/*
 * Copyright (C) 2015 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 com.android.internal.policy;

import android.graphics.Rect;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.os.Looper;
import android.view.Choreographer;
import android.view.DisplayListCanvas;
import android.view.RenderNode;
import android.view.ThreadedRenderer;

The thread which draws a fill in background while the app is resizing in areas where the app
content draw is lagging behind the resize operation.
It starts with the creation and it ends once someone calls destroy().
Any size changes can be passed by a call to setTargetRect will passed to the thread and
executed via the Choreographer.
@hide
/**
 * The thread which draws a fill in background while the app is resizing in areas where the app
 * content draw is lagging behind the resize operation.
 * It starts with the creation and it ends once someone calls destroy().
 * Any size changes can be passed by a call to setTargetRect will passed to the thread and
 * executed via the Choreographer.
 * @hide
 */
public class BackdropFrameRenderer extends Thread implements Choreographer.FrameCallback {

    private DecorView mDecorView;

    // This is containing the last requested size by a resize command. Note that this size might
    // or might not have been applied to the output already.
    private final Rect mTargetRect = new Rect();

    // The render nodes for the multi threaded renderer.
    private ThreadedRenderer mRenderer;
    private RenderNode mFrameAndBackdropNode;
    private RenderNode mSystemBarBackgroundNode;

    private final Rect mOldTargetRect = new Rect();
    private final Rect mNewTargetRect = new Rect();

    private Choreographer mChoreographer;

    // Cached size values from the last render for the case that the view hierarchy is gone
    // during a configuration change.
    private int mLastContentWidth;
    private int mLastContentHeight;
    private int mLastCaptionHeight;
    private int mLastXOffset;
    private int mLastYOffset;

    // Whether to report when next frame is drawn or not.
    private boolean mReportNextDraw;

    private Drawable mCaptionBackgroundDrawable;
    private Drawable mUserCaptionBackgroundDrawable;
    private Drawable mResizingBackgroundDrawable;
    private ColorDrawable mStatusBarColor;
    private ColorDrawable mNavigationBarColor;
    private boolean mOldFullscreen;
    private boolean mFullscreen;
    private final int mResizeMode;
    private final Rect mOldSystemInsets = new Rect();
    private final Rect mOldStableInsets = new Rect();
    private final Rect mSystemInsets = new Rect();
    private final Rect mStableInsets = new Rect();
    private final Rect mTmpRect = new Rect();

    public BackdropFrameRenderer(DecorView decorView, ThreadedRenderer renderer, Rect initialBounds,
            Drawable resizingBackgroundDrawable, Drawable captionBackgroundDrawable,
            Drawable userCaptionBackgroundDrawable, int statusBarColor, int navigationBarColor,
            boolean fullscreen, Rect systemInsets, Rect stableInsets, int resizeMode) {
        setName("ResizeFrame");

        mRenderer = renderer;
        onResourcesLoaded(decorView, resizingBackgroundDrawable, captionBackgroundDrawable,
                userCaptionBackgroundDrawable, statusBarColor, navigationBarColor);

        // Create a render node for the content and frame backdrop
        // which can be resized independently from the content.
        mFrameAndBackdropNode = RenderNode.create("FrameAndBackdropNode", null);

        mRenderer.addRenderNode(mFrameAndBackdropNode, true);

        // Set the initial bounds and draw once so that we do not get a broken frame.
        mTargetRect.set(initialBounds);
        mFullscreen = fullscreen;
        mOldFullscreen = fullscreen;
        mSystemInsets.set(systemInsets);
        mStableInsets.set(stableInsets);
        mOldSystemInsets.set(systemInsets);
        mOldStableInsets.set(stableInsets);
        mResizeMode = resizeMode;

