src/com/android/deskclock/timer/TimerService.java

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

package com.android.deskclock.timer;

import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.os.IBinder;

import com.android.deskclock.R;
import com.android.deskclock.data.DataModel;
import com.android.deskclock.data.Timer;
import com.android.deskclock.events.Events;

/**
 * <p>This service exists solely to allow {@link android.app.AlarmManager} and timer notifications
 * to alter the state of timers without disturbing the notification shade. If an activity were used
 * instead (even one that is not displayed) the notification manager implicitly closes the
 * notification shade which clashes with the use case of starting/pausing/resetting timers without
 * disturbing the notification shade.</p>
 *
 * <p>The service has a second benefit. It is used to start heads-up notifications for expired
 * timers in the foreground. This keeps the entire application in the foreground and thus prevents
 * the operating system from killing it while expired timers are firing.</p>
 */
public final class TimerService extends Service {

    private static final String ACTION_PREFIX = "com.android.deskclock.action.";

    /** Shows the tab with timers; scrolls to a specific timer. */
    public static final String ACTION_SHOW_TIMER = ACTION_PREFIX + "SHOW_TIMER";
    /** Pauses running timers; resets expired timers. */
    public static final String ACTION_PAUSE_TIMER = ACTION_PREFIX + "PAUSE_TIMER";
    /** Starts the sole timer. */
    public static final String ACTION_START_TIMER = ACTION_PREFIX + "START_TIMER";
    /** Resets the timer. */
    public static final String ACTION_RESET_TIMER = ACTION_PREFIX + "RESET_TIMER";
    /** Adds an extra minute to the timer. */
    public static final String ACTION_ADD_MINUTE_TIMER = ACTION_PREFIX + "ADD_MINUTE_TIMER";

    /** Extra for many actions specific to a given timer. */
    public static final String EXTRA_TIMER_ID = "com.android.deskclock.extra.TIMER_ID";

    private static final String ACTION_TIMER_EXPIRED =
            ACTION_PREFIX + "TIMER_EXPIRED";
    private static final String ACTION_UPDATE_NOTIFICATION =
            ACTION_PREFIX + "UPDATE_NOTIFICATION";
    private static final String ACTION_RESET_EXPIRED_TIMERS =
            ACTION_PREFIX + "RESET_EXPIRED_TIMERS";
    private static final String ACTION_RESET_UNEXPIRED_TIMERS =
            ACTION_PREFIX + "RESET_UNEXPIRED_TIMERS";
    private static final String ACTION_RESET_MISSED_TIMERS =
            ACTION_PREFIX + "RESET_MISSED_TIMERS";

    public static Intent createTimerExpiredIntent(Context context, Timer timer) {
        final int timerId = timer == null ? -1 : timer.getId();
        return new Intent(context, TimerService.class)
                .setAction(ACTION_TIMER_EXPIRED)
                .putExtra(EXTRA_TIMER_ID, timerId);
    }

    public static Intent createResetExpiredTimersIntent(Context context) {
        return new Intent(context, TimerService.class)
                .setAction(ACTION_RESET_EXPIRED_TIMERS);
    }

    public static Intent createResetUnexpiredTimersIntent(Context context) {
        return new Intent(context, TimerService.class)
                .setAction(ACTION_RESET_UNEXPIRED_TIMERS);
    }

    public static Intent createResetMissedTimersIntent(Context context) {
        return new Intent(context, TimerService.class)
                .setAction(ACTION_RESET_MISSED_TIMERS);
    }


    public static Intent createAddMinuteTimerIntent(Context context, int timerId) {
        return new Intent(context, TimerService.class)
                .setAction(ACTION_ADD_MINUTE_TIMER)
                .putExtra(EXTRA_TIMER_ID, timerId);
    }

    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        try {
            final String action = intent.getAction();
            final int label = intent.getIntExtra(Events.EXTRA_EVENT_LABEL, R.string.label_intent);

            if (action != null) {
                switch (action) {
                    case ACTION_UPDATE_NOTIFICATION: {
                        DataModel.getDataModel().updateTimerNotification();
                        return START_NOT_STICKY;
                    }
                    case ACTION_RESET_EXPIRED_TIMERS: {
                        DataModel.getDataModel().resetOrDeleteExpiredTimers(label);
                        return START_NOT_STICKY;
                    }
                    case ACTION_RESET_UNEXPIRED_TIMERS: {
                        DataModel.getDataModel().resetUnexpiredTimers(label);
                        return START_NOT_STICKY;
                    }
                    case ACTION_RESET_MISSED_TIMERS: {
                        DataModel.getDataModel().resetMissedTimers(label);
                        return START_NOT_STICKY;
                    }
                }
            }

            // Look up the timer in question.
            final int timerId = intent.getIntExtra(EXTRA_TIMER_ID, -1);
            final Timer timer = DataModel.getDataModel().getTimer(timerId);

            // If the timer cannot be located, ignore the action.
            if (timer == null) {
                return START_NOT_STICKY;
            }

            // Perform the action on the timer.
            if (action != null) {
                switch (action) {
                    case ACTION_START_TIMER: {
                        Events.sendTimerEvent(R.string.action_start, label);
                        DataModel.getDataModel().startTimer(this, timer);
                        break;
                    } case ACTION_PAUSE_TIMER: {
                        Events.sendTimerEvent(R.string.action_pause, label);
                        DataModel.getDataModel().pauseTimer(timer);
                        break;
                    } case ACTION_ADD_MINUTE_TIMER: {
                        Events.sendTimerEvent(R.string.action_add_minute, label);
                        DataModel.getDataModel().addTimerMinute(timer);
                        break;
                    } case ACTION_RESET_TIMER: {
                        DataModel.getDataModel().resetOrDeleteTimer(timer, label);
                        break;
                    } case ACTION_TIMER_EXPIRED: {
                        Events.sendTimerEvent(R.string.action_fire, label);
                        DataModel.getDataModel().expireTimer(this, timer);
                        break;
                    }
                }
            }
        } finally {
            // This service is foreground when expired timers exist and stopped when none exist.
            if (DataModel.getDataModel().getExpiredTimers().isEmpty()) {
                stopSelf();
            }
        }

        return START_NOT_STICKY;
    }
}