/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.service.notification;

import android.annotation.SdkConstant;
import android.annotation.SystemApi;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.os.Handler;
import android.os.IBinder;
import android.os.Looper;
import android.os.Message;
import android.os.RemoteException;
import android.util.Log;
import com.android.internal.os.SomeArgs;

/**
 * A service that helps the user manage notifications by modifying the
 * relative importance of notifications.
 * <p>To extend this class, you must declare the service in your manifest file with
 * the {@link android.Manifest.permission#BIND_NOTIFICATION_ASSISTANT_SERVICE} permission
 * and include an intent filter with the {@link #SERVICE_INTERFACE} action. For example:</p>
 * <pre>
 * &lt;service android:name=".NotificationAssistant"
 *          android:label="&#64;string/service_name"
 *          android:permission="android.permission.BIND_NOTIFICATION_ASSISTANT_SERVICE">
 *     &lt;intent-filter>
 *         &lt;action android:name="android.service.notification.NotificationAssistantService" />
 *     &lt;/intent-filter>
 * &lt;/service></pre>
 * @hide
 */
@SystemApi
public abstract class NotificationAssistantService extends NotificationListenerService {
    private static final String TAG = "NotificationAssistant";

    /**
     * The {@link Intent} that must be declared as handled by the service.
     */
    @SdkConstant(SdkConstant.SdkConstantType.SERVICE_ACTION)
    public static final String SERVICE_INTERFACE
            = "android.service.notification.NotificationAssistantService";

    /** Notification was canceled by the status bar reporting a click. */
    public static final int REASON_DELEGATE_CLICK = 1;

    /** Notification was canceled by the status bar reporting a user dismissal. */
    public static final int REASON_DELEGATE_CANCEL = 2;

    /** Notification was canceled by the status bar reporting a user dismiss all. */
    public static final int REASON_DELEGATE_CANCEL_ALL = 3;

    /** Notification was canceled by the status bar reporting an inflation error. */
    public static final int REASON_DELEGATE_ERROR = 4;

    /** Notification was canceled by the package manager modifying the package. */
    public static final int REASON_PACKAGE_CHANGED = 5;

    /** Notification was canceled by the owning user context being stopped. */
    public static final int REASON_USER_STOPPED = 6;

    /** Notification was canceled by the user banning the package. */
    public static final int REASON_PACKAGE_BANNED = 7;

    /** Notification was canceled by the app canceling this specific notification. */
    public static final int REASON_APP_CANCEL = 8;

    /** Notification was canceled by the app cancelling all its notifications. */
    public static final int REASON_APP_CANCEL_ALL = 9;

    /** Notification was canceled by a listener reporting a user dismissal. */
    public static final int REASON_LISTENER_CANCEL = 10;

    /** Notification was canceled by a listener reporting a user dismiss all. */
    public static final int REASON_LISTENER_CANCEL_ALL = 11;

    /** Notification was canceled because it was a member of a canceled group. */
    public static final int REASON_GROUP_SUMMARY_CANCELED = 12;

    /** Notification was canceled because it was an invisible member of a group. */
    public static final int REASON_GROUP_OPTIMIZATION = 13;

    /** Notification was canceled by the device administrator suspending the package. */
    public static final int REASON_PACKAGE_SUSPENDED = 14;

    /** Notification was canceled by the owning managed profile being turned off. */
    public static final int REASON_PROFILE_TURNED_OFF = 15;

    public class Adjustment {
        int mImportance;
        CharSequence mExplanation;
        Uri mReference;

        /**
         * Create a notification importance adjustment.
         *
         * @param importance The final importance of the notification.
         * @param explanation A human-readable justification for the adjustment.
         * @param reference A reference to an external object that augments the
         *                  explanation, such as a
         *                  {@link android.provider.ContactsContract.Contacts#CONTENT_LOOKUP_URI},
         *                  or null.
         */
        public Adjustment(int importance, CharSequence explanation, Uri reference) {
            mImportance = importance;
            mExplanation = explanation;
            mReference = reference;
        }
    }

    private Handler mHandler;

