/*
 * Copyright (C) 2013 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.server.wm;

import static android.app.ActivityTaskManager.SPLIT_SCREEN_CREATE_MODE_BOTTOM_OR_RIGHT;
import static android.app.ActivityTaskManager.SPLIT_SCREEN_CREATE_MODE_TOP_OR_LEFT;
import static android.app.WindowConfiguration.ACTIVITY_TYPE_ASSISTANT;
import static android.app.WindowConfiguration.ACTIVITY_TYPE_HOME;
import static android.app.WindowConfiguration.ACTIVITY_TYPE_RECENTS;
import static android.app.WindowConfiguration.ACTIVITY_TYPE_STANDARD;
import static android.app.WindowConfiguration.PINNED_WINDOWING_MODE_ELEVATION_IN_DIP;
import static android.app.WindowConfiguration.WINDOWING_MODE_FULLSCREEN;
import static android.app.WindowConfiguration.WINDOWING_MODE_SPLIT_SCREEN_PRIMARY;
import static android.content.pm.ActivityInfo.SCREEN_ORIENTATION_UNSET;
import static android.content.res.Configuration.ORIENTATION_PORTRAIT;
import static android.view.Display.DEFAULT_DISPLAY;
import static android.view.WindowManager.DOCKED_BOTTOM;
import static android.view.WindowManager.DOCKED_INVALID;
import static android.view.WindowManager.DOCKED_LEFT;
import static android.view.WindowManager.DOCKED_RIGHT;
import static android.view.WindowManager.DOCKED_TOP;

import static com.android.server.wm.BoundsAnimationController.FADE_IN;
import static com.android.server.wm.BoundsAnimationController.NO_PIP_MODE_CHANGED_CALLBACKS;
import static com.android.server.wm.BoundsAnimationController.SCHEDULE_PIP_MODE_CHANGED_ON_END;
import static com.android.server.wm.BoundsAnimationController.SCHEDULE_PIP_MODE_CHANGED_ON_START;
import static com.android.server.wm.BoundsAnimationController.SchedulePipModeChangedState;
import static com.android.server.wm.DragResizeMode.DRAG_RESIZE_MODE_DOCKED_DIVIDER;
import static com.android.server.wm.StackProto.ADJUSTED_BOUNDS;
import static com.android.server.wm.StackProto.ADJUSTED_FOR_IME;
import static com.android.server.wm.StackProto.ADJUST_DIVIDER_AMOUNT;
import static com.android.server.wm.StackProto.ADJUST_IME_AMOUNT;
import static com.android.server.wm.StackProto.ANIMATING_BOUNDS;
import static com.android.server.wm.StackProto.ANIMATION_BACKGROUND_SURFACE_IS_DIMMING;
import static com.android.server.wm.StackProto.BOUNDS;
import static com.android.server.wm.StackProto.DEFER_REMOVAL;
import static com.android.server.wm.StackProto.FILLS_PARENT;
import static com.android.server.wm.StackProto.ID;
import static com.android.server.wm.StackProto.MINIMIZE_AMOUNT;
import static com.android.server.wm.StackProto.TASKS;
import static com.android.server.wm.StackProto.WINDOW_CONTAINER;
import static com.android.server.wm.WindowManagerDebugConfig.DEBUG_STACK;
import static com.android.server.wm.WindowManagerDebugConfig.DEBUG_TASK_MOVEMENT;
import static com.android.server.wm.WindowManagerDebugConfig.TAG_WM;

import android.annotation.CallSuper;
import android.app.RemoteAction;
import android.content.res.Configuration;
import android.graphics.Point;
import android.graphics.Rect;
import android.graphics.Region;
import android.os.RemoteException;
import android.util.DisplayMetrics;
import android.util.EventLog;
import android.util.Slog;
import android.util.proto.ProtoOutputStream;
import android.view.DisplayCutout;
import android.view.DisplayInfo;
import android.view.SurfaceControl;

import com.android.internal.annotations.VisibleForTesting;
import com.android.internal.policy.DividerSnapAlgorithm;
import com.android.internal.policy.DividerSnapAlgorithm.SnapTarget;
import com.android.internal.policy.DockedDividerUtils;
import com.android.server.EventLogTags;

import java.io.PrintWriter;
import java.util.List;

public class TaskStack extends WindowContainer<Task> implements
        BoundsAnimationTarget, ConfigurationContainerListener {
    /** Minimum size of an adjusted stack bounds relative to original stack bounds. Used to
     * restrict IME adjustment so that a min portion of top stack remains visible.*/
    private static final float ADJUSTED_STACK_FRACTION_MIN = 0.3f;

    /** Dimming amount for non-focused stack when stacks are IME-adjusted. */
    private static final float IME_ADJUST_DIM_AMOUNT = 0.25f;

    /** Unique identifier */
    final int mStackId;

    /** For comparison with DisplayContent bounds. */
    private Rect mTmpRect = new Rect();
    private Rect mTmpRect2 = new Rect();
    private Rect mTmpRect3 = new Rect();

    /** For Pinned stack controlling. */
    private Rect mTmpFromBounds = new Rect();
    private Rect mTmpToBounds = new Rect();

    /** Stack bounds adjusted to screen content area (taking into account IM windows, etc.) */
    private final Rect mAdjustedBounds = new Rect();

    /**
     * Fully adjusted IME bounds. These are different from {@link #mAdjustedBounds} because they
     * represent the state when the animation has ended.
     */
    private final Rect mFullyAdjustedImeBounds = new Rect();

    private SurfaceControl mAnimationBackgroundSurface;
    private boolean mAnimationBackgroundSurfaceIsShown = false;

    /** The particular window with an Animation with non-zero background color. */
    private WindowStateAnimator mAnimationBackgroundAnimator;

    /** Application tokens that are exiting, but still on screen for animations. */
    final AppTokenList mExitingAppTokens = new AppTokenList();
    final AppTokenList mTmpAppTokens = new AppTokenList();

    /** Detach this stack from its display when animation completes. */
    // TODO: maybe tie this to WindowContainer#removeChild some how...
    boolean mDeferRemoval;

    private final Rect mTmpAdjustedBounds = new Rect();
    private boolean mAdjustedForIme;
    private boolean mImeGoingAway;
    private WindowState mImeWin;
    private float mMinimizeAmount;
    private float mAdjustImeAmount;
    private float mAdjustDividerAmount;
    private final int mDockedStackMinimizeThickness;

    // If this is true, we are in the bounds animating mode. The task will be down or upscaled to
    // perfectly fit the region it would have been cropped to. We may also avoid certain logic we
    // would otherwise apply while resizing, while resizing in the bounds animating mode.
    private boolean mBoundsAnimating = false;
    // Set when an animation has been requested but has not yet started from the UI thread. This is
    // cleared when the animation actually starts.
    private boolean mBoundsAnimatingRequested = false;
    private boolean mBoundsAnimatingToFullscreen = false;
    private boolean mCancelCurrentBoundsAnimation = false;
    private Rect mBoundsAnimationTarget = new Rect();
    private Rect mBoundsAnimationSourceHintBounds = new Rect();
    private @BoundsAnimationController.AnimationType int mAnimationType;

    Rect mPreAnimationBounds = new Rect();

    private Dimmer mDimmer = new Dimmer(this);

    // TODO: remove after unification.
    ActivityStack mActivityStack;

    /**
     * For {@link #prepareSurfaces}.
     */
    final Rect mTmpDimBoundsRect = new Rect();
    private final Point mLastSurfaceSize = new Point();

    private final AnimatingAppWindowTokenRegistry mAnimatingAppWindowTokenRegistry =
            new AnimatingAppWindowTokenRegistry();

    TaskStack(WindowManagerService service, int stackId, ActivityStack activityStack) {
        super(service);
        mStackId = stackId;
        mActivityStack = activityStack;
        activityStack.registerConfigurationChangeListener(this);
        mDockedStackMinimizeThickness = service.mContext.getResources().getDimensionPixelSize(
                com.android.internal.R.dimen.docked_stack_minimize_thickness);
        EventLog.writeEvent(EventLogTags.WM_STACK_CREATED, stackId);
    }

    Task findHomeTask() {
        if (!isActivityTypeHome() || mChildren.isEmpty()) {
            return null;
        }
        return mChildren.get(mChildren.size() - 1);
    }

    void prepareFreezingTaskBounds() {
        for (int taskNdx = mChildren.size() - 1; taskNdx >= 0; --taskNdx) {
            final Task task = mChildren.get(taskNdx);
            task.prepareFreezingBounds();
        }
    }

    /**
     * Overrides the adjusted bounds, i.e. sets temporary layout bounds which are different from
     * the normal task bounds.
     *
     * @param bounds The adjusted bounds.
     */
    private void setAdjustedBounds(Rect bounds) {
        if (mAdjustedBounds.equals(bounds) && !isAnimatingForIme()) {
            return;
        }

        mAdjustedBounds.set(bounds);
        final boolean adjusted = !mAdjustedBounds.isEmpty();
        Rect insetBounds = null;
        if (adjusted && isAdjustedForMinimizedDockedStack()) {
            insetBounds = getRawBounds();
        } else if (adjusted && mAdjustedForIme) {
            if (mImeGoingAway) {
                insetBounds = getRawBounds();
            } else {
                insetBounds = mFullyAdjustedImeBounds;
            }
        }
        alignTasksToAdjustedBounds(adjusted ? mAdjustedBounds : getRawBounds(), insetBounds);
        mDisplayContent.setLayoutNeeded();

        updateSurfaceBounds();
    }

    private void alignTasksToAdjustedBounds(Rect adjustedBounds, Rect tempInsetBounds) {
        if (matchParentBounds()) {
            return;
        }

        final boolean alignBottom = mAdjustedForIme && getDockSide() == DOCKED_TOP;

