package com.hzjr.widget;

import android.content.Context;
import android.graphics.Matrix;
import android.graphics.RectF;
import android.graphics.drawable.Drawable;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.ScaleGestureDetector.OnScaleGestureListener;
import android.view.View;
import android.view.View.OnTouchListener;
import android.view.ViewConfiguration;
import android.view.ViewTreeObserver.OnGlobalLayoutListener;

import com.hzjr.ui.activity.BorrowerImageActivity;

/**
 * Created by zjw on 2017/10/20 0020.
 */

public class ZoomImageView extends android.support.v7.widget.AppCompatImageView implements OnGlobalLayoutListener,
        OnScaleGestureListener, OnTouchListener{
    private boolean mOnce;

/**
 * 初始化时缩放的值
 */
private float mInitScale;

/**
 * 双击放大值到达的值
 */
private float mMidScale;

/**
 * 放大的最大值
 */
private float mMaxScale;

private Matrix mScaleMatrix;

/**
 * 捕获用户多指触控时缩放的比例
 */
private ScaleGestureDetector mScaleGestureDetector;

// **********自由移动的变量***********
/**
 * 记录上一次多点触控的数量
 */
private int mLastPointerCount;

private float mLastX;
private float mLastY;

private int mTouchSlop;
private boolean isCanDrag;

private boolean isCheckLeftAndRight;
private boolean isCheckTopAndBottom;

// *********双击放大与缩小*********
private GestureDetector mGestureDetector;

private boolean isAutoScale;
private Context mContext;
public ZoomImageView(Context context) {
    this(context, null);
    mContext=context;
}

public ZoomImageView(Context context, AttributeSet attrs) {
    this(context, attrs, 0);
}

public ZoomImageView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    // init
    mScaleMatrix = new Matrix();
    setScaleType(ScaleType.MATRIX);
    setOnTouchListener(this);
    mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();
    mScaleGestureDetector = new ScaleGestureDetector(context, this);
    mGestureDetector = new GestureDetector(context,
            new GestureDetector.SimpleOnGestureListener() {
                //单击退出
                @Override
                public boolean onSingleTapConfirmed(MotionEvent e) {
                    ((BorrowerImageActivity)mContext).finish();
                    return super.onSingleTapConfirmed(e);
                }
                @Override
                public boolean onDoubleTap(MotionEvent e) {

                    if (isAutoScale) {
                        return true;
                    }

                    float x = e.getX();
                    float y = e.getY();

                    if (getScale() < mMidScale) {
                        postDelayed(new AutoScaleRunnable(mMidScale, x, y), 16);
                        isAutoScale = true;
                    } else {
                        postDelayed(new AutoScaleRunnable(mInitScale, x, y), 16);
                        isAutoScale = true;
                    }
                    return true;
                }
            });
}



/**
 * 自动放大与缩小
 *
 * @author zhangyan@lzt.com.cn
 *
 */
private class AutoScaleRunnable implements Runnable {
    /**
     * 缩放的目标值
     */
    private float mTargetScale;
    // 缩放的中心点
    private float x;
    private float y;

    private final float BIGGER = 1.07f;
    private final float SMALL = 0.93f;

    private float tmpScale;

    /**
     * @param mTargetScale
     * @param x
     * @param y
     */
    public AutoScaleRunnable(float mTargetScale, float x, float y) {
        this.mTargetScale = mTargetScale;
        this.x = x;
        this.y = y;

        if (getScale() < mTargetScale) {
            tmpScale = BIGGER;
        }
        if (getScale() > mTargetScale) {
            tmpScale = SMALL;
        }
    }

    @Override
    public void run() {
        //进行缩放
        mScaleMatrix.postScale(tmpScale, tmpScale, x, y);
        checkBorderAndCenterWhenScale();
        setImageMatrix(mScaleMatrix);

        float currentScale = getScale();

        if ((tmpScale >1.0f && currentScale <mTargetScale) ||(tmpScale<1.0f &&currentScale>mTargetScale)) {
            //这个方法是重新调用run()方法
            postDelayed(this, 16);
        }else{
            //设置为我们的目标值
            float scale = mTargetScale/currentScale;
            mScaleMatrix.postScale(scale, scale, x, y);
            checkBorderAndCenterWhenScale();
            setImageMatrix(mScaleMatrix);

            isAutoScale = false;
        }
    }
}

/**
 * 获取ImageView加载完成的图片
 */
@Override
public void onGlobalLayout() {
    if (!mOnce) {
        // 得到控件的宽和高
        int width = getWidth();
        int height = getHeight();

