// BSD License (http://www.galagosearch.org/license)

 package org.galagosearch.core.tools;

 import java.io.IOException;

 import java.io.PrintWriter;

 import java.io.UnsupportedEncodingException;

 import java.net.URLEncoder;

 import java.util.Arrays;

 import java.util.HashSet;

 import java.util.Map.Entry;

 import java.util.Set;

 import javax.servlet.ServletException;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import org.galagosearch.core.parse.Document;

 import org.galagosearch.core.tools.Search.SearchResult;

 import org.galagosearch.core.tools.Search.SearchResultItem;

 import org.mortbay.jetty.handler.AbstractHandler;

 import org.znerd.xmlenc.XMLOutputter;

 /**

  * <p>Handles web search requests against a Galago index.  Also handles XML requests for

  * documents, snippets and search results.</p>

  *

  * <p>This class is set up to work with an embedded Jetty instance, but it should be

  * fairly easy to wrap into a Servlet for use with something else (Tomcat, Glassfish, etc.)</p>

  *

  * <p>URLs supported:</p>

  *

  * <table>

  *   <tr>

  *     <td>/</td>

  *     <td>Main Page</td>

  *   </tr>

  *   <tr>

  *     <td>/search</td>

  *     <td>HTML Search Results (q, start, n)</td>

  *   </tr>

  *   <tr>

  *     <td>/xmlsearch</td>

  *     <td>XML Search Results (q, start, n)</td>

  *   </tr>

  *   <tr>

  *     <td>/snippet</td>

  *     <td>XML Snippet Result (identifier, term+)</td>

  *   </tr>

  *   <tr>

  *     <td>/document</td>

  *     <td>Document Result (identifier)</td>

  *   </tr>

  * </table>

  *

  * @author trevor

  */

 public class SearchWebHandler extends AbstractHandler {

     Search search;

     public SearchWebHandler(Search search) {

         this.search = search;

     }

     public String getEscapedString(String text) {

         StringBuilder builder = new StringBuilder();

         for (int i = 0; i < text.length(); ++i) {

             char c = text.charAt(i);

             if (c >= 128) {

                 builder.append("&#" + (int)c + ";");

             } else {

                 builder.append(c);

             }

         }

         return builder.toString();

     }

     public void handleDocument(HttpServletRequest request, HttpServletResponse response) throws IOException {

         request.getParameterMap();

         String identifier = request.getParameter("identifier");

         Document document = search.getDocument(identifier);

         response.setContentType("text/html; charset=UTF-8");

         PrintWriter writer = response.getWriter();

         writer.write(getEscapedString(document.text));

         writer.close();

     }

     public void handleSnippet(HttpServletRequest request, HttpServletResponse response) throws IOException {

         String identifier = request.getParameter("identifier");

         String[] terms = request.getParameterValues("term");

         Set<String> queryTerms = new HashSet<String>(Arrays.asList(terms));

         Document document = search.getDocument(identifier);

         if (document == null) {

             response.setStatus(response.SC_NOT_FOUND);

         } else {

             response.setContentType("text/xml");

             PrintWriter writer = response.getWriter();

             String snippet = search.getSummary(document, queryTerms);

             String title = document.metadata.get("title");

             String url = document.metadata.get("url");

             if (snippet == null) snippet = "";

             response.setContentType("text/xml");

             writer.append("<response>\n");

             writer.append(String.format("<snippet>%s</snippet>\n", snippet));

             writer.append(String.format("<identifier>%s</identifier>\n", identifier));

             writer.append(String.format("<title>%s</title>\n", scrub(title)));

             writer.append(String.format("<url>%s</url>\n", scrub(url)));

             writer.append("</response>");

             writer.close();

         }

     }

     private String scrub(String s) throws UnsupportedEncodingException {

         if (s == null) return s;

         return s.replace("<", "&gt;")

                 .replace(">", "<")

                 .replace("&", "&");

     }

     public void handleSearch(HttpServletRequest request, HttpServletResponse response) throws Exception {

