package jalview.workers;

import java.util.ArrayList;
import java.util.Hashtable;
import java.util.List;
import java.util.Map;

import jalview.api.AlignCalcManagerI;
import jalview.api.AlignCalcWorkerI;

public class AlignCalcManager implements AlignCalcManagerI
{
  private List<Class> blackList=new ArrayList<Class>();
  /**
   * global record of calculations in progress
   */
  private static Hashtable<Class,AlignCalcWorkerI> inProgress=new Hashtable<Class,AlignCalcWorkerI>();
  /**
   * record of calculations pending or in progress in the current context
   */
  private Map<Class,List<AlignCalcWorkerI>> updating=new Hashtable<Class,List<AlignCalcWorkerI>>();
  
  @Override
  public void notifyStart(AlignCalcWorkerI worker)
  {
    List<AlignCalcWorkerI> upd = updating.get(worker.getClass());
    if (upd==null)
    {
      updating.put(worker.getClass(), upd=new ArrayList<AlignCalcWorkerI>());
    }
    upd.add(worker);
  }

  @Override
  public boolean alreadyDoing(AlignCalcWorkerI worker)
  {
    return inProgress.containsKey(worker.getClass());
  }

  @Override
  public void notifyWorking(AlignCalcWorkerI worker)
  {
    // TODO: decide if we should throw exceptions here if multiple workers start to work
    if (inProgress.get(worker.getClass())!=null)
    {
      System.err.println("Warning: Multiple workers are running of type "+worker.getClass());
    }
    inProgress.put(worker.getClass(), worker);
    
  }

  @Override
  public void workerComplete(AlignCalcWorkerI worker)
  {
    inProgress.remove(worker);
  }

  @Override
  public void workerCannotRun(AlignCalcWorkerI worker)
  {
    blackList.add(worker.getClass());
  }
  public boolean isBlackListed(Class workerType)
  {
    return blackList.contains(workerType);
  }

  @Override
  public void startWorker(AlignCalcWorkerI worker)
  {
    new Thread(worker).start();
  }
}