/*
 * Copyright 2011 Vaadin Ltd.
 * 
 * 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 com.vaadin.sass.visitor;

import java.util.ArrayList;
import java.util.HashMap;

import com.vaadin.sass.ScssStylesheet;
import com.vaadin.sass.tree.BlockNode;
import com.vaadin.sass.tree.Node;

/**
 * Handle nesting of blocks by moving child blocks to their parent, updating
 * their selector lists while doing so. Also parent selectors (&) are
 * handled here.
 * 
 * Sample SASS code (from www.sass-lang.com):
 * 
 * <pre>
 * table.hl {
 *   margin: 2em 0;
 *   td.ln {
 *     text-align: right;
 *   }
 * }
 * </pre>
 * 
 * Note that nested properties are handled by {@link NestedNodeHandler}, not
 * here.
 */
public class BlockNodeHandler {

    public static void traverse(BlockNode node) {

        Node parent = node.getParentNode();
        if (node.getChildren().size() == 0) {
            parent.removeChild(node);
            while (parent != null && parent instanceof BlockNode
                    && parent.getChildren().size() == 0) {
                Node temp = parent;
                parent = parent.getParentNode();
                parent.removeChild(temp);
            }

            return;
        }

        if (parent instanceof BlockNode) {
            combineParentSelectorListToChild(node);
        }
    }

    private static void combineParentSelectorListToChild(BlockNode node) {
        ArrayList<String> newList = new ArrayList<String>();
        BlockNode parentBlock = (BlockNode) node.getParentNode();
        for (String parentSelector : parentBlock.getSelectorList()) {
            for (String childSelector : node.getSelectorList()) {
                // handle parent selector
                if (childSelector.contains("&")) {
                    newList.add(childSelector.replace("&", parentSelector));
                } else {
                    newList.add(parentSelector + " " + childSelector);
                }
            }
        }
        node.setSelectorList(newList);
        Node oldParent = node.getParentNode();
        HashMap<Node, Node> lastNodeAdded = ScssStylesheet.getLastNodeAdded();
        if (lastNodeAdded.get(oldParent) != null) {
            oldParent.getParentNode().appendChild(node,
                    lastNodeAdded.get(oldParent));
        } else {
            oldParent.getParentNode().appendChild(node, oldParent);
        }

        lastNodeAdded.put(oldParent, node);
    }
}