/*
 * Copyright (C) 2014 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.systemui.recents;

import android.app.Activity;
import android.app.ActivityOptions;
import android.app.TaskStackBuilder;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.res.Configuration;
import android.net.Uri;
import android.os.Bundle;
import android.os.SystemClock;
import android.os.UserHandle;
import android.provider.Settings;
import android.util.Log;
import android.view.KeyEvent;
import android.view.View;
import android.view.ViewTreeObserver;
import android.view.WindowManager;
import android.view.WindowManager.LayoutParams;

import com.android.internal.logging.MetricsLogger;
import com.android.internal.logging.MetricsProto.MetricsEvent;
import com.android.systemui.R;
import com.android.systemui.recents.events.EventBus;
import com.android.systemui.recents.events.activity.CancelEnterRecentsWindowAnimationEvent;
import com.android.systemui.recents.events.activity.ConfigurationChangedEvent;
import com.android.systemui.recents.events.activity.DebugFlagsChangedEvent;
import com.android.systemui.recents.events.activity.DismissRecentsToHomeAnimationStarted;
import com.android.systemui.recents.events.activity.DockedFirstAnimationFrameEvent;
import com.android.systemui.recents.events.activity.EnterRecentsWindowAnimationCompletedEvent;
import com.android.systemui.recents.events.activity.EnterRecentsWindowLastAnimationFrameEvent;
import com.android.systemui.recents.events.activity.ExitRecentsWindowFirstAnimationFrameEvent;
import com.android.systemui.recents.events.activity.HideRecentsEvent;
import com.android.systemui.recents.events.activity.IterateRecentsEvent;
import com.android.systemui.recents.events.activity.LaunchTaskFailedEvent;
import com.android.systemui.recents.events.activity.LaunchTaskSucceededEvent;
import com.android.systemui.recents.events.activity.MultiWindowStateChangedEvent;
import com.android.systemui.recents.events.activity.ToggleRecentsEvent;
import com.android.systemui.recents.events.component.RecentsVisibilityChangedEvent;
import com.android.systemui.recents.events.component.ScreenPinningRequestEvent;
import com.android.systemui.recents.events.ui.AllTaskViewsDismissedEvent;
import com.android.systemui.recents.events.ui.DeleteTaskDataEvent;
import com.android.systemui.recents.events.ui.RecentsDrawnEvent;
import com.android.systemui.recents.events.ui.ShowApplicationInfoEvent;
import com.android.systemui.recents.events.ui.StackViewScrolledEvent;
import com.android.systemui.recents.events.ui.UpdateFreeformTaskViewVisibilityEvent;
import com.android.systemui.recents.events.ui.UserInteractionEvent;
import com.android.systemui.recents.events.ui.focus.DismissFocusedTaskViewEvent;
import com.android.systemui.recents.events.ui.focus.FocusNextTaskViewEvent;
import com.android.systemui.recents.events.ui.focus.FocusPreviousTaskViewEvent;
import com.android.systemui.recents.misc.DozeTrigger;
import com.android.systemui.recents.misc.SystemServicesProxy;
import com.android.systemui.recents.model.RecentsPackageMonitor;
import com.android.systemui.recents.model.RecentsTaskLoadPlan;
import com.android.systemui.recents.model.RecentsTaskLoader;
import com.android.systemui.recents.model.Task;
import com.android.systemui.recents.model.TaskStack;
import com.android.systemui.recents.views.AnimationProps;
import com.android.systemui.recents.views.RecentsView;
import com.android.systemui.recents.views.SystemBarScrimViews;
import com.android.systemui.statusbar.BaseStatusBar;

/**
 * The main Recents activity that is started from AlternateRecentsComponent.
 */
public class RecentsActivity extends Activity implements ViewTreeObserver.OnPreDrawListener {

    private final static String TAG = "RecentsActivity";
    private final static boolean DEBUG = false;

    public final static int EVENT_BUS_PRIORITY = Recents.EVENT_BUS_PRIORITY + 1;

    private RecentsPackageMonitor mPackageMonitor;
    private long mLastTabKeyEventTime;
    private int mLastOrientation = Configuration.ORIENTATION_UNDEFINED;
    private boolean mFinishedOnStartup;
    private boolean mIgnoreAltTabRelease;
    private boolean mIsVisible;

