/* Copyright 2002, 2003 Elliotte Rusty Harold
   
   This library is free software; you can redistribute it and/or modify
   it under the terms of version 2.1 of the GNU Lesser General Public 
   License as published by the Free Software Foundation.
   
   This library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
   GNU Lesser General Public License for more details.
   
   You should have received a copy of the GNU Lesser General Public
   License along with this library. If not, see
   <https://www.gnu.org/licenses/>.
   
   You can contact Elliotte Rusty Harold by sending e-mail to
   elharo@ibiblio.org. Please include the word "XOM" in the
   subject line. The XOM home page is located at https://xom.nu/
*/

package nu.xom.samples;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;

import nu.xom.Builder;
import nu.xom.Document;
import nu.xom.Element;
import nu.xom.Elements;
import nu.xom.ParsingException;
import nu.xom.Serializer;


/**
 * <p>
 * Demonstrates communication with an XML-RPC
 * server via the creation of a simple document,
 * transmission of that document over the network,
 * and reception and parsing of the server's response.
 * </p>
 * 
 * @author Elliotte Rusty Harold
 * @version 1.0
 *
 */
public class FibonacciXMLRPCClient {
  
  private static String defaultServer 
   = "http://www.elharo.com/fibonacci/XML-RPC";
   
  public static void main(String[] args) {

    if (args.length == 0) {
      System.out.println(
       "Usage: java nu.xom.samples.FibonacciXMLRPCClient "
       + " index serverURL"
      ); 
      return;
    }
    
    String index = args[0];
    
    String server;
    if (args.length <= 1) server = defaultServer;
    else server = args[1];
    
    try {
        URL u = new URL(server);
        URLConnection uc = u.openConnection();
        HttpURLConnection connection = (HttpURLConnection) uc;
        connection.setDoOutput(true);
        connection.setDoInput(true); 
        connection.setRequestMethod("POST");
        OutputStream out = connection.getOutputStream();
      
        Element methodCall = new Element("methodCall");
        Element methodName = new Element("methodName");
        methodName.appendChild("calculateFibonacci");
        Element params = new Element("params");
        Element param = new Element("param");
        Element value = new Element("value");
        Element data = new Element("int");
        data.appendChild(index);
        methodCall.appendChild(methodName); 
        methodCall.appendChild(params); 
        params.appendChild(param);
        param.appendChild(value);
        value.appendChild(data);
        Document doc = new Document(methodCall);

        Serializer serializer = new Serializer(out, "US-ASCII");
        serializer.write(doc);
          
        InputStream in = connection.getInputStream();
          
        Builder parser = new Builder();
        Document response = parser.build(in);

        in.close();
        out.close();
        connection.disconnect();

        Element methodResponse = response.getRootElement();          
        Elements body = methodResponse.getChildElements();
        if (body.size() != 1) {
            System.err.println("XML-RPC format error");
            return;
        }
        if (body.get(0).getQualifiedName().equals("params")) { 
            Element responseParam = body.get(0).getFirstChildElement("param");
            Element responseValue 
              = responseParam.getFirstChildElement("value");
            Element responseDouble 
              = responseValue.getFirstChildElement("double");        
            System.out.println(responseDouble.getValue());
        }
        else if (body.get(0).getQualifiedName().equals("fault")) {
            handleFault(body.get(0));
        }
        else {
            System.err.println("XML-RPC Format Error");
            return;   
        }
          
    }
    catch (ParsingException ex) {
      System.err.println("Server sent malformed output"); 
      System.err.println(ex); 
    }
    catch (NullPointerException ex) {
      System.err.println(
        "Server sent invalid output without the expected content."
      ); 
      System.err.println(ex); 
    }
    catch (IOException ex) {
      System.err.println(ex); 
    }
  
  }

    private static void handleFault(Element fault) {
      
        Element value =  fault.getFirstChildElement("value");      
        Element struct = value.getFirstChildElement("struct");      
        Elements members = struct.getChildElements("member");      
        Element member1 =  members.get(0);      
        Element member2 =  members.get(1);      
        String code = "";
        String detail = "";
        Element name1 = member1.getFirstChildElement("name");
        Element value1 = member1.getFirstChildElement("value");
        Element name2 = member2.getFirstChildElement("name");
        Element value2 = member2.getFirstChildElement("value");
        if (name1.getValue().equals("faultCode")) {
            code = value1.getValue();   
            detail = value2.getValue();
        }
        else if (name2.getValue().equals("faultCode")) {
            code = value2.getValue();   
            detail = value1.getValue();
        }   
        else {
            throw new RuntimeException("Incorrect fault message");  
        }
        System.err.println("Fault: ");
        System.err.println("  code: " + code);
        System.err.println("  " + detail);
    }  

}