static Bitmap big(Bitmap bitmap) {
		Matrix matrix = new Matrix();
		matrix.postScale(BLUR_DEGREE, BLUR_DEGREE);
		Bitmap resizeBmp = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
		return resizeBmp;
	}

	/**
	 * 缩小图片
	 *
	 * @param bitmap 需要缩小的图片
	 * @return 缩小的图片
	 */
	private static Bitmap small(Bitmap bitmap) {
		Matrix matrix = new Matrix();
		matrix.postScale(1/BLUR_DEGREE, 1/BLUR_DEGREE);
		Bitmap resizeBmp = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
		return resizeBmp;
	}

	/**
	 * 将图片模糊化
	 *
	 * @param sentBitmap 需要模糊的图片
	 * @param radius     模糊程度
	 * @return 模糊后的图片
	 */
	private static Bitmap fastblur(Bitmap sentBitmap, int radius) {

		Bitmap bitmap = sentBitmap.copy(sentBitmap.getConfig(), true);

		if (radius < 1) {
			return (null);
		}

		int w = bitmap.getWidth();
		int h = bitmap.getHeight();

		int[] pix = new int[w * h];
		bitmap.getPixels(pix, 0, w, 0, 0, w, h);

		int wm = w - 1;
		int hm = h - 1;
		int wh = w * h;
		int div = radius + radius + 1;

		int r[] = new int[wh];
		int g[] = new int[wh];
		int b[] = new int[wh];
		int rsum, gsum, bsum, x, y, i, p, yp, yi, yw;
		int vmin[] = new int[Math.max(w, h)];

		int divsum = (div + 1) >> 1;
		divsum *= divsum;
		int dv[] = new int[256 * divsum];
		for (i = 0; i < 256 * divsum; i++) {
			dv[i] = (i / divsum);
		}

		yw = yi = 0;

		int[][] stack = new int[div][3];
		int stackpointer;
		int stackstart;
		int[] sir;
		int rbs;
		int r1 = radius + 1;
		int routsum, goutsum, boutsum;
		int rinsum, ginsum, binsum;

		for (y = 0; y < h; y++) {
			rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
			for (i = -radius; i <= radius; i++) {
				p = pix[yi + Math.min(wm, Math.max(i, 0))];
				sir = stack[i + radius];
				sir[0] = (p & 0xff0000) >> 16;
				sir[1] = (p & 0x00ff00) >> 8;
				sir[2] = (p & 0x0000ff);
				rbs = r1 - Math.abs(i);
				rsum += sir[0] * rbs;
				gsum += sir[1] * rbs;
				bsum += sir[2] * rbs;
				if (i > 0) {
					rinsum += sir[0];
					ginsum += sir[1];
					binsum += sir[2];
				} else {
					routsum += sir[0];
					goutsum += sir[1];
					boutsum += sir[2];
				}
			}
			stackpointer = radius;

			for (x = 0; x < w; x++) {

				r[yi] = dv[rsum];
				g[yi] = dv[gsum];
				b[yi] = dv[bsum];

				rsum -= routsum;
				gsum -= goutsum;
				bsum -= boutsum;

				stackstart = stackpointer - radius + div;
				sir = stack[stackstart % div];

				routsum -= sir[0];
				goutsum -= sir[1];
				boutsum -= sir[2];

				if (y == 0) {
					vmin[x] = Math.min(x + radius + 1, wm);
				}
				p = pix[yw + vmin[x]];

				sir[0] = (p & 0xff0000) >> 16;
				sir[1] = (p & 0x00ff00) >> 8;
				sir[2] = (p & 0x0000ff);

				rinsum += sir[0];
				ginsum += sir[1];
				binsum += sir[2];

				rsum += rinsum;
				gsum += ginsum;
				bsum += binsum;

				stackpointer = (stackpointer + 1) % div;
				sir = stack[(stackpointer) % div];

				routsum += sir[0];
				goutsum += sir[1];
				boutsum += sir[2];

				rinsum -= sir[0];
				ginsum -= sir[1];
				binsum -= sir[2];

				yi++;
			}
			yw += w;
		}
		for (x = 0; x < w; x++) {
			rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
			yp = -radius * w;
			for (i = -radius; i <= radius; i++) {
				yi = Math.max(0, yp) + x;

				sir = stack[i + radius];

				sir[0] = r[yi];
				sir[1] = g[yi];
				sir[2] = b[yi];

				rbs = r1 - Math.abs(i);

				rsum += r[yi] * rbs;
				gsum += g[yi] * rbs;
				bsum += b[yi] * rbs;

				if (i > 0) {
					rinsum += sir[0];
					ginsum += sir[1];
					binsum += sir[2];
				} else {
					routsum += sir[0];
					goutsum += sir[1];
					boutsum += sir[2];
				}

				if (i < hm) {
					yp += w;
				}
			}
			yi = x;
			stackpointer = radius;
			for (y = 0; y < h; y++) {
				pix[yi] = (0xff000000 & pix[yi]) | (dv[rsum] << 16) | (dv[gsum] << 8) | dv[bsum];

				rsum -= routsum;
				gsum -= goutsum;
				bsum -= boutsum;

				stackstart = stackpointer - radius + div;
				sir = stack[stackstart % div];

				routsum -= sir[0];
				goutsum -= sir[1];
				boutsum -= sir[2];

				if (x == 0) {
					vmin[y] = Math.min(y + r1, hm) * w;
				}
				p = x + vmin[y];

				sir[0] = r[p];
				sir[1] = g[p];
				sir[2] = b[p];

				rinsum += sir[0];
				ginsum += sir[1];
				binsum += sir[2];

				rsum += rinsum;
				gsum += ginsum;
				bsum += binsum;

				stackpointer = (stackpointer + 1) % div;
				sir = stack[stackpointer];

				routsum += sir[0];
				goutsum += sir[1];
				boutsum += sir[2];

				rinsum -= sir[0];
				ginsum -= sir[1];
				binsum -= sir[2];

				yi += w;
			}
		}

		bitmap.setPixels(pix, 0, w, 0, 0, w, h);

		return (bitmap);
	}
}