/*
 *  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 org.apache.jk.config;

import java.io.File;
import java.io.IOException;
import java.io.StringReader;
import java.util.Hashtable;
import java.util.Vector;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.apache.tomcat.util.IntrospectionUtils;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;


/* Naming conventions:

JK_CONF_DIR == serverRoot/work  ( XXX /jkConfig ? )

- Each vhost has a sub-dir named after the canonycal name

- For each webapp in a vhost, there is a separate WEBAPP_NAME.jkmap

- In httpd.conf ( or equivalent servers ), in each virtual host you
should "Include JK_CONF_DIR/VHOST/jk_apache.conf". The config
file will contain the Alias declarations and other rules required
for apache operation. Same for other servers. 

- WebXml2Jk will be invoked by a config tool or automatically for each
webapp - it'll generate the WEBAPP.jkmap files and config fragments.

WebXml2Jk will _not_ generate anything else but mappings.
It should _not_ try to guess locations or anything else - that's
another components' job.

*/

/**
 * Read a web.xml file and generate the mappings for jk2.
 * It can be used from the command line or ant.
 * 
 * In order for the web server to serve static pages, all webapps
 * must be deployed on the computer that runs Apache, IIS, etc.
 *
 * Dynamic pages can be executed on that computer or other servers
 * in a pool, but even if the main server doesn't run tomcat,
 * it must have all the static files and WEB-INF/web.xml.
 * ( you could have a script remove everything else, including jsps - if
 *  security paranoia is present ).
 *
 * XXX We could have this in WEB-INF/urimap.properties.
 *
 * @author Costin Manolache
 */
public class WebXml2Jk {
    String vhost="";
    String cpath="";
    String docBase;
    String file;
    String worker="lb"; 

    // -------------------- Settings -------------------- 

    // XXX We can also generate location-independent mappings.
    
    /** Set the canonycal name of the virtual host.
     */
    public void setHost( String vhost ) {
        this.vhost=vhost; 
    }
    
    /** Set the canonical name of the virtual host.
     */
    public void setContext( String contextPath ) {
        this.cpath=contextPath;
    }

    
    /** Set the base directory where the application is
     *  deployed ( on the web server ).
     */
    public void setDocBase(String docBase ) {
        this.docBase=docBase;
    }

    // Automatically generated.
//     /** The file where the jk2 mapping will be generated
//      */
//     public void setJk2Conf( String outFile ) {
//         file=outFile;
//         type=CONFIG_JK2_URIMAP;
//     }

//     /** Backward compat: generate JkMounts for mod_jk1
//      */
//     public void setJkmountFile( String outFile ) {
//         file=outFile;
//         type=CONFIG_JK_MOUNT;
//     }

    /* By default we map to the lb - in jk2 this is automatically
     * created and includes all  tomcat instances.
     *
     * This is equivalent to the worker in jk1.
     */
    public void setGroup(String route ) {
        worker=route;
    }

    // -------------------- Generators --------------------
    public static interface MappingGenerator {
        void setWebXmlReader(WebXml2Jk wxml );

        /** Start section( vhost declarations, etc )
         */
        void generateStart() throws IOException ;

        void generateEnd() throws IOException ;
        
        void generateServletMapping( String servlet, String url )throws IOException ;
        void generateFilterMapping( String servlet, String url ) throws IOException ;

        void generateLoginConfig( String loginPage,
                                  String errPage, String authM ) throws IOException ;

        void generateErrorPage( int err, String location ) throws IOException ;
            
        void generateConstraints( Vector urls, Vector methods, Vector roles, boolean isSSL ) throws IOException ;
    }    
    
    // -------------------- Implementation --------------------
    Node webN;
    File jkDir;
    
    /** Return the top level node
     */
    public Node getWebXmlNode() {
        return webN;
    }

    public File getJkDir() {
        return jkDir;
    }
    
    /** Extract the wellcome files from the web.xml
     */
    public Vector getWellcomeFiles() {
        Node n0=getChild( webN, "welcome-file-list" );
        Vector wF=new Vector();
        if( n0!=null ) {
            for( Node mapN=getChild( webN, "welcome-file" );
                 mapN != null; mapN = getNext( mapN ) ) {
                wF.addElement( getContent(mapN));
            }
        }
        // XXX Add index.html, index.jsp
        return wF;
    }


    void generate(MappingGenerator gen ) throws IOException {
        gen.generateStart();
        log.info("Generating mappings for servlets " );
        for( Node mapN=getChild( webN, "servlet-mapping" );
             mapN != null; mapN = getNext( mapN ) ) {
            
