package expo.modules.backgroundfetch;

import android.app.AlarmManager;
import android.app.PendingIntent;
import android.app.job.JobParameters;
import android.app.job.JobService;
import android.content.Context;
import android.content.Intent;
import android.os.SystemClock;
import android.util.Log;

import expo.modules.core.interfaces.LifecycleEventListener;
import expo.modules.interfaces.taskManager.TaskConsumer;
import expo.modules.interfaces.taskManager.TaskConsumerInterface;
import expo.modules.interfaces.taskManager.TaskExecutionCallback;
import expo.modules.interfaces.taskManager.TaskInterface;
import expo.modules.interfaces.taskManager.TaskManagerUtilsInterface;

import java.util.Map;

public class BackgroundFetchTaskConsumer extends TaskConsumer implements TaskConsumerInterface, LifecycleEventListener {
  private static final String TAG = BackgroundFetchTaskConsumer.class.getSimpleName();
  private static final int DEFAULT_INTERVAL_MS = 10 * 60 * 1000; // 10 minutes

  private TaskInterface mTask;
  private PendingIntent mPendingIntent;

  public BackgroundFetchTaskConsumer(Context context, TaskManagerUtilsInterface taskManagerUtils) {
    super(context, taskManagerUtils);
  }

  //region TaskConsumerInterface

  @Override
  public String taskType() {
    return "backgroundFetch";
  }

  @Override
  public boolean canReceiveCustomBroadcast(String action) {
    // Let the TaskService know that we want to receive custom broadcasts
    // having "android.intent.action.BOOT_COMPLETED" or "Intent.ACTION_MY_PACKAGE_REPLACED" action.
    return Intent.ACTION_BOOT_COMPLETED.equals(action) || Intent.ACTION_MY_PACKAGE_REPLACED.equals(action);
  }

  @Override
  public void didRegister(TaskInterface task) {
    mTask = task;
  }

  @Override
  public void didUnregister() {
    // Stop an alarm.
    stopAlarm();

    // Cancel pending intent.
    getTaskManagerUtils().cancelTaskIntent(getContext(), mTask.getAppScopeKey(), mTask.getName());

    mTask = null;
    mPendingIntent = null;
  }

  @Override
  public void didReceiveBroadcast(Intent intent) {
    String action = intent.getAction();

    if (Intent.ACTION_BOOT_COMPLETED.equals(action)) {
      // Device has just been booted up, so we need restore an alarm if "startOnBoot" option is enabled.
      Map<String, Object> options = mTask.getOptions();
      boolean startOnBoot = options.containsKey("startOnBoot") && (boolean) options.get("startOnBoot");

      if (startOnBoot) {
        startAlarm();
      }
    } else if (Intent.ACTION_MY_PACKAGE_REPLACED.equals(action)) {
      // App has just been reinstalled, so we need restore an alarm.
      startAlarm();
    } else {
      Context context = getContext();
      TaskManagerUtilsInterface taskManagerUtils = getTaskManagerUtils();

      if (context != null) {
        taskManagerUtils.executeTask(mTask, null, null);
      }
    }
  }

  @Override
  public boolean didExecuteJob(final JobService jobService, final JobParameters params) {
    mTask.execute(null, null, new TaskExecutionCallback() {
      @Override
      public void onFinished(Map<String, Object> response) {
        jobService.jobFinished(params, false);
      }
    });

    // Returning `true` indicates that the job is still running, but in async mode.
    // In that case we're obligated to call `jobService.jobFinished` as soon as the async block finishes.
    return true;
  }

  //endregion
  //region private methods

  private AlarmManager getAlarmManager() {
    Context context = getContext();
    return context != null ? (AlarmManager) context.getSystemService(Context.ALARM_SERVICE) : null;
  }

  private int getIntervalMs() {
    Map<String, Object> options = mTask != null ? mTask.getOptions() : null;

    if (options != null && options.containsKey("minimumInterval")) {
      // Given option is in seconds.
      // It doesn't make much sense to offer millisecond accuracy since the interval is inexact.
      return ((Number) options.get("minimumInterval")).intValue() * 1000;
    }
    return DEFAULT_INTERVAL_MS;
  }

  private void startAlarm() {
    Context context = getContext();
    AlarmManager alarmManager = getAlarmManager();

    if (alarmManager == null) {
      return;
    }

    int interval = getIntervalMs();
    TaskManagerUtilsInterface taskManagerUtils = getTaskManagerUtils();

    mPendingIntent = taskManagerUtils.createTaskIntent(context, mTask);

    // Cancel existing alarm for this pending intent.
    alarmManager.cancel(mPendingIntent);

    Log.i(TAG, "Starting an alarm for task '" + mTask.getName() + "'.");

    alarmManager.setInexactRepeating(
      AlarmManager.ELAPSED_REALTIME_WAKEUP,
      SystemClock.elapsedRealtime() + interval,
      interval,
      mPendingIntent
    );
  }

  private void stopAlarm() {
    AlarmManager alarmManager = getAlarmManager();

    if (alarmManager != null && mPendingIntent != null) {
      Log.i(TAG, "Stopping an alarm for task '" + mTask.getName() + "'.");

      alarmManager.cancel(mPendingIntent);
    }
  }

  //endregion
  //region LifecycleEventListener

  @Override
  public void onHostResume() {
    stopAlarm();
  }

  @Override
  public void onHostPause() {
    startAlarm();
  }

  @Override
  public void onHostDestroy() {
    // Stop an alarm if "stopOnTerminate" is set to true (default).
    // Otherwise it should continue to work when the activity is terminated.
    Map<String, Object> options = mTask.getOptions();

    if (!options.containsKey("stopOnTerminate") || (boolean) options.get("stopOnTerminate")) {
      stopAlarm();
    }
  }

  //endregion
}