/*
 * Copyright (C) 2008 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.zxing.view;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.ComposeShader;
import android.graphics.LinearGradient;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.RadialGradient;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.Shader;
import android.graphics.SweepGradient;
import android.util.AttributeSet;
import android.view.View;

import com.google.zxing.R;
import com.google.zxing.ResultPoint;
import com.google.zxing.camera.CameraManager;


import java.util.Collection;
import java.util.HashSet;


/**
 * This view is overlaid on top of the camera preview. It adds the viewfinder rectangle and partial
 * transparency outside it, as well as the laser scanner animation and result points.
 * �Զ����View������ʱ�м���ʾ��
 */
public final class ViewfinderView extends View {

  private static final int[]  SCANNER_ALPHA                 =   {0, 64, 128, 192, 255, 192, 128, 64};
  private static final long   ANIMATION_DELAY               =   10L;
  private static final int    OPAQUE                        =   0xFF;
  private static final int    CORNER_RECT_WIDTH             =   8;  //扫描区边角的宽
  private static final int    CORNER_RECT_HEIGHT            =   40; //扫描区边角的高
  private static final int    SCANNER_LINE_MOVE_DISTANCE    =   5;  //扫描线移动距离
  private static final int    SCANNER_LINE_HEIGHT           =   10;  //扫描线宽度

  private final Paint paint;
  private Bitmap resultBitmap;
  //模糊区域颜色
  private final int maskColor;
  private final int resultColor;
  //扫描区域边框颜色
  private final int frameColor;
  //扫描线颜色
  private final int laserColor;
  //四角颜色
  private final int cornerColor;
  //扫描点的颜色
  private final int resultPointColor;
  private int scannerAlpha;
  //扫描区域提示文本
  private final String labelText;
  //扫描区域提示文本颜色
  private final int labelTextColor;
  private final float labelTextSize;

  public static int scannerStart = 0;
  public static int scannerEnd = 0;

  private Collection<ResultPoint> possibleResultPoints;
  private Collection<ResultPoint> lastPossibleResultPoints;

  // This constructor is used when the class is built from an XML resource.
  public ViewfinderView(Context context, AttributeSet attrs) {
    super(context, attrs);

    //初始化自定义属性信息
    TypedArray array = context.obtainStyledAttributes(attrs, R.styleable.ViewfinderView);
    laserColor = array.getColor(R.styleable.ViewfinderView_laser_color, 0x00FF00);
    cornerColor = array.getColor(R.styleable.ViewfinderView_corner_color, 0x00FF00);
    frameColor = array.getColor(R.styleable.ViewfinderView_frame_color, 0xFFFFFF);
    resultPointColor = array.getColor(R.styleable.ViewfinderView_result_point_color, 0xC0FFFF00);
    maskColor = array.getColor(R.styleable.ViewfinderView_mask_color, 0x60000000);
    resultColor = array.getColor(R.styleable.ViewfinderView_result_color, 0xB0000000);
    labelTextColor = array.getColor(R.styleable.ViewfinderView_label_text_color, 0x90FFFFFF);
    labelText = array.getString(R.styleable.ViewfinderView_label_text);
    labelTextSize = array.getFloat(R.styleable.ViewfinderView_label_text_size, 36f);

    // Initialize these once for performance rather than calling them every time in onDraw().
    paint = new Paint();
    paint.setAntiAlias(true);
    scannerAlpha = 0;
    possibleResultPoints = new HashSet<ResultPoint>(5);