        // Update bounds of containing tasks.
        for (int taskNdx = mChildren.size() - 1; taskNdx >= 0; --taskNdx) {
            final Task task = mChildren.get(taskNdx);
            task.alignToAdjustedBounds(adjustedBounds, tempInsetBounds, alignBottom);
        }
    }

    private void updateAnimationBackgroundBounds() {
        if (mAnimationBackgroundSurface == null) {
            return;
        }
        getRawBounds(mTmpRect);
        final Rect stackBounds = getBounds();
        getPendingTransaction()
                .setWindowCrop(mAnimationBackgroundSurface, mTmpRect.width(), mTmpRect.height())
                .setPosition(mAnimationBackgroundSurface, mTmpRect.left - stackBounds.left,
                        mTmpRect.top - stackBounds.top);
        scheduleAnimation();
    }

    private void hideAnimationSurface() {
        if (mAnimationBackgroundSurface == null) {
            return;
        }
        getPendingTransaction().hide(mAnimationBackgroundSurface);
        mAnimationBackgroundSurfaceIsShown = false;
        scheduleAnimation();
    }

    private void showAnimationSurface(float alpha) {
        if (mAnimationBackgroundSurface == null) {
            return;
        }
        getPendingTransaction().setLayer(mAnimationBackgroundSurface, Integer.MIN_VALUE)
                .setAlpha(mAnimationBackgroundSurface, alpha)
                .show(mAnimationBackgroundSurface);
        mAnimationBackgroundSurfaceIsShown = true;
        scheduleAnimation();
    }

    @Override
    public int setBounds(Rect bounds) {
        return setBounds(getRequestedOverrideBounds(), bounds);
    }

    private int setBounds(Rect existing, Rect bounds) {
        if (equivalentBounds(existing, bounds)) {
            return BOUNDS_CHANGE_NONE;
        }

        final int result = super.setBounds(bounds);

        if (getParent() != null) {
            updateAnimationBackgroundBounds();
        }

        updateAdjustedBounds();

        updateSurfaceBounds();
        return result;
    }

    /** Bounds of the stack without adjusting for other factors in the system like visibility
     * of docked stack.
     * Most callers should be using {@link ConfigurationContainer#getRequestedOverrideBounds} a
     * it takes into consideration other system factors. */
    void getRawBounds(Rect out) {
        out.set(getRawBounds());
    }

    Rect getRawBounds() {
        return super.getBounds();
    }

    @Override
    public void getBounds(Rect bounds) {
        bounds.set(getBounds());
    }

    @Override
    public Rect getBounds() {
        // If we're currently adjusting for IME or minimized docked stack, we use the adjusted
        // bounds; otherwise, no need to adjust the output bounds if fullscreen or the docked
        // stack is visible since it is already what we want to represent to the rest of the
        // system.
        if (!mAdjustedBounds.isEmpty()) {
            return mAdjustedBounds;
        } else {
            return super.getBounds();
        }
    }

    /**
     * Sets the bounds animation target bounds ahead of an animation.  This can't currently be done
     * in onAnimationStart() since that is started on the UiThread.
     */
    private void setAnimationFinalBounds(Rect sourceHintBounds, Rect destBounds,
            boolean toFullscreen) {
        mBoundsAnimatingRequested = true;
        mBoundsAnimatingToFullscreen = toFullscreen;
        if (destBounds != null) {
            mBoundsAnimationTarget.set(destBounds);
        } else {
            mBoundsAnimationTarget.setEmpty();
        }
        if (sourceHintBounds != null) {
            mBoundsAnimationSourceHintBounds.set(sourceHintBounds);
        } else if (!mBoundsAnimating) {
            // If the bounds are already animating, we don't want to reset the source hint. This is
            // because the source hint is sent when starting the animation from the client that
            // requested to enter pip. Other requests can adjust the pip bounds during an animation,
            // but could accidentally reset the source hint bounds.
            mBoundsAnimationSourceHintBounds.setEmpty();
        }

        mPreAnimationBounds.set(getRawBounds());
    }

    /**
     * @return the final bounds for the bounds animation.
     */
    void getFinalAnimationBounds(Rect outBounds) {
        outBounds.set(mBoundsAnimationTarget);
    }

    /**
     * @return the final source bounds for the bounds animation.
     */
    void getFinalAnimationSourceHintBounds(Rect outBounds) {
        outBounds.set(mBoundsAnimationSourceHintBounds);
    }

    /**
     * @return the final animation bounds if the task stack is currently being animated, or the
     *         current stack bounds otherwise.
     */
    void getAnimationOrCurrentBounds(Rect outBounds) {
        if ((mBoundsAnimatingRequested || mBoundsAnimating) && !mBoundsAnimationTarget.isEmpty()) {
            getFinalAnimationBounds(outBounds);
            return;
        }
        getBounds(outBounds);
    }

    /** Bounds of the stack with other system factors taken into consideration. */
    public void getDimBounds(Rect out) {
        getBounds(out);
    }

    /**
     * Updates the passed-in {@code inOutBounds} based on the current state of the
     * pinned controller. This gets run *after* the override configuration is updated, so it's
     * safe to rely on the controller's state in here (though eventually this dependence should
     * be removed).
     *
     * This does NOT modify this TaskStack's configuration. However, it does, for the time-being,
     * update pinned controller state.
     *
     * @param inOutBounds the bounds to update (both input and output).
     * @return true if bounds were updated to some non-empty value.
     */
    boolean calculatePinnedBoundsForConfigChange(Rect inOutBounds) {
        boolean animating = false;
        if ((mBoundsAnimatingRequested || mBoundsAnimating) && !mBoundsAnimationTarget.isEmpty()) {
            animating = true;
            getFinalAnimationBounds(mTmpRect2);
        } else {
            mTmpRect2.set(inOutBounds);
        }
        boolean updated = mDisplayContent.mPinnedStackControllerLocked.onTaskStackBoundsChanged(
                mTmpRect2, mTmpRect3);
        if (updated) {
            inOutBounds.set(mTmpRect3);

            // The final boundary is updated while there is an existing boundary animation. Let's
            // cancel this animation to prevent the obsolete animation overwritten updated bounds.
            if (animating && !inOutBounds.equals(mBoundsAnimationTarget)) {
                final DisplayContent displayContent = getDisplayContent();
                displayContent.mBoundsAnimationController.getHandler().post(() ->
                        displayContent.mBoundsAnimationController.cancel(this));
            }
            // Once we've set the bounds based on the rotation of the old bounds in the new
            // orientation, clear the animation target bounds since they are obsolete, and
            // cancel any currently running animations
            mBoundsAnimationTarget.setEmpty();
            mBoundsAnimationSourceHintBounds.setEmpty();
            mCancelCurrentBoundsAnimation = true;
        }
        return updated;
    }

    /**
     * Updates the passed-in {@code inOutBounds} based on the current state of the
     * docked controller. This gets run *after* the override configuration is updated, so it's
     * safe to rely on the controller's state in here (though eventually this dependence should
     * be removed).
     *
     * This does NOT modify this TaskStack's configuration. However, it does, for the time-being,
     * update docked controller state.
     *
     * @param parentConfig the parent configuration for reference.
     * @param inOutBounds the bounds to update (both input and output).
     */
    void calculateDockedBoundsForConfigChange(Configuration parentConfig, Rect inOutBounds) {
        final boolean primary =
                getRequestedOverrideWindowingMode() == WINDOWING_MODE_SPLIT_SCREEN_PRIMARY;
        repositionSplitScreenStackAfterRotation(parentConfig, primary, inOutBounds);
        final DisplayCutout cutout = mDisplayContent.getDisplayInfo().displayCutout;
        snapDockedStackAfterRotation(parentConfig, cutout, inOutBounds);
        if (primary) {
            final int newDockSide = getDockSide(parentConfig, inOutBounds);
            // Update the dock create mode and clear the dock create bounds, these
            // might change after a rotation and the original values will be invalid.
            mWmService.setDockedStackCreateStateLocked(
                    (newDockSide == DOCKED_LEFT || newDockSide == DOCKED_TOP)
                            ? SPLIT_SCREEN_CREATE_MODE_TOP_OR_LEFT
                            : SPLIT_SCREEN_CREATE_MODE_BOTTOM_OR_RIGHT,
                    null);
            mDisplayContent.getDockedDividerController().notifyDockSideChanged(newDockSide);
        }
    }