            String serv=getChildContent( mapN, "servlet-name");
            String url=getChildContent( mapN, "url-pattern");
            
            gen.generateServletMapping( serv, url );
        }

        log.info("Generating mappings for filters " );
        for( Node mapN=getChild( webN, "filter-mapping" );
             mapN != null; mapN = getNext( mapN ) ) {
            
            String filter=getChildContent( mapN, "filter-name");
            String url=getChildContent( mapN, "url-pattern");

            gen.generateFilterMapping(  filter, url );
        }


        for( Node mapN=getChild( webN, "error-page" );
             mapN != null; mapN = getNext( mapN ) ) {
            String errorCode= getChildContent( mapN, "error-code" );
            String location= getChildContent( mapN, "location" );

            if( errorCode!=null && ! "".equals( errorCode ) ) {
                try {
                    int err=new Integer( errorCode ).intValue();
                    gen.generateErrorPage(  err, location );
                } catch( Exception ex ) {
                    log.error( "Format error " + location, ex);
                }
            }
        }

        Node lcN=getChild( webN, "login-config" );
        if( lcN!=null ) {
            log.info("Generating mapping for login-config " );
            
            String authMeth=getContent( getChild( lcN, "auth-method"));
            if( authMeth == null ) authMeth="BASIC";

            Node n1=getChild( lcN, "form-login-config");
            String loginPage= getChildContent( n1, "form-login-page");
            String errPage= getChildContent( n1, "form-error-page");

	    if(loginPage != null) {
		int lpos = loginPage.lastIndexOf("/");
		String jscurl = loginPage.substring(0,lpos+1) + "j_security_check";
                gen.generateLoginConfig( jscurl, errPage, authMeth );
	    }
        }

        log.info("Generating mappings for security constraints " );
        for( Node mapN=getChild( webN, "security-constraint" );
             mapN != null; mapN = getNext( mapN )) {

            Vector methods=new Vector();
            Vector urls=new Vector();
            Vector roles=new Vector();
            boolean isSSL=false;
            
            Node wrcN=getChild( mapN, "web-resource-collection");
            for( Node uN=getChild(wrcN, "http-method");
                 uN!=null; uN=getNext( uN )) {
                methods.addElement( getContent( uN ));
            }
            for( Node uN=getChild(wrcN, "url-pattern");
                 uN!=null; uN=getNext( uN )) {
                urls.addElement( getContent( uN ));
            }

            // Not used at the moment
            Node acN=getChild( mapN, "auth-constraint");
            for( Node rN=getChild(acN, "role-name");
                 rN!=null; rN=getNext( rN )) {
                roles.addElement(getContent( rN ));
            }

            Node ucN=getChild( mapN, "user-data-constraint");
            String transp=getContent(getChild( ucN, "transport-guarantee"));
            if( transp!=null ) {
                if( "INTEGRAL".equalsIgnoreCase( transp ) ||
                    "CONFIDENTIAL".equalsIgnoreCase( transp ) ) {
                    isSSL=true;
                }
            }

            gen.generateConstraints( urls, methods, roles, isSSL );
        }
        gen.generateEnd();
    }
    
    // -------------------- Main and ant wrapper --------------------
    
    public void execute() {
        try {
            if( docBase== null) {
                log.error("No docbase - please specify the base directory of you web application ( -docBase PATH )");
                return;
            }
            if( cpath== null) {
                log.error("No context - please specify the mount ( -context PATH )");
                return;
            }
            File docbF=new File(docBase);
            File wXmlF=new File( docBase, "WEB-INF/web.xml");

            Document wXmlN=readXml(wXmlF);
            if( wXmlN == null ) return;

            webN = wXmlN.getDocumentElement();
            if( webN==null ) {
                log.error("Can't find web-app");
                return;
            }

            jkDir=new File( docbF, "WEB-INF/jk2" );
            jkDir.mkdirs();
            