  }

  @Override
  public void onDraw(Canvas canvas) {
    Rect frame = CameraManager.get().getFramingRect();
    if (frame == null) {
      return;
    }
    if(scannerStart == 0 || scannerEnd == 0) {
      scannerStart = frame.top;
      scannerEnd = frame.bottom;
    }

    int width = canvas.getWidth();
    int height = canvas.getHeight();
    // Draw the exterior (i.e. outside the framing rect) darkened
    drawExterior(canvas, frame, width, height);


    if (resultBitmap != null) {
      // Draw the opaque result bitmap over the scanning rectangle
      paint.setAlpha(OPAQUE);
      canvas.drawBitmap(resultBitmap, frame.left, frame.top, paint);
    } else {
      // Draw a two pixel solid black border inside the framing rect
      drawFrame(canvas, frame);
      // 绘制边角
      drawCorner(canvas, frame);
      //绘制提示信息
      drawTextInfo(canvas, frame);
      // Draw a red "laser scanner" line through the middle to show decoding is active
      drawLaserScanner(canvas, frame);

      Collection<ResultPoint> currentPossible = possibleResultPoints;
      Collection<ResultPoint> currentLast = lastPossibleResultPoints;
      if (currentPossible.isEmpty()) {
        lastPossibleResultPoints = null;
      } else {
        possibleResultPoints = new HashSet<ResultPoint>(5);
        lastPossibleResultPoints = currentPossible;
        paint.setAlpha(OPAQUE);
        paint.setColor(resultPointColor);
        for (ResultPoint point : currentPossible) {
          canvas.drawCircle(frame.left + point.getX(), frame.top + point.getY(), 6.0f, paint);
        }
      }
      if (currentLast != null) {
        paint.setAlpha(OPAQUE / 2);
        paint.setColor(resultPointColor);
        for (ResultPoint point : currentLast) {
          canvas.drawCircle(frame.left + point.getX(), frame.top + point.getY(), 3.0f, paint);
        }
      }

      // Request another update at the animation interval, but only repaint the laser line,
      // not the entire viewfinder mask.
      //指定重绘区域，该方法会在子线程中执行
      postInvalidateDelayed(ANIMATION_DELAY, frame.left, frame.top, frame.right, frame.bottom);
    }
  }

  //绘制文本
  private void drawTextInfo(Canvas canvas, Rect frame) {
    paint.setColor(labelTextColor);
    paint.setTextSize(labelTextSize);
    paint.setTextAlign(Paint.Align.CENTER);
    canvas.drawText(labelText, frame.left + frame.width() / 2, frame.top - CORNER_RECT_HEIGHT, paint);
  }


  //绘制边角
  private void drawCorner(Canvas canvas, Rect frame) {
    paint.setColor(cornerColor);
    //左上
    canvas.drawRect(frame.left, frame.top, frame.left + CORNER_RECT_WIDTH, frame.top + CORNER_RECT_HEIGHT, paint);
    canvas.drawRect(frame.left, frame.top, frame.left + CORNER_RECT_HEIGHT, frame.top + CORNER_RECT_WIDTH, paint);
    //右上
    canvas.drawRect(frame.right - CORNER_RECT_WIDTH, frame.top, frame.right, frame.top + CORNER_RECT_HEIGHT, paint);
    canvas.drawRect(frame.right - CORNER_RECT_HEIGHT, frame.top, frame.right, frame.top + CORNER_RECT_WIDTH, paint);
    //左下
    canvas.drawRect(frame.left, frame.bottom - CORNER_RECT_WIDTH, frame.left + CORNER_RECT_HEIGHT, frame.bottom, paint);
    canvas.drawRect(frame.left, frame.bottom - CORNER_RECT_HEIGHT, frame.left + CORNER_RECT_WIDTH, frame.bottom, paint);
    //右下
    canvas.drawRect(frame.right - CORNER_RECT_WIDTH, frame.bottom - CORNER_RECT_HEIGHT, frame.right, frame.bottom, paint);
    canvas.drawRect(frame.right - CORNER_RECT_HEIGHT, frame.bottom - CORNER_RECT_WIDTH, frame.right, frame.bottom, paint);
  }

