/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation 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:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.che.ide.ext.java.jdt.internal.corext.refactoring.util;

import org.eclipse.che.ide.ext.java.jdt.refactoring.CategorizedTextEditGroup;
import org.eclipse.che.ide.ext.java.jdt.refactoring.GroupCategorySet;
import org.eclipse.che.ide.ext.java.jdt.refactoring.TextChange;
import org.eclipse.che.ide.ext.java.jdt.refactoring.TextEditChangeGroup;
import org.eclipse.che.ide.ext.java.jdt.text.edits.MalformedTreeException;
import org.eclipse.che.ide.ext.java.jdt.text.edits.MultiTextEdit;
import org.eclipse.che.ide.ext.java.jdt.text.edits.TextEdit;
import org.eclipse.che.ide.ext.java.jdt.text.edits.TextEditGroup;
import org.eclipse.che.ide.runtime.Assert;


/**
 * A utility class to provide compatibility with the old
 * text change API of adding text edits directly and auto
 * inserting them into the tree.
 */
public class TextChangeCompatibility {

    public static void addTextEdit(TextChange change, String name, TextEdit edit) throws MalformedTreeException {
        Assert.isNotNull(change);
        Assert.isNotNull(name);
        Assert.isNotNull(edit);
        TextEdit root = change.getEdit();
        if (root == null) {
            root = new MultiTextEdit();
            change.setEdit(root);
        }
        insert(root, edit);
        change.addTextEditGroup(new TextEditGroup(name, edit));
    }

    public static void addTextEdit(TextChange change, String name, TextEdit edit, GroupCategorySet groupCategories)
            throws MalformedTreeException {
        Assert.isNotNull(change);
        Assert.isNotNull(name);
        Assert.isNotNull(edit);
        TextEdit root = change.getEdit();
        if (root == null) {
            root = new MultiTextEdit();
            change.setEdit(root);
        }
        insert(root, edit);
        change.addTextEditChangeGroup(new TextEditChangeGroup(change, new CategorizedTextEditGroup(name, edit,
                                                                                                   groupCategories)));
    }

    public static void insert(TextEdit parent, TextEdit edit) throws MalformedTreeException {
        if (!parent.hasChildren()) {
            parent.addChild(edit);
            return;
        }
        TextEdit[] children = parent.getChildren();
        // First dive down to find the right parent.
        for (int i = 0; i < children.length; i++) {
            TextEdit child = children[i];
            if (covers(child, edit)) {
                insert(child, edit);
                return;
            }
        }
        // We have the right parent. Now check if some of the children have to
        // be moved under the new edit since it is covering it.
        int removed = 0;
        for (int i = 0; i < children.length; i++) {
            TextEdit child = children[i];
            if (covers(edit, child)) {
                parent.removeChild(i - removed++);
                edit.addChild(child);
            }
        }
        parent.addChild(edit);
    }

    private static boolean covers(TextEdit thisEdit, TextEdit otherEdit) {
        if (thisEdit.getLength() == 0) // an insertion point can't cover anything
            return false;

        int thisOffset = thisEdit.getOffset();
        int thisEnd = thisEdit.getExclusiveEnd();
        if (otherEdit.getLength() == 0) {
            int otherOffset = otherEdit.getOffset();
            return thisOffset < otherOffset && otherOffset < thisEnd;
        } else {
            int otherOffset = otherEdit.getOffset();
            int otherEnd = otherEdit.getExclusiveEnd();
            return thisOffset <= otherOffset && otherEnd <= thisEnd;
        }
    }

}