    /** @hide */
    @Override
    public void registerAsSystemService(Context context, ComponentName componentName,
            int currentUser) throws RemoteException {
        super.registerAsSystemService(context, componentName, currentUser);
        mHandler = new MyHandler(getContext().getMainLooper());
    }

    @Override
    protected void attachBaseContext(Context base) {
        super.attachBaseContext(base);
        mHandler = new MyHandler(getContext().getMainLooper());
    }

    @Override
    public final IBinder onBind(Intent intent) {
        if (mWrapper == null) {
            mWrapper = new NotificationAssistantWrapper();
        }
        return mWrapper;
    }

    /**
     * A notification was posted by an app. Called before alert.
     *
     * @param sbn the new notification
     * @param importance the initial importance of the notification.
     * @param user true if the initial importance reflects an explicit user preference.
     * @return an adjustment or null to take no action, within 100ms.
     */
    abstract public Adjustment onNotificationEnqueued(StatusBarNotification sbn,
          int importance, boolean user);

    /**
     * The visibility of a notification has changed.
     *
     * @param key the notification key
     * @param time milliseconds since midnight, January 1, 1970 UTC.
     * @param visible true if the notification became visible, false if hidden.
     */
    public void onNotificationVisibilityChanged(String key, long time, boolean visible)
    {
        // Do nothing, Override this to collect visibility statistics.
    }

    /**
     * The user clicked on a notification.
     *
     * @param key the notification key
     * @param time milliseconds since midnight, January 1, 1970 UTC.
     */
    public void onNotificationClick(String key, long time)
    {
        // Do nothing, Override this to collect click statistics
    }

    /**
     * The user clicked on a notification action.
     *
     * @param key the notification key
     * @param time milliseconds since midnight, January 1, 1970 UTC.
     * @param actionIndex the index of the action button that was pressed.
     */
    public void onNotificationActionClick(String key, long time, int actionIndex)
    {
        // Do nothing, Override this to collect action button click statistics
    }

    /**
     * A notification was removed.

     * @param key the notification key
     * @param time milliseconds since midnight, January 1, 1970 UTC.
     * @param reason see {@link #REASON_LISTENER_CANCEL}, etc.
     */
    public void onNotificationRemoved(String key, long time, int reason) {
        // Do nothing, Override this to collect dismissal statistics
    }

    /**
     * Change the importance of an existing notification.  N.B. this won’t cause
     * an existing notification to alert, but might allow a future update to
     * this notification to alert.
     *
     * @param key the notification key
     * @param adjustment the new importance with an explanation
     */
    public final void adjustImportance(String key, Adjustment adjustment) {
        if (!isBound()) return;
        try {
            getNotificationInterface().setImportanceFromAssistant(mWrapper, key,
                    adjustment.mImportance, adjustment.mExplanation);
        } catch (android.os.RemoteException ex) {
            Log.v(TAG, "Unable to contact notification manager", ex);
        }
    }

    private class NotificationAssistantWrapper extends NotificationListenerWrapper {
        @Override
        public void onNotificationEnqueued(IStatusBarNotificationHolder sbnHolder,
                int importance, boolean user) {
            StatusBarNotification sbn;
            try {
                sbn = sbnHolder.get();
            } catch (RemoteException e) {
                Log.w(TAG, "onNotificationEnqueued: Error receiving StatusBarNotification", e);
                return;
            }

            SomeArgs args = SomeArgs.obtain();
            args.arg1 = sbn;
            args.argi1 = importance;
            args.argi2 = user ? 1 : 0;
            mHandler.obtainMessage(MyHandler.MSG_ON_NOTIFICATION_ENQUEUED,
                    args).sendToTarget();
        }