    // Top level views
    private RecentsView mRecentsView;
    private SystemBarScrimViews mScrimViews;

    // Runnables to finish the Recents activity
    private Intent mHomeIntent;

    // The trigger to automatically launch the current task
    private int mFocusTimerDuration;
    private DozeTrigger mIterateTrigger;
    private final UserInteractionEvent mUserInteractionEvent = new UserInteractionEvent();

    /**
     * A common Runnable to finish Recents by launching Home with an animation depending on the
     * last activity launch state. Generally we always launch home when we exit Recents rather than
     * just finishing the activity since we don't know what is behind Recents in the task stack.
     */
    class LaunchHomeRunnable implements Runnable {

        Intent mLaunchIntent;
        ActivityOptions mOpts;

        /**
         * Creates a finish runnable that starts the specified intent.
         */
        public LaunchHomeRunnable(Intent launchIntent, ActivityOptions opts) {
            mLaunchIntent = launchIntent;
            mOpts = opts;
        }

        @Override
        public void run() {
            try {
                ActivityOptions opts = mOpts;
                if (opts == null) {
                    opts = ActivityOptions.makeCustomAnimation(RecentsActivity.this,
                            R.anim.recents_to_launcher_enter, R.anim.recents_to_launcher_exit);
                }
                startActivityAsUser(mLaunchIntent, opts.toBundle(), UserHandle.CURRENT);
            } catch (Exception e) {
                Log.e(TAG, getString(R.string.recents_launch_error_message, "Home"), e);
            }
        }
    }

    /**
     * Broadcast receiver to handle messages from the system
     */
    final BroadcastReceiver mSystemBroadcastReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            if (action.equals(Intent.ACTION_SCREEN_OFF)) {
                // When the screen turns off, dismiss Recents to Home
                dismissRecentsToHomeIfVisible(false);
            }
        }
    };

    /**
     * Dismisses recents if we are already visible and the intent is to toggle the recents view.
     */
    boolean dismissRecentsToFocusedTask(int logCategory) {
        SystemServicesProxy ssp = Recents.getSystemServices();
        if (ssp.isRecentsTopMost(ssp.getTopMostTask(), null)) {
            // If we have a focused Task, launch that Task now
            if (mRecentsView.launchFocusedTask(logCategory)) return true;
        }
        return false;
    }

    /**
     * Dismisses recents back to the launch target task.
     */
    boolean dismissRecentsToLaunchTargetTaskOrHome() {
        SystemServicesProxy ssp = Recents.getSystemServices();
        if (ssp.isRecentsTopMost(ssp.getTopMostTask(), null)) {
            // If we have a focused Task, launch that Task now
            if (mRecentsView.launchPreviousTask()) return true;
            // If none of the other cases apply, then just go Home
            dismissRecentsToHome(true /* animateTaskViews */);
        }
        return false;
    }

    /**
     * Dismisses recents if we are already visible and the intent is to toggle the recents view.
     */
    boolean dismissRecentsToFocusedTaskOrHome() {
        SystemServicesProxy ssp = Recents.getSystemServices();
        if (ssp.isRecentsTopMost(ssp.getTopMostTask(), null)) {
            // If we have a focused Task, launch that Task now
            if (mRecentsView.launchFocusedTask(0 /* logCategory */)) return true;
            // If none of the other cases apply, then just go Home
            dismissRecentsToHome(true /* animateTaskViews */);
            return true;
        }
        return false;
    }

    /**
     * Dismisses Recents directly to Home without checking whether it is currently visible.
     */
    void dismissRecentsToHome(boolean animateTaskViews) {
        dismissRecentsToHome(animateTaskViews, null);
    }

