/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.appwidget;

import android.annotation.NonNull;
import android.annotation.Nullable;
import android.app.Activity;
import android.content.ActivityNotFoundException;
import android.content.Context;
import android.content.IntentSender;
import android.content.pm.PackageManager;
import android.os.Binder;
import android.os.Bundle;
import android.os.Handler;
import android.os.IBinder;
import android.os.Looper;
import android.os.Message;
import android.os.Process;
import android.os.RemoteException;
import android.os.ServiceManager;
import android.util.DisplayMetrics;
import android.util.SparseArray;
import android.widget.RemoteViews;
import android.widget.RemoteViews.OnClickHandler;

import com.android.internal.R;
import com.android.internal.appwidget.IAppWidgetHost;
import com.android.internal.appwidget.IAppWidgetService;

import java.lang.ref.WeakReference;
import java.util.List;

AppWidgetHost provides the interaction with the AppWidget service for apps,
like the home screen, that want to embed AppWidgets in their UI.
/**
 * AppWidgetHost provides the interaction with the AppWidget service for apps,
 * like the home screen, that want to embed AppWidgets in their UI.
 */
public class AppWidgetHost {

    static final int HANDLE_UPDATE = 1;
    static final int HANDLE_PROVIDER_CHANGED = 2;
    static final int HANDLE_PROVIDERS_CHANGED = 3;
    static final int HANDLE_VIEW_DATA_CHANGED = 4;

    final static Object sServiceLock = new Object();
    static IAppWidgetService sService;
    static boolean sServiceInitialized = false;
    private DisplayMetrics mDisplayMetrics;

    private String mContextOpPackageName;
    private final Handler mHandler;
    private final int mHostId;
    private final Callbacks mCallbacks;
    private final SparseArray<AppWidgetHostView> mViews = new SparseArray<>();
    private OnClickHandler mOnClickHandler;

    static class Callbacks extends IAppWidgetHost.Stub {
        private final WeakReference<Handler> mWeakHandler;

        public Callbacks(Handler handler) {
            mWeakHandler = new WeakReference<>(handler);
        }

        public void updateAppWidget(int appWidgetId, RemoteViews views) {
            if (isLocalBinder() && views != null) {
                views = views.clone();
            }
            Handler handler = mWeakHandler.get();
            if (handler == null) {
                return;
            }
            Message msg = handler.obtainMessage(HANDLE_UPDATE, appWidgetId, 0, views);
            msg.sendToTarget();
        }

        public void providerChanged(int appWidgetId, AppWidgetProviderInfo info) {
            if (isLocalBinder() && info != null) {
                info = info.clone();
            }
            Handler handler = mWeakHandler.get();
            if (handler == null) {
                return;
            }
            Message msg = handler.obtainMessage(HANDLE_PROVIDER_CHANGED,
                    appWidgetId, 0, info);
            msg.sendToTarget();
        }

        public void providersChanged() {
            Handler handler = mWeakHandler.get();
            if (handler == null) {
                return;
            }
            handler.obtainMessage(HANDLE_PROVIDERS_CHANGED).sendToTarget();
        }

        public void viewDataChanged(int appWidgetId, int viewId) {
            Handler handler = mWeakHandler.get();
            if (handler == null) {
                return;
            }
            Message msg = handler.obtainMessage(HANDLE_VIEW_DATA_CHANGED,
                    appWidgetId, viewId);
            msg.sendToTarget();
        }

        private static boolean isLocalBinder() {
            return Process.myPid() == Binder.getCallingPid();
        }
    }

    class UpdateHandler extends Handler {
        public UpdateHandler(Looper looper) {
            super(looper);
        }

        public void handleMessage(Message msg) {
            switch (msg.what) {
                case HANDLE_UPDATE: {
                    updateAppWidgetView(msg.arg1, (RemoteViews)msg.obj);
                    break;
                }
                case HANDLE_PROVIDER_CHANGED: {
                    onProviderChanged(msg.arg1, (AppWidgetProviderInfo)msg.obj);
                    break;
                }
                case HANDLE_PROVIDERS_CHANGED: {
                    onProvidersChanged();
                    break;
                }
                case HANDLE_VIEW_DATA_CHANGED: {
                    viewDataChanged(msg.arg1, msg.arg2);
                    break;
                }
            }
        }
    }

    public AppWidgetHost(Context context, int hostId) {
        this(context, hostId, null, context.getMainLooper());
    }

