/*
 * Copyright (c) 2007-2012 Eike Stepper (Berlin, Germany) and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Simon McDuff - initial API and implementation
 *    Eike Stepper - maintenance
 */
package org.eclipse.emf.internal.cdo.analyzer;

import org.eclipse.emf.cdo.CDOObject;
import org.eclipse.emf.cdo.common.id.CDOID;
import org.eclipse.emf.cdo.common.util.CDOFetchRule;

import org.eclipse.emf.ecore.EClass;
import org.eclipse.emf.ecore.EReference;
import org.eclipse.emf.ecore.EStructuralFeature;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @author Simon McDuff
 */
public class CDOFeatureAnalyzerUI extends CDOAbstractFeatureRuleAnalyzer
{
  private static final long ELAPSE_TIME = 400L;

  private Map<CDOClusterOfFetchRule, CDOClusterOfFetchRule> featureRules = new HashMap<CDOClusterOfFetchRule, CDOClusterOfFetchRule>();

  private CDOClusterOfFetchRule currentClusterOfFetchRule;

  private long maxTimeBetweenOperation;

  public CDOFeatureAnalyzerUI()
  {
    this(ELAPSE_TIME);
  }

  public CDOFeatureAnalyzerUI(long maxTimeBetweenOperation)
  {
    this.maxTimeBetweenOperation = maxTimeBetweenOperation;
  }

  public CDOID getContext()
  {
    if (lastTraverseFeature.isMany())
    {
      return CDOID.NULL;
    }

    return lastTraverseCDOObject.cdoID();
  }

  public synchronized CDOClusterOfFetchRule getFeatureRule(EClass eClass, EStructuralFeature feature)
  {
    CDOClusterOfFetchRule search = new CDOClusterOfFetchRule(eClass, feature);
    CDOClusterOfFetchRule featureRule = featureRules.get(search);
    if (featureRule == null)
    {
      featureRule = search;
      featureRules.put(search, featureRule);
    }

    return featureRule;
  }

  public List<CDOFetchRule> getFetchRules(Collection<CDOID> ids)
  {
    List<CDOFetchRule> list = new ArrayList<CDOFetchRule>();

    boolean addRootFeature = true;
    if (lastTraverseFeature != null)
    {
      fetchData();

      if (lastTraverseFeature.isMany())
      {
        addRootFeature = false;
      }

      CDOClusterOfFetchRule search = new CDOClusterOfFetchRule(lastTraverseCDOObject.eClass(), lastTraverseFeature);
      CDOClusterOfFetchRule fetchOfRule = featureRules.get(search);
      if (fetchOfRule == null)
      {
        return null;
      }

      Collection<CDOFetchRule> fetchRules = fetchOfRule.getFeatureInfo().getRules(null, null);

      for (CDOFetchRule fetchRule : fetchRules)
      {
        if (addRootFeature == true || lastTraverseCDOObject.eClass() != fetchRule.getEClass())
        {
          list.add(fetchRule);
        }
      }
    }

    return list;
  }

  @Override
  protected void doPreTraverseFeature(CDOObject cdoObject, EStructuralFeature feature, int index)
  {
    // Don`t handle containment relationship
    // TODO Simon: Do you really mean containment here? The check is different...
    // TODO Clarify feature maps
    if (feature instanceof EReference)
    {
      if (lastElapseTimeBetweenOperations > maxTimeBetweenOperation || currentClusterOfFetchRule == null)
      {
        // The user interacted with the UI. Restart a new ClusterOfFetchRule
        currentClusterOfFetchRule = getFeatureRule(cdoObject.eClass(), feature);
      }
    }
  }

  @Override
  protected void doPostTraverseFeature(CDOObject cdoObject, EStructuralFeature feature, int index, Object object)
  {
    if (didFetch())
    {
      currentClusterOfFetchRule.getFeatureInfo().activate(cdoObject.eClass(), feature);
    }
  }
}