        @Override
        public void onNotificationVisibilityChanged(String key, long time, boolean visible) {
            SomeArgs args = SomeArgs.obtain();
            args.arg1 = key;
            args.arg2 = time;
            args.argi1 = visible ? 1 : 0;
            mHandler.obtainMessage(MyHandler.MSG_ON_NOTIFICATION_VISIBILITY_CHANGED,
                    args).sendToTarget();
        }

        @Override
        public void onNotificationClick(String key, long time) {
            SomeArgs args = SomeArgs.obtain();
            args.arg1 = key;
            args.arg2 = time;
            mHandler.obtainMessage(MyHandler.MSG_ON_NOTIFICATION_CLICK,
                    args).sendToTarget();
        }

        @Override
        public void onNotificationActionClick(String key, long time, int actionIndex) {
            SomeArgs args = SomeArgs.obtain();
            args.arg1 = key;
            args.arg2 = time;
            args.argi1 = actionIndex;
            mHandler.obtainMessage(MyHandler.MSG_ON_NOTIFICATION_ACTION_CLICK,
                    args).sendToTarget();
        }

        @Override
        public void onNotificationRemovedReason(String key, long time, int reason) {
            SomeArgs args = SomeArgs.obtain();
            args.arg1 = key;
            args.arg2 = time;
            args.argi1 = reason;
            mHandler.obtainMessage(MyHandler.MSG_ON_NOTIFICATION_REMOVED_REASON,
                    args).sendToTarget();
        }
    }

    private final class MyHandler extends Handler {
        public static final int MSG_ON_NOTIFICATION_ENQUEUED = 1;
        public static final int MSG_ON_NOTIFICATION_VISIBILITY_CHANGED = 2;
        public static final int MSG_ON_NOTIFICATION_CLICK = 3;
        public static final int MSG_ON_NOTIFICATION_ACTION_CLICK = 4;
        public static final int MSG_ON_NOTIFICATION_REMOVED_REASON = 5;

        public MyHandler(Looper looper) {
            super(looper, null, false);
        }

        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case MSG_ON_NOTIFICATION_ENQUEUED: {
                    SomeArgs args = (SomeArgs) msg.obj;
                    StatusBarNotification sbn = (StatusBarNotification) args.arg1;
                    final int importance = args.argi1;
                    final boolean user = args.argi2 == 1;
                    args.recycle();
                    Adjustment adjustment = onNotificationEnqueued(sbn, importance, user);
                    if (adjustment != null) {
                        adjustImportance(sbn.getKey(), adjustment);
                    }
                } break;

                case MSG_ON_NOTIFICATION_VISIBILITY_CHANGED: {
                    SomeArgs args = (SomeArgs) msg.obj;
                    final String key = (String) args.arg1;
                    final long time = (long) args.arg2;
                    final boolean visible = args.argi1 == 1;
                    args.recycle();
                    onNotificationVisibilityChanged(key, time, visible);
                } break;

                case MSG_ON_NOTIFICATION_CLICK: {
                    SomeArgs args = (SomeArgs) msg.obj;
                    final String key = (String) args.arg1;
                    final long time = (long) args.arg2;
                    args.recycle();
                    onNotificationClick(key, time);
                } break;

                case MSG_ON_NOTIFICATION_ACTION_CLICK: {
                    SomeArgs args = (SomeArgs) msg.obj;
                    final String key = (String) args.arg1;
                    final long time = (long) args.arg2;
                    final int actionIndex = args.argi1;
                    args.recycle();
                    onNotificationActionClick(key, time, actionIndex);
                } break;

                case MSG_ON_NOTIFICATION_REMOVED_REASON: {
                    SomeArgs args = (SomeArgs) msg.obj;
                    final String key = (String) args.arg1;
                    final long time = (long) args.arg2;
                    final int reason = args.argi1;
                    args.recycle();
                    onNotificationRemoved(key, time, reason);
                } break;
            }
        }
    }
}