/*
    * Copyright 2011 Jakub Narloch
    *
    * 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 org.exolab.castor.xml;
  
  import java.util.ArrayList;
  import java.util.Enumeration;
  import java.util.List;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.xml.sax.helpers.AttributeListImpl;
  
  /**
   * This class is an actual namespace stack implementation, responsible for adding and removing
   * namespace scopes, as well as resolving namespace urls and prefixes by traversing all the
   * namespace stack.
   * 
   * @author <a href="mailto:jmnarloch AT gmail DOT com">Jakub Narloch</a>
   * @since 1.3.3
   */
  @SuppressWarnings("deprecation")
  public class NamespacesStack {
  
    private final Log logger = LogFactory.getLog(this.getClass());
  
    /**
     * Represents the string used for indicating default namespace, by default empty string is used.
     */
    private static final String DEFAULT_NAMESPACE = "";
  
    /**
     * Represents a stack of namespaces.
     */
    private List<Namespaces> namespaceStack = new ArrayList<Namespaces>();
  
    /**
     * Adds a namespace to current scope.
     * 
     * @param namespacePrefix the namespace prefix
     * @param namespaceUri the namespace uri
     */
    public void addNamespace(String namespacePrefix, String namespaceUri) {
      Namespaces namespaces = getCurrentNamespaceScope();
      if (namespaces != null) {
        namespaces.addNamespace(namespacePrefix, namespaceUri);
      }
    }
  
    /**
     * Adds the default namespace to current scope.
     * 
     * @param namespaceUri the namespace uri
     */
    public void addDefaultNamespace(String namespaceUri) {
      addNamespace(DEFAULT_NAMESPACE, namespaceUri);
    }
  
    /**
     * Removes the namespace from current scope using the namespace prefix
     * 
     * @param namespacePrefix the prefix of the namespace to remove
     */
    public void removeNamespace(String namespacePrefix) {
      getCurrentNamespaceScope().removeNamespace(namespacePrefix);
    }
  
    /**
     * Retrieves the namespace uri bound to specified prefix.
     * 
     * @param namespacePrefix the namespace prefix
     * 
     * @return the namespace uri bound to the prefix, or null if no namespace has been bound for the
     *         given prefix
     */
    public String getNamespaceURI(String namespacePrefix) {
      String namespaceUri = null;
      for (int ind = namespaceStack.size() - 1; ind >= 0 && namespaceUri == null; ind--) {
        namespaceUri = namespaceStack.get(ind).getNamespaceURI(namespacePrefix);
      }
      return namespaceUri;
    }
  
    /**
     * Declares the namespaces using the attribute list.
     * 
     * @param attributeList the list of attributes containing the namespaces
     * @param localOnly whether the namespaces will only registered in current namespace context or in
     *        entire stack
    */
   @SuppressWarnings("deprecation")
   public void declareAsAttributes(AttributeListImpl attributeList, boolean localOnly) {
     getCurrentNamespaceScope().declareAsAttributes(attributeList);
     if (!localOnly) {
       for (int ind = namespaceStack.size() - 1; ind >= 0; ind--) {
 
         namespaceStack.get(ind).declareAsAttributes(attributeList);
       }
     }
   }
 
   /**
    * Retrieves the default namespace namespace uri.
    * 
    * @return the default namespace uri
    */
   public String getDefaultNamespaceURI() {
     return getNamespaceURI(DEFAULT_NAMESPACE);
   }
 
   /**
    * Retrieves the namespace prefix for the given namespace uri.
    * 
    * @param namespaceUri the namespace uri
    * 
    * @return the
    */
   public String getNamespacePrefix(String namespaceUri) {
     String namespacePrefix = null;
     for (int ind = namespaceStack.size() - 1; ind >= 0 && namespacePrefix == null; ind--) {
       namespacePrefix = namespaceStack.get(ind).getNamespacePrefix(namespaceUri);
     }
     return namespacePrefix;
   }
 
   /**
    * Retrieves the non default namespace prefix for the given namespace uri.
    * 
    * @param namespaceUri the namespace uri
    * 
    * @return the
    */
   public String getNonDefaultNamespacePrefix(String namespaceUri) {
     String namespacePrefix = null;
     for (int ind = namespaceStack.size() - 1; ind >= 0 && namespacePrefix == null; ind--) {
       namespacePrefix = namespaceStack.get(ind).getNonDefaultNamespacePrefix(namespaceUri);
     }
     return namespacePrefix;
   }
 
   /**
    * Retrieves the namespace prefixes registered in current scope.
    * 
    * @return the enumeration of namespace prefixes
    */
   public Enumeration<String> getLocalNamespacePrefixes() {
     Namespaces namespaces = getCurrentNamespaceScope();
     return namespaces != null ? namespaces.getLocalNamespacePrefixes() : null;
   }
 
   /**
    * Adds a new namespace scope.
    */
   public void addNewNamespaceScope() {
     namespaceStack.add(new Namespaces());
   }
 
   /**
    * Removes the namespace scope.
    */
   public void removeNamespaceScope() {
     // removes the current namespace
     if (!namespaceStack.isEmpty()) {
       namespaceStack.remove(namespaceStack.size() - 1);
     } else {
       this.logger.error("Trying to remove a namespaces scope from an empty stack of Namespaces");
     }
   }
 
   /**
    * Retrieves the current namespace scope.
    * 
    * @return the current namespace scope.
    */
   public Namespaces getCurrentNamespaceScope() {
     if (namespaceStack.isEmpty()) {
       addNewNamespaceScope();
     }
     return namespaceStack.get(namespaceStack.size() - 1);
   }
 }