  //绘制扫描线
  private void drawLaserScanner(Canvas canvas, Rect frame) {
    paint.setColor(laserColor);
    //扫描线闪烁效果
//    paint.setAlpha(SCANNER_ALPHA[scannerAlpha]);
//    scannerAlpha = (scannerAlpha + 1) % SCANNER_ALPHA.length;
//    int middle = frame.height() / 2 + frame.top;
//    canvas.drawRect(frame.left + 2, middle - 1, frame.right - 1, middle + 2, paint);
    //线性渐变
    LinearGradient linearGradient = new LinearGradient(
            frame.left, scannerStart,
            frame.left, scannerStart + SCANNER_LINE_HEIGHT,
            shadeColor(laserColor),
            laserColor,
            Shader.TileMode.MIRROR);

    RadialGradient radialGradient = new RadialGradient(
            (float)(frame.left + frame.width() / 2),
            (float)(scannerStart + SCANNER_LINE_HEIGHT / 2),
              360f,
            laserColor,
            shadeColor(laserColor),
            Shader.TileMode.MIRROR);

    SweepGradient sweepGradient = new SweepGradient(
            (float)(frame.left + frame.width() / 2),
            (float)(scannerStart + SCANNER_LINE_HEIGHT),
            shadeColor(laserColor),
            laserColor);

    ComposeShader composeShader = new ComposeShader(radialGradient, linearGradient, PorterDuff.Mode.ADD);

    paint.setShader(radialGradient);
    if(scannerStart <= scannerEnd) {
      //矩形
//      canvas.drawRect(frame.left, scannerStart, frame.right, scannerStart + SCANNER_LINE_HEIGHT, paint);
      //椭圆
      RectF rectF = new RectF(frame.left + 2 * SCANNER_LINE_HEIGHT, scannerStart, frame.right - 2 * SCANNER_LINE_HEIGHT, scannerStart + SCANNER_LINE_HEIGHT);
      canvas.drawOval(rectF, paint);
      scannerStart += SCANNER_LINE_MOVE_DISTANCE;
    } else {
      scannerStart = frame.top;
    }
    paint.setShader(null);
  }

  //处理颜色模糊
  public int shadeColor(int color) {
    String hax = Integer.toHexString(color);
    String result = "20"+hax.substring(2);
    return Integer.valueOf(result, 16);
  }

  // 绘制扫描区边框 Draw a two pixel solid black border inside the framing rect
  private void drawFrame(Canvas canvas, Rect frame) {
    paint.setColor(frameColor);
    canvas.drawRect(frame.left, frame.top, frame.right + 1, frame.top + 2, paint);
    canvas.drawRect(frame.left, frame.top + 2, frame.left + 2, frame.bottom - 1, paint);
    canvas.drawRect(frame.right - 1, frame.top, frame.right + 1, frame.bottom - 1, paint);
    canvas.drawRect(frame.left, frame.bottom - 1, frame.right + 1, frame.bottom + 1, paint);
  }

  // 绘制模糊区域 Draw the exterior (i.e. outside the framing rect) darkened
  private void drawExterior(Canvas canvas, Rect frame, int width, int height) {
    paint.setColor(resultBitmap != null ? resultColor : maskColor);
    canvas.drawRect(0, 0, width, frame.top, paint);
    canvas.drawRect(0, frame.top, frame.left, frame.bottom + 1, paint);
    canvas.drawRect(frame.right + 1, frame.top, width, frame.bottom + 1, paint);
    canvas.drawRect(0, frame.bottom + 1, width, height, paint);
  }

  public void drawViewfinder() {
    resultBitmap = null;
    invalidate();
  }

  /**
   * Draw a bitmap with the result points highlighted instead of the live scanning display.
   *
   * @param barcode An image of the decoded barcode.
   */
  public void drawResultBitmap(Bitmap barcode) {
    resultBitmap = barcode;
    invalidate();
  }

  public void addPossibleResultPoint(ResultPoint point) {
    possibleResultPoints.add(point);
  }

}