    /**
     * Dismisses Recents directly to Home without checking whether it is currently visible.
     *
     * @param overrideAnimation If not null, will override the default animation that is based on
     *                          how Recents was launched.
     */
    void dismissRecentsToHome(boolean animateTaskViews, ActivityOptions overrideAnimation) {
        DismissRecentsToHomeAnimationStarted dismissEvent =
                new DismissRecentsToHomeAnimationStarted(animateTaskViews);
        dismissEvent.addPostAnimationCallback(new LaunchHomeRunnable(mHomeIntent,
                overrideAnimation));
        dismissEvent.addPostAnimationCallback(new Runnable() {
            @Override
            public void run() {
                Recents.getSystemServices().sendCloseSystemWindows(
                        BaseStatusBar.SYSTEM_DIALOG_REASON_HOME_KEY);
            }
        });
        EventBus.getDefault().send(dismissEvent);
    }

    /** Dismisses Recents directly to Home if we currently aren't transitioning. */
    boolean dismissRecentsToHomeIfVisible(boolean animated) {
        SystemServicesProxy ssp = Recents.getSystemServices();
        if (ssp.isRecentsTopMost(ssp.getTopMostTask(), null)) {
            // Return to Home
            dismissRecentsToHome(animated);
            return true;
        }
        return false;
    }

    /** Called with the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mFinishedOnStartup = false;

        // In the case that the activity starts up before the Recents component has initialized
        // (usually when debugging/pushing the SysUI apk), just finish this activity.
        SystemServicesProxy ssp = Recents.getSystemServices();
        if (ssp == null) {
            mFinishedOnStartup = true;
            finish();
            return;
        }

        // Register this activity with the event bus
        EventBus.getDefault().register(this, EVENT_BUS_PRIORITY);

        // Initialize the package monitor
        mPackageMonitor = new RecentsPackageMonitor();
        mPackageMonitor.register(this);

        // Set the Recents layout
        setContentView(R.layout.recents);
        takeKeyEvents(true);
        mRecentsView = (RecentsView) findViewById(R.id.recents_view);
        mRecentsView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_STABLE |
                View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN |
                View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION);
        mScrimViews = new SystemBarScrimViews(this);
        getWindow().getAttributes().privateFlags |=
                WindowManager.LayoutParams.PRIVATE_FLAG_FORCE_DECOR_VIEW_VISIBILITY;

        mLastOrientation = getResources().getConfiguration().orientation;
        mFocusTimerDuration = getResources().getInteger(R.integer.recents_auto_advance_duration);
        mIterateTrigger = new DozeTrigger(mFocusTimerDuration, new Runnable() {
            @Override
            public void run() {
                dismissRecentsToFocusedTask(MetricsEvent.OVERVIEW_SELECT_TIMEOUT);
            }
        });

        // Set the window background
        getWindow().setBackgroundDrawable(mRecentsView.getBackgroundScrim());

        // Create the home intent runnable
        mHomeIntent = new Intent(Intent.ACTION_MAIN, null);
        mHomeIntent.addCategory(Intent.CATEGORY_HOME);
        mHomeIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK |
                Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED);

        // Register the broadcast receiver to handle messages when the screen is turned off
        IntentFilter filter = new IntentFilter();
        filter.addAction(Intent.ACTION_SCREEN_OFF);
        registerReceiver(mSystemBroadcastReceiver, filter);

        getWindow().addPrivateFlags(LayoutParams.PRIVATE_FLAG_NO_MOVE_ANIMATION);

        // Reload the stack view
        reloadStackView();
    }

    @Override
    protected void onStart() {
        super.onStart();

        // Notify that recents is now visible
        EventBus.getDefault().send(new RecentsVisibilityChangedEvent(this, true));
        MetricsLogger.visible(this, MetricsEvent.OVERVIEW_ACTIVITY);
    }

    @Override
    protected void onNewIntent(Intent intent) {
        super.onNewIntent(intent);

