/*
 * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
 *
 * 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 net.micode.notes.ui;

import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.ContentUris;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;

import net.micode.notes.data.Notes;
import net.micode.notes.data.Notes.NoteColumns;


//AlarmInitReceiver 类继承自BroadcastReceiver， 广播接收者用于获取系统启动或其他特定事件的通知
public class AlarmInitReceiver extends BroadcastReceiver {

    //数据库查询的列名数组，只查询ID和提醒日期
    private static final String [] PROJECTION = new String [] {
        NoteColumns.ID,             //便签的ID
        NoteColumns.ALERTED_DATE    //便签的提醒日期
    };

    //定义两个静态常量，代表数据表列索引ID和提醒日期
    private static final int COLUMN_ID                = 0;
    private static final int COLUMN_ALERTED_DATE      = 1;

    //当广播被接收时执行此方法
    @Override
    public void onReceive(Context context, Intent intent) {
        //获取系统的时间
        long currentDate = System.currentTimeMillis();
        //通过内容解析器查询便签，寻找提醒时间大于当前时间且类型为TYPE_NOTE的便签
        Cursor c = context.getContentResolver().query(Notes.CONTENT_NOTE_URI, // CONTENT_NOTE_URI是访问便签数据的URI
                PROJECTION,
                NoteColumns.ALERTED_DATE + ">? AND " + NoteColumns.TYPE + "=" + Notes.TYPE_NOTE,
                new String[] { String.valueOf(currentDate) },
                null);

        //遍历查询出的结果
        if (c != null) {
            if (c.moveToFirst()) { //移动游标到第一条记录
                do {
                    //读取提醒日期时间
                    long alertDate = c.getLong(COLUMN_ALERTED_DATE);
                    //创建指向AlarmReceiver的Intent
                    Intent sender = new Intent(context, AlarmReceiver.class);
                    sender.setData(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, c.getLong(COLUMN_ID)));
                    //创建一个即将执行的PendingIntent
                    PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0, sender, 0);
                    //获取系统AlarmManager
                    AlarmManager alermManager = (AlarmManager) context
                            .getSystemService(Context.ALARM_SERVICE);
                    //使用AlarmManager设置一个闹钟，当系统时间达到提醒日期时触发广播
                    alermManager.set(AlarmManager.RTC_WAKEUP, alertDate, pendingIntent);
                } while (c.moveToNext()); //移动到下一条记录
            }
            c.close(); //关闭游标
        }
    }
}
