package org.greenstone.gsdl3.action;

import org.greenstone.gsdl3.core.ModuleInterface;
import org.greenstone.gsdl3.util.*;
// XML classes
import org.w3c.dom.Node; 
import org.w3c.dom.NodeList; 
import org.w3c.dom.Document; 
import org.w3c.dom.Element; 

import java.util.HashMap;
import java.util.Map;
import java.util.Iterator;
import java.io.File;

public class ProcessAction extends Action {
    
    /** process a request */
    public Element process (Element message) {

	// assume only one request
	Element request = (Element)GSXML.getChildByTagName(message, GSXML.REQUEST_ELEM);

	// we ignore the subaction for now - all types are processed by the same method
	//String subaction = request.getAttribute(GSXML.SUBACTION_ATT);
	// get the param list
	Element cgi_param_list = (Element)GSXML.getChildByTagName(request, GSXML.PARAM_ELEM+GSXML.LIST_MODIFIER);
	HashMap params = GSXML.extractParams(cgi_param_list, false);
	String service_name = (String) params.get(GSCGI.SERVICE_ARG);
	String cluster_name = (String) params.get(GSCGI.CLUSTER_ARG);
	String request_only_p = (String)params.get(GSCGI.REQUEST_ONLY_ARG);
	boolean request_only = false;
	if (request_only_p!=null) {
	    request_only = (request_only_p.equals("1")?true:false);
	}
	String request_type = (String) params.get(GSCGI.REQUEST_TYPE_ARG);
	// the return page
	Element page = doc_.createElement(GSXML.PAGE_ELEM);
	page.setAttribute(GSXML.LANG_ATT, request.getAttribute(GSXML.LANG_ATT));
	System.out.println("(ProcessAction) Page:\n" + converter_.getPrettyString(page));

	// what is carried out depends on the request_type
	// if rt=d, then a describe request is done,
	// is rt=r, a request and then a describe request is done
	// if rt=s, a status request is done.

	// if ro=1, then this calls for a process only page - we do the request
	// (rt should be r or s) and just give the response straight back
	// without any page processing

	//the stylesheet
	String stylesheet = GSFile.stylesheetFile(config_, "process.xsl");
	
	if (!request_only) {
	    // check that the stylesheet is present
	    if (stylesheet==null) {
		System.err.println("ProcessAction Error: process stylesheet not found!");
		return null;
	    }
	}

	// where to send requests
	String to = cluster_name; 
	to = GSPath.appendLink(to, service_name);

	if (!request_type.equals("d")) {
	    // if rt=s or rt=r, do the request
	    
	    Element mr_query_message = doc_.createElement(GSXML.MESSAGE_ELEM);
	    Element mr_query_request = doc_.createElement(GSXML.REQUEST_ELEM);
	    mr_query_message.appendChild(mr_query_request);
	    
	    mr_query_request.setAttribute(GSXML.LANG_ATT, page.getAttribute(GSXML.LANG_ATT)); 
	    mr_query_request.setAttribute(GSXML.TO_ATT, to);
	    
	    Element param_list;
	    if (request_type.equals("s")) { // status
		mr_query_request.setAttribute(GSXML.TYPE_ATT, GSXML.REQUEST_TYPE_STATUS);
		// only need the handle param
		param_list = doc_.createElement(GSXML.PARAM_ELEM+GSXML.LIST_MODIFIER);
		Element param = doc_.createElement(GSXML.PARAM_ELEM);
		param.setAttribute(GSXML.NAME_ATT, GSCGI.PROCESS_ID_ARG);
		param.setAttribute(GSXML.VALUE_ATT, (String)params.get(GSCGI.PROCESS_ID_ARG));
		param_list.appendChild(param);
	    } else {
		mr_query_request.setAttribute(GSXML.TYPE_ATT, GSXML.REQUEST_TYPE_PROCESS);
		// add in the params - except the ones only used by the action
		param_list = getServiceParamList(cgi_param_list);
		