        // Reload the stack view
        reloadStackView();
    }

    /**
     * Reloads the stack views upon launching Recents.
     */
    private void reloadStackView() {
        // If the Recents component has preloaded a load plan, then use that to prevent
        // reconstructing the task stack
        RecentsTaskLoader loader = Recents.getTaskLoader();
        RecentsTaskLoadPlan loadPlan = RecentsImpl.consumeInstanceLoadPlan();
        if (loadPlan == null) {
            loadPlan = loader.createLoadPlan(this);
        }

        // Start loading tasks according to the load plan
        RecentsConfiguration config = Recents.getConfiguration();
        RecentsActivityLaunchState launchState = config.getLaunchState();
        if (!loadPlan.hasTasks()) {
            loader.preloadTasks(loadPlan, launchState.launchedToTaskId,
                    launchState.launchedFromHome);
        }

        RecentsTaskLoadPlan.Options loadOpts = new RecentsTaskLoadPlan.Options();
        loadOpts.runningTaskId = launchState.launchedToTaskId;
        loadOpts.numVisibleTasks = launchState.launchedNumVisibleTasks;
        loadOpts.numVisibleTaskThumbnails = launchState.launchedNumVisibleThumbnails;
        loader.loadTasks(this, loadPlan, loadOpts);
        TaskStack stack = loadPlan.getTaskStack();
        mRecentsView.onReload(mIsVisible, stack.getTaskCount() == 0);
        mRecentsView.updateStack(stack);

        // Update the nav bar scrim, but defer the animation until the enter-window event
        boolean animateNavBarScrim = !launchState.launchedViaDockGesture;
        updateNavBarScrim(animateNavBarScrim, null);

        // If this is a new instance relaunched by AM, without going through the normal mechanisms,
        // then we have to manually trigger the enter animation state
        boolean wasLaunchedByAm = !launchState.launchedFromHome &&
                !launchState.launchedFromApp;
        if (wasLaunchedByAm) {
            EventBus.getDefault().send(new EnterRecentsWindowAnimationCompletedEvent());
        }

        // Keep track of whether we launched from the nav bar button or via alt-tab
        if (launchState.launchedWithAltTab) {
            MetricsLogger.count(this, "overview_trigger_alttab", 1);
        } else {
            MetricsLogger.count(this, "overview_trigger_nav_btn", 1);
        }

        // Keep track of whether we launched from an app or from home
        if (launchState.launchedFromApp) {
            Task launchTarget = stack.getLaunchTarget();
            int launchTaskIndexInStack = launchTarget != null
                    ? stack.indexOfStackTask(launchTarget)
                    : 0;
            MetricsLogger.count(this, "overview_source_app", 1);
            // If from an app, track the stack index of the app in the stack (for affiliated tasks)
            MetricsLogger.histogram(this, "overview_source_app_index", launchTaskIndexInStack);
        } else {
            MetricsLogger.count(this, "overview_source_home", 1);
        }

        // Keep track of the total stack task count
        int taskCount = mRecentsView.getStack().getTaskCount();
        MetricsLogger.histogram(this, "overview_task_count", taskCount);

        // After we have resumed, set the visible state until the next onStop() call
        mIsVisible = true;
    }

    @Override
    public void onEnterAnimationComplete() {
        super.onEnterAnimationComplete();
        EventBus.getDefault().send(new EnterRecentsWindowAnimationCompletedEvent());
    }

    @Override
    protected void onResume() {
        super.onResume();

        // Notify of the next draw
        mRecentsView.getViewTreeObserver().addOnPreDrawListener(
                new ViewTreeObserver.OnPreDrawListener() {

                    @Override
                    public boolean onPreDraw() {
                        mRecentsView.getViewTreeObserver().removeOnPreDrawListener(this);
                        EventBus.getDefault().post(new RecentsDrawnEvent());
                        return true;
                    }
                });
    }

    @Override
    protected void onPause() {
        super.onPause();

        mIgnoreAltTabRelease = false;
        mIterateTrigger.stopDozing();
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);

        // Update the nav bar for the current orientation
        updateNavBarScrim(false /* animateNavBarScrim */, AnimationProps.IMMEDIATE);