    /**
     * Some primary split screen sides are not allowed by the policy. This method queries the policy
     * and moves the primary stack around if needed.
     *
     * @param parentConfig the configuration of the stack's parent.
     * @param primary true if adjusting the primary docked stack, false for secondary.
     * @param inOutBounds the bounds of the stack to adjust.
     */
    void repositionSplitScreenStackAfterRotation(Configuration parentConfig, boolean primary,
            Rect inOutBounds) {
        final int dockSide = getDockSide(mDisplayContent, parentConfig, inOutBounds);
        final int otherDockSide = DockedDividerUtils.invertDockSide(dockSide);
        final int primaryDockSide = primary ? dockSide : otherDockSide;
        if (mDisplayContent.getDockedDividerController()
                .canPrimaryStackDockTo(primaryDockSide,
                        parentConfig.windowConfiguration.getBounds(),
                        parentConfig.windowConfiguration.getRotation())) {
            return;
        }
        final Rect parentBounds = parentConfig.windowConfiguration.getBounds();
        switch (otherDockSide) {
            case DOCKED_LEFT:
                int movement = inOutBounds.left;
                inOutBounds.left -= movement;
                inOutBounds.right -= movement;
                break;
            case DOCKED_RIGHT:
                movement = parentBounds.right - inOutBounds.right;
                inOutBounds.left += movement;
                inOutBounds.right += movement;
                break;
            case DOCKED_TOP:
                movement = inOutBounds.top;
                inOutBounds.top -= movement;
                inOutBounds.bottom -= movement;
                break;
            case DOCKED_BOTTOM:
                movement = parentBounds.bottom - inOutBounds.bottom;
                inOutBounds.top += movement;
                inOutBounds.bottom += movement;
                break;
        }
    }

    /**
     * Snaps the bounds after rotation to the closest snap target for the docked stack.
     */
    void snapDockedStackAfterRotation(Configuration parentConfig, DisplayCutout displayCutout,
            Rect outBounds) {

        // Calculate the current position.
        final int dividerSize = mDisplayContent.getDockedDividerController().getContentWidth();
        final int dockSide = getDockSide(parentConfig, outBounds);
        final int dividerPosition = DockedDividerUtils.calculatePositionForBounds(outBounds,
                dockSide, dividerSize);
        final int displayWidth = parentConfig.windowConfiguration.getBounds().width();
        final int displayHeight = parentConfig.windowConfiguration.getBounds().height();

        // Snap the position to a target.
        final int rotation = parentConfig.windowConfiguration.getRotation();
        final int orientation = parentConfig.orientation;
        mDisplayContent.getDisplayPolicy().getStableInsetsLw(rotation, displayWidth, displayHeight,
                displayCutout, outBounds);
        final DividerSnapAlgorithm algorithm = new DividerSnapAlgorithm(
                mWmService.mContext.getResources(), displayWidth, displayHeight,
                dividerSize, orientation == Configuration.ORIENTATION_PORTRAIT, outBounds,
                getDockSide(), isMinimizedDockAndHomeStackResizable());
        final SnapTarget target = algorithm.calculateNonDismissingSnapTarget(dividerPosition);

        // Recalculate the bounds based on the position of the target.
        DockedDividerUtils.calculateBoundsForPosition(target.position, dockSide,
                outBounds, displayWidth, displayHeight,
                dividerSize);
    }

    // TODO: Checkout the call points of this method and the ones below to see how they can fit in WC.
    void addTask(Task task, int position) {
        addTask(task, position, task.showForAllUsers(), true /* moveParents */);
    }

    /**
     * Put a Task in this stack. Used for adding only.
     * When task is added to top of the stack, the entire branch of the hierarchy (including stack
     * and display) will be brought to top.
     * @param task The task to add.
     * @param position Target position to add the task to.
     * @param showForAllUsers Whether to show the task regardless of the current user.
     */
    void addTask(Task task, int position, boolean showForAllUsers, boolean moveParents) {
        final TaskStack currentStack = task.mStack;
        // TODO: We pass stack to task's constructor, but we still need to call this method.
        // This doesn't make sense, mStack will already be set equal to "this" at this point.
        if (currentStack != null && currentStack.mStackId != mStackId) {
            throw new IllegalStateException("Trying to add taskId=" + task.mTaskId
                    + " to stackId=" + mStackId
                    + ", but it is already attached to stackId=" + task.mStack.mStackId);
        }

        // Add child task.
        task.mStack = this;
        addChild(task, null);

        // Move child to a proper position, as some restriction for position might apply.
        positionChildAt(position, task, moveParents /* includingParents */, showForAllUsers);
    }

    void positionChildAt(Task child, int position) {
        if (DEBUG_STACK) {
            Slog.i(TAG_WM, "positionChildAt: positioning task=" + child + " at " + position);
        }
        if (child == null) {
            if (DEBUG_STACK) {
                Slog.i(TAG_WM, "positionChildAt: could not find task=" + this);
            }
            return;
        }
        child.positionAt(position);
        getDisplayContent().layoutAndAssignWindowLayersIfNeeded();
    }

    void positionChildAtTop(Task child, boolean includingParents) {
        if (child == null) {
            // TODO: Fix the call-points that cause this to happen.
            return;
        }

        positionChildAt(POSITION_TOP, child, includingParents);

        final DisplayContent displayContent = getDisplayContent();
        if (displayContent.mAppTransition.isTransitionSet()) {
            child.setSendingToBottom(false);
        }
        displayContent.layoutAndAssignWindowLayersIfNeeded();
    }

    void positionChildAtBottom(Task child, boolean includingParents) {
        if (child == null) {
            // TODO: Fix the call-points that cause this to happen.
            return;
        }

        positionChildAt(POSITION_BOTTOM, child, includingParents);

        if (getDisplayContent().mAppTransition.isTransitionSet()) {
            child.setSendingToBottom(true);
        }
        getDisplayContent().layoutAndAssignWindowLayersIfNeeded();
    }

    @Override
    void positionChildAt(int position, Task child, boolean includingParents) {
        positionChildAt(position, child, includingParents, child.showForAllUsers());
    }

    /**
     * Overridden version of {@link TaskStack#positionChildAt(int, Task, boolean)}. Used in
     * {@link TaskStack#addTask(Task, int, boolean showForAllUsers, boolean)}, as it can receive
     * showForAllUsers param from {@link AppWindowToken} instead of {@link Task#showForAllUsers()}.
     */
    private void positionChildAt(int position, Task child, boolean includingParents,
            boolean showForAllUsers) {
        final int targetPosition = findPositionForTask(child, position, showForAllUsers,
                false /* addingNew */);
        super.positionChildAt(targetPosition, child, includingParents);

        // Log positioning.
        if (DEBUG_TASK_MOVEMENT)
            Slog.d(TAG_WM, "positionTask: task=" + this + " position=" + position);

        final int toTop = targetPosition == mChildren.size() - 1 ? 1 : 0;
        EventLog.writeEvent(EventLogTags.WM_TASK_MOVED, child.mTaskId, toTop, targetPosition);
    }

    void reparent(int displayId, Rect outStackBounds, boolean onTop) {
        final DisplayContent targetDc = mWmService.mRoot.getDisplayContent(displayId);
        if (targetDc == null) {
            throw new IllegalArgumentException("Trying to move stackId=" + mStackId
                    + " to unknown displayId=" + displayId);
        }

        targetDc.moveStackToDisplay(this, onTop);
        if (matchParentBounds()) {
            outStackBounds.setEmpty();
        } else {
            getRawBounds(outStackBounds);
        }
    }

    // TODO: We should really have users as a window container in the hierarchy so that we don't
    // have to do complicated things like we are doing in this method.
    private int findPositionForTask(Task task, int targetPosition, boolean showForAllUsers,
            boolean addingNew) {
        final boolean canShowTask =
                showForAllUsers || mWmService.isCurrentProfileLocked(task.mUserId);

        final int stackSize = mChildren.size();
        int minPosition = 0;
        int maxPosition = addingNew ? stackSize : stackSize - 1;

        if (canShowTask) {
            minPosition = computeMinPosition(minPosition, stackSize);
        } else {
            maxPosition = computeMaxPosition(maxPosition);
        }

        // preserve POSITION_BOTTOM/POSITION_TOP positions if they are still valid.
        if (targetPosition == POSITION_BOTTOM && minPosition == 0) {
            return POSITION_BOTTOM;
        } else if (targetPosition == POSITION_TOP
                && maxPosition == (addingNew ? stackSize : stackSize - 1)) {
            return POSITION_TOP;
        }
        // Reset position based on minimum/maximum possible positions.
        return Math.min(Math.max(targetPosition, minPosition), maxPosition);
    }

    /** Calculate the minimum possible position for a task that can be shown to the user.
     *  The minimum position will be above all other tasks that can't be shown.
     *  @param minPosition The minimum position the caller is suggesting.
     *                  We will start adjusting up from here.
     *  @param size The size of the current task list.
     */
    private int computeMinPosition(int minPosition, int size) {
        while (minPosition < size) {
            final Task tmpTask = mChildren.get(minPosition);
            final boolean canShowTmpTask =
                    tmpTask.showForAllUsers()
                            || mWmService.isCurrentProfileLocked(tmpTask.mUserId);
            if (canShowTmpTask) {
                break;
            }
            minPosition++;
        }
        return minPosition;
    }

    /** Calculate the maximum possible position for a task that can't be shown to the user.
     *  The maximum position will be below all other tasks that can be shown.
     *  @param maxPosition The maximum position the caller is suggesting.
     *                  We will start adjusting down from here.
     */
    private int computeMaxPosition(int maxPosition) {
        while (maxPosition > 0) {
            final Task tmpTask = mChildren.get(maxPosition);
            final boolean canShowTmpTask =
                    tmpTask.showForAllUsers()
                            || mWmService.isCurrentProfileLocked(tmpTask.mUserId);
            if (!canShowTmpTask) {
                break;
            }
            maxPosition--;
        }
        return maxPosition;
    }