        // Kick off our draw thread.
        start();
    }

    void onResourcesLoaded(DecorView decorView, Drawable resizingBackgroundDrawable,
            Drawable captionBackgroundDrawableDrawable, Drawable userCaptionBackgroundDrawable,
            int statusBarColor, int navigationBarColor) {
        mDecorView = decorView;
        mResizingBackgroundDrawable = resizingBackgroundDrawable != null
                        && resizingBackgroundDrawable.getConstantState() != null
                ? resizingBackgroundDrawable.getConstantState().newDrawable()
                : null;
        mCaptionBackgroundDrawable = captionBackgroundDrawableDrawable != null
                        && captionBackgroundDrawableDrawable.getConstantState() != null
                ? captionBackgroundDrawableDrawable.getConstantState().newDrawable()
                : null;
        mUserCaptionBackgroundDrawable = userCaptionBackgroundDrawable != null
                        && userCaptionBackgroundDrawable.getConstantState() != null
                ? userCaptionBackgroundDrawable.getConstantState().newDrawable()
                : null;
        if (mCaptionBackgroundDrawable == null) {
            mCaptionBackgroundDrawable = mResizingBackgroundDrawable;
        }
        if (statusBarColor != 0) {
            mStatusBarColor = new ColorDrawable(statusBarColor);
            addSystemBarNodeIfNeeded();
        } else {
            mStatusBarColor = null;
        }
        if (navigationBarColor != 0) {
            mNavigationBarColor = new ColorDrawable(navigationBarColor);
            addSystemBarNodeIfNeeded();
        } else {
            mNavigationBarColor = null;
        }
    }

    private void addSystemBarNodeIfNeeded() {
        if (mSystemBarBackgroundNode != null) {
            return;
        }
        mSystemBarBackgroundNode = RenderNode.create("SystemBarBackgroundNode", null);
        mRenderer.addRenderNode(mSystemBarBackgroundNode, false);
    }

    
Call this function asynchronously when the window size has been changed or when the insets
have changed or whether window switched between a fullscreen or non-fullscreen layout.
The change will be picked up once per frame and the frame will be re-rendered accordingly.
Params:
newTargetBounds – The new target bounds.
fullscreen – Whether the window is currently drawing in fullscreen.
systemInsets – The current visible system insets for the window.
stableInsets – The stable insets for the window./**
     * Call this function asynchronously when the window size has been changed or when the insets
     * have changed or whether window switched between a fullscreen or non-fullscreen layout.
     * The change will be picked up once per frame and the frame will be re-rendered accordingly.
     *
     * @param newTargetBounds The new target bounds.
     * @param fullscreen Whether the window is currently drawing in fullscreen.
     * @param systemInsets The current visible system insets for the window.
     * @param stableInsets The stable insets for the window.
     */
    public void setTargetRect(Rect newTargetBounds, boolean fullscreen, Rect systemInsets,
            Rect stableInsets) {
        synchronized (this) {
            mFullscreen = fullscreen;
            mTargetRect.set(newTargetBounds);
            mSystemInsets.set(systemInsets);
            mStableInsets.set(stableInsets);
            // Notify of a bounds change.
            pingRenderLocked(false /* drawImmediate */);
        }
    }

    
The window got replaced due to a configuration change.
/**
     * The window got replaced due to a configuration change.
     */
    public void onConfigurationChange() {
        synchronized (this) {
            if (mRenderer != null) {
                // Enforce a window redraw.
                mOldTargetRect.set(0, 0, 0, 0);
                pingRenderLocked(false /* drawImmediate */);
            }
        }
    }

    
All resources of the renderer will be released. This function can be called from the
the UI thread as well as the renderer thread.
/**
     * All resources of the renderer will be released. This function can be called from the
     * the UI thread as well as the renderer thread.
     */
    public void releaseRenderer() {
        synchronized (this) {
            if (mRenderer != null) {
                // Invalidate the current content bounds.
                mRenderer.setContentDrawBounds(0, 0, 0, 0);

                // Remove the render node again
                // (see comment above - better to do that only once).
                mRenderer.removeRenderNode(mFrameAndBackdropNode);
                if (mSystemBarBackgroundNode != null) {
                    mRenderer.removeRenderNode(mSystemBarBackgroundNode);
                }

                mRenderer = null;

                // Exit the renderer loop.
                pingRenderLocked(false /* drawImmediate */);
            }
        }
    }

    @Override
    public void run() {
        try {
            Looper.prepare();
            synchronized (this) {
                mChoreographer = Choreographer.getInstance();
            }
            Looper.loop();
        } finally {
            releaseRenderer();
        }
        synchronized (this) {
            // Make sure no more messages are being sent.
            mChoreographer = null;
            Choreographer.releaseInstance();
        }
    }