    
@hide
/**
     * @hide
     */
    public AppWidgetHost(Context context, int hostId, OnClickHandler handler, Looper looper) {
        mContextOpPackageName = context.getOpPackageName();
        mHostId = hostId;
        mOnClickHandler = handler;
        mHandler = new UpdateHandler(looper);
        mCallbacks = new Callbacks(mHandler);
        mDisplayMetrics = context.getResources().getDisplayMetrics();
        bindService(context);
    }

    private static void bindService(Context context) {
        synchronized (sServiceLock) {
            if (sServiceInitialized) {
                return;
            }
            sServiceInitialized = true;
            PackageManager packageManager = context.getPackageManager();
            if (!packageManager.hasSystemFeature(PackageManager.FEATURE_APP_WIDGETS)
                    && !context.getResources().getBoolean(R.bool.config_enableAppWidgetService)) {
                return;
            }
            IBinder b = ServiceManager.getService(Context.APPWIDGET_SERVICE);
            sService = IAppWidgetService.Stub.asInterface(b);
        }
    }

    
Start receiving onAppWidgetChanged calls for your AppWidgets.  Call this when your activity
becomes visible, i.e. from onStart() in your Activity.
/**
     * Start receiving onAppWidgetChanged calls for your AppWidgets.  Call this when your activity
     * becomes visible, i.e. from onStart() in your Activity.
     */
    public void startListening() {
        if (sService == null) {
            return;
        }
        final int[] idsToUpdate;
        synchronized (mViews) {
            int N = mViews.size();
            idsToUpdate = new int[N];
            for (int i = 0; i < N; i++) {
                idsToUpdate[i] = mViews.keyAt(i);
            }
        }
        List<PendingHostUpdate> updates;
        try {
            updates = sService.startListening(
                    mCallbacks, mContextOpPackageName, mHostId, idsToUpdate).getList();
        }
        catch (RemoteException e) {
            throw new RuntimeException("system server dead?", e);
        }

        int N = updates.size();
        for (int i = 0; i < N; i++) {
            PendingHostUpdate update = updates.get(i);
            switch (update.type) {
                case PendingHostUpdate.TYPE_VIEWS_UPDATE:
                    updateAppWidgetView(update.appWidgetId, update.views);
                    break;
                case PendingHostUpdate.TYPE_PROVIDER_CHANGED:
                    onProviderChanged(update.appWidgetId, update.widgetInfo);
                    break;
                case PendingHostUpdate.TYPE_VIEW_DATA_CHANGED:
                    viewDataChanged(update.appWidgetId, update.viewId);
            }
        }
    }

    
Stop receiving onAppWidgetChanged calls for your AppWidgets.  Call this when your activity is
no longer visible, i.e. from onStop() in your Activity.
/**
     * Stop receiving onAppWidgetChanged calls for your AppWidgets.  Call this when your activity is
     * no longer visible, i.e. from onStop() in your Activity.
     */
    public void stopListening() {
        if (sService == null) {
            return;
        }
        try {
            sService.stopListening(mContextOpPackageName, mHostId);
        }
        catch (RemoteException e) {
            throw new RuntimeException("system server dead?", e);
        }
    }

    
Get a appWidgetId for a host in the calling process.
Returns:
a appWidgetId/**
     * Get a appWidgetId for a host in the calling process.
     *
     * @return a appWidgetId
     */
    public int allocateAppWidgetId() {
        if (sService == null) {
            return -1;
        }
        try {
            return sService.allocateAppWidgetId(mContextOpPackageName, mHostId);
        }
        catch (RemoteException e) {
            throw new RuntimeException("system server dead?", e);
        }
    }

    
Starts an app widget provider configure activity for result on behalf of the caller. Use this method if the provider is in another profile as you are not allowed to start an activity in another profile. You can optionally provide a request code that is returned in Activity.onActivityResult(int, int, Intent) and an options bundle to be passed to the started activity. 