    /**
     * Delete a Task from this stack. If it is the last Task in the stack, move this stack to the
     * back.
     * @param task The Task to delete.
     */
    @Override
    void removeChild(Task task) {
        if (DEBUG_TASK_MOVEMENT) Slog.d(TAG_WM, "removeChild: task=" + task);

        super.removeChild(task);
        task.mStack = null;

        if (mDisplayContent != null) {
            if (mChildren.isEmpty()) {
                getParent().positionChildAt(POSITION_BOTTOM, this, false /* includingParents */);
            }
            mDisplayContent.setLayoutNeeded();
        }
        for (int appNdx = mExitingAppTokens.size() - 1; appNdx >= 0; --appNdx) {
            final AppWindowToken wtoken = mExitingAppTokens.get(appNdx);
            if (wtoken.getTask() == task) {
                wtoken.mIsExiting = false;
                mExitingAppTokens.remove(appNdx);
            }
        }
    }

    @Override
    public void onConfigurationChanged(Configuration newParentConfig) {
        final int prevWindowingMode = getWindowingMode();
        super.onConfigurationChanged(newParentConfig);

        // Only need to update surface size here since the super method will handle updating
        // surface position.
        updateSurfaceSize(getPendingTransaction());
        final int windowingMode = getWindowingMode();
        final boolean isAlwaysOnTop = isAlwaysOnTop();

        if (mDisplayContent == null) {
            return;
        }

        if (prevWindowingMode != windowingMode) {
            mDisplayContent.onStackWindowingModeChanged(this);

            if (inSplitScreenSecondaryWindowingMode()) {
                // When the stack is resized due to entering split screen secondary, offset the
                // windows to compensate for the new stack position.
                forAllWindows(w -> {
                    w.mWinAnimator.setOffsetPositionForStackResize(true);
                }, true);
            }
        }
    }

    private void updateSurfaceBounds() {
        updateSurfaceSize(getPendingTransaction());
        updateSurfacePosition();
        scheduleAnimation();
    }

    /**
     * Calculate an amount by which to expand the stack bounds in each direction.
     * Used to make room for shadows in the pinned windowing mode.
     */
    int getStackOutset() {
        DisplayContent displayContent = getDisplayContent();
        if (inPinnedWindowingMode() && displayContent != null) {
            final DisplayMetrics displayMetrics = displayContent.getDisplayMetrics();

            // We multiply by two to match the client logic for converting view elevation
            // to insets, as in {@link WindowManager.LayoutParams#setSurfaceInsets}
            return (int)Math.ceil(mWmService.dipToPixel(PINNED_WINDOWING_MODE_ELEVATION_IN_DIP,
                    displayMetrics) * 2);
        }
        return 0;
    }

    @Override
    void getRelativeDisplayedPosition(Point outPos) {
        super.getRelativeDisplayedPosition(outPos);
        final int outset = getStackOutset();
        outPos.x -= outset;
        outPos.y -= outset;
    }

    private void updateSurfaceSize(SurfaceControl.Transaction transaction) {
        if (mSurfaceControl == null) {
            return;
        }

        final Rect stackBounds = getDisplayedBounds();
        int width = stackBounds.width();
        int height = stackBounds.height();

        final int outset = getStackOutset();
        width += 2*outset;
        height += 2*outset;

        if (width == mLastSurfaceSize.x && height == mLastSurfaceSize.y) {
            return;
        }
        if (getWindowConfiguration().tasksAreFloating()) {
            // Don't crop freeform windows to the stack.
            transaction.setWindowCrop(mSurfaceControl, -1, -1);
        } else {
            transaction.setWindowCrop(mSurfaceControl, width, height);
        }
        mLastSurfaceSize.set(width, height);
    }

    @VisibleForTesting
    Point getLastSurfaceSize() {
        return mLastSurfaceSize;
    }

    @Override
    void onDisplayChanged(DisplayContent dc) {
        if (mDisplayContent != null && mDisplayContent != dc) {
            throw new IllegalStateException("onDisplayChanged: Already attached");
        }

        super.onDisplayChanged(dc);

        updateSurfaceBounds();
        if (mAnimationBackgroundSurface == null) {
            mAnimationBackgroundSurface = makeChildSurface(null).setColorLayer()
                    .setName("animation background stackId=" + mStackId)
                    .build();
        }
    }

    /**
     * Determines the stack and task bounds of the other stack when in docked mode. The current task
     * bounds is passed in but depending on the stack, the task and stack must match. Only in
     * minimized mode with resizable launcher, the other stack ignores calculating the stack bounds
     * and uses the task bounds passed in as the stack and task bounds, otherwise the stack bounds
     * is calculated and is also used for its task bounds.
     * If any of the out bounds are empty, it represents default bounds
     *
     * @param currentTempTaskBounds the current task bounds of the other stack
     * @param outStackBounds the calculated stack bounds of the other stack
     * @param outTempTaskBounds the calculated task bounds of the other stack
     */
    void getStackDockedModeBoundsLocked(Configuration parentConfig, Rect dockedBounds,
            Rect currentTempTaskBounds, Rect outStackBounds, Rect outTempTaskBounds) {
        outTempTaskBounds.setEmpty();

        if (dockedBounds == null || dockedBounds.isEmpty()) {
            // Calculate the primary docked bounds.
            final boolean dockedOnTopOrLeft = mWmService.mDockedStackCreateMode
                    == SPLIT_SCREEN_CREATE_MODE_TOP_OR_LEFT;
            getStackDockedModeBounds(parentConfig,
                    true /* primary */, outStackBounds, dockedBounds,
                    mDisplayContent.mDividerControllerLocked.getContentWidth(), dockedOnTopOrLeft);
            return;
        }
        final int dockedSide = getDockSide(parentConfig, dockedBounds);

        // When the home stack is resizable, should always have the same stack and task bounds
        if (isActivityTypeHome()) {
            final Task homeTask = findHomeTask();
            if (homeTask != null && homeTask.isResizeable()) {
                // Calculate the home stack bounds when in docked mode and the home stack is
                // resizeable.
                getDisplayContent().mDividerControllerLocked
                        .getHomeStackBoundsInDockedMode(parentConfig,
                                dockedSide, outStackBounds);
            } else {
                // Home stack isn't resizeable, so don't specify stack bounds.
                outStackBounds.setEmpty();
            }

            outTempTaskBounds.set(outStackBounds);
            return;
        }

        // When minimized state, the stack bounds for all non-home and docked stack bounds should
        // match the passed task bounds
        if (isMinimizedDockAndHomeStackResizable() && currentTempTaskBounds != null) {
            outStackBounds.set(currentTempTaskBounds);
            return;
        }

        if (dockedSide == DOCKED_INVALID) {
            // Not sure how you got here...Only thing we can do is return current bounds.
            Slog.e(TAG_WM, "Failed to get valid docked side for docked stack");
            outStackBounds.set(getRawBounds());
            return;
        }

        final boolean dockedOnTopOrLeft = dockedSide == DOCKED_TOP || dockedSide == DOCKED_LEFT;
        getStackDockedModeBounds(parentConfig,
                false /* primary */, outStackBounds, dockedBounds,
                mDisplayContent.mDividerControllerLocked.getContentWidth(), dockedOnTopOrLeft);
    }

    /**
     * Outputs the bounds a stack should be given the presence of a docked stack on the display.
     * @param parentConfig The parent configuration.
     * @param primary {@code true} if getting the primary stack bounds.
     * @param outBounds Output bounds that should be used for the stack.
     * @param dockedBounds Bounds of the docked stack.
     * @param dockDividerWidth We need to know the width of the divider make to the output bounds
     *                         close to the side of the dock.
     * @param dockOnTopOrLeft If the docked stack is on the top or left side of the screen.
     */
    private void getStackDockedModeBounds(Configuration parentConfig, boolean primary,
            Rect outBounds, Rect dockedBounds, int dockDividerWidth,
            boolean dockOnTopOrLeft) {
        final Rect displayRect = parentConfig.windowConfiguration.getBounds();
        final boolean splitHorizontally = displayRect.width() > displayRect.height();

        outBounds.set(displayRect);
        if (primary) {
            if (mWmService.mDockedStackCreateBounds != null) {
                outBounds.set(mWmService.mDockedStackCreateBounds);
                return;
            }

            // The initial bounds of the docked stack when it is created about half the screen space
            // and its bounds can be adjusted after that. The bounds of all other stacks are
            // adjusted to occupy whatever screen space the docked stack isn't occupying.
            final DisplayCutout displayCutout = mDisplayContent.getDisplayInfo().displayCutout;
            mDisplayContent.getDisplayPolicy().getStableInsetsLw(
                    parentConfig.windowConfiguration.getRotation(),
                    displayRect.width(), displayRect.height(), displayCutout, mTmpRect2);
            final int position = new DividerSnapAlgorithm(mWmService.mContext.getResources(),
                    displayRect.width(),
                    displayRect.height(),
                    dockDividerWidth,
                    parentConfig.orientation == ORIENTATION_PORTRAIT,
                    mTmpRect2).getMiddleTarget().position;

            if (dockOnTopOrLeft) {
                if (splitHorizontally) {
                    outBounds.right = position;
                } else {
                    outBounds.bottom = position;
                }
            } else {
                if (splitHorizontally) {
                    outBounds.left = position + dockDividerWidth;
                } else {
                    outBounds.top = position + dockDividerWidth;
                }
            }
            return;
        }

