package org.greenstone.gsdl3.service;

// Greenstone classes
import org.greenstone.gsdl3.util.*;

//Google Web Services API classes
//import com.google.soap.search.GoogleSearch;
import com.google.soap.search.GoogleSearchFault;
import com.google.soap.search.GoogleSearchResult;
import com.google.soap.search.GoogleSearchResultElement;
import com.google.soap.search.GoogleSearchDirectoryCategory;

// XML classes
import org.w3c.dom.Element; 
import org.w3c.dom.Document;
import org.w3c.dom.NodeList; 

//Java classes
import java.util.ArrayList;
import java.util.HashMap;
import java.io.File;
import java.io.InputStream;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URLConnection;
import java.net.URL;
import java.net.Authenticator;
import java.net.PasswordAuthentication;
import java.net.MalformedURLException;
import java.lang.Object;


/**
 *
 * @author <a href="mailto:chi@cs.waikato.ac.nz">Chi-Yu Huang</a>
 *
 */

public class GoogleSearch
    extends AbstractSearch {
    
    //Parameters connect to Proxy Server
    private boolean using_proxy = false;
    private String proxy_host = null;
    private int proxy_port;
    private String proxy_user = null;
    private char [] proxy_passwd = null;

    // google key
    private String client_key = null;
    
    public GoogleSearch()
    {
    }
	    
    //Configure GoogleSearch Service
    public boolean configure(Element info, Element extra_info) 
    { 
	if (!super.configure(info, extra_info)) {
	    return false;
	}
	System.err.println("Configuring GoogleSearch");
	Element server_elem = (Element)GSXML.getChildByTagName(info, "googleServer");
	if (server_elem == null) {
	    System.err.println("GoogleSearch.configure error: no googleServer element found");
	    return false;
	}
	
	client_key = server_elem.getAttribute("key");
	if (client_key.equals("")) {
	    System.err.println("GoogleSearch.configure error: no client_key for the googleServer element");
	    return false;
	}
	
	does_paging = true;
	does_chunking = false;

	// are we behind a proxy??
	// all the details should have been set up by the Message Router
	proxy_host = System.getProperty("http.proxyHost");
	if (proxy_host != null && !proxy_host.equals("")) {
	    using_proxy = true;
	    try {
		proxy_port = Integer.parseInt(System.getProperty("http.proxyPort").trim());
	    } catch (Exception e) {
		System.err.println("GoogleSearch.configure error: couldn't get proxy port, defaulting to 80");
		proxy_port = 80;
	    }
	    PasswordAuthentication pa = Authenticator.requestPasswordAuthentication(proxy_host, null, proxy_port, "http", "", null);
	    proxy_user = pa.getUserName();
	    proxy_passwd = pa.getPassword();
	}
	return true;
    }
    
    /** Process a text query - implemented by concrete subclasses */
    protected Element processTextQuery(Element request) {
	
	//Connect to Google Web API service
	com.google.soap.search.GoogleSearch search = new com.google.soap.search.GoogleSearch();

	// Set mandatory attributes
	search.setKey(client_key);

	// proxy??
	if (using_proxy) {
	    search.setProxyHost(proxy_host);
	    search.setProxyPort(proxy_port);
	    search.setProxyUserName(proxy_user);
	    search.setProxyPassword(new String(proxy_passwd));
	}

	//set optional attributes
	search.setSafeSearch(true);
	
	// Create a new (empty) result message
	Element result = this.doc.createElement(GSXML.RESPONSE_ELEM);
	result.setAttribute(GSXML.FROM_ATT, TEXT_QUERY_SERVICE);
	result.setAttribute(GSXML.TYPE_ATT, GSXML.REQUEST_TYPE_PROCESS);
	Element doc_node_list = this.doc.createElement(GSXML.DOC_NODE_ELEM+GSXML.LIST_MODIFIER);
	result.appendChild(doc_node_list);
	Element query_metadata_list = this.doc.createElement(GSXML.METADATA_ELEM+GSXML.LIST_MODIFIER);
	result.appendChild(query_metadata_list);

