Change minimum android version to Lollipop(API level 21)

app/build.gradle

@@ -6,7 +6,7 @@ android {
     defaultConfig {
         applicationId "app.insti"
         manifestPlaceholders 'appAuthRedirectScheme': 'https'
-        minSdkVersion 17
+        minSdkVersion 21
         targetSdkVersion 27
         versionCode 8
         versionName "1.0.3"

app/src/main/java/app/insti/notifications/NotificationEventReceiver.java

+package com.iitb.moodindigo.mi2016;
+
+import android.app.AlarmManager;
+import android.app.PendingIntent;
+import android.content.Context;
+import android.content.Intent;
+import android.support.v4.content.WakefulBroadcastReceiver;
+import android.util.Log;
+
+import java.util.Calendar;
+import java.util.Date;
+
+public class
+NotificationEventReceiver extends WakefulBroadcastReceiver {
+
+    private static final String ACTION_START_NOTIFICATION_SERVICE = "ACTION_START_NOTIFICATION_SERVICE";
+    private static final String ACTION_DELETE_NOTIFICATION = "ACTION_DELETE_NOTIFICATION";
+    private static final int NOTIFICATIONS_INTERVAL_IN_HOURS = 1;
+
+    public static void setupAlarm(Context context) {
+        AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
+        PendingIntent alarmIntent = getStartPendingIntent(context);
+        alarmManager.setRepeating(AlarmManager.RTC_WAKEUP,
+                getTriggerAt(new Date()),
+                1000 * 60 * 15, //Change this to 1000 * 60 for testing => runs every minute
+                alarmIntent);
+    }
+
+    private static long getTriggerAt(Date now) {
+        Calendar calendar = Calendar.getInstance();
+        calendar.setTime(now);
+        //calendar.add(Calendar.HOUR, NOTIFICATIONS_INTERVAL_IN_HOURS);
+        return calendar.getTimeInMillis();
+    }
+
+    private static PendingIntent getStartPendingIntent(Context context) {
+        Intent intent = new Intent(context, NotificationEventReceiver.class);
+        intent.setAction(ACTION_START_NOTIFICATION_SERVICE);
+        return PendingIntent.getBroadcast(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
+    }
+
+    public static PendingIntent getDeleteIntent(Context context) {
+        Intent intent = new Intent(context, NotificationEventReceiver.class);
+        intent.setAction(ACTION_DELETE_NOTIFICATION);
+        return PendingIntent.getBroadcast(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
+    }
+
+    @Override
+    public void onReceive(Context context, Intent intent) {
+        String action = intent.getAction();
+        Intent serviceIntent = null;
+        if (ACTION_START_NOTIFICATION_SERVICE.equals(action)) {
+            Log.i(getClass().getSimpleName(), "onReceive from alarm, starting notification service");
+            serviceIntent = NotificationIntentService.createIntentStartNotificationService(context);
+        } else if (ACTION_DELETE_NOTIFICATION.equals(action)) {
+            Log.i(getClass().getSimpleName(), "onReceive delete notification action, starting notification service to handle delete");
+            serviceIntent = NotificationIntentService.createIntentDeleteNotification(context);
+        }
+
+        if (serviceIntent != null) {
+            startWakefulService(context, serviceIntent);
+        }
+    }
+}
\ No newline at end of file