         SearchResult result = performSearch(request);

         response.setContentType("text/html");

         String displayQuery = scrub(request.getParameter("q"));

         String encodedQuery = URLEncoder.encode(request.getParameter("q"), "UTF-8");

         PrintWriter writer = response.getWriter();

         writer.append("<html>\n");

         writer.append("<head>\n");

         writer.append(String.format("<title>%s - Galago Search</title>\n", displayQuery));

         writeStyle(writer);

         writer.append("<script type=\"text/javascript\">\n");

         writer.append("function toggleDebug() {\n");

         writer.append("   var object = document.getElementById('debug');\n");

         writer.append("   if (object.style.display != 'block') {\n");

         writer.append("     object.style.display = 'block';\n");

         writer.append("  } else {\n");

         writer.append("     object.style.display = 'none';\n");

         writer.append("  }\n");

         writer.append("}\n");

         writer.append("</script>\n");

         writer.append("</head>\n<body>\n");

         writer.append("<div id=\"header\">\n");

         writer.append("<table><tr>");

         writer.append("<td><a href=\"http://www.galagosearch.org\">" +

                       "<img src=\"http://www.galagosearch.org/galago.png\"></a></td>");

         writer.append("<td><br/><form action=\"search\">" +

                       String.format("<input name=\"q\" size=\"40\" value=\"%s\" />", displayQuery) +

                       "<input value=\"Search\" type=\"submit\" /></form></td>");

         writer.append("</tr>");

         writer.append("</table>\n");

         writer.append("</div>\n");

         writer.append("<center>[<a href=\"#\" onClick=\"toggleDebug(); return false;\">debug</a>]</center>");

         writer.append("<div id=\"debug\">");

         writer.append("<table>");

         writer.append(String.format("<tr><td>%s</td><td>%s</td></tr>",

                       "Parsed Query", result.query.toString()));

         writer.append(String.format("<tr><td>%s</td><td>%s</td></tr>",

                       "Transformed Query", result.transformedQuery.toString()));

         writer.append("</table>");

         writer.append("</div>");

         for (SearchResultItem item : result.items) {

             writer.append("<div id=\"result\">\n");

             writer.append(String.format("<a href=\"document?identifier=%s\">%s</a><br/>" +

                                         "<div id=\"summary\">%s</div>\n" +

                                         "<div id=\"meta\">%s - %s</div>\n",

                                         item.identifier,

                                         item.displayTitle,

                                         item.summary,

                                         scrub(item.identifier),

                                         scrub(item.url)));

             writer.append("</div>\n");

         }

         String startAtString = request.getParameter("start");

         String countString = request.getParameter("n");

         int startAt = 0;

         int count = 10;

         if (startAtString != null) {

             startAt = Integer.parseInt(startAtString);

         }

         if (countString != null) {

             count = Integer.parseInt(countString);

         }

         writer.append("<center>\n");

         if (startAt != 0) {

             writer.append(String.format("<a href=\"search?q=%s&start=%d&n=%d\">Previous</a>",

                                         encodedQuery, Math.max(startAt-count,0), count));

             if (result.items.size() >= count) {

                 writer.append(" | ");

             }

         }

         if (result.items.size() >= count) {

             writer.append(String.format("<a href=\"search?q=%s&start=%d&n=%d\">Next</a>",

                                         encodedQuery, startAt+count, count));

         }

         writer.append("</center>");

         writer.append("</body>");

         writer.append("</html>");

         writer.close();

     }

     public void handleSearchXML(HttpServletRequest request, HttpServletResponse response) throws IllegalStateException, IllegalArgumentException, IOException, Exception {

         SearchResult result = performSearch(request);

         PrintWriter writer = response.getWriter();

