package connect.view.clip;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.RectF;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.GestureDetector;
import android.view.GestureDetector.SimpleOnGestureListener;
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.ViewTreeObserver;
import android.widget.ImageView;

public class ClipZoomImageView extends ImageView implements OnScaleGestureListener, OnTouchListener,
        ViewTreeObserver.OnGlobalLayoutListener {

    private static final String TAG = ClipZoomImageView.class.getSimpleName();
    public static float SCALE_MAX = 4.0f;
    private static float SCALE_MID = 2.0f;

    /**
     * The scale of initialization, if the picture is wider or higher than the screen, this value will be less than 0
     */
    private float initScale = 1.0f;
    private boolean once = true;

    /**
     * 9 values for storing matrices
     */
    private final float[] matrixValues = new float[9];

    /**
     * Zoom gesture detection
     */
    private ScaleGestureDetector mScaleGestureDetector = null;
    private final Matrix mScaleMatrix = new Matrix();

    /**
     * Double click detection
     */
    private GestureDetector mGestureDetector;
    private boolean isAutoScale;

    private int mTouchSlop;

    private float mLastX;
    private float mLastY;

    private boolean isCanDrag;
    private int lastPointerCount;

    public ClipZoomImageView(Context context) {
        this(context, null);
    }

    public ClipZoomImageView(Context context, AttributeSet attrs) {
        super(context, attrs);

        setScaleType(ScaleType.MATRIX);
        mGestureDetector = new GestureDetector(context,
                new SimpleOnGestureListener() {
                    @Override
                    public boolean onDoubleTap(MotionEvent e) {
                        if (isAutoScale)
                            return true;

                        float x = e.getX();
                        float y = e.getY();
                        if (getScale() < SCALE_MID) {
                            ClipZoomImageView.this.postDelayed(
                                    new AutoScaleRunnable(SCALE_MID, x, y), 16);
                            isAutoScale = true;
                        } else {
                            ClipZoomImageView.this.postDelayed(
                                    new AutoScaleRunnable(initScale, x, y), 16);
                            isAutoScale = true;
                        }

                        return true;
                    }
                });
        mScaleGestureDetector = new ScaleGestureDetector(context, this);
        this.setOnTouchListener(this);
    }

    /**
     * Automatic scaling task
     */
    private class AutoScaleRunnable implements Runnable {
        static final float BIGGER = 1.07f;
        static final float SMALLER = 0.93f;
        private float mTargetScale;
        private float tmpScale;

        /**
         * Zoom Center
         */
        private float x;
        private float y;

        /**
         * Zoom in on the target, according to the target value and the current value, judge should be enlarged or reduced
         *
         * @param targetScale
         */
        public AutoScaleRunnable(float targetScale, float x, float y) {
            this.mTargetScale = targetScale;
            this.x = x;
            this.y = y;
            if (getScale() < mTargetScale) {
                tmpScale = BIGGER;
            } else {
                tmpScale = SMALLER;
            }

        }

        @Override
        public void run() {
            mScaleMatrix.postScale(tmpScale, tmpScale, x, y);
            checkBorder();
            setImageMatrix(mScaleMatrix);

            final float currentScale = getScale();
            if (((tmpScale > 1f) && (currentScale < mTargetScale))
                    || ((tmpScale < 1f) && (mTargetScale < currentScale))) {
                ClipZoomImageView.this.postDelayed(this, 16);
            } else {
                final float deltaScale = mTargetScale / currentScale;
                mScaleMatrix.postScale(deltaScale, deltaScale, x, y);
                checkBorder();
                setImageMatrix(mScaleMatrix);
                isAutoScale = false;
            }

        }
    }

    @Override
    public boolean onScale(ScaleGestureDetector detector) {
        float scale = getScale();
        float scaleFactor = detector.getScaleFactor();

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

        if ((scale < SCALE_MAX && scaleFactor > 1.0f)
                || (scale > initScale && scaleFactor < 1.0f)) {

            if (scaleFactor * scale < initScale) {
                scaleFactor = initScale / scale;
            }
            if (scaleFactor * scale > SCALE_MAX) {
                scaleFactor = SCALE_MAX / scale;
            }

            mScaleMatrix.postScale(scaleFactor, scaleFactor,
                    detector.getFocusX(), detector.getFocusY());
            checkBorder();
            setImageMatrix(mScaleMatrix);
        }
        return true;

    }

    /**
     * According to the current image of the Matrix to obtain the scope of the picture
     *
     * @return
     */
    private RectF getMatrixRectF() {
        Matrix matrix = mScaleMatrix;
        RectF rect = new RectF();
        Drawable d = getDrawable();
        if (null != d) {
            rect.set(0, 0, d.getIntrinsicWidth(), d.getIntrinsicHeight());
            matrix.mapRect(rect);
        }
        return rect;
    }

    @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, y = 0;
        final int pointerCount = event.getPointerCount();
        for (int i = 0; i < pointerCount; i++) {
            x += event.getX(i);
            y += event.getY(i);
        }
        x = x / pointerCount;
        y = y / pointerCount;

        if (pointerCount != lastPointerCount) {
            isCanDrag = false;
            mLastX = x;
            mLastY = y;
        }

        lastPointerCount = pointerCount;
        switch (event.getAction()) {
            case MotionEvent.ACTION_MOVE:
                float dx = x - mLastX;
                float dy = y - mLastY;

