/*
    * Copyright 2001-2005 The Apache Software Foundation.
    *
    * 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 net.sf.nxqd.xmldb;
  
  import java.io.File;
  import java.io.StringReader;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.HashMap;
  import java.util.ArrayList;
  import java.util.Enumeration;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  
  import javax.xml.transform.TransformerException;
  import javax.xml.transform.sax.SAXSource;
  import javax.xml.transform.stream.StreamSource;
  
  import org.xml.sax.InputSource;
  import org.xmldb.api.base.Collection;
  import org.xmldb.api.base.ErrorCodes;
  import org.xmldb.api.base.Resource;
  import org.xmldb.api.base.ResourceSet;
  import org.xmldb.api.base.XMLDBException;
  import org.xmldb.api.modules.XPathQueryService;
  import org.xmldb.api.reference.ResourceSetImpl;
  import org.xmldb.api.reference.modules.XMLResourceImpl;
  import org.xmldb.api.base.Resource;
  import org.xmldb.api.modules.XMLResource;
  
  import net.sf.nxqd.NxqdContainer;
  import net.sf.nxqd.NxqdException;
  
  /**
   * The class <code>NxqdXPathQueryService</code> is an implemenation of
   * <code>org.xmldb.api.modules.XPathQueryService</code>.
   *
   * @see org.xmldb.api.modules.XPathQueryService
   *
   * @author <a href="mailto:webhiker@sourceforge.net">webhiker</a>
   * @version 1.0
   */
  public class NxqdXPathQueryService extends NxqdService implements XPathQueryService {
      private static Logger logger = Logger.getLogger(NxqdXPathQueryService.class.getName());
  
      /**
       *  
       */
      public NxqdXPathQueryService(NxqdCollection parent) throws XMLDBException {
  	super(NxqdXPathQueryService.class.getName(),"1.0");
  	setCollection(parent);
      }
  
      /**
       * @see org.xmldb.api.modules.XPathQueryService#setNamespace(java.lang.String,
       *      java.lang.String)
       */
      public void setNamespace(String prefix, String uri) throws XMLDBException {
          setProperty(prefix, uri);
      }
  
      /**
       * @see org.xmldb.api.modules.XPathQueryService#getNamespace(java.lang.String)
       */
      public String getNamespace(String prefix) throws XMLDBException {
          return getProperty(prefix);
      }
  
      /**
       * @see org.xmldb.api.modules.XPathQueryService#removeNamespace(java.lang.String)
       */
      public void removeNamespace(String prefix) throws XMLDBException {
          removeProperty(prefix);
      }
  
      /**
       * @see org.xmldb.api.modules.XPathQueryService#clearNamespaces()
       */
      public void clearNamespaces() throws XMLDBException {
  	String key;
          for (Enumeration e = keys(); e.hasMoreElements() ;) {
  	    key = e.nextElement().toString();
  	    if ((!key.equals(NAME))&&
  		(!key.equals(VERSION))) {
  		removeProperty(key);
 	    }
 	}
     }
 
     private Map getNamespaceMap() {
 	Map namespaceMap = new HashMap();
 	String key;
         for (Enumeration e = keys(); e.hasMoreElements() ;) {
 	    key = e.nextElement().toString();
 	    if ((!key.equals(NAME))&&
 		(!key.equals(VERSION))) {
 		namespaceMap.put(key, getProperty(key));
 	    }
 	}
 	return namespaceMap;
     }
 
     /**
      * @see org.xmldb.api.modules.XPathQueryService#query(java.lang.String)
      * 
      */
     public ResourceSet query(String query) throws XMLDBException {
         logger.fine("query("+query+")");
         ResourceSet result = new ResourceSetImpl(getCollection());
 	queryCollection(query,
 			(NxqdCollection)getCollection(),
 			getNamespaceMap(),
 			result,
 			true);
         return result;
     }
 
     public static void queryCollection(final String query, 
 				       final NxqdCollection collection,
 				       final Map namespaces,
 				       ResourceSet results,
 				       final boolean recurseChildren)
 	throws XMLDBException {
 	try {
 	    // query this collection's documents
 	    NxqdContainer container = collection.getContainer();
 	    List currRes = internalQuery(collection.getContainer(),
 					 query,
 					 namespaces);
 	    Resource resource;
 	    for (int i = 0; i < currRes.size(); i++) {
 		resource = new NxqdXMLResource(collection,
 					       collection.getName()+Integer.toString(i),
 					       XMLResource.RESOURCE_TYPE);
 		results.addResource(resource);
 	    }
 	    if (recurseChildren) {
 		// now query the children of this collection and add each result
 		// to the growing list of results
 		// TODO - trim off a level from the XPath statements???
 		String resNames[] = collection.listChildCollections();
 		Collection child;
 		//logger.info("checking children>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>");
 		for (int i = 0; i < resNames.length; i++) {
 		    //logger.info("checking child>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>"+resNames[i]);
 		    queryCollection(query,
 				    (NxqdCollection)collection.getChildCollection(resNames[i]),
 				    namespaces,
 				    results,
 				    recurseChildren);
 		    // logger.info("got result>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>"+results.getSize());
 		}
 	    }
 	}
 	catch (NxqdException ne) {
 	    ne.printStackTrace();
 	    throw new XMLDBException(ErrorCodes.VENDOR_ERROR,
 				     "Error querying Collection :" + ne.getMessage(),
 				     ne);
 	}
     }
 
     /**
      * @see org.xmldb.api.modules.XPathQueryService#queryResource(java.lang.String,
      *      java.lang.String)
      */
     public ResourceSet queryResource(String id, String query)
 	throws XMLDBException {
         ResourceSet result = new ResourceSetImpl(getCollection());
 	queryCollection("doc(\""+((NxqdCollection)getCollection()).getContainer().getName()+"/"+id+"\")"+query,
 			(NxqdCollection)getCollection(),
 			getNamespaceMap(),
 			result,
 			false);
         return result;
     }
 
     /**
      * The <code>internalQuery</code> method executes the specified queryExpression
      * on this container. If not already containing a collection(...) or
      * document(...) portion, it will be automatically appended.
      *
      * @param queryExpression a <code>String</code> value
      * @return a <code>List</code> value which will contain XML fragments
      * as <code>String</code> objects.
      * @exception NxqdException if an error occurs
      */
     private static List internalQuery(NxqdContainer container,
 				      final String queryExpression) throws NxqdException {
 	return internalQuery(container, queryExpression, null);
     }
 
 
     /**
      * The <code>internalQuery</code> method executes the specified XPath queryExpression
      * on this container. If not already containing a collection(...) or
      * document(...) portion, it will be automatically appended.
      *
      * @param queryExpression a <code>String</code> value
      * @param nameSpaces a <code>Map</code> value
      * @return a <code>List</code> value which will contain XML fragments
      * as <code>String</code> objects.
      * @exception NxqdException if an error occurs
      */
     private static List internalQuery(NxqdContainer container,
 				      final String queryExpression,
 		      final Map nameSpaces) throws NxqdException {
 	// convert regular query into Sleepycat form, unless the user already used
 	// this form
 	String sleepycatQuery;
 	if ((queryExpression.toLowerCase().indexOf("collection(")>=0)||
 	    ((queryExpression.toLowerCase().indexOf("doc(")>=0))) {
 	    sleepycatQuery = queryExpression;
 	}
 	else {
 	    sleepycatQuery = "(collection(\"" + container.getName() + "\"))"+queryExpression;
 	}
 	
 	return container.getNxqdManager().query(sleepycatQuery, nameSpaces);
     }
 
 }