package net.sabi.pester;

import java.util.Comparator;
import danger.app.Application;
import danger.app.DataStore;
import danger.app.Event;
import danger.app.SettingsDB;
import danger.app.SettingsDBException;
import danger.internal.Date;
import danger.util.StdActiveList;
import danger.util.DEBUG;

public class Alarms extends StdActiveList {
    // max # records in a datastore
    private static final int MAX_ALARM_COUNT = 50;

    private static Alarms sAlarmList = null;
    private static Listener sListener;
    private static SettingsDB sSettingsDB;

    private DataStore mDataStore;

    private Alarms() {
	mDataStore = DataStore.createDataStore("alarms", true /* auto sync */);
	byte[][] alarmsData = mDataStore.getRecords();
	int i;
	for (i = 0 ; i < alarmsData.length ; ++i) {
	    Alarm alarm = new Alarm();
	    alarm.fromByteArray(alarmsData[i]);
	    alarm.setUID(mDataStore.getRecordUID(i));
	    insertItemSorted(alarm, alarm);
	    alarm.resume();
	}
    }

    public static Alarms getList() {
	if (sAlarmList == null) {
	    Application.registerForEvent(sListener, Event.EVENT_TIME_CHANGED);
	    sSettingsDB = new SettingsDB("settings", true /* auto sync */);
	    sListener = new Listener();
	    sAlarmList = new Alarms();
	}
	return sAlarmList;
    }

    public static void addAlarm(Alarm alarm) {
	sAlarmList.insertItemSorted(alarm, alarm);
    }
    public static void removeAlarm(Alarm alarm) {
	sAlarmList.removeItem(alarm);
    }

    // XXX handle EVENT_DATASTORE_RESTORED: note that in the event of
    // a hard reset, items may come back out of order, so we need to
    // implement an in-place sort, then insert the current alarm list.
    // Aiee.  Also, what on earth happens when UIDs aren't synchronized?
    
    protected void onItemAdded(Object item, int index) {
	if (sAlarmList == null) // restoring from service
	    return;
	Alarm alarm = (Alarm)item;
	DEBUG.p("adding: " + alarm +
		" next UID: " + mDataStore.getAutoSyncNextUID());
	index = mDataStore.addRecord(alarm.toByteArray(), index);
	alarm.setUID(mDataStore.getRecordUID(index));
	DEBUG.p("added UID " + alarm.getUID() + " @ " + index);
    }

    protected void onItemRemoved(Object item, int index) {
	Alarm alarm = (Alarm)item;
	// XXX make sure +/- UIDs are OK
	int uid = alarm.getUID();
	if (uid == 0)
	    return;
	DEBUG.p("removing; " + alarm + " UID " + uid);
	mDataStore.removeRecordByUID(uid);
    }

    public void onItemUpdated(Object item, int index) {
	if (sAlarmList == null) // restoring from service
	    return;
	Alarm alarm = (Alarm)item;
	// XXX check that updating a + UID by a - one is OK
	mDataStore.setRecordDataByUID(alarm.getUID(), alarm.toByteArray(), true);
	DEBUG.p("updated: " + alarm + " UID " + alarm.getUID());
    }

    private static String KEY_DEFAULT_ALARM = "default alarm";

    public static Alarm getDefaultAlarm() {
	Alarm defaultAlarm = new Alarm();
	try {
	    defaultAlarm.fromByteArray(sSettingsDB.getBytes(KEY_DEFAULT_ALARM));
	} catch (SettingsDBException e) {
	    defaultAlarm = new Alarm();
	    defaultAlarm.setDate(new Date());
	    defaultAlarm.setPeriod(600, false);
	}
	return defaultAlarm;
    }
    public static void setDefaultAlarm(Alarm alarm) {
	sSettingsDB.setBytes(KEY_DEFAULT_ALARM, alarm.toByteArray());
    }

    static class Listener extends danger.app.Listener
	implements danger.util.ActiveList.ForEach {
	
	public void receive(Object item) {
	    ((Alarm)item).timeChanged();
	}

	public boolean receiveEvent(Event e) {
	    if (e.type == Event.EVENT_TIME_CHANGED) {
		Alarms.getList().forEach(this);
		return true;
	    }
	    return super.receiveEvent(e);
	}
    }
}