        // Other stacks occupy whatever space is left by the docked stack.
        if (!dockOnTopOrLeft) {
            if (splitHorizontally) {
                outBounds.right = dockedBounds.left - dockDividerWidth;
            } else {
                outBounds.bottom = dockedBounds.top - dockDividerWidth;
            }
        } else {
            if (splitHorizontally) {
                outBounds.left = dockedBounds.right + dockDividerWidth;
            } else {
                outBounds.top = dockedBounds.bottom + dockDividerWidth;
            }
        }
        DockedDividerUtils.sanitizeStackBounds(outBounds, !dockOnTopOrLeft);
    }

    void resetDockedStackToMiddle() {
        if (inSplitScreenPrimaryWindowingMode()) {
            throw new IllegalStateException("Not a docked stack=" + this);
        }

        mWmService.mDockedStackCreateBounds = null;

        final Rect bounds = new Rect();
        final Rect tempBounds = new Rect();
        TaskStack dockedStack = mDisplayContent.getSplitScreenPrimaryStackIgnoringVisibility();
        Rect dockedBounds =
                (dockedStack == null || dockedStack == this) ? null : dockedStack.getRawBounds();
        getStackDockedModeBoundsLocked(mDisplayContent.getConfiguration(), dockedBounds,
                null /* currentTempTaskBounds */, bounds, tempBounds);
        mActivityStack.requestResize(bounds);
    }

    @Override
    void removeIfPossible() {
        if (isSelfOrChildAnimating()) {
            mDeferRemoval = true;
            return;
        }
        removeImmediately();
    }

    @Override
    void removeImmediately() {
        if (mActivityStack != null) {
            mActivityStack.unregisterConfigurationChangeListener(this);
        }
        super.removeImmediately();
    }

    @Override
    void onParentChanged() {
        super.onParentChanged();

        if (getParent() != null || mDisplayContent == null) {
            return;
        }

        EventLog.writeEvent(EventLogTags.WM_STACK_REMOVED, mStackId);

        if (mAnimationBackgroundSurface != null) {
            mAnimationBackgroundSurface.remove();
            mAnimationBackgroundSurface = null;
        }

        mDisplayContent = null;
        mWmService.mWindowPlacerLocked.requestTraversal();
    }

    void resetAnimationBackgroundAnimator() {
        mAnimationBackgroundAnimator = null;
        hideAnimationSurface();
    }

    void setAnimationBackground(WindowStateAnimator winAnimator, int color) {
        if (mAnimationBackgroundAnimator == null) {
            mAnimationBackgroundAnimator = winAnimator;
            showAnimationSurface(((color >> 24) & 0xff) / 255f);
        }
    }

    // TODO: Should each user have there own stacks?
    @Override
    void switchUser() {
        super.switchUser();
        int top = mChildren.size();
        for (int taskNdx = 0; taskNdx < top; ++taskNdx) {
            Task task = mChildren.get(taskNdx);
            if (mWmService.isCurrentProfileLocked(task.mUserId) || task.showForAllUsers()) {
                mChildren.remove(taskNdx);
                mChildren.add(task);
                --top;
            }
        }
    }

    /**
     * Adjusts the stack bounds if the IME is visible.
     *
     * @param imeWin The IME window.
     * @param keepLastAmount Use {@code true} to keep the last adjusted amount from
     *                       {@link DockedStackDividerController} for adjusting the stack bounds,
     *                       Use {@code false} to reset adjusted amount as 0.
     * @see #updateAdjustForIme(float, float, boolean)
     */
    void setAdjustedForIme(WindowState imeWin, boolean keepLastAmount) {
        mImeWin = imeWin;
        mImeGoingAway = false;
        if (!mAdjustedForIme || keepLastAmount) {
            mAdjustedForIme = true;
            DockedStackDividerController controller = getDisplayContent().mDividerControllerLocked;
            final float adjustImeAmount = keepLastAmount ? controller.mLastAnimationProgress : 0f;
            final float adjustDividerAmount = keepLastAmount ? controller.mLastDividerProgress : 0f;
            updateAdjustForIme(adjustImeAmount, adjustDividerAmount, true /* force */);
        }
    }

    boolean isAdjustedForIme() {
        return mAdjustedForIme;
    }

    boolean isAnimatingForIme() {
        return mImeWin != null && mImeWin.isAnimatingLw();
    }

    /**
     * Update the stack's bounds (crop or position) according to the IME window's
     * current position. When IME window is animated, the bottom stack is animated
     * together to track the IME window's current position, and the top stack is
     * cropped as necessary.
     *
     * @return true if a traversal should be performed after the adjustment.
     */
    boolean updateAdjustForIme(float adjustAmount, float adjustDividerAmount, boolean force) {
        if (adjustAmount != mAdjustImeAmount
                || adjustDividerAmount != mAdjustDividerAmount || force) {
            mAdjustImeAmount = adjustAmount;
            mAdjustDividerAmount = adjustDividerAmount;
            updateAdjustedBounds();
            return isVisible();
        } else {
            return false;
        }
    }

    /**
     * Resets the adjustment after it got adjusted for the IME.
     * @param adjustBoundsNow if true, reset and update the bounds immediately and forget about
     *                        animations; otherwise, set flag and animates the window away together
     *                        with IME window.
     */
    void resetAdjustedForIme(boolean adjustBoundsNow) {
        if (adjustBoundsNow) {
            mImeWin = null;
            mImeGoingAway = false;
            mAdjustImeAmount = 0f;
            mAdjustDividerAmount = 0f;
            if (!mAdjustedForIme) {
                return;
            }
            mAdjustedForIme = false;
            updateAdjustedBounds();
            mWmService.setResizeDimLayer(false, getWindowingMode(), 1.0f);
        } else {
            mImeGoingAway |= mAdjustedForIme;
        }
    }

    /**
     * Sets the amount how much we currently minimize our stack.
     *
     * @param minimizeAmount The amount, between 0 and 1.
     * @return Whether the amount has changed and a layout is needed.
     */
    boolean setAdjustedForMinimizedDock(float minimizeAmount) {
        if (minimizeAmount != mMinimizeAmount) {
            mMinimizeAmount = minimizeAmount;
            updateAdjustedBounds();
            return isVisible();
        } else {
            return false;
        }
    }

    boolean shouldIgnoreInput() {
        return isAdjustedForMinimizedDockedStack() ||
                (inSplitScreenPrimaryWindowingMode() && isMinimizedDockAndHomeStackResizable());
    }

    /**
     * Puts all visible tasks that are adjusted for IME into resizing mode and adds the windows
     * to the list of to be drawn windows the service is waiting for.
     */
    void beginImeAdjustAnimation() {
        for (int j = mChildren.size() - 1; j >= 0; j--) {
            final Task task = mChildren.get(j);
            if (task.hasContentToDisplay()) {
                task.setDragResizing(true, DRAG_RESIZE_MODE_DOCKED_DIVIDER);
                task.setWaitingForDrawnIfResizingChanged();
            }
        }
    }

    /**
     * Resets the resizing state of all windows.
     */
    void endImeAdjustAnimation() {
        for (int j = mChildren.size() - 1; j >= 0; j--) {
            mChildren.get(j).setDragResizing(false, DRAG_RESIZE_MODE_DOCKED_DIVIDER);
        }
    }

    int getMinTopStackBottom(final Rect displayContentRect, int originalStackBottom) {
        return displayContentRect.top + (int)
                ((originalStackBottom - displayContentRect.top) * ADJUSTED_STACK_FRACTION_MIN);
    }

    private boolean adjustForIME(final WindowState imeWin) {
        // To prevent task stack resize animation may flicking when playing app transition
        // animation & IME window enter animation in parallel, we need to make sure app
        // transition is done and then adjust task size for IME, skip the new adjusted frame when
        // app transition is still running.
        if (getDisplayContent().mAppTransition.isRunning()) {
            return false;
        }

        final int dockedSide = getDockSide();
        final boolean dockedTopOrBottom = dockedSide == DOCKED_TOP || dockedSide == DOCKED_BOTTOM;
        if (imeWin == null || !dockedTopOrBottom) {
            return false;
        }

        final Rect displayStableRect = mTmpRect;
        final Rect contentBounds = mTmpRect2;

        // Calculate the content bounds excluding the area occupied by IME
        getDisplayContent().getStableRect(displayStableRect);
        contentBounds.set(displayStableRect);
        int imeTop = Math.max(imeWin.getFrameLw().top, contentBounds.top);

        imeTop += imeWin.getGivenContentInsetsLw().top;
        if (contentBounds.bottom > imeTop) {
            contentBounds.bottom = imeTop;
        }

        final int yOffset = displayStableRect.bottom - contentBounds.bottom;

        final int dividerWidth =
                getDisplayContent().mDividerControllerLocked.getContentWidth();
        final int dividerWidthInactive =
                getDisplayContent().mDividerControllerLocked.getContentWidthInactive();

        if (dockedSide == DOCKED_TOP) {
            // If this stack is docked on top, we make it smaller so the bottom stack is not
            // occluded by IME. We shift its bottom up by the height of the IME, but
            // leaves at least 30% of the top stack visible.
            final int minTopStackBottom =
                    getMinTopStackBottom(displayStableRect, getRawBounds().bottom);
            final int bottom = Math.max(
                    getRawBounds().bottom - yOffset + dividerWidth - dividerWidthInactive,
                    minTopStackBottom);
            mTmpAdjustedBounds.set(getRawBounds());
            mTmpAdjustedBounds.bottom = (int) (mAdjustImeAmount * bottom + (1 - mAdjustImeAmount)
                    * getRawBounds().bottom);
            mFullyAdjustedImeBounds.set(getRawBounds());
        } else {
            // When the stack is on bottom and has no focus, it's only adjusted for divider width.
            final int dividerWidthDelta = dividerWidthInactive - dividerWidth;

