/*
 * Copyright (C) 2014 The Android Open Source Project
 *
 * 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 android.transition;

import android.animation.Animator;
import android.animation.AnimatorSet;
import android.animation.TypeEvaluator;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Picture;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;

Static utility methods for Transitions.
@hide
/**
 * Static utility methods for Transitions.
 *
 * @hide
 */
public class TransitionUtils {
    private static int MAX_IMAGE_SIZE = (1024 * 1024);

    static Animator mergeAnimators(Animator animator1, Animator animator2) {
        if (animator1 == null) {
            return animator2;
        } else if (animator2 == null) {
            return animator1;
        } else {
            AnimatorSet animatorSet = new AnimatorSet();
            animatorSet.playTogether(animator1, animator2);
            return animatorSet;
        }
    }

    public static Transition mergeTransitions(Transition... transitions) {
        int count = 0;
        int nonNullIndex = -1;
        for (int i = 0; i < transitions.length; i++) {
            if (transitions[i] != null) {
                count++;
                nonNullIndex = i;
            }
        }

        if (count == 0) {
            return null;
        }

        if (count == 1) {
            return transitions[nonNullIndex];
        }

        TransitionSet transitionSet = new TransitionSet();
        for (int i = 0; i < transitions.length; i++) {
            if (transitions[i] != null) {
                transitionSet.addTransition(transitions[i]);
            }
        }
        return transitionSet;
    }

    
Creates a View using the bitmap copy of view. If view is large,
the copy will use a scaled bitmap of the given view.
Params:
sceneRoot – The ViewGroup in which the view copy will be displayed.
view – The view to create a copy of.
parent – The parent of view./**
     * Creates a View using the bitmap copy of <code>view</code>. If <code>view</code> is large,
     * the copy will use a scaled bitmap of the given view.
     *
     * @param sceneRoot The ViewGroup in which the view copy will be displayed.
     * @param view The view to create a copy of.
     * @param parent The parent of view.
     */
    public static View copyViewImage(ViewGroup sceneRoot, View view, View parent) {
        Matrix matrix = new Matrix();
        matrix.setTranslate(-parent.getScrollX(), -parent.getScrollY());
        view.transformMatrixToGlobal(matrix);
        sceneRoot.transformMatrixToLocal(matrix);
        RectF bounds = new RectF(0, 0, view.getWidth(), view.getHeight());
        matrix.mapRect(bounds);
        int left = Math.round(bounds.left);
        int top = Math.round(bounds.top);
        int right = Math.round(bounds.right);
        int bottom = Math.round(bounds.bottom);

        ImageView copy = new ImageView(view.getContext());
        copy.setScaleType(ImageView.ScaleType.CENTER_CROP);
        Bitmap bitmap = createViewBitmap(view, matrix, bounds, sceneRoot);
        if (bitmap != null) {
            copy.setImageBitmap(bitmap);
        }
        int widthSpec = View.MeasureSpec.makeMeasureSpec(right - left, View.MeasureSpec.EXACTLY);
        int heightSpec = View.MeasureSpec.makeMeasureSpec(bottom - top, View.MeasureSpec.EXACTLY);
        copy.measure(widthSpec, heightSpec);
        copy.layout(left, top, right, bottom);
        return copy;
    }

    
Get a copy of bitmap of given drawable, return null if intrinsic size is zero
/**
     * Get a copy of bitmap of given drawable, return null if intrinsic size is zero
     */
    public static Bitmap createDrawableBitmap(Drawable drawable, View hostView) {
        int width = drawable.getIntrinsicWidth();
        int height = drawable.getIntrinsicHeight();
        if (width <= 0 || height <= 0) {
            return null;
        }
        float scale = Math.min(1f, ((float)MAX_IMAGE_SIZE) / (width * height));
        if (drawable instanceof BitmapDrawable && scale == 1f) {
            // return same bitmap if scale down not needed
            return ((BitmapDrawable) drawable).getBitmap();
        }
        int bitmapWidth = (int) (width * scale);
        int bitmapHeight = (int) (height * scale);
        final Picture picture = new Picture();
        final Canvas canvas = picture.beginRecording(width, height);
        // Do stuff with the canvas
        Rect existingBounds = drawable.getBounds();
        int left = existingBounds.left;
        int top = existingBounds.top;
        int right = existingBounds.right;
        int bottom = existingBounds.bottom;
        drawable.setBounds(0, 0, bitmapWidth, bitmapHeight);
        drawable.draw(canvas);
        drawable.setBounds(left, top, right, bottom);
        picture.endRecording();
        return Bitmap.createBitmap(picture);
    }

