/*******************************************************************************
 * Copyright (c) 2000, 2017 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.corext.refactoring.reorg;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.eclipse.core.runtime.Assert;

import org.eclipse.core.resources.IFile;

import org.eclipse.jdt.core.IClassFile;
import org.eclipse.jdt.core.ICompilationUnit;
import org.eclipse.jdt.core.IJavaElement;
import org.eclipse.jdt.core.ISourceReference;
import org.eclipse.jdt.core.JavaModelException;


public class SourceReferenceUtil {

	//no instances
	private SourceReferenceUtil(){}

	public static IFile getFile(ISourceReference ref) {
		ICompilationUnit unit= getCompilationUnit(ref);
		return (IFile) unit.getPrimary().getResource();
	}

	public static ICompilationUnit getCompilationUnit(ISourceReference o){
		Assert.isTrue(! (o instanceof IClassFile));

		if (o instanceof ICompilationUnit)
			return (ICompilationUnit)o;
		if (o instanceof IJavaElement)
			return (ICompilationUnit) ((IJavaElement)o).getAncestor(IJavaElement.COMPILATION_UNIT);
		return null;
	}

	@SuppressWarnings("unlikely-arg-type")
	private static boolean hasParentInSet(IJavaElement elem, Set<ISourceReference> set){
		IJavaElement parent= elem.getParent();
		while (parent != null) {
			if (set.contains(parent))
				return true;
			parent= parent.getParent();
		}
		return false;
	}

	public static ISourceReference[] removeAllWithParentsSelected(ISourceReference[] elems){
		Set<ISourceReference> set= new HashSet<>(Arrays.asList(elems));
		List<ISourceReference> result= new ArrayList<>(elems.length);
		for (ISourceReference elem : elems) {
			if (! (elem instanceof IJavaElement))
				result.add(elem);
			else{
				if (! hasParentInSet(((IJavaElement)elem), set))
					result.add(elem);
			}
		}
		return result.toArray(new ISourceReference[result.size()]);
	}

	public static ISourceReference[] sortByOffset(ISourceReference[] methods){
		Arrays.sort(methods, (o1, o2) -> {
			try{
				return o2.getSourceRange().getOffset() - o1.getSourceRange().getOffset();
			} catch (JavaModelException e){
				return o2.hashCode() - o1.hashCode();
			}
		});
		return methods;
	}
}