	Element param_list = (Element) GSXML.getChildByTagName(request, GSXML.PARAM_ELEM+GSXML.LIST_MODIFIER);
	if (param_list == null) {
	    System.err.println("GoogleSearch.processTextQuery Error:: TextQuery request had no paramList.");
	    return result;  // Return the empty result
	}

	// Process the request parameters
	HashMap params = GSXML.extractParams(param_list, false);

	// Make sure a query has been specified
	String query = (String) params.get(QUERY_PARAM);
	if (query == null || query.equals("")) {
	    System.err.println("GoogleSearch.processTextQuery Error: TextQuery request had no query string.");
	    return result;  // Return the empty result
	}
       	// tidy whitespace
	query = query.replaceAll("\\s+", "+");
	
	search.setQueryString(query);

	//Check hits_per_page
	int hits_per_page;
	try {
	    hits_per_page = Integer.parseInt(((String)params.get(HITS_PER_PAGE_PARAM)).trim());
	} catch (Exception e) {
	    System.err.println("GoogleSearch.processTextQuery error: couldn't get hits per page param, defaulting to 10");
	    hits_per_page = 10;
	}
	//Check the start_page number
	int start_page;
	try {
	    start_page = Integer.parseInt(((String) params.get(START_PAGE_PARAM)).trim());
	} catch (Exception e) {
	    System.err.println("GoogleSearch.processTextQuery error: couldn't get start page param, defaulting to 1");
	    start_page = 1;
	}
	
	//Invoke Actual Search
	
	// Google only allows 10 hits per request
	int loop = hits_per_page/10;
	int remainder = hits_per_page%10;
	int google_start_page = (start_page-1)*hits_per_page;
	int pages_per_loop;
	for (int j=0; j < loop; j++){
	    if (j < (loop-1) || remainder == 0) {
		pages_per_loop = 10;
	    } else {
		pages_per_loop = remainder;
	    }
	    search.setMaxResults(pages_per_loop); 
	    search.setStartResult(google_start_page);
	    google_start_page = google_start_page + pages_per_loop;
	    GoogleSearchResult google_result;
	    try{
		google_result = search.doSearch();
	    } catch (GoogleSearchFault ex) {
		System.err.println("GoogleSearch.processTextQuery error: the call to the Google Web APIs failed:" + ex.toString());
		// add the error to the result
		return result;
	    }
	    if (j==0) {
		
		//Total amount of documents Google Search returned
		// only need to do this on the first loop
		
		long numdocs_matched = google_result.getEstimatedTotalResultsCount();	    
		GSXML.addMetadata(this.doc, query_metadata_list, "numDocsMatched", ""+numdocs_matched);
		
	    }
	    GoogleSearchResultElement[] details = google_result.getResultElements();
	    for (int i=0; i<details.length; i++){
		Element doc_node = this.doc.createElement(GSXML.DOC_NODE_ELEM);
		doc_node_list.appendChild(doc_node);
		
		Element metadata_list = this.doc.createElement(GSXML.METADATA_ELEM+GSXML.LIST_MODIFIER);
		doc_node.appendChild(metadata_list);
		
		String google_url = details[i].getURL();  
		String google_title = details[i].getTitle();
		String google_snippet = details[i].getSnippet();
		if (google_url !=null) {
		    GSXML.addMetadata(this.doc, metadata_list, "URL", google_url);
		}
		if (google_title != null) {
		    GSXML.addMetadata(this.doc, metadata_list, "Title", google_title);
		}
		if (google_snippet != null) {
		    GSXML.addMetadata(this.doc, metadata_list, "Snippet", google_snippet);
		}
	    }
	} // for each loop
	return result;
    }
    
    protected void getIndexData(ArrayList index_ids, ArrayList index_names,String lang){
       	index_ids.add("idx");
	index_names.add("Google main index");
    }
    
}