        // Notify of the config change
        int newOrientation = getResources().getConfiguration().orientation;
        EventBus.getDefault().send(new ConfigurationChangedEvent(false /* fromMultiWindow */,
                (mLastOrientation != newOrientation)));
        mLastOrientation = newOrientation;
    }

    @Override
    public void onMultiWindowChanged(boolean inMultiWindow) {
        super.onMultiWindowChanged(inMultiWindow);
        EventBus.getDefault().send(new ConfigurationChangedEvent(true /* fromMultiWindow */,
                false /* fromOrientationChange */));

        if (mRecentsView != null) {
            // Reload the task stack completely
            RecentsConfiguration config = Recents.getConfiguration();
            RecentsActivityLaunchState launchState = config.getLaunchState();
            RecentsTaskLoader loader = Recents.getTaskLoader();
            RecentsTaskLoadPlan loadPlan = loader.createLoadPlan(this);
            loader.preloadTasks(loadPlan, -1 /* topTaskId */, false /* isTopTaskHome */);

            RecentsTaskLoadPlan.Options loadOpts = new RecentsTaskLoadPlan.Options();
            loadOpts.numVisibleTasks = launchState.launchedNumVisibleTasks;
            loadOpts.numVisibleTaskThumbnails = launchState.launchedNumVisibleThumbnails;
            loader.loadTasks(this, loadPlan, loadOpts);

            mRecentsView.updateStack(loadPlan.getTaskStack());
        }

        EventBus.getDefault().send(new MultiWindowStateChangedEvent(inMultiWindow));
    }

    @Override
    protected void onStop() {
        super.onStop();

        // Notify that recents is now hidden
        mIsVisible = false;
        EventBus.getDefault().send(new RecentsVisibilityChangedEvent(this, false));
        MetricsLogger.hidden(this, MetricsEvent.OVERVIEW_ACTIVITY);

        // Workaround for b/22542869, if the RecentsActivity is started again, but without going
        // through SystemUI, we need to reset the config launch flags to ensure that we do not
        // wait on the system to send a signal that was never queued.
        RecentsConfiguration config = Recents.getConfiguration();
        RecentsActivityLaunchState launchState = config.getLaunchState();
        launchState.reset();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();

        // In the case that the activity finished on startup, just skip the unregistration below
        if (mFinishedOnStartup) {
            return;
        }

        // Unregister the system broadcast receivers
        unregisterReceiver(mSystemBroadcastReceiver);

        // Unregister any broadcast receivers for the task loader
        mPackageMonitor.unregister();

        EventBus.getDefault().unregister(this);
    }

    @Override
    public void onAttachedToWindow() {
        super.onAttachedToWindow();
        EventBus.getDefault().register(mScrimViews, EVENT_BUS_PRIORITY);
    }

    @Override
    public void onDetachedFromWindow() {
        super.onDetachedFromWindow();
        EventBus.getDefault().unregister(mScrimViews);
    }

    @Override
    public void onTrimMemory(int level) {
        RecentsTaskLoader loader = Recents.getTaskLoader();
        if (loader != null) {
            loader.onTrimMemory(level);
        }
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        switch (keyCode) {
            case KeyEvent.KEYCODE_TAB: {
                int altTabKeyDelay = getResources().getInteger(R.integer.recents_alt_tab_key_delay);
                boolean hasRepKeyTimeElapsed = (SystemClock.elapsedRealtime() -
                        mLastTabKeyEventTime) > altTabKeyDelay;
                if (event.getRepeatCount() <= 0 || hasRepKeyTimeElapsed) {
                    // Focus the next task in the stack
                    final boolean backward = event.isShiftPressed();
                    if (backward) {
                        EventBus.getDefault().send(new FocusPreviousTaskViewEvent());
                    } else {
                        EventBus.getDefault().send(
                                new FocusNextTaskViewEvent(0 /* timerIndicatorDuration */));
                    }
                    mLastTabKeyEventTime = SystemClock.elapsedRealtime();