            MappingGenerator generator=new GeneratorJk2();
            generator.setWebXmlReader( this );
            generate( generator );

            generator=new GeneratorJk1();
            generator.setWebXmlReader( this );
            generate( generator );

            generator=new GeneratorApache2();
            generator.setWebXmlReader( this );
            generate( generator );

        } catch( Exception ex ) {
            ex.printStackTrace();
        }
    }


    public static void main(String args[] ) {
        try {
            if( args.length == 1 &&
                ( "-?".equals(args[0]) || "-h".equals( args[0])) ) {
                System.out.println("Usage: ");
                System.out.println("  WebXml2Jk [OPTIONS]");
                System.out.println();
                System.out.println("  -docBase DIR        The location of the webapp. Required");
                System.out.println("  -group GROUP        Group, if you have multiple tomcats with diffrent content. " );
                System.out.println("                      The default is 'lb', and should be used in most cases");
                System.out.println("  -host HOSTNAME      Canonical hostname - for virtual hosts");
                System.out.println("  -context /CPATH     Context path where the app will be mounted");
                return;
            }

            WebXml2Jk w2jk=new WebXml2Jk();

            /* do ant-style property setting */
            IntrospectionUtils.processArgs( w2jk, args, new String[] {},
                                            null, new Hashtable());
            w2jk.execute();
        } catch( Exception ex ) {
            ex.printStackTrace();
        }

    }

    private static org.apache.commons.logging.Log log=
        org.apache.commons.logging.LogFactory.getLog( WebXml2Jk.class );

    
    // -------------------- DOM utils --------------------

    /** Get the content of a node
     */
    public static String getContent(Node n ) {
        if( n==null ) return null;
        Node n1=n.getFirstChild();
        // XXX Check if it's a text node

        String s1=n1.getNodeValue();
        return s1.trim();
    }
    
    /** Get the first child
     */
    public static Node getChild( Node parent, String name ) {
        if( parent==null ) return null;
        Node first=parent.getFirstChild();
        if( first==null ) return null;
        for (Node node = first; node != null;
             node = node.getNextSibling()) {
            //System.out.println("getNode: " + name + " " + node.getNodeName());
            if( name.equals( node.getNodeName() ) ) {
                return node;
            }
        }
        return null;
    }

    /** Get the first child's content ( i.e. it's included TEXT node )
     */
    public static String getChildContent( Node parent, String name ) {
        Node first=parent.getFirstChild();
        if( first==null ) return null;
        for (Node node = first; node != null;
             node = node.getNextSibling()) {
            //System.out.println("getNode: " + name + " " + node.getNodeName());
            if( name.equals( node.getNodeName() ) ) {
                return getContent( node );
            }
        }
        return null;
    }

    /** Get the node in the list of siblings
     */
    public static Node getNext( Node current ) {
        Node first=current.getNextSibling();
        String name=current.getNodeName();
        if( first==null ) return null;
        for (Node node = first; node != null;
             node = node.getNextSibling()) {
            //System.out.println("getNode: " + name + " " + node.getNodeName());
            if( name.equals( node.getNodeName() ) ) {
                return node;
            }
        }
        return null;
    }

    public static class NullResolver implements EntityResolver {
        public InputSource resolveEntity (String publicId,
                                                   String systemId)
            throws SAXException, IOException
        {
            if (log.isDebugEnabled())
                log.debug("ResolveEntity: " + publicId + " " + systemId);
            return new InputSource(new StringReader(""));
        }
    }
    
    public static Document readXml(File xmlF)
        throws SAXException, IOException, ParserConfigurationException
    {
        if( ! xmlF.exists() ) {
            log.error("No xml file " + xmlF );
            return null;
        }
        DocumentBuilderFactory dbf =
            DocumentBuilderFactory.newInstance();

        dbf.setValidating(false);
        dbf.setIgnoringComments(false);
        dbf.setIgnoringElementContentWhitespace(true);
        //dbf.setCoalescing(true);
        //dbf.setExpandEntityReferences(true);

        DocumentBuilder db = null;
        db = dbf.newDocumentBuilder();
        db.setEntityResolver( new NullResolver() );
        
        // db.setErrorHandler( new MyErrorHandler());

        Document doc = db.parse(xmlF);
        return doc;
    }

}