            // When the stack is on bottom and has focus, it needs to be moved up so as to
            // not occluded by IME, and at the same time adjusted for divider width.
            // We try to move it up by the height of the IME window, but only to the extent
            // that leaves at least 30% of the top stack visible.
            // 'top' is where the top of bottom stack will move to in this case.
            final int topBeforeImeAdjust =
                    getRawBounds().top - dividerWidth + dividerWidthInactive;
            final int minTopStackBottom =
                    getMinTopStackBottom(displayStableRect,
                            getRawBounds().top - dividerWidth);
            final int top = Math.max(
                    getRawBounds().top - yOffset, minTopStackBottom + dividerWidthInactive);

            mTmpAdjustedBounds.set(getRawBounds());
            // Account for the adjustment for IME and divider width separately.
            // (top - topBeforeImeAdjust) is the amount of movement due to IME only,
            // and dividerWidthDelta is due to divider width change only.
            mTmpAdjustedBounds.top = getRawBounds().top +
                    (int) (mAdjustImeAmount * (top - topBeforeImeAdjust) +
                            mAdjustDividerAmount * dividerWidthDelta);
            mFullyAdjustedImeBounds.set(getRawBounds());
            mFullyAdjustedImeBounds.top = top;
            mFullyAdjustedImeBounds.bottom = top + getRawBounds().height();
        }
        return true;
    }

    private boolean adjustForMinimizedDockedStack(float minimizeAmount) {
        final int dockSide = getDockSide();
        if (dockSide == DOCKED_INVALID && !mTmpAdjustedBounds.isEmpty()) {
            return false;
        }

        if (dockSide == DOCKED_TOP) {
            mWmService.getStableInsetsLocked(DEFAULT_DISPLAY, mTmpRect);
            int topInset = mTmpRect.top;
            mTmpAdjustedBounds.set(getRawBounds());
            mTmpAdjustedBounds.bottom = (int) (minimizeAmount * topInset + (1 - minimizeAmount)
                    * getRawBounds().bottom);
        } else if (dockSide == DOCKED_LEFT) {
            mTmpAdjustedBounds.set(getRawBounds());
            final int width = getRawBounds().width();
            mTmpAdjustedBounds.right =
                    (int) (minimizeAmount * mDockedStackMinimizeThickness
                            + (1 - minimizeAmount) * getRawBounds().right);
            mTmpAdjustedBounds.left = mTmpAdjustedBounds.right - width;
        } else if (dockSide == DOCKED_RIGHT) {
            mTmpAdjustedBounds.set(getRawBounds());
            mTmpAdjustedBounds.left = (int) (minimizeAmount *
                    (getRawBounds().right - mDockedStackMinimizeThickness)
                            + (1 - minimizeAmount) * getRawBounds().left);
        }
        return true;
    }

    private boolean isMinimizedDockAndHomeStackResizable() {
        return mDisplayContent.mDividerControllerLocked.isMinimizedDock()
                && mDisplayContent.mDividerControllerLocked.isHomeStackResizable();
    }

    /**
     * @return the distance in pixels how much the stack gets minimized from it's original size
     */
    int getMinimizeDistance() {
        final int dockSide = getDockSide();
        if (dockSide == DOCKED_INVALID) {
            return 0;
        }

        if (dockSide == DOCKED_TOP) {
            mWmService.getStableInsetsLocked(DEFAULT_DISPLAY, mTmpRect);
            int topInset = mTmpRect.top;
            return getRawBounds().bottom - topInset;
        } else if (dockSide == DOCKED_LEFT || dockSide == DOCKED_RIGHT) {
            return getRawBounds().width() - mDockedStackMinimizeThickness;
        } else {
            return 0;
        }
    }

    /**
     * Updates the adjustment depending on it's current state.
     */
    private void updateAdjustedBounds() {
        boolean adjust = false;
        if (mMinimizeAmount != 0f) {
            adjust = adjustForMinimizedDockedStack(mMinimizeAmount);
        } else if (mAdjustedForIme) {
            adjust = adjustForIME(mImeWin);
        }
        if (!adjust) {
            mTmpAdjustedBounds.setEmpty();
        }
        setAdjustedBounds(mTmpAdjustedBounds);

        final boolean isImeTarget = (mWmService.getImeFocusStackLocked() == this);
        if (mAdjustedForIme && adjust && !isImeTarget) {
            final float alpha = Math.max(mAdjustImeAmount, mAdjustDividerAmount)
                    * IME_ADJUST_DIM_AMOUNT;
            mWmService.setResizeDimLayer(true, getWindowingMode(), alpha);
        }
    }

    void applyAdjustForImeIfNeeded(Task task) {
        if (mMinimizeAmount != 0f || !mAdjustedForIme || mAdjustedBounds.isEmpty()) {
            return;
        }

        final Rect insetBounds = mImeGoingAway ? getRawBounds() : mFullyAdjustedImeBounds;
        task.alignToAdjustedBounds(mAdjustedBounds, insetBounds, getDockSide() == DOCKED_TOP);
        mDisplayContent.setLayoutNeeded();
    }


    boolean isAdjustedForMinimizedDockedStack() {
        return mMinimizeAmount != 0f;
    }

    /**
     * @return {@code true} if we have a {@link Task} that is animating (currently only used for the
     *         recents animation); {@code false} otherwise.
     */
    boolean isTaskAnimating() {
        for (int j = mChildren.size() - 1; j >= 0; j--) {
            final Task task = mChildren.get(j);
            if (task.isTaskAnimating()) {
                return true;
            }
        }
        return false;
    }

    @CallSuper
    @Override
    public void writeToProto(ProtoOutputStream proto, long fieldId,
            @WindowTraceLogLevel int logLevel) {
        if (logLevel == WindowTraceLogLevel.CRITICAL && !isVisible()) {
            return;
        }

        final long token = proto.start(fieldId);
        super.writeToProto(proto, WINDOW_CONTAINER, logLevel);
        proto.write(ID, mStackId);
        for (int taskNdx = mChildren.size() - 1; taskNdx >= 0; taskNdx--) {
            mChildren.get(taskNdx).writeToProto(proto, TASKS, logLevel);
        }
        proto.write(FILLS_PARENT, matchParentBounds());
        getRawBounds().writeToProto(proto, BOUNDS);
        proto.write(ANIMATION_BACKGROUND_SURFACE_IS_DIMMING, mAnimationBackgroundSurfaceIsShown);
        proto.write(DEFER_REMOVAL, mDeferRemoval);
        proto.write(MINIMIZE_AMOUNT, mMinimizeAmount);
        proto.write(ADJUSTED_FOR_IME, mAdjustedForIme);
        proto.write(ADJUST_IME_AMOUNT, mAdjustImeAmount);
        proto.write(ADJUST_DIVIDER_AMOUNT, mAdjustDividerAmount);
        mAdjustedBounds.writeToProto(proto, ADJUSTED_BOUNDS);
        proto.write(ANIMATING_BOUNDS, mBoundsAnimating);
        proto.end(token);
    }

    @Override
     void dump(PrintWriter pw, String prefix, boolean dumpAll) {
        pw.println(prefix + "mStackId=" + mStackId);
        pw.println(prefix + "mDeferRemoval=" + mDeferRemoval);
        pw.println(prefix + "mBounds=" + getRawBounds().toShortString());
        if (mMinimizeAmount != 0f) {
            pw.println(prefix + "mMinimizeAmount=" + mMinimizeAmount);
        }
        if (mAdjustedForIme) {
            pw.println(prefix + "mAdjustedForIme=true");
            pw.println(prefix + "mAdjustImeAmount=" + mAdjustImeAmount);
            pw.println(prefix + "mAdjustDividerAmount=" + mAdjustDividerAmount);
        }
        if (!mAdjustedBounds.isEmpty()) {
            pw.println(prefix + "mAdjustedBounds=" + mAdjustedBounds.toShortString());
        }
        for (int taskNdx = mChildren.size() - 1; taskNdx >= 0; taskNdx--) {
            mChildren.get(taskNdx).dump(pw, prefix + "  ", dumpAll);
        }
        if (mAnimationBackgroundSurfaceIsShown) {
            pw.println(prefix + "mWindowAnimationBackgroundSurface is shown");
        }
        if (!mExitingAppTokens.isEmpty()) {
            pw.println();
            pw.println("  Exiting application tokens:");
            for (int i = mExitingAppTokens.size() - 1; i >= 0; i--) {
                WindowToken token = mExitingAppTokens.get(i);
                pw.print("  Exiting App #"); pw.print(i);
                pw.print(' '); pw.print(token);
                pw.println(':');
                token.dump(pw, "    ", dumpAll);
            }
        }
        mAnimatingAppWindowTokenRegistry.dump(pw, "AnimatingApps:", prefix);
    }