                    // In the case of another ALT event, don't ignore the next release
                    if (event.isAltPressed()) {
                        mIgnoreAltTabRelease = false;
                    }
                }
                return true;
            }
            case KeyEvent.KEYCODE_DPAD_UP: {
                EventBus.getDefault().send(
                        new FocusNextTaskViewEvent(0 /* timerIndicatorDuration */));
                return true;
            }
            case KeyEvent.KEYCODE_DPAD_DOWN: {
                EventBus.getDefault().send(new FocusPreviousTaskViewEvent());
                return true;
            }
            case KeyEvent.KEYCODE_DEL:
            case KeyEvent.KEYCODE_FORWARD_DEL: {
                if (event.getRepeatCount() <= 0) {
                    EventBus.getDefault().send(new DismissFocusedTaskViewEvent());

                    // Keep track of deletions by keyboard
                    MetricsLogger.histogram(this, "overview_task_dismissed_source",
                            Constants.Metrics.DismissSourceKeyboard);
                    return true;
                }
            }
            default:
                break;
        }
        return super.onKeyDown(keyCode, event);
    }

    @Override
    public void onUserInteraction() {
        EventBus.getDefault().send(mUserInteractionEvent);
    }

    @Override
    public void onBackPressed() {
        // Back behaves like the recents button so just trigger a toggle event
        EventBus.getDefault().send(new ToggleRecentsEvent());
    }

    /**** EventBus events ****/

    public final void onBusEvent(ToggleRecentsEvent event) {
        RecentsActivityLaunchState launchState = Recents.getConfiguration().getLaunchState();
        if (launchState.launchedFromHome) {
            dismissRecentsToHome(true /* animateTaskViews */);
        } else {
            dismissRecentsToLaunchTargetTaskOrHome();
        }
    }

    public final void onBusEvent(IterateRecentsEvent event) {
        final RecentsDebugFlags debugFlags = Recents.getDebugFlags();

        // Start dozing after the recents button is clicked
        int timerIndicatorDuration = 0;
        if (debugFlags.isFastToggleRecentsEnabled()) {
            timerIndicatorDuration = getResources().getInteger(
                    R.integer.recents_subsequent_auto_advance_duration);

            mIterateTrigger.setDozeDuration(timerIndicatorDuration);
            if (!mIterateTrigger.isDozing()) {
                mIterateTrigger.startDozing();
            } else {
                mIterateTrigger.poke();
            }
        }

        // Focus the next task
        EventBus.getDefault().send(new FocusNextTaskViewEvent(timerIndicatorDuration));

        MetricsLogger.action(this, MetricsEvent.ACTION_OVERVIEW_PAGE);
    }

    public final void onBusEvent(UserInteractionEvent event) {
        // Stop the fast-toggle dozer
        mIterateTrigger.stopDozing();
    }

    public final void onBusEvent(HideRecentsEvent event) {
        if (event.triggeredFromAltTab) {
            // If we are hiding from releasing Alt-Tab, dismiss Recents to the focused app
            if (!mIgnoreAltTabRelease) {
                dismissRecentsToFocusedTaskOrHome();
            }
        } else if (event.triggeredFromHomeKey) {
            dismissRecentsToHome(true /* animateTaskViews */);

            // Cancel any pending dozes
            EventBus.getDefault().send(mUserInteractionEvent);
        } else {
            // Do nothing
        }
    }

    public final void onBusEvent(EnterRecentsWindowLastAnimationFrameEvent event) {
        EventBus.getDefault().send(new UpdateFreeformTaskViewVisibilityEvent(true));
        mRecentsView.getViewTreeObserver().addOnPreDrawListener(this);
        mRecentsView.invalidate();
    }

    public final void onBusEvent(ExitRecentsWindowFirstAnimationFrameEvent event) {
        if (mRecentsView.isLastTaskLaunchedFreeform()) {
            EventBus.getDefault().send(new UpdateFreeformTaskViewVisibilityEvent(false));
        }
        mRecentsView.getViewTreeObserver().addOnPreDrawListener(this);
        mRecentsView.invalidate();
    }

    public final void onBusEvent(DockedFirstAnimationFrameEvent event) {
        mRecentsView.getViewTreeObserver().addOnPreDrawListener(this);
        mRecentsView.invalidate();
    }