        // 得到我们的图片，以及宽和高
        Drawable drawable = getDrawable();
        if (drawable == null) {
            return;
        }
        int dh = drawable.getIntrinsicHeight();
        int dw = drawable.getIntrinsicWidth();

        float scale = 1.0f;

        // 图片的宽度大于控件的宽度，图片的高度小于空间的高度，我们将其缩小
        if (dw > width && dh < height) {
            scale = width * 1.0f / dw;
        }

        // 图片的宽度小于控件的宽度，图片的高度大于空间的高度，我们将其缩小
        if (dh > height && dw < width) {
            scale = height * 1.0f / dh;
        }

        // 缩小值
        if (dw > width && dh > height) {
            scale = Math.min(width * 1.0f / dw, height * 1.0f / dh);
        }

        // 放大值
        if (dw < width && dh < height) {
            scale = Math.min(width * 1.0f / dw, height * 1.0f / dh);
        }

        /**
         * 得到了初始化时缩放的比例
         */
        mInitScale = scale;
        mMaxScale = mInitScale * 4;
        mMidScale = mInitScale * 2;

        // 将图片移动至控件的中间
        int dx = getWidth() / 2 - dw / 2;
        int dy = getHeight() / 2 - dh / 2;

        mScaleMatrix.postTranslate(dx, dy);
        mScaleMatrix.postScale(mInitScale, mInitScale, width / 2,
                height / 2);
        setImageMatrix(mScaleMatrix);

        mOnce = true;
    }
}

/**
 * 注册OnGlobalLayoutListener这个接口
 */
@Override
protected void onAttachedToWindow() {
    super.onAttachedToWindow();
    getViewTreeObserver().addOnGlobalLayoutListener(this);
}

/**
 * 取消OnGlobalLayoutListener这个接口
 */
@SuppressWarnings("deprecation")
@Override
protected void onDetachedFromWindow() {
    super.onDetachedFromWindow();
    getViewTreeObserver().removeGlobalOnLayoutListener(this);
}

/**
 * 获取当前图片的缩放值
 *
 * @return
 */
public float getScale() {
    float[] values = new float[9];
    mScaleMatrix.getValues(values);
    return values[Matrix.MSCALE_X];
}

// 缩放区间时initScale maxScale
@Override
public boolean onScale(ScaleGestureDetector detector) {
    float scale = getScale();
    float scaleFactor = detector.getScaleFactor();

    if (getDrawable() == null) {
        return true;
    }

    // 缩放范围的控制
    if ((scale < mMaxScale && scaleFactor > 1.0f)
            || (scale > mInitScale && scaleFactor < 1.0f)) {
        if (scale * scaleFactor < mInitScale) {
            scaleFactor = mInitScale / scale;
        }

        if (scale * scaleFactor > mMaxScale) {
            scale = mMaxScale / scale;
        }

        // 缩放
        mScaleMatrix.postScale(scaleFactor, scaleFactor,
                detector.getFocusX(), detector.getFocusY());

        checkBorderAndCenterWhenScale();

        setImageMatrix(mScaleMatrix);
    }

    return true;
}

/**
 * 获得图片放大缩小以后的宽和高，以及left，right，top，bottom
 *
 * @return
 */
private RectF getMatrixRectF() {
    Matrix matrix = mScaleMatrix;
    RectF rectF = new RectF();
    Drawable d = getDrawable();
    if (d != null) {
        rectF.set(0, 0, d.getIntrinsicWidth(), d.getIntrinsicHeight());
        matrix.mapRect(rectF);
    }
    return rectF;
}

/**
 * 在缩放的时候进行边界以及我们的位置的控制
 */
private void checkBorderAndCenterWhenScale() {
    RectF rectF = getMatrixRectF();
    float deltaX = 0;
    float deltaY = 0;

    int width = getWidth();
    int height = getHeight();