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

                        RectF rectF = getMatrixRectF();
                        if (rectF.width() <= getWidth() - mHorizontalPadding * 2) {
                            dx = 0;
                        }
                        if (rectF.height() <= getHeight() - mVerticalPadding * 2) {
                            dy = 0;
                        }
                        mScaleMatrix.postTranslate(dx, dy);
                        checkBorder();
                        setImageMatrix(mScaleMatrix);
                    }
                }
                mLastX = x;
                mLastY = y;
                break;

            case MotionEvent.ACTION_UP:
            case MotionEvent.ACTION_CANCEL:
                lastPointerCount = 0;
                break;
        }

        return true;
    }

    /**
     * Get the current scaling
     *
     * @return
     */
    public final float getScale() {
        mScaleMatrix.getValues(matrixValues);
        return matrixValues[Matrix.MSCALE_X];
    }

    @Override
    protected void onAttachedToWindow() {
        super.onAttachedToWindow();
        getViewTreeObserver().addOnGlobalLayoutListener(this);
    }

    @SuppressWarnings("deprecation")
    @Override
    protected void onDetachedFromWindow() {
        super.onDetachedFromWindow();
        getViewTreeObserver().removeGlobalOnLayoutListener(this);
    }

    private int mHorizontalPadding;
    private int mVerticalPadding;

    @Override
    public void onGlobalLayout() {
        if (once) {
            Drawable d = getDrawable();
            if (d == null)
                return;
            mVerticalPadding = (getHeight() - (getWidth() - 2 * mHorizontalPadding)) / 2;

            int width = getWidth();
            int height = getHeight();
            int dw = d.getIntrinsicWidth();
            int dh = d.getIntrinsicHeight();
            float scale = 1.0f;
            if (dw > getWidth() - mHorizontalPadding * 2
                    && dh > getHeight() - mVerticalPadding * 2) {
                scale = (getWidth() * 1.0f) / dw;
            }

            if (dw < getWidth() - mHorizontalPadding * 2
                    && dh > getHeight() - mVerticalPadding * 2) {
                scale = (getWidth() * 1.0f - mHorizontalPadding * 2) / dw;
            }

            if (dh < getHeight() - mVerticalPadding * 2
                    && dw > getWidth() - mHorizontalPadding * 2) {
                scale = (getHeight() * 1.0f - mVerticalPadding * 2) / dh;
            }

            if (dw < getWidth() - mHorizontalPadding * 2
                    && dh < getHeight() - mVerticalPadding * 2) {
                float scaleW = (getWidth() * 1.0f - mHorizontalPadding * 2)
                        / dw;
                float scaleH = (getHeight() * 1.0f - mVerticalPadding * 2) / dh;
                scale = Math.max(scaleW, scaleH);
            }

            initScale = scale;
            SCALE_MID = initScale * 2;
            SCALE_MAX = initScale * 4;
            mScaleMatrix.postTranslate((width - dw) / 2, (height - dh) / 2);
            mScaleMatrix.postScale(scale, scale, getWidth() / 2,
                    getHeight() / 2);
            setImageMatrix(mScaleMatrix);
            once = false;
        }

    }

    /**
     * Cut the image and return the bitmap object after the cut
     *
     * @return
     */
    public Bitmap clip() {
        Bitmap bitmap = Bitmap.createBitmap(getWidth(), getHeight(),
                Bitmap.Config.RGB_565);
        Canvas canvas = new Canvas(bitmap);
        draw(canvas);
        return Bitmap.createBitmap(bitmap, mHorizontalPadding,
                mVerticalPadding, getWidth() - 2 * mHorizontalPadding,
                getWidth() - 2 * mHorizontalPadding);
    }

    /**
     * Boundary detection
     */
    private void checkBorder() {

        RectF rect = getMatrixRectF();
        float deltaX = 0;
        float deltaY = 0;

        int width = getWidth();
        int height = getHeight();
        Log.e(TAG, "rect.width() =  " + rect.width()
                + " , width - 2 * mHorizontalPadding ="
                + (width - 2 * mHorizontalPadding));

        if (rect.width() + 0.01 >= width - 2 * mHorizontalPadding) {
            if (rect.left > mHorizontalPadding) {
                deltaX = -rect.left + mHorizontalPadding;
            }
            if (rect.right < width - mHorizontalPadding) {
                deltaX = width - mHorizontalPadding - rect.right;
            }
        }
        if (rect.height() + 0.01 >= height - 2 * mVerticalPadding) {
            if (rect.top > mVerticalPadding) {
                deltaY = -rect.top + mVerticalPadding;
            }
            if (rect.bottom < height - mVerticalPadding) {
                deltaY = height - mVerticalPadding - rect.bottom;
            }
        }
        mScaleMatrix.postTranslate(deltaX, deltaY);

    }

    /**
     * Whether the drag behavior
     *
     * @param dx
     * @param dy
     * @return
     */
    private boolean isCanDrag(float dx, float dy) {
        return Math.sqrt((dx * dx) + (dy * dy)) >= mTouchSlop;
    }

    public void setHorizontalPadding(int mHorizontalPadding) {
        this.mHorizontalPadding = mHorizontalPadding;
    }

}