/* ************************************************************************* *
 *                                                                           *
 *        Copyright (c) 2004 Peter Cappello  <cappello@cs.ucsb.edu>          *
 *                                                                           *
 *    Permission is hereby granted, free of charge, to any person obtaining  *
 *  a copy of this software and associated documentation files (the          *
 *  "Software"), to deal in the Software without restriction, including      *
 *  without limitation the rights to use, copy, modify, merge, publish,      *
 *  distribute, sublicense, and/or sell copies of the Software, and to       *
 *  permit persons to whom the Software is furnished to do so, subject to    *
 *  the following conditions:                                                *
 *                                                                           *
 *    The above copyright notice and this permission notice shall be         *
 *  included in all copies or substantial portions of the Software.          *
 *                                                                           *
 *    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,        *
 *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF       *
 *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
 *  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY     *
 *  CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,     *
 *  TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE        *
 *  SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                   *
 *                                                                           *
 * ************************************************************************* */

/**
 *  Demonstrates a non-Java client invoking a Jicos Task, in this case, the
 *  Fibonacci sequence.
 * 
 * @author  Peter Cappello  <cappello@cs.ucsb.edu>
 * @author  Andy Pippin     <pippin@cs.ucsb.edu>
 */

package edu.ucsb.cs.jicos.examples.external.fibonacci;

import edu.ucsb.cs.jicos.services.*;
import edu.ucsb.cs.jicos.services.tasks.*;
import edu.ucsb.cs.jicos.services.external.ExternalData;
import edu.ucsb.cs.jicos.services.external.ExternalRequest;
import edu.ucsb.cs.jicos.services.external.XmlDocument;
import edu.ucsb.cs.jicos.services.external.XmlConverter;
import edu.ucsb.cs.jicos.services.external.services.CollectorHttp;
import edu.ucsb.cs.jicos.services.external.services.ExternalRequestProcessor;


final public class Fibonacci extends Task implements XmlConverter
{
    //
    //-- Constants -------------------------------------------------------
    
    private static final int DEFAULT_Number = 8;

    //
    //-- Variables -------------------------------------------------------
    
    private int n;

    //
    //-- Constructors ----------------------------------------------------
    
    /**
     * Constructs a Fibonacci task with the given number.
     * 
     * @param   n  The nth Fibonacci number to return.
     */
    public Fibonacci(int n)
    {
        this.n = n;
    }

    /**
     * Perform this task.
     * 
     * @param   environment  The Jicos environment of the task.
     * @return  A result, or a new (composition) Task.
     */
    public Object execute( Environment environment )
    {
        if (n < 2)
        {
            return new Integer( 1 );
        }
        else
        {
            compute( new Fibonacci( n - 1 ) );
            compute( new Fibonacci( n - 2 ) );
            return new AddInteger();
        }
    }

    /**
     * Set the nth Fibonacci number to compute.
     * 
     * @param   n  The nth Fibonacci number
     */
    public void setN( int n )
    {
        this.n = n;
    }

    /**
     * Get the nth Fibnonacci number that this task is going to compute.
     * 
     * @return  The nth Fibnonacci number for this task.
     */
    public int getN()
    {
        return (this.n);
    }
    
    //
    //-- For External Results --------------------------------------------

    /**
     * Default, no-argument constructor necessary for Class.newInstance().
     */
    public Fibonacci()
    {
        this.n = 0;
    }

    /**
     * Convert the class to XML-encoded rstring representation.
     * 
     * @param   prefix  Precede each line of text with this string.
     * @return  XML represetation.
     */
    public String toXml( String prefix )
    {
        String xml = null;
        String pre = (null != prefix) ? prefix : "";

        xml
            = pre + "<Fibonacci>\r\n"
            + pre + "  <n xsi:type=\"xsd:Integer\">" + this.n + "</n>\r\n"
            + pre + "</Fibonacci>\r\n"
            ;

        return (xml);
    }

    /**
     * Populate the instance from the data given.
     * 
     * @param   externalData  Data from the external client.
     * @return  Success (<CODE>true</CODE>), or failure (<CODE>false</CODE>).
     */
    public boolean fromXml( ExternalData externalData )
    {
        boolean success = false;
        String n = null;

        if (null != (n = externalData.getValue( "/Fibonacci/n" )))
        {
            try
            {
                setN( Integer.parseInt( n ) );
                success = true;
            }
            catch (NumberFormatException formatException)
            {
                // ignore
            }
        }

        return (success);
    }    

    /**
     *  Create the input object from the data given.
     * 
     * @param   externalData  Data from the external client.
     * @return  The input object, if any, or <CODE>null</CODE>.
     */
    public Object createInput( ExternalData externalData )
    {
        return ((Object) null);
    }

    /**
     *  Create the Shared object from the data given.
     * 
     * @param   externalData  Data from the external client.
     * @return  The Shared object, if any, or <CODE>null</CODE>.
     */
    public Shared createShared( ExternalData externalData )
    {
        return ((Shared) null);
    }

    /**
     * Get the XSLT Style sheet used to transform a result of this task to HTML.
     * 
     * @param styleSheetType
     *            The type of XSLT style sheet.
     * @return A DOM object that represents the Style sheet, or <CODE>null
     *         </CODE> if not defined for this type.
     */
    public org.w3c.dom.Document getStyleSheet( int styleSheetType )
    {
        return( null );
    }