    
The implementation of the FrameCallback.
Params:
frameTimeNanos – The time in nanoseconds when the frame started being rendered, in the System.nanoTime() timebase. Divide this value by 1000000/**
     * The implementation of the FrameCallback.
     * @param frameTimeNanos The time in nanoseconds when the frame started being rendered,
     * in the {@link System#nanoTime()} timebase.  Divide this value by {@code 1000000}
     */
    @Override
    public void doFrame(long frameTimeNanos) {
        synchronized (this) {
            if (mRenderer == null) {
                reportDrawIfNeeded();
                // Tell the looper to stop. We are done.
                Looper.myLooper().quit();
                return;
            }
            doFrameUncheckedLocked();
        }
    }

    private void doFrameUncheckedLocked() {
        mNewTargetRect.set(mTargetRect);
        if (!mNewTargetRect.equals(mOldTargetRect)
                || mOldFullscreen != mFullscreen
                || !mStableInsets.equals(mOldStableInsets)
                || !mSystemInsets.equals(mOldSystemInsets)
                || mReportNextDraw) {
            mOldFullscreen = mFullscreen;
            mOldTargetRect.set(mNewTargetRect);
            mOldSystemInsets.set(mSystemInsets);
            mOldStableInsets.set(mStableInsets);
            redrawLocked(mNewTargetRect, mFullscreen, mSystemInsets, mStableInsets);
        }
    }

    
The content is about to be drawn and we got the location of where it will be shown.
If a "redrawLocked" call has already been processed, we will re-issue the call
if the previous call was ignored since the size was unknown.
Params:
xOffset – The x offset where the content is drawn to.
yOffset – The y offset where the content is drawn to.
xSize – The width size of the content. This should not be 0.
ySize – The height of the content.
Returns:
true if a frame should be requested after the content is drawn; false otherwise./**
     * The content is about to be drawn and we got the location of where it will be shown.
     * If a "redrawLocked" call has already been processed, we will re-issue the call
     * if the previous call was ignored since the size was unknown.
     * @param xOffset The x offset where the content is drawn to.
     * @param yOffset The y offset where the content is drawn to.
     * @param xSize The width size of the content. This should not be 0.
     * @param ySize The height of the content.
     * @return true if a frame should be requested after the content is drawn; false otherwise.
     */
    public boolean onContentDrawn(int xOffset, int yOffset, int xSize, int ySize) {
        synchronized (this) {
            final boolean firstCall = mLastContentWidth == 0;
            // The current content buffer is drawn here.
            mLastContentWidth = xSize;
            mLastContentHeight = ySize - mLastCaptionHeight;
            mLastXOffset = xOffset;
            mLastYOffset = yOffset;

            // Inform the renderer of the content's new bounds
            mRenderer.setContentDrawBounds(
                    mLastXOffset,
                    mLastYOffset,
                    mLastXOffset + mLastContentWidth,
                    mLastYOffset + mLastCaptionHeight + mLastContentHeight);

            // If this was the first call and redrawLocked got already called prior
            // to us, we should re-issue a redrawLocked now.
            return firstCall
                    && (mLastCaptionHeight != 0 || !mDecorView.isShowingCaption());
        }
    }

    public void onRequestDraw(boolean reportNextDraw) {
        synchronized (this) {
            mReportNextDraw = reportNextDraw;
            mOldTargetRect.set(0, 0, 0, 0);
            pingRenderLocked(true /* drawImmediate */);
        }
    }

    
Redraws the background, the caption and the system inset backgrounds if something changed.
Params:
newBounds – The window bounds which needs to be drawn.
fullscreen – Whether the window is currently drawing in fullscreen.
systemInsets – The current visible system insets for the window.
stableInsets – The stable insets for the window./**
     * Redraws the background, the caption and the system inset backgrounds if something changed.
     *
     * @param newBounds The window bounds which needs to be drawn.
     * @param fullscreen Whether the window is currently drawing in fullscreen.
     * @param systemInsets The current visible system insets for the window.
     * @param stableInsets The stable insets for the window.
     */
    private void redrawLocked(Rect newBounds, boolean fullscreen, Rect systemInsets,
            Rect stableInsets) {

        // While a configuration change is taking place the view hierarchy might become
        // inaccessible. For that case we remember the previous metrics to avoid flashes.
        // Note that even when there is no visible caption, the caption child will exist.
        final int captionHeight = mDecorView.getCaptionHeight();

        // The caption height will probably never dynamically change while we are resizing.
        // Once set to something other then 0 it should be kept that way.
        if (captionHeight != 0) {
            // Remember the height of the caption.
            mLastCaptionHeight = captionHeight;
        }

