package org.greenstone.gsdl3.service;

import java.io.File;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.HashMap;

import org.apache.log4j.Logger;
import org.greenstone.gsdl3.util.GSXML;
import org.greenstone.gsdl3.util.XMLConverter;
import org.greenstone.gsdl3.util.UserContext;

import org.greenstone.gsdl3.core.MessageRouter;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;


public class ServiceUtil extends ServiceRack
{
	static Logger logger = Logger.getLogger(org.greenstone.gsdl3.service.ServiceUtil.class.getName());

    protected static final String METADATA_RETRIEVAL_SERVICE = "DocumentMetadataRetrieve";

	/**********************************************************
	 * The list of services the utility service rack supports *
	 *********************************************************/
	protected static final String GET_ALL_IMAGES_IN_COLLECTION = "GetAllImagesInCollection";
	/*********************************************************/
	
	String[] services = { GET_ALL_IMAGES_IN_COLLECTION };
	
	public boolean configure(Element info, Element extra_info)
	{
		if (!super.configure(info, extra_info))
		{
			return false;
		}

		logger.info("Configuring ServiceUtil...");
		this.config_info = info;

		for (int i = 0; i < services.length; i++)
		{
			Element service = this.desc_doc.createElement(GSXML.SERVICE_ELEM);
			service.setAttribute(GSXML.TYPE_ATT, GSXML.SERVICE_TYPE_RETRIEVE);
			service.setAttribute(GSXML.NAME_ATT, services[i]);
			this.short_service_info.appendChild(service);
		}

		return true;
	}

	protected Element getServiceDescription(Document doc, String service_id, String lang, String subset)
	{
		for (int i = 0; i < services.length; i++)
		{
			if (service_id.equals(services[i]))
			{
				Element service_elem = doc.createElement(GSXML.SERVICE_ELEM);
				service_elem.setAttribute(GSXML.TYPE_ATT, GSXML.SERVICE_TYPE_RETRIEVE);
				service_elem.setAttribute(GSXML.NAME_ATT, services[i]);
				return service_elem;
			}
		}

		return null;
	}
	
	protected Element processGetAllImagesInCollection(Element request)
	{
	  Document result_doc = XMLConverter.newDOM();
		Element result = GSXML.createBasicResponse(result_doc, GET_ALL_IMAGES_IN_COLLECTION);

		if (request == null)
		{
			GSXML.addError(result, GET_ALL_IMAGES_IN_COLLECTION + ": Request is null", GSXML.ERROR_TYPE_SYNTAX);
			return result;
		}
		
		String lang = request.getAttribute(GSXML.LANG_ATT);
		String uid = request.getAttribute(GSXML.USER_ID_ATT);
		
		// Get the parameters of the request
		Element param_list = (Element) GSXML.getChildByTagName(request, GSXML.PARAM_ELEM+GSXML.LIST_MODIFIER);

		if (param_list == null) {
			GSXML.addError(result, GET_ALL_IMAGES_IN_COLLECTION + ": No param list specified", GSXML.ERROR_TYPE_SYNTAX);
			return result;  // Return the empty result
		}

		HashMap<String, Serializable> params = GSXML.extractParams(param_list, false);
		
		String regex = (String)params.get("extregex");
		if(regex == null)
		{
			GSXML.addError(result, GET_ALL_IMAGES_IN_COLLECTION + ": No file name extensions specified", GSXML.ERROR_TYPE_SYNTAX);
			return result;
		}
		regex = ".*" + regex + ".*";
		
		String collection = (String)params.get("c");
		if(collection == null)
		{
			GSXML.addError(result, GET_ALL_IMAGES_IN_COLLECTION + ": No collection specified", GSXML.ERROR_TYPE_SYNTAX);
			return result;
		}

		String indexDirStr = this.site_home + File.separator + "collect" + File.separator + collection + File.separator + "index" + File.separator + "assoc";
		File indexDir = new File(indexDirStr);
		ArrayList<String> images = new ArrayList<String>();
		getImagesRecursive(indexDir, regex, images);
		
		Element imageListElem = result_doc.createElement("imageList");
		result.appendChild(imageListElem);
		for(String i : images)
		{
		    System.err.println("*** image i = " + i);
		    String assoc_dir = getAssocDir(i,indexDirStr);
		    System.err.println("*** image i assoc dir = " + assoc_dir);

		    String doc_id = queryMRforDOCID(collection,assoc_dir);
		    System.err.println("*** doc id = " + doc_id);
		    System.err.println("======");
			    
			Element imageElem = result_doc.createElement("image");
			imageElem.setAttribute("docid", doc_id);
			imageElem.appendChild(result_doc.createTextNode(i));
			imageListElem.appendChild(imageElem);
		}
		return result;
	}
	
	/********************
	 * Helper functions *
	 *******************/


    private String getAssocDir(String full_filename, String remove_prefix)
    {
	String dir = null;
	
	int remove_prefix_len = remove_prefix.length();

	String dir_and_filetail = full_filename.substring(remove_prefix_len+1);

	int dir_end_pos = dir_and_filetail.lastIndexOf("/");
	if (dir_end_pos > 0) {
	    dir = dir_and_filetail.substring(0,dir_end_pos);
	}
	else {
	    dir = dir_and_filetail;	    
	}

	System.err.println("**** dir = " + dir);

	return dir;
    }


    
  private String queryMRforDOCID(String collection, String assocfiledir) {
    Document gsDoc = XMLConverter.newDOM();

    Element metaMessage = gsDoc.createElement(GSXML.MESSAGE_ELEM);
    Element metaRequest = GSXML.createBasicRequest(gsDoc, GSXML.REQUEST_TYPE_PROCESS, collection + "/" + METADATA_RETRIEVAL_SERVICE, new UserContext());
    metaMessage.appendChild(metaRequest);

    Element paramList = gsDoc.createElement(GSXML.PARAM_ELEM + GSXML.LIST_MODIFIER);
    metaRequest.appendChild(paramList);
    
    Element param = gsDoc.createElement(GSXML.PARAM_ELEM);    
    param.setAttribute(GSXML.NAME_ATT, "metadata");
    param.setAttribute(GSXML.VALUE_ATT, "contains");
    paramList.appendChild(param);

    Element docList = gsDoc.createElement(GSXML.DOC_NODE_ELEM + GSXML.LIST_MODIFIER);
    metaRequest.appendChild(docList);

    Element doc = gsDoc.createElement(GSXML.DOC_NODE_ELEM);
    doc.setAttribute(GSXML.NODE_ID_ATT, assocfiledir);
    docList.appendChild(doc);
    
    Element metaResponse = (Element) router.process(metaMessage);
    
    NodeList metadataList = metaResponse.getElementsByTagName(GSXML.METADATA_ELEM);
    if (metadataList.getLength() == 0) {
      
      logger.error("Could not find the document ID related to this url");
      return null;
    }
      
    Element metadata = (Element) metadataList.item(0);
    String document = metadata.getTextContent();
    if (document != null && document.equals("")) {
      document = null;
    }
    return document;
      
 
  }


    
	protected void getImagesRecursive(File current, String regex, ArrayList<String> images)
	{
		if(current.isDirectory())
		{
			File[] files = current.listFiles();
			for(File f : files)
			{
				getImagesRecursive(f, regex, images);
			}
		}
		else
		{
			String path = current.getAbsolutePath();
			String filename = path.substring(path.lastIndexOf(File.separator) + File.separator.length());

			if(filename.matches(regex))
			{
				images.add(path);
			}
			else
			{
		
			}
		}
	}
}