/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 freemarker.ext.dom;

import freemarker.core.Environment;
import freemarker.template.Template;

For internal use only; don't depend on this, there's no backward compatibility guarantee at all!
This class is to work around the lack of module system in Java, i.e., so that other FreeMarker packages can
access things inside this package that users shouldn't. 
/**
 * For internal use only; don't depend on this, there's no backward compatibility guarantee at all!
 * This class is to work around the lack of module system in Java, i.e., so that other FreeMarker packages can
 * access things inside this package that users shouldn't. 
 */
final class DomStringUtil {

    private DomStringUtil() {
        // Not meant to be instantiated
    }

    static boolean isXMLNameLike(String name) {
        return isXMLNameLike(name, 0);
    }
    
    
Check if the name looks like an XML element name.
Params:
firstCharIdx – The index of the character in the string parameter that we treat as the beginning of the
     string to check. This is to spare substringing that has become more expensive in Java 7.
Returns:
whether the name is a valid XML element name. (This routine might only be 99% accurate. REVISIT)/**
     * Check if the name looks like an XML element name.
     * 
     * @param firstCharIdx The index of the character in the string parameter that we treat as the beginning of the
     *      string to check. This is to spare substringing that has become more expensive in Java 7.  
     * 
     * @return whether the name is a valid XML element name. (This routine might only be 99% accurate. REVISIT)
     */
    static boolean isXMLNameLike(String name, int firstCharIdx) {
        int ln = name.length();
        for (int i = firstCharIdx; i < ln; i++) {
            char c = name.charAt(i);
            if (i == firstCharIdx && (c == '-' || c == '.' || Character.isDigit(c))) {
                return false;
            }
            if (!Character.isLetterOrDigit(c) && c != '_' && c != '-' && c != '.') {
                if (c == ':') {
                    if (i + 1 < ln && name.charAt(i + 1) == ':') {
                        // "::" is used in XPath
                        return false;
                    }
                    // We don't return here, as a lonely ":" is allowed.
                } else {
                    return false;
                }
            }
        }
        return true;
    }    

    
Returns:
whether the qname matches the combination of nodeName, nsURI, and environment prefix settings./**
     * @return whether the qname matches the combination of nodeName, nsURI, and environment prefix settings. 
     */
    static boolean matchesName(String qname, String nodeName, String nsURI, Environment env) {
        String defaultNS = env.getDefaultNS();
        if ((defaultNS != null) && defaultNS.equals(nsURI)) {
            return qname.equals(nodeName) 
               || qname.equals(Template.DEFAULT_NAMESPACE_PREFIX + ":" + nodeName); 
        }
        if ("".equals(nsURI)) {
            if (defaultNS != null) {
                return qname.equals(Template.NO_NS_PREFIX + ":" + nodeName);
            } else {
                return qname.equals(nodeName) || qname.equals(Template.NO_NS_PREFIX + ":" + nodeName);
            }
        }
        String prefix = env.getPrefixForNamespace(nsURI);
        if (prefix == null) {
            return false; // Is this the right thing here???
        }
        return qname.equals(prefix + ":" + nodeName);
    }
    
}