app/src/main/java/app/insti/notifications/NotificationIntentService.java

+package com.iitb.moodindigo.mi2016;
+
+import android.app.IntentService;
+import android.app.Notification;
+import android.app.NotificationManager;
+import android.app.PendingIntent;
+import android.content.Context;
+import android.content.Intent;
+import android.content.SharedPreferences;
+import android.graphics.BitmapFactory;
+import android.support.v4.app.NotificationCompat;
+import android.support.v4.content.WakefulBroadcastReceiver;
+import android.util.Log;
+
+import com.google.gson.Gson;
+import com.google.gson.reflect.TypeToken;
+import com.iitb.moodindigo.mi2016.ServerConnection.GsonModels;
+
+import java.lang.reflect.Type;
+import java.util.Date;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+public class NotificationIntentService extends IntentService {
+
+    private static final String ACTION_START = "ACTION_START";
+    private static final String ACTION_DELETE = "ACTION_DELETE";
+    private static final String ACTION_NAVIGATE = "ACTION_NAVIGATE";
+    private static final String ACTION_NOT_GOING = "ACTION_NOT_GOING";
+    private static int NOTIFICATION_ID = 1;
+    private SharedPreferences.Editor goingSharedPreferencesEditor;
+    private NotificationManager manager;
+
+    public NotificationIntentService() {
+        super(NotificationIntentService.class.getSimpleName());
+    }
+
+    public static Intent createIntentStartNotificationService(Context context) {
+        Intent intent = new Intent(context, NotificationIntentService.class);
+        intent.setAction(ACTION_START);
+        return intent;
+    }
+
+    public static Intent createIntentDeleteNotification(Context context) {
+        Intent intent = new Intent(context, NotificationIntentService.class);
+        intent.setAction(ACTION_DELETE);
+        return intent;
+    }
+
+    public static long getDateDiff(Date date1, Date date2, TimeUnit timeUnit) {
+        long diffInMillies = date2.getTime() - date1.getTime();
+        return timeUnit.convert(diffInMillies, TimeUnit.MILLISECONDS);
+    }
+
+    @Override
+    protected void onHandleIntent(Intent intent) {
+        Log.d(getClass().getSimpleName(), "onHandleIntent, started handling a notification event");
+        try {
+            String action = intent.getAction();
+            if (ACTION_START.equals(action)) {
+                processStartNotification();
+            }
+            if (ACTION_DELETE.equals(action)) {
+                processDeleteNotification(intent);
+            }
+            if ("ACTION_NOT_GOING".equals(action)) {
+                if (Cache.getGoingEventsList() != null) {
+                    GsonModels.Event event = (new Gson().fromJson(intent.getStringExtra("EVENT_JSON"), GsonModels.Event.class));
+                    Cache.removeFromGoingList(event);
+                    goingSharedPreferencesEditor = this.getSharedPreferences("GOING", Context.MODE_PRIVATE).edit();
+                    String goingEventsListJson = (new Gson()).toJson(Cache.getGoingEventsList());
+                    goingSharedPreferencesEditor.putString("GOING_LIST", goingEventsListJson);
+                    goingSharedPreferencesEditor.apply();
+                }
+                manager = (NotificationManager) this.getSystemService(Context.NOTIFICATION_SERVICE);
+                manager.cancel(intent.getIntExtra("NOTIFICATION_ID", -1));
+            }
+        } finally {
+            WakefulBroadcastReceiver.completeWakefulIntent(intent);
+        }
+    }
+
+    private void processDeleteNotification(Intent intent) {
+        // Log something?
+    }
+
+    private void processStartNotification() {
+        // Do something. For example, fetch fresh data from backend to create a rich notification?
+
+        SharedPreferences goingPreferences = getApplicationContext().getSharedPreferences("GOING", Context.MODE_PRIVATE);
+        String goingList = goingPreferences.getString("GOING_LIST", null);
+        Type type = new TypeToken<List<GsonModels.Event>>() {
+        }.getType();
+        List<GsonModels.Event> goingListGson = (new Gson()).fromJson(goingList, type);
+        if (goingListGson == null) {
+            ;
+        } else {
+            for (int i = 0; i < goingListGson.size(); i++) {
+                GsonModels.Event event = goingListGson.get(i);
+                long timediff = getDateDiff(new Date(), event.getDate(), TimeUnit.MINUTES);
+                if (timediff <= 30 && timediff > 0) { // Change this to 30*10000 for testing
+                    NOTIFICATION_ID = (int) Long.parseLong(event.get_id().substring(6, 11), 16);
+                    final NotificationCompat.Builder builder = new NotificationCompat.Builder(this);
+                    builder.setContentTitle(event.getTitle())
+                            .setAutoCancel(true)
+                            .setColor(getResources().getColor(R.color.yellow))
+                            .setContentText("Event is about to start in " + getDateDiff(new Date(), event.getDate(), TimeUnit.MINUTES) + ((getDateDiff(new Date(), event.getDate(), TimeUnit.MINUTES) == 1) ? " minute." : " minutes."))
+                            .setLargeIcon(BitmapFactory.decodeResource(getResources(), R.drawable.ic_event_white_24dp))
+                            .setSmallIcon(R.drawable.ic_event_white_24dp);
+
+                    Intent intent = new Intent(this, MainActivity.class);
+                    intent.setAction("OPEN_EVENT");
+                    String eventJson = (new Gson()).toJson(event);
+                    intent.putExtra("EVENT_JSON", eventJson);
+
+                    PendingIntent pendingIntent = PendingIntent.getActivity(this,
+                            NOTIFICATION_ID,
+                            intent,
+                            PendingIntent.FLAG_UPDATE_CURRENT);
+                    builder.setContentIntent(pendingIntent);
+                    builder.setDeleteIntent(NotificationEventReceiver.getDeleteIntent(this));
+
+                    Intent navigateIntent = new Intent(this, MainActivity.class);
+                    navigateIntent.setAction(ACTION_NAVIGATE);
+                    navigateIntent.putExtra("EVENT_JSON", eventJson);
+                    navigateIntent.putExtra("NOTIFICATION_ID", NOTIFICATION_ID);
+                    PendingIntent navigatePendingIntent = PendingIntent.getActivity(this, 0, navigateIntent, PendingIntent.FLAG_UPDATE_CURRENT);
+                    builder.addAction(R.drawable.ic_navigation_white_24dp, "Navigate", navigatePendingIntent);
+
+                    Intent notGoingIntent = new Intent(this, NotificationIntentService.class);
+                    notGoingIntent.setAction(ACTION_NOT_GOING);
+                    notGoingIntent.putExtra("EVENT_JSON", eventJson);
+                    notGoingIntent.putExtra("NOTIFICATION_ID", NOTIFICATION_ID);
+                    PendingIntent notGoingPendingIntent = PendingIntent.getService(this, 0, notGoingIntent, PendingIntent.FLAG_UPDATE_CURRENT);
+                    builder.addAction(R.drawable.ic_close_white_24dp, "Not Going", notGoingPendingIntent);
+
+                    manager = (NotificationManager) this.getSystemService(Context.NOTIFICATION_SERVICE);
+                    Notification notification = builder.build();
+                    notification.defaults |= Notification.DEFAULT_SOUND;
+                    notification.defaults |= Notification.DEFAULT_VIBRATE;
+                    manager.notify(NOTIFICATION_ID, notification);
+                }
+            }
+        }
+    }
+}
\ No newline at end of file

app/src/main/java/app/insti/notifications/NotificationServiceStarterReceiver.java

+package com.iitb.moodindigo.mi2016;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+
+public final class NotificationServiceStarterReceiver extends BroadcastReceiver {
+
+    @Override
+    public void onReceive(Context context, Intent intent) {
+        NotificationEventReceiver.setupAlarm(context);
+    }
+}
\ No newline at end of file