package com.example.poweruser.fcemsandroid;

import android.content.Context;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.widget.ImageView;


public class TouchImageView extends ImageView {
    Matrix matrix;
    // We can be in one of these 3 states
    static final int NONE = 0;
    static final int DRAG = 1;
    static final int ZOOM = 2;

    int mode = NONE;

    // Remember some things for zooming
    PointF last = new PointF();
    PointF start = new PointF();
    float minScale = 1f;
    float maxScale = 3f;
    float[] m;
    int viewWidth, viewHeight;

    static final int CLICK = 3;

    float saveScale = 1f;

    protected float origWidth, origHeight;

    int oldMeasuredWidth, oldMeasuredHeight;

ScaleGestureDetector mScaleDetector;

Context context;

public TouchImageView() {}

public TouchImageView(Context context) {
    super(context);
    sharedConstructing(context);
}

public TouchImageView(Context context, AttributeSet attrs) {
    super(context, attrs);
    sharedConstructing(context);
}

private void sharedConstructing(Context context) {

    super.setClickable(true);

    this.context = context;

    mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());

    matrix = new Matrix();

    m = new float[9];

    setImageMatrix(matrix);

    setScaleType(ScaleType.MATRIX);

    setOnTouchListener(new OnTouchListener() {

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

            mScaleDetector.onTouchEvent(event);

            PointF curr = new PointF(event.getX(), event.getY());

            switch (event.getAction()) {

                case MotionEvent.ACTION_DOWN:

                    last.set(curr);

                    start.set(last);

                    mode = DRAG;

                    break;

                case MotionEvent.ACTION_MOVE:

                    if (mode == DRAG) {

                        float deltaX = curr.x - last.x;

                        float deltaY = curr.y - last.y;

                        float fixTransX = getFixDragTrans(deltaX, viewWidth, origWidth * saveScale);

                        float fixTransY = getFixDragTrans(deltaY, viewHeight, origHeight * saveScale);

                        matrix.postTranslate(fixTransX, fixTransY);

                        fixTrans();

                        last.set(curr.x, curr.y);

                    }

                    break;

                case MotionEvent.ACTION_UP:

                    mode = NONE;

                    int xDiff = (int) Math.abs(curr.x - start.x);

                    int yDiff = (int) Math.abs(curr.y - start.y);

                    if (xDiff < CLICK && yDiff < CLICK)

                        performClick();

                    break;

                case MotionEvent.ACTION_POINTER_UP:

                    mode = NONE;

                    break;

            }

            setImageMatrix(matrix);

            invalidate();

            return true; // indicate event was handled

        }

    });
}

public void setMaxZoom(float x) {

    maxScale = x;

}

private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {

    @Override
    public boolean onScaleBegin(ScaleGestureDetector detector) {

        mode = ZOOM;

        return true;

    }

    @Override
    public boolean onScale(ScaleGestureDetector detector) {

        float mScaleFactor = detector.getScaleFactor();

        float origScale = saveScale;

        saveScale *= mScaleFactor;

        if (saveScale > maxScale) {

            saveScale = maxScale;

            mScaleFactor = maxScale / origScale;

        } else if (saveScale < minScale) {

            saveScale = minScale;

            mScaleFactor = minScale / origScale;

        }

        if (origWidth * saveScale <= viewWidth || origHeight * saveScale <= viewHeight)

            matrix.postScale(mScaleFactor, mScaleFactor, viewWidth / 2, viewHeight / 2);

        else

            matrix.postScale(mScaleFactor, mScaleFactor, detector.getFocusX(), detector.getFocusY());

        fixTrans();

        return true;

    }

}

void fixTrans() {

    matrix.getValues(m);

    float transX = m[Matrix.MTRANS_X];

    float transY = m[Matrix.MTRANS_Y];

    float fixTransX = getFixTrans(transX, viewWidth, origWidth * saveScale);

    float fixTransY = getFixTrans(transY, viewHeight, origHeight * saveScale);

    if (fixTransX != 0 || fixTransY != 0)

        matrix.postTranslate(fixTransX, fixTransY);

}



float getFixTrans(float trans, float viewSize, float contentSize) {

    float minTrans, maxTrans;

    if (contentSize <= viewSize) {

        minTrans = 0;

        maxTrans = viewSize - contentSize;

    } else {

        minTrans = viewSize - contentSize;

        maxTrans = 0;

    }

    if (trans < minTrans)

        return -trans + minTrans;

    if (trans > maxTrans)

        return -trans + maxTrans;

    return 0;

}

float getFixDragTrans(float delta, float viewSize, float contentSize) {

    if (contentSize <= viewSize) {

        return 0;

    }

    return delta;

}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

    super.onMeasure(widthMeasureSpec, heightMeasureSpec);

    viewWidth = MeasureSpec.getSize(widthMeasureSpec);

    viewHeight = MeasureSpec.getSize(heightMeasureSpec);

    //
    // Rescales image on rotation
    //
    if (oldMeasuredHeight == viewWidth && oldMeasuredHeight == viewHeight

            || viewWidth == 0 || viewHeight == 0)

        return;

    oldMeasuredHeight = viewHeight;

    oldMeasuredWidth = viewWidth;

    if (saveScale == 1) {

        //Fit to screen.

        float scale;

        Drawable drawable = getDrawable();

        if (drawable == null || drawable.getIntrinsicWidth() == 0 || drawable.getIntrinsicHeight() == 0)

            return;

        int bmWidth = drawable.getIntrinsicWidth();

        int bmHeight = drawable.getIntrinsicHeight();

        Log.d("bmSize", "bmWidth: " + bmWidth + " bmHeight : " + bmHeight);

        float scaleX = (float) viewWidth / (float) bmWidth;

        float scaleY = (float) viewHeight / (float) bmHeight;

        scale = Math.min(scaleX, scaleY);

        matrix.setScale(scale, scale);

        // Center the image

        float redundantYSpace = (float) viewHeight - (scale * (float) bmHeight);

        float redundantXSpace = (float) viewWidth - (scale * (float) bmWidth);

        redundantYSpace /= (float) 2;

        redundantXSpace /= (float) 2;

        matrix.postTranslate(redundantXSpace, redundantYSpace);

        origWidth = viewWidth - 2 * redundantXSpace;

        origHeight = viewHeight - 2 * redundantYSpace;

        setImageMatrix(matrix);

    }

    fixTrans();

}