        // Make sure that the other thread has already prepared the render draw calls for the
        // content. If any size is 0, we have to wait for it to be drawn first.
        if ((mLastCaptionHeight == 0 && mDecorView.isShowingCaption()) ||
                mLastContentWidth == 0 || mLastContentHeight == 0) {
            return;
        }

        // Since the surface is spanning the entire screen, we have to add the start offset of
        // the bounds to get to the surface location.
        final int left = mLastXOffset + newBounds.left;
        final int top = mLastYOffset + newBounds.top;
        final int width = newBounds.width();
        final int height = newBounds.height();

        mFrameAndBackdropNode.setLeftTopRightBottom(left, top, left + width, top + height);

        // Draw the caption and content backdrops in to our render node.
        DisplayListCanvas canvas = mFrameAndBackdropNode.start(width, height);
        final Drawable drawable = mUserCaptionBackgroundDrawable != null
                ? mUserCaptionBackgroundDrawable : mCaptionBackgroundDrawable;

        if (drawable != null) {
            drawable.setBounds(0, 0, left + width, top + mLastCaptionHeight);
            drawable.draw(canvas);
        }

        // The backdrop: clear everything with the background. Clipping is done elsewhere.
        if (mResizingBackgroundDrawable != null) {
            mResizingBackgroundDrawable.setBounds(0, mLastCaptionHeight, left + width, top + height);
            mResizingBackgroundDrawable.draw(canvas);
        }
        mFrameAndBackdropNode.end(canvas);

        drawColorViews(left, top, width, height, fullscreen, systemInsets, stableInsets);

        // We need to render the node explicitly
        mRenderer.drawRenderNode(mFrameAndBackdropNode);

        reportDrawIfNeeded();
    }

    private void drawColorViews(int left, int top, int width, int height,
            boolean fullscreen, Rect systemInsets, Rect stableInsets) {
        if (mSystemBarBackgroundNode == null) {
            return;
        }
        DisplayListCanvas canvas = mSystemBarBackgroundNode.start(width, height);
        mSystemBarBackgroundNode.setLeftTopRightBottom(left, top, left + width, top + height);
        final int topInset = DecorView.getColorViewTopInset(mStableInsets.top, mSystemInsets.top);
        if (mStatusBarColor != null) {
            mStatusBarColor.setBounds(0, 0, left + width, topInset);
            mStatusBarColor.draw(canvas);
        }

        // We only want to draw the navigation bar if our window is currently fullscreen because we
        // don't want the navigation bar background be moving around when resizing in docked mode.
        // However, we need it for the transitions into/out of docked mode.
        if (mNavigationBarColor != null && fullscreen) {
            DecorView.getNavigationBarRect(width, height, stableInsets, systemInsets, mTmpRect);
            mNavigationBarColor.setBounds(mTmpRect);
            mNavigationBarColor.draw(canvas);
        }
        mSystemBarBackgroundNode.end(canvas);
        mRenderer.drawRenderNode(mSystemBarBackgroundNode);
    }

    
Notify view root that a frame has been drawn by us, if it has requested so. /** Notify view root that a frame has been drawn by us, if it has requested so. */
    private void reportDrawIfNeeded() {
        if (mReportNextDraw) {
            if (mDecorView.isAttachedToWindow()) {
                mDecorView.getViewRootImpl().reportDrawFinish();
            }
            mReportNextDraw = false;
        }
    }

    
Sends a message to the renderer to wake up and perform the next action which can be
either the next rendering or the self destruction if mRenderer is null.
Note: This call must be synchronized.
Params:
drawImmediate – if we should draw immediately instead of scheduling a frame/**
     * Sends a message to the renderer to wake up and perform the next action which can be
     * either the next rendering or the self destruction if mRenderer is null.
     * Note: This call must be synchronized.
     *
     * @param drawImmediate if we should draw immediately instead of scheduling a frame
     */
    private void pingRenderLocked(boolean drawImmediate) {
        if (mChoreographer != null && !drawImmediate) {
            mChoreographer.postFrameCallback(this);
        } else {
            doFrameUncheckedLocked();
        }
    }

    void setUserCaptionBackgroundDrawable(Drawable userCaptionBackgroundDrawable) {
        mUserCaptionBackgroundDrawable = userCaptionBackgroundDrawable;
    }
}