package jalview.ws2;

import java.io.IOException;
import java.util.EventObject;
import java.util.List;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

import jalview.bin.Cache;
import jalview.ws2.WebServiceWorkerI.WSJob;

public class WebServiceExecutor
{
  private ScheduledExecutorService executor =
      Executors.newSingleThreadScheduledExecutor();
  
  public void submit(final WebServiceWorkerI worker)
  {
    for (var job : worker.getJobs()) {
      executor.submit(() -> submitJob(worker, job));
      executor.schedule(() -> pollJob(worker, job), 1, TimeUnit.SECONDS);
    }
  }
  
  private void submitJob(WebServiceWorkerI worker, WSJob job) {
    try {
      job.setJobID(worker.startJob(job).getJobID());
      job.resetAllowedExceptions();
      executor.schedule(() -> pollJob(worker, job), 1, TimeUnit.SECONDS);
    }
    catch (IOException e) {
      Cache.log.error("Exception occurred during job submission", e);
      if (!job.deductAllowedExceptions()) {
        job.setState(WSJobState.SERVER_ERROR);
      }
    }
    if (!job.getState().isSubmitted()) {
      executor.schedule(() -> submitJob(worker, job), 5, TimeUnit.SECONDS);
    }
  }
  
  private void pollJob(WebServiceWorkerI worker, WSJob job) {
    try {
      worker.pollJob(job);
      job.resetAllowedExceptions();
    }
    catch (IOException e) {
      Cache.log.error("Exception occurred duringn job pollign", e);
      if (!job.deductAllowedExceptions()) {
        job.setState(WSJobState.SERVER_ERROR);
      }
    }
    if (!job.getState().isDone()) {
      executor.schedule(() -> pollJob(worker, job), 1, TimeUnit.SECONDS);
    }
  }
  
  public static interface WebServiceThreadListenerI
  {
    public void threadSubmitted(WebServiceWorkerI thread);
    public void threadStarted(WebServiceWorkerI thread);
    public void stateChanged(WebServiceWorkerI thread, WSJobState oldState,
        WSJobState newState);
    public void logAppended(WebServiceWorkerI thread, String text);
    public void errorLogAppended(WebServiceWorkerI thread, String text);
    public void cancelled(WebServiceWorkerI thread);
  }
  
  
  List<WebServiceThreadListenerI> listeners = new CopyOnWriteArrayList<>();
  
  public void addServiceListener(WebServiceThreadListenerI listener)
  {
    if (!listeners.contains(listener))
      listeners.add(listener);
  }
  
  public void removeServiceListener(WebServiceThreadListenerI listener)
  {
    listeners.remove(listener);
  }
}