Note that the provided app widget has to be bound for this method to work.

Params:
activity – The activity from which to start the configure one.
appWidgetId – The bound app widget whose provider's config activity to start.
requestCode – Optional request code retuned with the result.
intentFlags – Optional intent flags.
Throws:
ActivityNotFoundException – If the activity is not found.
See Also:
AppWidgetProviderInfo.getProfile()/**
     * Starts an app widget provider configure activity for result on behalf of the caller.
     * Use this method if the provider is in another profile as you are not allowed to start
     * an activity in another profile. You can optionally provide a request code that is
     * returned in {@link Activity#onActivityResult(int, int, android.content.Intent)} and
     * an options bundle to be passed to the started activity.
     * <p>
     * Note that the provided app widget has to be bound for this method to work.
     * </p>
     *
     * @param activity The activity from which to start the configure one.
     * @param appWidgetId The bound app widget whose provider's config activity to start.
     * @param requestCode Optional request code retuned with the result.
     * @param intentFlags Optional intent flags.
     *
     * @throws android.content.ActivityNotFoundException If the activity is not found.
     *
     * @see AppWidgetProviderInfo#getProfile()
     */
    public final void startAppWidgetConfigureActivityForResult(@NonNull Activity activity,
            int appWidgetId, int intentFlags, int requestCode, @Nullable Bundle options) {
        if (sService == null) {
            return;
        }
        try {
            IntentSender intentSender = sService.createAppWidgetConfigIntentSender(
                    mContextOpPackageName, appWidgetId, intentFlags);
            if (intentSender != null) {
                activity.startIntentSenderForResult(intentSender, requestCode, null, 0, 0, 0,
                        options);
            } else {
                throw new ActivityNotFoundException();
            }
        } catch (IntentSender.SendIntentException e) {
            throw new ActivityNotFoundException();
        } catch (RemoteException e) {
            throw new RuntimeException("system server dead?", e);
        }
    }

    
Gets a list of all the appWidgetIds that are bound to the current host
/**
     * Gets a list of all the appWidgetIds that are bound to the current host
     */
    public int[] getAppWidgetIds() {
        if (sService == null) {
            return new int[0];
        }
        try {
            return sService.getAppWidgetIdsForHost(mContextOpPackageName, mHostId);
        } catch (RemoteException e) {
            throw new RuntimeException("system server dead?", e);
        }
    }

    
Stop listening to changes for this AppWidget.
/**
     * Stop listening to changes for this AppWidget.
     */
    public void deleteAppWidgetId(int appWidgetId) {
        if (sService == null) {
            return;
        }
        synchronized (mViews) {
            mViews.remove(appWidgetId);
            try {
                sService.deleteAppWidgetId(mContextOpPackageName, appWidgetId);
            }
            catch (RemoteException e) {
                throw new RuntimeException("system server dead?", e);
            }
        }
    }

    
Remove all records about this host from the AppWidget manager.

  
Call this when initializing your database, as it might be because of a data wipe.
  
Call this to have the AppWidget manager release all resources associated with your
  host.  Any future calls about this host will cause the records to be re-allocated.

/**
     * Remove all records about this host from the AppWidget manager.
     * <ul>
     *   <li>Call this when initializing your database, as it might be because of a data wipe.</li>
     *   <li>Call this to have the AppWidget manager release all resources associated with your
     *   host.  Any future calls about this host will cause the records to be re-allocated.</li>
     * </ul>
     */
    public void deleteHost() {
        if (sService == null) {
            return;
        }
        try {
            sService.deleteHost(mContextOpPackageName, mHostId);
        }
        catch (RemoteException e) {
            throw new RuntimeException("system server dead?", e);
        }
    }

    
Remove all records about all hosts for your package.

