//
// SwitchRMI  Framework
// Copyright (c) 2000-2002 by Michael J. Henderson & Associates.
//
// Michael Henderson
// http://switchrmi.sf.net
// mailto:mikehenderson@dunelm.org.uk
//
// This library is free software.
//
// You may redistribute it and/or modify it under the terms of the GNU
// Lesser General Public License as published by the Free Software Foundation.
//
// Version 2.1 of the license should be included with this distribution in
// the file LICENSE, as well as License.html. If the license is not
// included with this distribution, you may find a copy at the FSF web
// site at 'www.gnu.org' or 'www.fsf.org', or you may write to the
// Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139 USA.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied waranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//
// $Id: XmlRpcMethodSignatures.java,v 1.1 2002/11/11 22:19:48 mikehenderson Exp $
package com.mjh.switchrmi.protocol.xmlrpc;

import com.mjh.dom.DomUtil;

import java.io.InputStream;

import java.util.*;

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

import org.apache.log4j.Logger;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

public class XmlRpcMethodSignatures
{
    private static final Logger log = 
            Logger.getLogger(XmlRpcMethodSignatures.class.getName());
    private static HashMap classMap = new HashMap();
    private static HashMap ignoredClassMap = new HashMap();
    private static HashMap encodedSignatureMap = new HashMap();

    public static synchronized String getExternalNameForEncodedSignature(String signature)
    {
        String declaringClassName = 
                signature.substring(0, signature.indexOf(':'));

        if (log.isDebugEnabled())
        {
            log.debug("declaringClassName = " + declaringClassName);
        }

        XmlRpcMethods xmlrpcMethods = 
                findMethodsForClassName(declaringClassName);

        return (xmlrpcMethods == null)
               ? null
               : xmlrpcMethods.getExternalNameForEncodedSignature(signature);
    }

    private static XmlRpcMethods findMethodsForClassName(String declaringClassName)
    {
        XmlRpcMethods xmlrpcMethods = null;

        if (ignoredClassMap.get(declaringClassName) == null)
        {
            xmlrpcMethods = (XmlRpcMethods) classMap.get(declaringClassName);

            if (xmlrpcMethods == null)
            {
                xmlrpcMethods = XmlRpcMethodSignatures.loadMethodsForClassName(
                                        declaringClassName);

                if (xmlrpcMethods != null)
                {
                    classMap.put(declaringClassName, xmlrpcMethods);
                }
                else
                {
                    ignoredClassMap.put(declaringClassName, declaringClassName);
                }
            }
        }

        return xmlrpcMethods;
    }

    public static String getEncodedSignatureForExternalName(Class targetClass, 
                                                            String externalName)
    {
        String result = null;
        Class[] interfaces = targetClass.getInterfaces();

        for (int i = 0; i < interfaces.length; i++)
        {
            Class interfaze = interfaces[i];
            String interfaceName = interfaze.getName();
            XmlRpcMethods xmlrpcMethods = 
                    findMethodsForClassName(interfaceName);

            if (xmlrpcMethods != null)
            {
                result = xmlrpcMethods.getEncodedSignatureForExternalName(
                                 externalName);

                if (result != null)
                {
                    break;
                }
            }
        }

        return result;
    }

    private static XmlRpcMethods loadMethodsForClassName(String declaringClassName)
    {
        XmlRpcMethods result = null;

        try
        {
            String resourceName = 
                    "/" + declaringClassName.replace('.', '/')
                    + ".xmlrpcSignatures";
            InputStream in = XmlRpcMethodSignatures.class.getResourceAsStream(
                                     resourceName);

            if (in != null)
            {
                result = new XmlRpcMethods(in);
            }
        }
        catch (Exception ex)
        {
            log.debug("Exception", ex);
        }

        return result;
    }

    static class XmlRpcMethods
    {
        private final static String METHOD_TAG = "method";
        private final static String INTERNAL_ATTR = "internal";
        private final static String EXTERNAL_ATTR = "external";
        private HashMap internals = new HashMap();
        private HashMap externals = new HashMap();

        public XmlRpcMethods(InputStream in)
                      throws Exception
        {
            parse(in);
        }

        public String getExternalNameForEncodedSignature(String signature)
        {
            return (String) externals.get(signature);
        }

        public String getEncodedSignatureForExternalName(String external)
        {
            return (String) internals.get(external);
        }

        public String toString()
        {
            return "XmlRpcMethods {\n" + "  internals = " + internals + ";\n"
                   + "  externals = " + externals + ";\n" + "}";
        }

        private void parse(InputStream in)
                    throws Exception
        {
            boolean debug = log.isDebugEnabled();

            try
            {
                DocumentBuilderFactory factory = 
                        DocumentBuilderFactory.newInstance();

                if (log.isDebugEnabled())
                {
                    log.debug("factory = " + factory);
                }

                DocumentBuilder builder = factory.newDocumentBuilder();

                if (log.isDebugEnabled())
                {
                    log.debug("builder = " + builder);
                }

                Document doc = (Document) builder.parse(in);

                Node root = doc.getDocumentElement();
                NodeList list = 
                        DomUtil.getChildElementsByTagName(root, METHOD_TAG);
                int length = list.getLength();

                if (debug)
                {
                    log.debug("length = " + length);
                }

                for (int i = 0; i < length; i++)
                {
                    Element element = (Element) list.item(i);

                    if (element.hasAttribute(INTERNAL_ATTR)
                        && element.hasAttribute(EXTERNAL_ATTR))
                    {
                        String internal = element.getAttribute(INTERNAL_ATTR);
                        String external = element.getAttribute(EXTERNAL_ATTR);

                        if (debug)
                        {
                            log.debug(external + " = " + internal);
                        }

                        internals.put(external, internal);
                        externals.put(internal, external);
                    }
                    else
                    {
                        throw new Exception("<" + METHOD_TAG
                                            + " > missing attribute "
                                            + INTERNAL_ATTR + " or "
                                            + EXTERNAL_ATTR);
                    }
                }
            }
            catch (Exception ex)
            {
                if (log.isDebugEnabled())
                {
                    log.debug("While Parsing", ex);
                }

                throw ex;
            }
        }
    }
}