    @Override
    boolean fillsParent() {
        return matchParentBounds();
    }

    @Override
    public String toString() {
        return "{stackId=" + mStackId + " tasks=" + mChildren + "}";
    }

    String getName() {
        return toShortString();
    }

    public String toShortString() {
        return "Stack=" + mStackId;
    }

    /**
     * For docked workspace (or workspace that's side-by-side to the docked), provides
     * information which side of the screen was the dock anchored.
     */
    int getDockSide() {
        return getDockSide(mDisplayContent.getConfiguration(), getRawBounds());
    }

    int getDockSideForDisplay(DisplayContent dc) {
        return getDockSide(dc, dc.getConfiguration(), getRawBounds());
    }

    int getDockSide(Configuration parentConfig, Rect bounds) {
        if (mDisplayContent == null) {
            return DOCKED_INVALID;
        }
        return getDockSide(mDisplayContent, parentConfig, bounds);
    }

    private int getDockSide(DisplayContent dc, Configuration parentConfig, Rect bounds) {
        return dc.getDockedDividerController().getDockSide(bounds,
                parentConfig.windowConfiguration.getBounds(),
                parentConfig.orientation, parentConfig.windowConfiguration.getRotation());
    }

    boolean hasTaskForUser(int userId) {
        for (int i = mChildren.size() - 1; i >= 0; i--) {
            final Task task = mChildren.get(i);
            if (task.mUserId == userId) {
                return true;
            }
        }
        return false;
    }

    void findTaskForResizePoint(int x, int y, int delta,
            DisplayContent.TaskForResizePointSearchResult results) {
        if (!getWindowConfiguration().canResizeTask()) {
            results.searchDone = true;
            return;
        }

        for (int i = mChildren.size() - 1; i >= 0; --i) {
            final Task task = mChildren.get(i);
            if (task.getWindowingMode() == WINDOWING_MODE_FULLSCREEN) {
                results.searchDone = true;
                return;
            }

            // We need to use the task's dim bounds (which is derived from the visible bounds of
            // its apps windows) for any touch-related tests. Can't use the task's original
            // bounds because it might be adjusted to fit the content frame. One example is when
            // the task is put to top-left quadrant, the actual visible area would not start at
            // (0,0) after it's adjusted for the status bar.
            task.getDimBounds(mTmpRect);
            mTmpRect.inset(-delta, -delta);
            if (mTmpRect.contains(x, y)) {
                mTmpRect.inset(delta, delta);

                results.searchDone = true;

                if (!mTmpRect.contains(x, y)) {
                    results.taskForResize = task;
                    return;
                }
                // User touched inside the task. No need to look further,
                // focus transfer will be handled in ACTION_UP.
                return;
            }
        }
    }

    void setTouchExcludeRegion(Task focusedTask, int delta, Region touchExcludeRegion,
            Rect contentRect, Rect postExclude) {
        for (int i = mChildren.size() - 1; i >= 0; --i) {
            final Task task = mChildren.get(i);
            AppWindowToken token = task.getTopVisibleAppToken();
            if (token == null || !token.hasContentToDisplay()) {
                continue;
            }

            /**
             * Exclusion region is the region that TapDetector doesn't care about.
             * Here we want to remove all non-focused tasks from the exclusion region.
             * We also remove the outside touch area for resizing for all freeform
             * tasks (including the focused).
             *
             * We save the focused task region once we find it, and add it back at the end.
             *
             * If the task is home stack and it is resizable in the minimized state, we want to
             * exclude the docked stack from touch so we need the entire screen area and not just a
             * small portion which the home stack currently is resized to.
             */

            if (task.isActivityTypeHome() && isMinimizedDockAndHomeStackResizable()) {
                mDisplayContent.getBounds(mTmpRect);
            } else {
                task.getDimBounds(mTmpRect);
            }

            if (task == focusedTask) {
                // Add the focused task rect back into the exclude region once we are done
                // processing stacks.
                postExclude.set(mTmpRect);
            }

            final boolean isFreeformed = task.inFreeformWindowingMode();
            if (task != focusedTask || isFreeformed) {
                if (isFreeformed) {
                    // If the task is freeformed, enlarge the area to account for outside
                    // touch area for resize.
                    mTmpRect.inset(-delta, -delta);
                    // Intersect with display content rect. If we have system decor (status bar/
                    // navigation bar), we want to exclude that from the tap detection.
                    // Otherwise, if the app is partially placed under some system button (eg.
                    // Recents, Home), pressing that button would cause a full series of
                    // unwanted transfer focus/resume/pause, before we could go home.
                    mTmpRect.intersect(contentRect);
                }
                touchExcludeRegion.op(mTmpRect, Region.Op.DIFFERENCE);
            }
        }
    }

    public boolean setPinnedStackSize(Rect stackBounds, Rect tempTaskBounds) {
        // Hold the lock since this is called from the BoundsAnimator running on the UiThread
        synchronized (mWmService.mGlobalLock) {
            if (mCancelCurrentBoundsAnimation) {
                return false;
            }
        }

        try {
            mWmService.mActivityTaskManager.resizePinnedStack(stackBounds, tempTaskBounds);
        } catch (RemoteException e) {
            // I don't believe you.
        }
        return true;
    }

    void onAllWindowsDrawn() {
        if (!mBoundsAnimating && !mBoundsAnimatingRequested) {
            return;
        }

        getDisplayContent().mBoundsAnimationController.onAllWindowsDrawn();
    }

    @Override  // AnimatesBounds
    public boolean onAnimationStart(boolean schedulePipModeChangedCallback, boolean forceUpdate,
            @BoundsAnimationController.AnimationType int animationType) {
        // Hold the lock since this is called from the BoundsAnimator running on the UiThread
        synchronized (mWmService.mGlobalLock) {
            if (!isAttached()) {
                // Don't run the animation if the stack is already detached
                return false;
            }

            mBoundsAnimatingRequested = false;
            mBoundsAnimating = true;
            mAnimationType = animationType;

            // If we are changing UI mode, as in the PiP to fullscreen
            // transition, then we need to wait for the window to draw.
            if (schedulePipModeChangedCallback) {
                forAllWindows((w) -> { w.mWinAnimator.resetDrawState(); },
                        false /* traverseTopToBottom */);
            }
        }

        if (inPinnedWindowingMode()) {
            try {
                mWmService.mActivityTaskManager.notifyPinnedStackAnimationStarted();
            } catch (RemoteException e) {
                // I don't believe you...
            }

            if ((schedulePipModeChangedCallback || animationType == FADE_IN)
                    && mActivityStack != null) {
                // We need to schedule the PiP mode change before the animation up. It is possible
                // in this case for the animation down to not have been completed, so always
                // force-schedule and update to the client to ensure that it is notified that it
                // is no longer in picture-in-picture mode
                mActivityStack.updatePictureInPictureModeForPinnedStackAnimation(null,
                        forceUpdate);
            }
        }
        return true;
    }

    @Override  // AnimatesBounds
    public void onAnimationEnd(boolean schedulePipModeChangedCallback, Rect finalStackSize,
            boolean moveToFullscreen) {
        if (inPinnedWindowingMode()) {
            // Update to the final bounds if requested. This is done here instead of in the bounds
            // animator to allow us to coordinate this after we notify the PiP mode changed

            if (schedulePipModeChangedCallback) {
                // We need to schedule the PiP mode change after the animation down, so use the
                // final bounds
                mActivityStack.updatePictureInPictureModeForPinnedStackAnimation(
                        mBoundsAnimationTarget, false /* forceUpdate */);
            }

            if (mAnimationType == BoundsAnimationController.FADE_IN) {
                setPinnedStackAlpha(1f);
                mActivityStack.mService.notifyPinnedStackAnimationEnded();
                return;
            }

            if (finalStackSize != null && !mCancelCurrentBoundsAnimation) {
                setPinnedStackSize(finalStackSize, null);
            } else {
                // We have been canceled, so the final stack size is null, still run the
                // animation-end logic
                onPipAnimationEndResize();
            }

            mActivityStack.mService.notifyPinnedStackAnimationEnded();
            if (moveToFullscreen) {
                mActivityStack.mService.moveTasksToFullscreenStack(mStackId, true /* onTop */);
            }
        } else {
            // No PiP animation, just run the normal animation-end logic
            onPipAnimationEndResize();
        }
    }

    /**
     * @return the current stack bounds transformed to the given {@param aspectRatio}. If
     *         the default bounds is {@code null}, then the {@param aspectRatio} is applied to the
     *         default bounds.
     */
    Rect getPictureInPictureBounds(float aspectRatio, Rect stackBounds) {
        if (!mWmService.mSupportsPictureInPicture) {
            return null;
        }

        final DisplayContent displayContent = getDisplayContent();
        if (displayContent == null) {
            return null;
        }

        if (!inPinnedWindowingMode()) {
            return null;
        }

        final PinnedStackController pinnedStackController =
                displayContent.getPinnedStackController();
        if (stackBounds == null) {
            // Calculate the aspect ratio bounds from the default bounds
            stackBounds = pinnedStackController.getDefaultOrLastSavedBounds();
        }

        if (pinnedStackController.isValidPictureInPictureAspectRatio(aspectRatio)) {
            return pinnedStackController.transformBoundsToAspectRatio(stackBounds, aspectRatio,
                    true /* useCurrentMinEdgeSize */);
        } else {
            return stackBounds;
        }
    }