  
Call this when initializing your database, as it might be because of a data wipe.
  
Call this to have the AppWidget manager release all resources associated with your
  host.  Any future calls about this host will cause the records to be re-allocated.

/**
     * Remove all records about all hosts for your package.
     * <ul>
     *   <li>Call this when initializing your database, as it might be because of a data wipe.</li>
     *   <li>Call this to have the AppWidget manager release all resources associated with your
     *   host.  Any future calls about this host will cause the records to be re-allocated.</li>
     * </ul>
     */
    public static void deleteAllHosts() {
        if (sService == null) {
            return;
        }
        try {
            sService.deleteAllHosts();
        }
        catch (RemoteException e) {
            throw new RuntimeException("system server dead?", e);
        }
    }

    
Create the AppWidgetHostView for the given widget.
The AppWidgetHost retains a pointer to the newly-created View.
/**
     * Create the AppWidgetHostView for the given widget.
     * The AppWidgetHost retains a pointer to the newly-created View.
     */
    public final AppWidgetHostView createView(Context context, int appWidgetId,
            AppWidgetProviderInfo appWidget) {
        if (sService == null) {
            return null;
        }
        AppWidgetHostView view = onCreateView(context, appWidgetId, appWidget);
        view.setOnClickHandler(mOnClickHandler);
        view.setAppWidget(appWidgetId, appWidget);
        synchronized (mViews) {
            mViews.put(appWidgetId, view);
        }
        RemoteViews views;
        try {
            views = sService.getAppWidgetViews(mContextOpPackageName, appWidgetId);
        } catch (RemoteException e) {
            throw new RuntimeException("system server dead?", e);
        }
        view.updateAppWidget(views);

        return view;
    }

    
Called to create the AppWidgetHostView.  Override to return a custom subclass if you
need it.  {@more}
/**
     * Called to create the AppWidgetHostView.  Override to return a custom subclass if you
     * need it.  {@more}
     */
    protected AppWidgetHostView onCreateView(Context context, int appWidgetId,
            AppWidgetProviderInfo appWidget) {
        return new AppWidgetHostView(context, mOnClickHandler);
    }

    
Called when the AppWidget provider for a AppWidget has been upgraded to a new apk.
/**
     * Called when the AppWidget provider for a AppWidget has been upgraded to a new apk.
     */
    protected void onProviderChanged(int appWidgetId, AppWidgetProviderInfo appWidget) {
        AppWidgetHostView v;

        // Convert complex to dp -- we are getting the AppWidgetProviderInfo from the
        // AppWidgetService, which doesn't have our context, hence we need to do the
        // conversion here.
        appWidget.updateDimensions(mDisplayMetrics);
        synchronized (mViews) {
            v = mViews.get(appWidgetId);
        }
        if (v != null) {
            v.resetAppWidget(appWidget);
        }
    }

    
Called when the set of available widgets changes (ie. widget containing packages
are added, updated or removed, or widget components are enabled or disabled.)
/**
     * Called when the set of available widgets changes (ie. widget containing packages
     * are added, updated or removed, or widget components are enabled or disabled.)
     */
    protected void onProvidersChanged() {
        // Does nothing
    }

    void updateAppWidgetView(int appWidgetId, RemoteViews views) {
        AppWidgetHostView v;
        synchronized (mViews) {
            v = mViews.get(appWidgetId);
        }
        if (v != null) {
            v.updateAppWidget(views);
        }
    }

    void viewDataChanged(int appWidgetId, int viewId) {
        AppWidgetHostView v;
        synchronized (mViews) {
            v = mViews.get(appWidgetId);
        }
        if (v != null) {
            v.viewDataChanged(viewId);
        }
    }

    
Clear the list of Views that have been created by this AppWidgetHost.
/**
     * Clear the list of Views that have been created by this AppWidgetHost.
     */
    protected void clearViews() {
        synchronized (mViews) {
            mViews.clear();
        }
    }
}