package com.melloware.jukes.ws;
   
   import java.util.ArrayList;
   import java.util.HashMap;
   import java.util.Map;
   import java.util.Collection;
   
   import org.apache.commons.logging.Log;
   import org.apache.commons.logging.LogFactory;
  
  import javax.xml.parsers.DocumentBuilder;
  import javax.xml.parsers.DocumentBuilderFactory;
  
  import org.w3c.dom.Document;
  import org.w3c.dom.Node;
  import org.w3c.dom.NodeList;
  
  import com.melloware.jukes.util.MessageUtil;
  import com.melloware.jukes.exception.WebServiceException;
  import com.melloware.jukes.gui.tool.Resources;
  
  /**
   * Static methods for performing web services calls to the Amazon E-Commerce Web
   * Services application.
   * <p>
   * Copyright (c) 1999-2007 Melloware, Inc. <http://www.melloware.com>
   * @author Emil A. Lefkof III <info@melloware.com>
   * @version 4.0
   * AZ Development 2010
   */
  
  @SuppressWarnings("unchecked")
  public final class AmazonSearch {
     private static final Log LOG = LogFactory.getLog(AmazonSearch.class);
  
     // the sort order (orig-rel-date, artistrank, titlerank)
     public static final String SORT_TITLE = "titlerank";
     public static final String SORT_ARTIST = "artistrank";
     public static final String SORT_DATE = "orig-rel-date";
  
     // the area to search amazon
     private static final String SEARCH_INDEX = "Music";
  
     // the data to bring back
     private static final String RG_IMAGES = "Images";
     private static final String RG_ITEMS = "ItemAttributes";
     private static final String RG_TRACKS = "Tracks";
     
     private static final String AWS_ACCESS_KEY_ID = "AKIAJWPLM2OQCW444Q5A"; //AZ Development Key
  
     /*
      * Your AWS Secret Key corresponding to the above ID, as taken from the AWS
      * Your Account page.
      */
     private static final String AWS_SECRET_KEY = "MrhTu2j6htEUEh+i1iLpJkuqwatnefZ+K3hI4hWf"; //AZ Development Key
   
     /**
      * Default constructor. Private so no instantiation.
      */
     private AmazonSearch() {
        super();
     }
    
     /**
      * Finds a collection of Amazon products by Disc Name.
      * <p>
      * @param aDiscTitle the name of the disc to search for
      * @param endPoint one of the end-points, according to the region of interest
      * @return a collection of AmazonItems matching the search criteria
      * @throws WebServiceException if any error occurs querying the AmazonWebService
      */
     public static Collection findItemsByDisc(String aDiscTitle, String endPoint) throws WebServiceException {
        return findItemsByArtistDiscSort("", aDiscTitle, endPoint, SORT_TITLE);
     }
  
     /**
      * Finds a collection of Amazon products by Artist Name.
      * <p>
      * @param aArtistName the name of the artist to search for
      * @param endPoint one of the end-points, according to the region of interest
      * @return a collection of AmazonItems matching the search criteria
      * @throws WebServiceException if any error occurs querying the AmazonWebService
      */
     public static Collection findItemsByArtist(String aArtistName, String endPoint) throws WebServiceException {
        return findItemsByArtistDiscSort(aArtistName, "", endPoint, SORT_TITLE);
     }
  
     /**
      * Finds a collection of Amazon products by artist and disc name.
      * <p>
      * @param aArtistName the name of the artist to search for
      * @param aDiscTitle the name of the disc to search for
      * @param endPoint one of the end-points, according to the region of interest    * @return a collection of AmazonItems matching the search criteria
      * @throws WebServiceException if any error occurs querying the AmazonWebService
      */
     public static Collection findItemsByArtistDisc(String aArtistName, String aDiscTitle, String endPoint) throws WebServiceException {
        return findItemsByArtistDiscSort(aArtistName, aDiscTitle, endPoint, SORT_TITLE);
     }
  