         XMLOutputter outputter = new XMLOutputter(writer, "UTF-8");

         response.setContentType("text/xml");

         outputter.startTag("response");

         writer.append("<response>\n");

         for (SearchResultItem item : result.items) {

             outputter.startTag("result");

             outputter.startTag("identifier");

             outputter.pcdata(item.identifier);

             outputter.endTag();

             outputter.startTag("title");

             outputter.pcdata(item.displayTitle);

             outputter.endTag();

             outputter.startTag("url");

             outputter.pcdata(item.url);

             outputter.endTag();

             outputter.startTag("snippet");

             outputter.pcdata(item.summary);

             outputter.endTag();

             outputter.startTag("rank");

             outputter.pcdata("" + item.rank);

             outputter.endTag();

             outputter.startTag("metadata");

             for (Entry<String, String> entry : item.metadata.entrySet()) {

                 outputter.startTag("item");

                 outputter.startTag("key");

                 outputter.pcdata(entry.getKey());

                 outputter.endTag();

                 outputter.startTag("value");

                 outputter.pcdata(entry.getValue());

                 outputter.endTag();

             }

             outputter.endTag();

         }

     }

     public void writeStyle(PrintWriter writer) {

         writer.write("<style type=\"text/css\">\n");

         writer.write("body { font-family: Helvetica, sans-serif; }\n");

         writer.write("img { border-style: none; }\n");

         writer.write("#box { border: 1px solid #ccc; margin: 100px auto; width: 500px;" +

                      "background: rgb(210, 233, 217); }\n");

         writer.write("#box a { font-size: small; text-decoration: none; }\n");

         writer.write("#box a:link { color: rgb(0, 93, 40); }\n");

         writer.write("#box a:visited { color: rgb(90, 93, 90); }\n");

         writer.write("#header { background: rgb(210, 233, 217); border: 1px solid #ccc; }\n");

         writer.write("#result { padding: 10px 5px; max-width: 550px; }\n");

         writer.write("#meta { font-size: small; color: rgb(60, 100, 60); }\n");

         writer.write("#summary { font-size: small; }\n");

         writer.write("#debug { display: none; }\n");

         writer.write("</style>");

     }

     public void handleMainPage(HttpServletRequest request, HttpServletResponse response) throws IOException {

         PrintWriter writer = response.getWriter();

         response.setContentType("text/html");

         writer.append("<html>\n");

         writer.append("<head>\n");

         writeStyle(writer);

         writer.append("<title>Galago Search</title></head>");

         writer.append("<body>");

         writer.append("<center><br/><br/><div id=\"box\">" +

                       "<a href=\"http://www.galagosearch.org\">" +

                       "<img src=\"http://www.galagosearch.org/galago.png\"/></a><br/>\n");

         writer.append("<form action=\"search\"><input name=\"q\" size=\"40\">" +

                       "<input value=\"Search\" type=\"submit\" /></form><br/><br/>");

         writer.append("</div></center></body></html>\n");

         writer.close();

     }

     public void handle(String target,

             HttpServletRequest request,

             HttpServletResponse response,

             int dispatch) throws IOException, ServletException {

         if (request.getPathInfo().equals("/search")) {

             try {

                 handleSearch(request, response);

             } catch(Exception e) {

                 throw new ServletException("Caught exception from handleSearch", e);

             }

         } else if (request.getPathInfo().equals("/document")) {

             handleDocument(request, response);

         } else if (request.getPathInfo().equals("/searchxml")) {

             try {

                 handleSearchXML(request, response);

             } catch(Exception e) {

                 throw new ServletException("Caught exception from handleSearchXML", e);

             }

         } else if (request.getPathInfo().equals("/snippet")) {

             handleSnippet(request, response);

         } else {

             handleMainPage(request, response);

         }

     }

     private SearchResult performSearch(HttpServletRequest request) throws Exception {

         String query = request.getParameter("q");

         String startAtString = request.getParameter("start");

         String countString = request.getParameter("n");

         int startAt = (startAtString == null) ? 0 : Integer.parseInt(startAtString);

         int resultCount = (countString == null) ? 10 : Integer.parseInt(countString);

         SearchResult result = search.runQuery(query, startAt, resultCount, true);

         return result;

     }

 }