    /**
     *  Given the Object from Jicos, that is the result of the computation,
     *  create the appropriate XmlDocument to be returned to the client
     *  (via the Collector).
     * 
     * @param   result
     * @return  An XmlDocument representing the result to be returned.
     * @throws Exception  Variety of reasons.
     */
    public XmlDocument createResult( Object result ) throws Exception
    {
        String xml = null;

        if (null == result)
        {
            throw new NullPointerException( "Result cannot be null" );
        }
        else
        {
            int FofN = ((Integer) result).intValue();

            // This contains extra attributes necessary for SOAP.
            xml
                = "<?xml version=\"1.1\" encoding=\"UTF-8\" ?>\r\n"
                + "<ExternalResponse>\r\n"
                + "  <Fibonacci>\r\n"
                + "    <n xsi:type=\"xsd:Integer\">" + this.n + "</n>\r\n"
                + "    <FofN xsi:type=\"xsd:Integer\">" + FofN + "</FofN>\r\n"
                + "  </Fibonacci>\r\n"
                + "</ExternalResponse>\r\n"
                ;
        }

        return (new XmlDocument( xml ));
    }

    /**
     *  Manual create the HTML that would be returned by the CollectorHttp.
     *  Since there is no over-riding function for getStyleSheet(int), the
     *  default stylesheet (<CODE>null</CODE>) will be returned.
     * 
     * @param   xmlResult The XML representation of the result from Jicos.
     * @param   hostPort  The "hostname:port" of the CollectorHttp.
     * @return  The HTML string without the HTTP header to be returned.
     */
    public String toHtmlString( XmlDocument xmlResult, String hostPort )
    {
        String strFib = null;

        // Fix the hostname/port.
        if (null == hostPort)
        {
            hostPort = "localhost";
        }

        // Get the result if it exists.
        if (null != xmlResult)
        {
            strFib = xmlResult.getValue( "/ExternalResponse/Fibonacci/FofN" );
            if ("".equals( strFib ))
            {
                strFib = null;
            }
        }

        int number = this.n;
        if (0 >= number)
        {
            number = DEFAULT_Number;
        }

        String html		
            = "<HTML>\r\n"
            + "<HEAD>\r\n"
            + "  <TITLE>Fibonacci Solver</TITLE>\r\n"
            + "</HEAD>\r\n"
            + "<BODY>\r\n"
            + CollectorHttp.jicosHtmlHeader()
            + "<CENTER><H2>Fibonacci Solver</H2></CENTER>\r\n"
            + "\r\n"
		    ;

        // If there is an answer, format it.
        if( null != strFib )
        {
            html = html
                + "<!-- Answer from previous request. -->\r\n"
                + "<!>\r\n"
                + "<FONT COLOR=green>Previous Result:</FONT><BR>\r\n"
                + "<BLOCKQUOTE>\r\n"
                + "<TABLE>\r\n"
                + "  <TR>\r\n"
                + "    <TD VALIGN=\"center\">Fibonacci( <B>" + this.n
                        + "</B> )&nbsp;=&nbsp;</TD>\r\n"
                + "    <TD VALIGN=\"center\"><FONT COLOR=blue SIZE=\"+2\">"
                        + strFib + "</FONT></TD>\r\n"
                + "  </TR>\r\n"
                + "</TABLE>\r\n"
                + "</BLOCKQUOTE>\r\n"
                + "<BR>\r\n"
                ;
        }
	
        // A request for a Fibonacci number.
        html = html
            + "\r\n"
            + "<!-- Ask for new number (start form). -->\r\n"
            + "<!>\r\n"
            + "<BR><BR>\r\n"
            + "<FORM ACTION=\"http://" + hostPort + ExternalRequest.TOP_LEVEL
                    + "\" METHOD=\"post\">\r\n"
            + "<INPUT TYPE=\"hidden\"\r\n"
            + "       NAME=\"" + ExternalRequestProcessor.TASKNAME_ATTRIBUTE
                    + "\"\r\n"
            + "       VALUE=\"" + this.getClass().getName() + "\"></INPUT>\r\n"
            + "<CENTER>\r\n"
            + "<TABLE>\r\n"
            + "  <TR>\r\n"
            + "    <TD BGCOLOR=\"black\">\r\n"
            + "      <TABLE BORDER=0 CELLPADDING=\"3px\" BGCOLOR=\"#EEEEEE\">\r\n"
            + "        <TR>\r\n"
            + "          <TD WIDTH=\"100\" ALIGN=\"right\"><FONT COLOR=\"blue\" "
                    + "SIZE=\"+1\">Number:</FONT></TD>\r\n"
            + "          <TD><INPUT TYPE=\"text\" SIZE=\"5\" VALUE=\"" + number
                    + "\"\r\n"
            + "                     NAME=\"" + ExternalRequest.TOP_LEVEL
                    + "/Fibonacci/n\"></INPUT></TD>\r\n"
            + "          <TD WIDTH=\"100\" ALIGN=\"left\"><INPUT TYPE=\"submit\">"
                    + "</INPUT></TD>\r\n"
            + "        </TR>\r\n"
            + "      </TABLE>\r\n"
            + "    </TD>\r\n"
            + "  </TR>\r\n"
            + "</TABLE>\r\n"
            + "</CENTER>\r\n"
            + "<BR><BR>\r\n"
            + "<!>\r\n"
            + CollectorHttp.createResponseSelect( null )
            + "<!>\r\n"
            + "</FORM>\r\n"
            + "<!>\r\n"
            + "<!-- End form. -->\r\n"
            + CollectorHttp.jicosHtmlFooter()
            + "</BODY>\r\n"
            + "</HTML>\r\n"
            ;
	
        return (html);
    }

}