    // 缩放时进行边界检测，防止出现白边
    if (rectF.width() >= width) {
        if (rectF.left > 0) {
            deltaX = -rectF.left;
        }
        if (rectF.right < width) {
            deltaX = width - rectF.right;
        }
    }

    if (rectF.height() >= height) {
        if (rectF.top > 0) {
            deltaY = -rectF.top;
        }
        if (rectF.bottom < height) {
            deltaY = height - rectF.bottom;
        }
    }

    /**
     * 如果宽度或高度小于空间的宽或者高，则让其居中
     */
    if (rectF.width() < width) {
        deltaX = width / 2f - rectF.right + rectF.width() / 2f;
    }

    if (rectF.height() < height) {
        deltaY = height / 2f - rectF.bottom + rectF.height() / 2f;
    }

    mScaleMatrix.postTranslate(deltaX, deltaY);
}

@Override
public boolean onScaleBegin(ScaleGestureDetector detector) {

    return true;
}

@Override
public void onScaleEnd(ScaleGestureDetector detector) {

}

@Override
public boolean onTouch(View v, MotionEvent event) {

    if (mGestureDetector.onTouchEvent(event)) {
        return true;
    }

    mScaleGestureDetector.onTouchEvent(event);

    float x = 0;
    float y = 0;
    // 拿到多点触控的数量
    int pointerCount = event.getPointerCount();
    for (int i = 0; i < pointerCount; i++) {
        x += event.getX(i);
        y += event.getY(i);
    }

    x /= pointerCount;
    y /= pointerCount;

    if (mLastPointerCount != pointerCount) {
        isCanDrag = false;
        mLastX = x;
        mLastY = y;
    }
    mLastPointerCount = pointerCount;
    RectF rectF = getMatrixRectF();
    switch (event.getAction()) {

        case MotionEvent.ACTION_DOWN:
            if (rectF.width()>getWidth() +0.01|| rectF.height()>getHeight()+0.01) {
                if(getParent() instanceof ViewPager)
                    getParent().requestDisallowInterceptTouchEvent(true);
            }
            break;

        case MotionEvent.ACTION_MOVE:
            if (rectF.width()>getWidth()+0.01 || rectF.height()>getHeight()+0.01) {
                if(getParent() instanceof ViewPager)
                    getParent().requestDisallowInterceptTouchEvent(true);
            }
            float dx = x - mLastX;
            float dy = y - mLastY;

            if (!isCanDrag) {
                isCanDrag = isMoveAction(dx, dy);
            }

            if (isCanDrag) {
                if (getDrawable() != null) {
                    isCheckLeftAndRight = isCheckTopAndBottom = true;
                    // 如果宽度小于控件宽度，不允许横向移动
                    if (rectF.width() < getWidth()) {
                        isCheckLeftAndRight = false;
                        dx = 0;
                    }
                    // 如果高度小于控件高度，不允许纵向移动
                    if (rectF.height() < getHeight()) {
                        isCheckTopAndBottom = false;
                        dy = 0;
                    }
                    mScaleMatrix.postTranslate(dx, dy);

                    checkBorderWhenTranslate();

                    setImageMatrix(mScaleMatrix);
                }
            }
            mLastX = x;
            mLastY = y;
            break;
        case MotionEvent.ACTION_UP:
        case MotionEvent.ACTION_CANCEL:
            mLastPointerCount = 0;
            break;

        default:
            break;
    }

    return true;
}

/**
 * 当移动时进行边界检查
 */
private void checkBorderWhenTranslate() {
    RectF rectF = getMatrixRectF();
    float deltaX = 0;
    float deltaY = 0;

    int width = getWidth();
    int heigth = getHeight();

    if (rectF.top > 0 && isCheckTopAndBottom) {
        deltaY = -rectF.top;
    }
    if (rectF.bottom < heigth && isCheckTopAndBottom) {
        deltaY = heigth - rectF.bottom;
    }
    if (rectF.left > 0 && isCheckLeftAndRight) {
        deltaX = -rectF.left;
    }
    if (rectF.right < width && isCheckLeftAndRight) {
        deltaX = width - rectF.right;
    }
    mScaleMatrix.postTranslate(deltaX, deltaY);

}

/**
 * 判断是否是move
 *
 * @param dx
 * @param dy
 * @return
 */
private boolean isMoveAction(float dx, float dy) {
    return Math.sqrt(dx * dx + dy * dy) > mTouchSlop;
}
}