    /**
     * Animates the pinned stack.
     */
    void animateResizePinnedStack(Rect toBounds, Rect sourceHintBounds,
            int animationDuration, boolean fromFullscreen) {
        if (!inPinnedWindowingMode()) {
            return;
        }
        // Get the from-bounds
        final Rect fromBounds = new Rect();
        getBounds(fromBounds);

        // Get non-null fullscreen to-bounds for animating if the bounds are null
        @SchedulePipModeChangedState int schedulePipModeChangedState =
                NO_PIP_MODE_CHANGED_CALLBACKS;
        final boolean toFullscreen = toBounds == null;
        if (toFullscreen) {
            if (fromFullscreen) {
                throw new IllegalArgumentException("Should not defer scheduling PiP mode"
                        + " change on animation to fullscreen.");
            }
            schedulePipModeChangedState = SCHEDULE_PIP_MODE_CHANGED_ON_START;

            mWmService.getStackBounds(
                    WINDOWING_MODE_FULLSCREEN, ACTIVITY_TYPE_STANDARD, mTmpToBounds);
            if (!mTmpToBounds.isEmpty()) {
                // If there is a fullscreen bounds, use that
                toBounds = new Rect(mTmpToBounds);
            } else {
                // Otherwise, use the display bounds
                toBounds = new Rect();
                getDisplayContent().getBounds(toBounds);
            }
        } else if (fromFullscreen) {
            schedulePipModeChangedState = SCHEDULE_PIP_MODE_CHANGED_ON_END;
        }

        setAnimationFinalBounds(sourceHintBounds, toBounds, toFullscreen);

        final Rect finalToBounds = toBounds;
        final @SchedulePipModeChangedState int finalSchedulePipModeChangedState =
                schedulePipModeChangedState;
        final DisplayContent displayContent = getDisplayContent();
        @BoundsAnimationController.AnimationType int intendedAnimationType =
                displayContent.mBoundsAnimationController.getAnimationType();
        if (intendedAnimationType == FADE_IN) {
            if (fromFullscreen) {
                setPinnedStackAlpha(0f);
            }
            if (toBounds.width() == fromBounds.width()
                    && toBounds.height() == fromBounds.height()) {
                intendedAnimationType = BoundsAnimationController.BOUNDS;
            }
        }

        final @BoundsAnimationController.AnimationType int animationType = intendedAnimationType;
        mCancelCurrentBoundsAnimation = false;
        displayContent.mBoundsAnimationController.getHandler().post(() -> {
            displayContent.mBoundsAnimationController.animateBounds(this, fromBounds,
                    finalToBounds, animationDuration, finalSchedulePipModeChangedState,
                    fromFullscreen, toFullscreen, animationType);
        });
    }

    /**
     * Sets the current picture-in-picture aspect ratio.
     */
    void setPictureInPictureAspectRatio(float aspectRatio) {
        if (!mWmService.mSupportsPictureInPicture) {
            return;
        }

        if (!inPinnedWindowingMode()) {
            return;
        }

        final PinnedStackController pinnedStackController =
                getDisplayContent().getPinnedStackController();

        if (Float.compare(aspectRatio, pinnedStackController.getAspectRatio()) == 0) {
            return;
        }
        getAnimationOrCurrentBounds(mTmpFromBounds);
        mTmpToBounds.set(mTmpFromBounds);
        getPictureInPictureBounds(aspectRatio, mTmpToBounds);
        if (!mTmpToBounds.equals(mTmpFromBounds)) {
            animateResizePinnedStack(mTmpToBounds, null /* sourceHintBounds */,
                    -1 /* duration */, false /* fromFullscreen */);
        }
        pinnedStackController.setAspectRatio(
                pinnedStackController.isValidPictureInPictureAspectRatio(aspectRatio)
                        ? aspectRatio : -1f);
    }

    /**
     * Sets the current picture-in-picture actions.
     */
    void setPictureInPictureActions(List<RemoteAction> actions) {
        if (!mWmService.mSupportsPictureInPicture) {
            return;
        }

        if (!inPinnedWindowingMode()) {
            return;
        }

        getDisplayContent().getPinnedStackController().setActions(actions);
    }

    @Override
    public boolean isAttached() {
        synchronized (mWmService.mGlobalLock) {
            return mDisplayContent != null;
        }
    }

    /**
     * Called immediately prior to resizing the tasks at the end of the pinned stack animation.
     */
    public void onPipAnimationEndResize() {
        synchronized (mWmService.mGlobalLock) {
            mBoundsAnimating = false;
            for (int i = 0; i < mChildren.size(); i++) {
                final Task t = mChildren.get(i);
                t.clearPreserveNonFloatingState();
            }
            mWmService.requestTraversal();
        }
    }

    @Override
    public boolean shouldDeferStartOnMoveToFullscreen() {
        synchronized (mWmService.mGlobalLock) {
            if (!isAttached()) {
                // Unnecessary to pause the animation because the stack is detached.
                return false;
            }

            // Workaround for the recents animation -- normally we need to wait for the new activity
            // to show before starting the PiP animation, but because we start and show the home
            // activity early for the recents animation prior to the PiP animation starting, there
            // is no subsequent all-drawn signal. In this case, we can skip the pause when the home
            // stack is already visible and drawn.
            final TaskStack homeStack = mDisplayContent.getHomeStack();
            if (homeStack == null) {
                return true;
            }
            final Task homeTask = homeStack.getTopChild();
            if (homeTask == null) {
                return true;
            }
            final AppWindowToken homeApp = homeTask.getTopVisibleAppToken();
            if (!homeTask.isVisible() || homeApp == null) {
                return true;
            }
            return !homeApp.allDrawn;
        }
    }

    /**
     * @return True if we are currently animating the pinned stack from fullscreen to non-fullscreen
     *         bounds and we have a deferred PiP mode changed callback set with the animation.
     */
    public boolean deferScheduleMultiWindowModeChanged() {
        if (inPinnedWindowingMode()) {
            return (mBoundsAnimatingRequested || mBoundsAnimating);
        }
        return false;
    }

    public boolean isForceScaled() {
        return mBoundsAnimating;
    }

    public boolean isAnimatingBounds() {
        return mBoundsAnimating;
    }

    public boolean lastAnimatingBoundsWasToFullscreen() {
        return mBoundsAnimatingToFullscreen;
    }

    public boolean isAnimatingBoundsToFullscreen() {
        return isAnimatingBounds() && lastAnimatingBoundsWasToFullscreen();
    }

    public boolean pinnedStackResizeDisallowed() {
        if (mBoundsAnimating && mCancelCurrentBoundsAnimation) {
            return true;
        }
        return false;
    }

    /** Returns true if a removal action is still being deferred. */
    boolean checkCompleteDeferredRemoval() {
        if (isSelfOrChildAnimating()) {
            return true;
        }
        if (mDeferRemoval) {
            removeImmediately();
        }

        return super.checkCompleteDeferredRemoval();
    }

    @Override
    int getOrientation() {
        return (canSpecifyOrientation()) ? super.getOrientation() : SCREEN_ORIENTATION_UNSET;
    }

    private boolean canSpecifyOrientation() {
        final int windowingMode = getWindowingMode();
        final int activityType = getActivityType();
        return windowingMode == WINDOWING_MODE_FULLSCREEN
                || activityType == ACTIVITY_TYPE_HOME
                || activityType == ACTIVITY_TYPE_RECENTS
                || activityType == ACTIVITY_TYPE_ASSISTANT;
    }

    @Override
    Dimmer getDimmer() {
        return mDimmer;
    }

    @Override
    void prepareSurfaces() {
        mDimmer.resetDimStates();
        super.prepareSurfaces();
        getDimBounds(mTmpDimBoundsRect);

        // Bounds need to be relative, as the dim layer is a child.
        mTmpDimBoundsRect.offsetTo(0, 0);
        if (mDimmer.updateDims(getPendingTransaction(), mTmpDimBoundsRect)) {
            scheduleAnimation();
        }
    }

    @Override
    public boolean setPinnedStackAlpha(float alpha) {
        // Hold the lock since this is called from the BoundsAnimator running on the UiThread
        synchronized (mWmService.mGlobalLock) {
            final SurfaceControl sc = getSurfaceControl();
            if (sc == null || !sc.isValid()) {
                // If the stack is already removed, don't bother updating any stack animation
                return false;
            }
            getPendingTransaction().setAlpha(sc, mCancelCurrentBoundsAnimation ? 1 : alpha);
            scheduleAnimation();
            return !mCancelCurrentBoundsAnimation;
        }
    }

    public DisplayInfo getDisplayInfo() {
        return mDisplayContent.getDisplayInfo();
    }

    void dim(float alpha) {
        mDimmer.dimAbove(getPendingTransaction(), alpha);
        scheduleAnimation();
    }

    void stopDimming() {
        mDimmer.stopDim(getPendingTransaction());
        scheduleAnimation();
    }

    AnimatingAppWindowTokenRegistry getAnimatingAppWindowTokenRegistry() {
        return mAnimatingAppWindowTokenRegistry;
    }
}