Signal-Android/app/src/main/java/org/thoughtcrime/securesms/jobmanager/JobSchedulerScheduler.java

package org.thoughtcrime.securesms.jobmanager;

import android.app.Application;
import android.app.job.JobInfo;
import android.app.job.JobParameters;
import android.app.job.JobScheduler;
import android.app.job.JobService;
import android.content.ComponentName;

import androidx.annotation.NonNull;
import androidx.annotation.RequiresApi;

import com.annimon.stream.Collectors;
import com.annimon.stream.Stream;

import org.signal.core.util.logging.Log;
import org.thoughtcrime.securesms.dependencies.ApplicationDependencies;

import java.util.List;
import java.util.Locale;

@RequiresApi(26)
public final class JobSchedulerScheduler implements Scheduler {

  private static final String TAG = Log.tag(JobSchedulerScheduler.class);

  private final Application application;

  JobSchedulerScheduler(@NonNull Application application) {
    this.application = application;
  }

  @RequiresApi(26)
  @Override
  public void schedule(long delay, @NonNull List<Constraint> constraints) {
    JobScheduler jobScheduler = application.getSystemService(JobScheduler.class);

    String constraintNames = constraints.isEmpty() ? ""
                                                   : Stream.of(constraints)
                                                           .map(Constraint::getJobSchedulerKeyPart)
                                                           .withoutNulls()
                                                           .sorted()
                                                           .collect(Collectors.joining("-"));

    int jobId = constraintNames.hashCode();

    if (jobScheduler.getPendingJob(jobId) != null) {
      return;
    }

    Log.i(TAG, String.format(Locale.US, "JobScheduler enqueue of %s (%d)", constraintNames, jobId));

    JobInfo.Builder jobInfoBuilder = new JobInfo.Builder(jobId, new ComponentName(application, SystemService.class))
                                                .setMinimumLatency(delay)
                                                .setPersisted(true);

    for (Constraint constraint : constraints) {
      constraint.applyToJobInfo(jobInfoBuilder);
    }

    jobScheduler.schedule(jobInfoBuilder.build());
  }

  @RequiresApi(api = 26)
  public static class SystemService extends JobService {

    @Override
    public boolean onStartJob(JobParameters params) {
      JobManager jobManager = ApplicationDependencies.getJobManager();

      Log.i(TAG, "Waking due to job: " + params.getJobId());

      jobManager.addOnEmptyQueueListener(new JobManager.EmptyQueueListener() {
        @Override
        public void onQueueEmpty() {
          jobManager.removeOnEmptyQueueListener(this);
          jobFinished(params, false);
        }
      });

      jobManager.wakeUp();

      return true;
    }

    @Override
    public boolean onStopJob(JobParameters params) {
      return false;
    }
  }
}