    public final void onBusEvent(CancelEnterRecentsWindowAnimationEvent event) {
        RecentsActivityLaunchState launchState = Recents.getConfiguration().getLaunchState();
        int launchToTaskId = launchState.launchedToTaskId;
        if (launchToTaskId != -1 &&
                (event.launchTask == null || launchToTaskId != event.launchTask.key.id)) {
            SystemServicesProxy ssp = Recents.getSystemServices();
            ssp.cancelWindowTransition(launchState.launchedToTaskId);
            ssp.cancelThumbnailTransition(getTaskId());
        }
    }

    public final void onBusEvent(ShowApplicationInfoEvent event) {
        // Create a new task stack with the application info details activity
        Intent intent = new Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS,
                Uri.fromParts("package", event.task.key.getComponent().getPackageName(), null));
        intent.setComponent(intent.resolveActivity(getPackageManager()));
        TaskStackBuilder.create(this)
                .addNextIntentWithParentStack(intent).startActivities(null,
                        new UserHandle(event.task.key.userId));

        // Keep track of app-info invocations
        MetricsLogger.count(this, "overview_app_info", 1);
    }

    public final void onBusEvent(DeleteTaskDataEvent event) {
        // Remove any stored data from the loader
        RecentsTaskLoader loader = Recents.getTaskLoader();
        loader.deleteTaskData(event.task, false);

        // Remove the task from activity manager
        SystemServicesProxy ssp = Recents.getSystemServices();
        ssp.removeTask(event.task.key.id);
    }

    public final void onBusEvent(AllTaskViewsDismissedEvent event) {
        SystemServicesProxy ssp = Recents.getSystemServices();
        if (ssp.hasDockedTask()) {
            mRecentsView.showEmptyView(event.msgResId);
        } else {
            // Just go straight home (no animation necessary because there are no more task views)
            dismissRecentsToHome(false /* animateTaskViews */);
        }

        // Keep track of all-deletions
        MetricsLogger.count(this, "overview_task_all_dismissed", 1);
    }

    public final void onBusEvent(LaunchTaskSucceededEvent event) {
        MetricsLogger.histogram(this, "overview_task_launch_index", event.taskIndexFromStackFront);
    }

    public final void onBusEvent(LaunchTaskFailedEvent event) {
        // Return to Home
        dismissRecentsToHome(true /* animateTaskViews */);

        MetricsLogger.count(this, "overview_task_launch_failed", 1);
    }

    public final void onBusEvent(ScreenPinningRequestEvent event) {
        MetricsLogger.count(this, "overview_screen_pinned", 1);
    }

    public final void onBusEvent(DebugFlagsChangedEvent event) {
        // Just finish recents so that we can reload the flags anew on the next instantiation
        finish();
    }

    public final void onBusEvent(StackViewScrolledEvent event) {
        // Once the user has scrolled while holding alt-tab, then we should ignore the release of
        // the key
        mIgnoreAltTabRelease = true;
    }

    @Override
    public boolean onPreDraw() {
        mRecentsView.getViewTreeObserver().removeOnPreDrawListener(this);
        // We post to make sure that this information is delivered after this traversals is
        // finished.
        mRecentsView.post(new Runnable() {
            @Override
            public void run() {
                Recents.getSystemServices().endProlongedAnimations();
            }
        });
        return true;
    }

    /**
     * Updates the nav bar scrim.
     */
    private void updateNavBarScrim(boolean animateNavBarScrim, AnimationProps animation) {
        // Animate the SystemUI scrims into view
        SystemServicesProxy ssp = Recents.getSystemServices();
        int taskCount = mRecentsView.getStack().getTaskCount();
        boolean hasNavBarScrim = (taskCount > 0) && !ssp.hasTransposedNavBar();
        mScrimViews.prepareEnterRecentsAnimation(hasNavBarScrim, animateNavBarScrim);
        if (animateNavBarScrim && animation != null) {
            mScrimViews.animateNavBarScrimVisibility(true, animation);
        }
    }
}