    
Creates a Bitmap of the given view, using the Matrix matrix to transform to the local
coordinates. matrix will be modified during the bitmap creation.
If the bitmap is large, it will be scaled uniformly down to at most 1MB size.
Params:
view – The view to create a bitmap for.
matrix – The matrix converting the view local coordinates to the coordinates that
              the bitmap will be displayed in. matrix will be modified before
              returning.
bounds – The bounds of the bitmap in the destination coordinate system (where the
              view should be presented. Typically, this is matrix.mapRect(viewBounds);
sceneRoot – A ViewGroup that is attached to the window to temporarily contain the view
                 if it isn't attached to the window.
Returns:
A bitmap of the given view or null if bounds has no width or height./**
     * Creates a Bitmap of the given view, using the Matrix matrix to transform to the local
     * coordinates. <code>matrix</code> will be modified during the bitmap creation.
     *
     * <p>If the bitmap is large, it will be scaled uniformly down to at most 1MB size.</p>
     * @param view The view to create a bitmap for.
     * @param matrix The matrix converting the view local coordinates to the coordinates that
     *               the bitmap will be displayed in. <code>matrix</code> will be modified before
     *               returning.
     * @param bounds The bounds of the bitmap in the destination coordinate system (where the
     *               view should be presented. Typically, this is matrix.mapRect(viewBounds);
     * @param sceneRoot A ViewGroup that is attached to the window to temporarily contain the view
     *                  if it isn't attached to the window.
     * @return A bitmap of the given view or null if bounds has no width or height.
     */
    public static Bitmap createViewBitmap(View view, Matrix matrix, RectF bounds,
            ViewGroup sceneRoot) {
        final boolean addToOverlay = !view.isAttachedToWindow();
        ViewGroup parent = null;
        int indexInParent = 0;
        if (addToOverlay) {
            if (sceneRoot == null || !sceneRoot.isAttachedToWindow()) {
                return null;
            }
            parent = (ViewGroup) view.getParent();
            indexInParent = parent.indexOfChild(view);
            sceneRoot.getOverlay().add(view);
        }
        Bitmap bitmap = null;
        int bitmapWidth = Math.round(bounds.width());
        int bitmapHeight = Math.round(bounds.height());
        if (bitmapWidth > 0 && bitmapHeight > 0) {
            float scale = Math.min(1f, ((float) MAX_IMAGE_SIZE) / (bitmapWidth * bitmapHeight));
            bitmapWidth *= scale;
            bitmapHeight *= scale;
            matrix.postTranslate(-bounds.left, -bounds.top);
            matrix.postScale(scale, scale);

            final Picture picture = new Picture();
            final Canvas canvas = picture.beginRecording(bitmapWidth, bitmapHeight);
            canvas.concat(matrix);
            view.draw(canvas);
            picture.endRecording();
            bitmap = Bitmap.createBitmap(picture);
        }
        if (addToOverlay) {
            sceneRoot.getOverlay().remove(view);
            parent.addView(view, indexInParent);
        }
        return bitmap;
    }

    public static class MatrixEvaluator implements TypeEvaluator<Matrix> {

        float[] mTempStartValues = new float[9];

        float[] mTempEndValues = new float[9];

        Matrix mTempMatrix = new Matrix();

        @Override
        public Matrix evaluate(float fraction, Matrix startValue, Matrix endValue) {
            startValue.getValues(mTempStartValues);
            endValue.getValues(mTempEndValues);
            for (int i = 0; i < 9; i++) {
                float diff = mTempEndValues[i] - mTempStartValues[i];
                mTempEndValues[i] = mTempStartValues[i] + (fraction * diff);
            }
            mTempMatrix.setValues(mTempEndValues);
            return mTempMatrix;
        }
    }
}