/*
 * Copyright 2003-2014 JetBrains s.r.o.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package jetbrains.mps.migration.global;

import jetbrains.mps.components.CoreComponent;
import jetbrains.mps.project.Project;

import java.util.HashMap;
import java.util.Map;

/**
 * A storage for properties, which define the persistent state of project migrations
 * Default value is null. Null value is not distinguishable from not-set
 */
public class MigrationPropertiesManager implements CoreComponent {
  private static MigrationPropertiesManager INSTANCE;

  public static MigrationPropertiesManager getInstance() {
    return INSTANCE;
  }

  @Override
  public void init() {
    if (INSTANCE != null) {
      throw new IllegalStateException("double initialization");
    }

    INSTANCE = this;
  }

  @Override
  public void dispose() {
    INSTANCE = null;
  }

  //----------

  private Map<Project, MigrationProperties> contributors = new HashMap<Project, MigrationProperties>();

  public MigrationProperties getProperties(Project p) {
    return contributors.get(p);
  }

  public void addProperties(Project p, MigrationProperties mp) {
    contributors.put(p, mp);
  }

  public void removeProperties(Project p) {
    contributors.remove(p);
  }
}