	    }
	    mr_query_request.appendChild(param_list);
    
	    
	    Element mr_query_response = (Element)mr_.process(mr_query_message);
	    Element result_response = (Element)GSXML.getChildByTagName(mr_query_response, GSXML.RESPONSE_ELEM);
	    
	    if (request_only) {
		// just send the reponse as is
		return result_response;
	    }
	    
	    // else append the response to the page
	    page.appendChild(doc_.importNode(result_response, true));
	}
	
	// add the lang stuff from message
	page.appendChild(doc_.importNode(GSXML.getChildByTagName(message, GSXML.DISPLAY_ELEM), true));
	// add the system stuff from message
	page.appendChild(doc_.importNode(GSXML.getChildByTagName(message, GSXML.CONFIGURATION_ELEM), true));
	

	// another part of the page is the service description

	// request the service info for the selected service - should be cached
	Element mr_info_message = doc_.createElement(GSXML.MESSAGE_ELEM);
	Element mr_info_request = doc_.createElement(GSXML.REQUEST_ELEM);
	mr_info_message.appendChild(mr_info_request);
	mr_info_request.setAttribute(GSXML.TYPE_ATT, GSXML.REQUEST_TYPE_DESCRIBE);
	mr_info_request.setAttribute(GSXML.LANG_ATT, page.getAttribute(GSXML.LANG_ATT));

	mr_info_request.setAttribute(GSXML.TO_ATT, to);
	
	Element mr_info_response = (Element) mr_.process(mr_info_message);

	String path = GSXML.RESPONSE_ELEM;
	path = GSPath.appendLink(path, GSXML.SERVICE_ELEM);
	Element description = (Element)doc_.importNode(GSXML.getNodeByPath(mr_info_response, path), true);

	Element pl = (Element)GSXML.getChildByTagName(description, GSXML.PARAM_ELEM+GSXML.LIST_MODIFIER);
	
	if (pl !=null) {
	    // add short names to the params in the param list
	    cgi_.paramListAddShortNames(pl);

	    // for each param in the description, overwrite teh default value with the currently set value if present 
	    Element param = (Element)pl.getFirstChild();
	    while (param !=null) {
		if (param.getNodeName().equals(GSXML.PARAM_ELEM)) { // just in case
		    String name = param.getAttribute(GSXML.NAME_ATT);
		    String current = (String)params.get(name);
		    if (current !=null && !current.equals("")) {
			param.setAttribute(GSXML.DEFAULT_ATT, current);
		    }
		}
		param = (Element)param.getNextSibling();
	    }
	}
	page.appendChild(description);

  	// part of the data for the page is the cgi-params
	// if we have this here, do we need to do the previous step?
	Element cgi_request = (Element)doc_.importNode(request, true);
	page.appendChild(cgi_request);
	
	// now process the page and return the result
	Document style_doc = converter_.getDOM(new File(stylesheet));
	
	GSXSLT.absoluteIncludePaths(style_doc, config_);
	return (Element)transformer_.transform(style_doc, page);    
    }

    protected Element getServiceParamList(Element cgi_param_list) {

	Element new_param_list = doc_.createElement(GSXML.PARAM_ELEM+GSXML.LIST_MODIFIER);
	Element param;
	NodeList cgi_params = cgi_param_list.getChildNodes();
	for (int i=0; i<cgi_params.getLength(); i++) {
	    Element p = (Element) cgi_params.item(i);
	    String name = p.getAttribute(GSXML.NAME_ATT);
	    if (name.equals(GSCGI.SERVICE_ARG) || name.equals(GSCGI.REQUEST_TYPE_ARG) || name.equals(GSCGI.CLUSTER_ARG)) {
		continue;
	    }
	    // esle add it in to the list
	    new_param_list.appendChild(doc_.importNode(p, true));
	}
	return new_param_list;
    }
}