AlarmService.java

package org.smartpaws.notifications;

import android.app.AlarmManager;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.graphics.Color;
import android.support.v4.app.NotificationCompat;

import org.json.JSONArray;
import org.json.JSONObject;
import org.smartpaws.MainActivity;
import org.smartpaws.R;
import org.smartpaws.objects.Event;
import org.smartpaws.util.TimeUtils;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class AlarmService extends BroadcastReceiver {

    private static AlarmManager ALARM_MANAGER;
    private static NotificationManager NOTIFICATION_MANAGER;
    private static List<Reminder> REMINDERS = new ArrayList<>();

    private static Context CONTEXT;

    public static Context getContext() {
        return CONTEXT;
    }

    public static void setContext(Context context) {
        CONTEXT = context;
        ALARM_MANAGER = (AlarmManager)CONTEXT.getSystemService(Context.ALARM_SERVICE);
        NOTIFICATION_MANAGER = (NotificationManager)CONTEXT.getSystemService(Context.NOTIFICATION_SERVICE);
    }

    public static void setReminder(Event event, int minsBefore, String room) {
        if (minsBefore <= 0) {
            removeReminder(event);
            return;
        }

        Calendar cal = Calendar.getInstance();
        cal.setTime(event.getDateStart());
        cal.add(Calendar.MINUTE, -minsBefore);

        if (cal.before(Calendar.getInstance())) return;

        Intent intent = new Intent(CONTEXT, AlarmService.class);

        Reminder reminder = new Reminder(event, minsBefore, room);
        intent.putExtra("reminder", reminder);

        PendingIntent alarm = PendingIntent.getBroadcast(CONTEXT, event.getId(), intent, 0);

        removeReminder(event); // Remove any existing alarms for the same event
        ALARM_MANAGER.set(AlarmManager.RTC_WAKEUP, cal.getTimeInMillis(), alarm);
        REMINDERS.add(reminder);
        ShutdownWakeReceiver.saveReminders();
    }

    public static void removeReminder(Event event) {
        Intent intent = new Intent(CONTEXT, AlarmService.class);

        for (Reminder reminder : REMINDERS) {
            if (reminder.getEvent().getId() == event.getId()) {
                ALARM_MANAGER.cancel(PendingIntent.getBroadcast(CONTEXT, reminder.getEvent().getId(), intent, 0));
                REMINDERS.remove(reminder);
                break;
            }
        }
        ShutdownWakeReceiver.saveReminders();
    }

    private Notification createNotification(Event event, String room) {
        Intent intent = new Intent(CONTEXT, MainActivity.class);
        PendingIntent pendingIntent = PendingIntent.getActivity(CONTEXT, 0, intent, 0);

        String timeTill = TimeUtils.getTimeTill(event.getName(), event.getDateStart());

        return new NotificationCompat.Builder(CONTEXT)
                .setContentTitle(event.getName())
                .setContentText(timeTill + " - " + room)
                .setColor(Color.argb(255, 255, 143, 0))
                .setAutoCancel(true)
                .setLights(Color.argb(255, 174, 234, 0), 1000, 500)
                .setDefaults(Notification.DEFAULT_VIBRATE | Notification.DEFAULT_SOUND)
                .setContentIntent(pendingIntent)
                .setSmallIcon(R.drawable.ic_create_black_24dp)
                .extend(new NotificationCompat.WearableExtender().setContentIcon(R.drawable.ic_create_black_24dp)) // TODO: Update icon
                .build();
    }

    public static void clearReminders() {
        for (Reminder container : REMINDERS) {
            removeReminder(container.event);
        }
        REMINDERS.clear();
    }

    public static Reminder[] getReminders() {
        return REMINDERS.toArray(new Reminder[REMINDERS.size()]);
    }

    @Override
    public void onReceive(Context context, Intent intent) {
        setContext(context);

        Reminder container = (Reminder) intent.getSerializableExtra("reminder");

        // If 15 minutes have passed since this should have been called, let's ignore it
        Calendar cal = Calendar.getInstance();
        cal.setTime(container.event.getDateStart());
        cal.add(Calendar.MINUTE, 15);
        if (cal.before(Calendar.getInstance())) return;

        NOTIFICATION_MANAGER.notify(container.event.getId(), createNotification(container.event, container.getRoom()));
        notifyPebble(container.event, container.getRoom());
        removeReminder(container.event);
    }

    private void notifyPebble(Event event, String room) {
        final Intent i = new Intent("com.getpebble.action.SEND_NOTIFICATION");

        String timeTill = TimeUtils.getTimeTill(event.getName(), event.getDateStart());

        final Map<String, String> data = new HashMap<>();
        data.put("title", event.getName());
        data.put("body", timeTill + " - " + room);
        final JSONObject jsonData = new JSONObject(data);
        final String notificationData = new JSONArray().put(jsonData).toString();

        i.putExtra("messageType", "PEBBLE_ALERT");
        i.putExtra("sender", "SmartPaws");
        i.putExtra("notificationData", notificationData);
        MainActivity.INSTANCE.sendBroadcast(i);
    }

    public static class Reminder implements Serializable {
        private final Event event;
        private final int minsBefore;
        private final String room;

        Reminder(Event event, int minsBefore, String room) {
            this.event = event;
            this.minsBefore = minsBefore;
            this.room = room;
        }

        public Event getEvent() {
            return event;
        }

        public int getMinsBefore() {
            return minsBefore;
        }

        public String getRoom() {
            return room;
        }
    }
}