/*
Copyright 2012 GanttProject Team

This file is part of GanttProject, an opensource project management tool.

GanttProject is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

GanttProject is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GanttProject.  If not, see <http://www.gnu.org/licenses/>.
*/
package net.sourceforge.ganttproject.action.task;

import java.util.Collection;

import net.sourceforge.ganttproject.task.Task;
import net.sourceforge.ganttproject.task.TaskContainmentHierarchyFacade;
import net.sourceforge.ganttproject.task.TaskManager;

import com.google.common.base.Function;

/**
 * Creates functions resolving move targets for outdent operations. When outdenting move target does not depend on
 * the selection so we always return the same instance
 *
 * @author dbarashev
 */
class OutdentTargetFunctionFactory implements Function<Collection<Task>, Function<Task, Task>> {
  private final TaskManager myTaskManager;
  private final Function<Task, Task> myGetMoveTargetFxn = new Function<Task, Task>() {
    @Override
    public Task apply(Task whatMove) {
      Task currentParent = getTaskHierarchy().getContainer(whatMove);
      if (currentParent == myTaskManager.getRootTask()) {
        return null;
      }
      return getTaskHierarchy().getContainer(currentParent);
    }
  };

  OutdentTargetFunctionFactory(TaskManager taskManager) {
    myTaskManager = taskManager;
  }

  protected TaskContainmentHierarchyFacade getTaskHierarchy() {
    return myTaskManager.getTaskHierarchy();
  }

  @Override
  public Function<Task, Task> apply(Collection<Task> outdentRoots) {
    return myGetMoveTargetFxn;
  }
}