SessionTimeFixer.java

package pl.llp.aircasting.sync;

import pl.llp.aircasting.model.Measurement;
import pl.llp.aircasting.model.MeasurementStream;
import pl.llp.aircasting.model.Session;

import java.util.Date;
import java.util.List;

public class SessionTimeFixer
{
  public void fromUTCtoLocal(Session session)
  {
    if(needsTimeFix(session))
    {
      fixStartEndTimeFromMeasurements(session);
    }

    int minutes = getOffset(session);
    int offset = minutes * 60 * 1000;

    Date start = session.getStart();
    Date end = session.getEnd();
    session.setStart(new Date(start.getTime() + offset));
    session.setEnd(new Date(end.getTime() + offset));

    List<MeasurementStream> streams = session.getActiveMeasurementStreams();
    for (MeasurementStream stream : streams)
    {
      List<Measurement> measurements = stream.getMeasurements();
      for (Measurement measurement : measurements)
      {
        measurement.setTime(new Date(measurement.getTime().getTime() + offset));
      }
    }
  }

  boolean needsTimeFix(Session session)
  {
    return session.getStart() == null || session.getEnd() == null;
  }

  private int getOffset(Session session)
  {
    List<MeasurementStream> streams = session.getActiveMeasurementStreams();
    for (MeasurementStream stream : streams)
    {
      List<Measurement> measurements = stream.getMeasurements();
      for (Measurement measurement : measurements)
      {
        return measurement.getTimeZoneOffsetMinutes();
      }
    }
    return 0;
  }

  void fixStartEndTimeFromMeasurements(Session session)
  {
    Date start = session.getStart();
    Date end = session.getEnd();

    for (MeasurementStream stream : session.getMeasurementStreams())
    {
      List<Measurement> measurements = stream.getMeasurements();
      if (measurements.isEmpty())
      {
        continue;
      }

      Measurement first = measurements.get(0);
      Measurement last = measurements.get(measurements.size() - 1);

      if (start == null)
      {
        start = first.getTime();
      }
      else
      {
        start = start.before(first.getTime()) ? start : first.getTime();
      }

      if (end == null)
      {
        end = last.getTime();
      }
      else
      {
        end = end.before(last.getTime()) ? last.getTime() : end;
      }
    }

    if (start == null || end == null)
    {
      String message = "Session [" + session.getId() + "] has incorrect start/end date [" + start + "/" + end + "]";
      throw new SessionSyncException(message);
    }

    session.setStart(new Date(start.getTime()));
    session.setEnd(new Date(end.getTime()));
  }
}