/*
** Copyright 2006, 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,
** See the License for the specific language governing permissions and
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** limitations under the License.
*/

package com.android.providers.calendar;

import android.content.BroadcastReceiver;
import android.content.ContentResolver;
import android.content.Context;
import android.content.Intent;
import android.os.PowerManager;
import android.util.Log;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * This IntentReceiver executes when the boot completes and ensures that
 * the Calendar provider has started and then initializes the alarm
 * scheduler for the Calendar provider.  This needs to be done after
 * the boot completes because the alarm manager may not have been started
 * yet.
 */
public class CalendarReceiver extends BroadcastReceiver {
    private static final String TAG = "CalendarReceiver";
    static final String SCHEDULE = "com.android.providers.calendar.SCHEDULE_ALARM";

    private final ExecutorService executor = Executors.newCachedThreadPool();
    private PowerManager.WakeLock mWakeLock;

    @Override
    public void onReceive(Context context, Intent intent) {
        if (mWakeLock == null) {
            PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
            mWakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "CalendarReceiver_Provider");
            mWakeLock.setReferenceCounted(true);
        }
        mWakeLock.acquire();

        final String action = intent.getAction();
        final ContentResolver cr = context.getContentResolver();
        final PendingResult result = goAsync();
        executor.submit(new Runnable() {
            @Override
            public void run() {
                if (action.equals(SCHEDULE)) {
                    cr.update(CalendarAlarmManager.SCHEDULE_ALARM_URI, null /* values */,
                          null /* where */, null /* selectionArgs */);
                } else if (action.equals(Intent.ACTION_BOOT_COMPLETED)) {
                    removeScheduledAlarms(cr);
                }
                result.finish();
                mWakeLock.release();
            }
        });
    }

    /*
     * Remove alarms from the CalendarAlerts table that have been marked
     * as "scheduled" but not fired yet.  We do this because the
     * AlarmManagerService loses all information about alarms when the
     * power turns off but we store the information in a database table
     * that persists across reboots. See the documentation for
     * scheduleNextAlarmLocked() for more information.
     *
     * We don't expect this to be called more than once.  If it were, we would have to
     * worry about serializing the use of the service.
     */
    private void removeScheduledAlarms(ContentResolver resolver) {
        if (Log.isLoggable(TAG, Log.DEBUG)) {
            Log.d(TAG, "Removing scheduled alarms");
        }
        resolver.update(CalendarAlarmManager.SCHEDULE_ALARM_REMOVE_URI, null /* values */,
                null /* where */, null /* selectionArgs */);
    }
}