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
    public 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 */);
	// register us for Event.EVENT_DATASTORE_RESTORED, which only
	// seems to be documented at:
	// <http://developer.danger.com/forum/index.php?t=msg&th=27>
	mDataStore.setAutoSyncNotifyee(sListener);
	refreshFromDataStore(false);
    }

    void refreshFromDataStore(boolean datastoreRestored) {
	sAlarmList = null;
	removeAllItems();
	if (datastoreRestored)
	    mDataStore.doneResolvingConflict(); // resolves UID conflicts
	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();
	}
	try {
	    MessageFinder.setMessageListFromByteArray(sSettingsDB.getBytes(KEY_RECENT_MESSAGES));
	} catch (SettingsDBException e) {
	    MessageFinder.setDefaultMessageList();
	}
	sAlarmList = this;
    }

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

    public static boolean canCreateAlarm() {
	return (sAlarmList.size() < MAX_ALARM_COUNT);
    }
    public static void addAlarm(Alarm alarm) {
	sAlarmList.insertItemSorted(alarm, alarm);
    }
    public static void removeAlarm(Alarm alarm) {
	sAlarmList.removeItem(alarm);
    }
    public static void recentMessagesChanged() {
	sSettingsDB.setBytes(KEY_RECENT_MESSAGES,
			     MessageFinder.messageListAsByteArray());
    }

    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());
	alarm.setUID(mDataStore.getRecordUID(index));
	DEBUG.p("added UID " + alarm.getUID() + " @ " + index);
    }

    protected void onItemRemoved(Object item, int index) {
	if (sAlarmList == null) // restoring from service (after hard reset)
	    return;
	Alarm alarm = (Alarm)item;
	int uid = alarm.getUID();
	if (uid == 0)
	    return;
	mDataStore.removeRecordByUID(uid);
	DEBUG.p("removed UID " + alarm.getUID());
    }

    public void onItemUpdated(Object item, int index) {
	if (sAlarmList == null) // restoring from service
	    return;
	Alarm alarm = (Alarm)item;
	mDataStore.setRecordDataByUID(alarm.getUID(), alarm.toByteArray(), true);
	DEBUG.p("updated: " + alarm + " UID " + alarm.getUID());
    }

    private static String KEY_DEFAULT_ALARM = "default alarm";
    private static String KEY_RECENT_MESSAGES = "recent messages";

    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;
	    } else if (e.type == Event.EVENT_DATASTORE_RESTORED) {
		String dbName = (String)e.argument;
		DEBUG.p("DATASTORE_RESTORED: " + dbName);
		if (!dbName.endsWith("alarms")) {
		    // because we only get/set the default alarm on demand
		    // there's no need to handle conflicts with the settings...
		    // XXX but what happens if we set a (default) alarm, then
		    // the SettingsDB restores?
		    Alarms.getList().refreshFromDataStore(true);
		}
	    }
	    return super.receiveEvent(e);
	}
    }
}