    /**
     * Finds a collection of Amazon products by artist and disc name.
     * <p>
     * @param aArtistName the name of the artist to search for
     * @param aDiscTitle the name of the disc to search for
     * @param endPoint one of the following end-points, according to the region you are interested in.
     *      US: ecs.amazonaws.com
     *      CA: ecs.amazonaws.ca
     *      UK: ecs.amazonaws.co.uk
     *      DE: ecs.amazonaws.de
     *      FR: ecs.amazonaws.fr
     *      JP: ecs.amazonaws.jp 
     * @param aSort what field to sort by
     * @return a collection of AmazonItems matching the search criteria
     * @throws WebServiceException if any error occurs querying the AmazonWebService
     */
    public static Collection findItemsByArtistDiscSort(String aArtistName, String aDiscTitle, String endPoint, String aSort)
             throws WebServiceException {
       if (LOG.isDebugEnabled()) {
          LOG.debug("Amazon findItemsByArtistDiscSort: " + aArtistName + " - " + aDiscTitle + " - " + aSort);
       }
 
       SignedRequestsHelper helper;
       String requestUrl = null;
       Collection collection = null;
 
       try {
     	  helper = SignedRequestsHelper.getInstance(endPoint, AWS_ACCESS_KEY_ID, AWS_SECRET_KEY); 
           //request parameters are stored in a map.
           Map<String, String> params = new HashMap<String, String>();
           params.put("Service", "AWSECommerceService");
           params.put("Version", "2009-03-31");
           params.put("Operation", "ItemSearch");
           params.put("SearchIndex", SEARCH_INDEX);
           params.put("Artist", aArtistName);
           params.put("Title", aDiscTitle);
           params.put("ResponseGroup", RG_IMAGES + "," + RG_ITEMS + "," + RG_TRACKS);
           params.put("Sort", aSort);
 
           requestUrl = helper.sign(params);
           DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
           DocumentBuilder db = dbf.newDocumentBuilder();
           Document doc = db.parse(requestUrl);
           //Find error messages in Amazon response
           NodeList errorList = doc.getElementsByTagName("Error");
           String errorMessage = null;
           if (errorList.getLength() != 0) {
         	  Node n = errorList.item(0);
         	  final NodeList nList = n.getChildNodes();
 		      if (nList.getLength() != 0) {
 		    	  for (int i=0; i<nList.getLength(); i=i+1){
 		    		  Node node = nList.item(i);	
 		    		  if (node.getNodeName().equalsIgnoreCase("Message")) {
 		    			 errorMessage = node.getTextContent();  
 		    		  }
 		    	  }
 		      }	
 		    MessageUtil.showInformation(null, Resources.getString("label.AmazonResponse") + errorMessage);   
           } else {
           //Find Items in Amazon response 	  
           NodeList nodeList = doc.getElementsByTagName("Item");
           if (nodeList.getLength()==0) {
         	  MessageUtil.showInformation(null, Resources.getString("messages.NoItemsFound"));  
           }
          //Loads a collection with AmazonItems from an Item node-list
          collection = loadItems(nodeList);
          }
       } catch (NullPointerException e) {
           LOG.error(e.getMessage(), e);
           throw new WebServiceException(e); 
       } catch (Exception ex) {
          LOG.error(ex.getMessage(), ex);
          throw new WebServiceException(ex);
       } 
 
       return collection;
    }
 
    /**
     * Loads a collection with AmazonItems from an Item node-list of AWS-response.
     * <p>
     * @param aItems the items to load
     * @return a collection of AmazonItem objects or an empty collection
     */
    private static Collection loadItems(NodeList aItems) {
       ArrayList collection = new ArrayList();
     if (aItems != null) {
         for (int i=0; i<aItems.getLength(); i=i+1){
             collection.add(new AmazonItem(aItems.item(i)));
          }
       }
       return collection;
    }
 
 }