Hypatia/app/src/main/java/us/spotco/malwarescanner/MalwareScannerService.java

package us.spotco.malwarescanner;

import android.app.Notification;
import android.app.NotificationManager;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.os.Environment;
import android.os.FileObserver;
import android.os.IBinder;
import android.support.v4.app.NotificationCompat;

import java.io.File;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadPoolExecutor;

import gnu.trove.set.hash.THashSet;

public class MalwareScannerService extends Service {

    private THashSet<RecursiveFileObserver> malwareMonitors = new THashSet<>();
    private ThreadPoolExecutor threadPoolExecutor = null;
    private NotificationCompat.Builder foregroundNotification = null;
    private NotificationManager notificationManager = null;

    @Override
    public final IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public final int onStartCommand(Intent intent, int flags, int startId) {
        malwareMonitors.clear();
        addMalwareMonitor(Environment.getExternalStorageDirectory().toString());

        threadPoolExecutor = (ThreadPoolExecutor) Executors.newScheduledThreadPool(Utils.getMaxThreads() + malwareMonitors.size());
        threadPoolExecutor.execute(new Runnable() {
            @Override
            public void run() {
                Database.loadDatabase(getApplicationContext(), true, Database.signatureDatabases);
            }
        });

        for (final RecursiveFileObserver malwareMonitor : malwareMonitors) {
            threadPoolExecutor.execute(new Runnable() {
                @Override
                public void run() {
                    malwareMonitor.startWatching();
                }
            });
        }

        notificationManager = (NotificationManager) getApplicationContext().getSystemService(Context.NOTIFICATION_SERVICE);
        setForeground();
        return START_STICKY;
    }

    private final void addMalwareMonitor(String monitorPath) {
        malwareMonitors.add(new RecursiveFileObserver(monitorPath) {
            @Override
            public void onEvent(int event, String path) {
                switch (event) {
                    case FileObserver.MOVED_TO:
                    case FileObserver.CLOSE_WRITE:
                        File file = new File(path);
                        if (file.exists() && /*file.length() > 0 &&*/ file.length() <= Utils.MAX_SCAN_SIZE_REALTIME) {
                            THashSet<File> filesToScan = new THashSet<>();
                            filesToScan.add(file);
                            new MalwareScanner(null, getApplicationContext(), false).executeOnExecutor(threadPoolExecutor, filesToScan);
                        }
                        updateForegroundNotification();
                        break;
                }
            }
        });
    }

    @Override
    public final void onDestroy() {
        for (RecursiveFileObserver malwareMonitor : malwareMonitors) {
            malwareMonitor.stopWatching();
        }
        malwareMonitors.clear();
        System.gc();
        //Toast.makeText(this, "Theia: Realtime Scanning Stopped", Toast.LENGTH_SHORT).show();
    }

    private void setForeground() {
        foregroundNotification =
                new NotificationCompat.Builder(this)
                        .setSmallIcon(R.drawable.ic_notification)
                        .setContentTitle(getText(R.string.lblNotificationRealtimeTitle))
                        .setContentText(getText(R.string.lblNotificationRealtimeText))
                        .setPriority(Notification.PRIORITY_MIN)
                        .setShowWhen(false);

        startForeground(-1, foregroundNotification.build());
    }

    private void updateForegroundNotification() {
        foregroundNotification.setSubText(Utils.FILES_SCANNED + " files scanned");
        notificationManager.notify(-1, foregroundNotification.build());
    }

}