import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.*;
import java.util.*;
import java.net.*;

public class KeywordSearch extends LitsearchBase {

    public String drawPage(HttpServletRequest request,
			   HttpServletResponse response) throws Exception {
	String searchType = request.getParameter("type");
	String searchQuery = request.getParameter("query");
	if (searchQuery == null || searchType == null) {
	    Template t = new Template(TEMPLATE_DIR + "keywordsearch.html");
	    return t.toString();
	}

	searchQuery = searchQuery.trim();
	String text = "";
	String[] stripes = new String[2];
	stripes[0] = "<tr bgcolor='#e0e0e0'>";
	stripes[1] = "<tr bgcolor='#ffffff'>";
	int curColor = 0;

	ArrayList terms = new ArrayList();
	while (true) {
	    int i = searchQuery.indexOf(' ');
	    if (i == -1) {
		terms.add(PorterStemmer.stem(searchQuery));
		break;
	    }
	    terms.add(PorterStemmer.stem(searchQuery.substring(0, i)));
	    searchQuery = searchQuery.substring(i + 1).trim();
	}
	String highlight = "";
	Iterator itr = terms.iterator();
	while (itr.hasNext()) {
	    highlight += (String) itr.next() + ",";
	}

	ArrayList results = new ArrayList();
	if (searchType.equals("all") || terms.size() == 1) {
	    results = doPageSearch(terms, " AND ");
	} else if (searchType.equals("any") && terms.size() > 1) {
	    results = doPageSearch(terms, " OR ");
	} else if (searchType.equals("phrase") && terms.size() > 1) {
	    results = doPhraseSearch(terms);
	}
	text += "<table cellpadding='4' cellspacing='1' width='100%'>";
	text += stripes[curColor % 2] + "<td colspan=3>";
	text += "Found " + results.size() + " results for your query: <b>\"" +
	    request.getParameter("query") + "\"</b></td></tr>\n";
	text += stripes[curColor++ %2] + 
	    "<td>Title</td><td>Author</td><td>Page (click to view)</td></tr>\n";

	if (results.size() == 0) return text + "</td></tr></table>";

	ConnectionWrapper wrapper = null;
	try {
	    wrapper = DatabaseHook.getConnection();
	    Connection c = wrapper.connection();
	    Statement stmt = c.createStatement();
	    ResultSet rs;	
	    String query;

	    itr = results.iterator();
	    String orClause = "";
	    boolean firstTime = true;
	    while (itr.hasNext()) {
		if (!firstTime)   orClause += " OR ";
		else              firstTime = false;

		String id = (String) itr.next();
		orClause += "(u.global_start <= " + id + 
		    " AND u.global_end >= " + id + ")";
	    }
	    
	    query = "SELECT w.id, w.title, b.name, u.page " +
		"FROM UniquePage u, Work w, WrittenBy b " +
		"WHERE (" + orClause + 
		") AND w.id = u.work AND b.work = w.id " +
		"ORDER BY w.title, u.page LIMIT 200";
	    rs = stmt.executeQuery(query);
	    while (rs.next()) {
		text += stripes[curColor++ % 2];
		text += "<td><a href='DescribeWork?work=" + rs.getInt("id") + "'>" + 
		    rs.getString("title") + "</a></td>";
		text += "<td>by <a href='DescribeAuthor?name=" + 
		    URLEncoder.encode(rs.getString("name")) + "'>" + rs.getString("name") + "</a></td>";
		text += "<td><b><a href='Reader?work=" + rs.getInt("id") + "&page=" +  
		    rs.getInt("page") + "&highlight=" + highlight + "'>page " + rs.getInt("page") + "</a></b></td></tr>\n";
	    }


	    text += stripes[curColor++ % 2];
	    text += "<td colspan=3><a href='KeywordSearch'>Search Again</a>\n";
	    text += "</td></tr></table>";
	    
	    wrapper.checkIn();
	    return text;

	} catch (Exception e) {
	    wrapper.checkIn();
	    throw e;
	}
    }


    public ArrayList doPageSearch(ArrayList terms, String connector) throws Exception {
	ConnectionWrapper wrapper = null;
	try {
	    wrapper = DatabaseHook.getConnection();
	    Connection c = wrapper.connection();
	    Statement stmt = c.createStatement();
	    ResultSet rs = null;
	    String query;

	    String fromClause = " FROM ";
	    String whereClause = "";
	    for (int i = 0; i < terms.size(); i++) {
		if (i > 0) {
		    fromClause += ", ";
		    whereClause += " AND ";
		}
		fromClause += "PageContainsWord c" + i + ", Word w" + i + ", UniquePage p" + i;
		whereClause +=  " c" + i + ".word = w" + i + ".id AND p" + i + ".id = c" + i +
		    ".page AND w" + i + ".word=" + formatString((String) terms.get(i));
		whereClause += " AND p0.id = p" + i +".id ";
	    }

	    ArrayList result = new ArrayList();
	    query = "SELECT (p0.global_start + 1) " + fromClause + " WHERE " + whereClause + " LIMIT 200";
	    
	    rs = stmt.executeQuery(query);
	    while(rs.next()) {
		result.add(rs.getString(1));
		}
	    
	    wrapper.checkIn();
	    
	    //throw new Exception(query);
	    return result;

	} catch (Exception e) {
	    wrapper.checkIn();
	    throw e;
        }
    }





    public ArrayList doPhraseSearch(ArrayList terms)throws Exception {
	ConnectionWrapper wrapper = null;
	ArrayList result = null;
	if (terms.size() == 0) return result;
	try {
	    wrapper = DatabaseHook.getConnection();
	    Connection c = wrapper.connection();
	    Statement stmt = c.createStatement();
	    ResultSet rs;
	    String query;
	    
	    int offset = 0;
	    if (terms.size() % 2 == 1) {
		ArrayList tmp1 = new ArrayList();
		ArrayList tmp2 = new ArrayList();
		query = "SELECT DISTINCT i1.gpos " +
		    "FROM WordInstance i1, Word w1, Word w2 " +
		    "WHERE w1.id = i1.prev AND w2.id = i1.word " +
		    "AND w1.word=" + formatString((String) terms.get(0)) +
		    " AND w2.word=" + formatString((String) terms.get(1));
		terms.remove(0);
		rs = stmt.executeQuery(query);
		while(rs.next()) tmp1.add(rs.getString(1));
		query = "SELECT DISTINCT (i1.gpos-1) " +
		    "FROM WordInstance i1, Word w1, Word w2 " +
		    "WHERE w1.id = i1.prev AND w2.id = i1.word " +
		    "AND w1.word=" + formatString((String) terms.get(0)) +
		    " AND w2.word=" + formatString((String) terms.get(1));
		terms.remove(0);
		terms.remove(0);
		rs = stmt.executeQuery(query);
		while(rs.next()) tmp2.add(rs.getString(1));
		result = ListOps.intersect(tmp1, tmp2);
		offset+=2;
	    }

	    while(terms.size() > 0) {
		ArrayList tmp = new ArrayList();
		query = "SELECT DISTINCT (i1.gpos - " + offset + ") " +
		    "FROM WordInstance i1, Word w1, Word w2 " +
		    "WHERE w1.id = i1.prev AND w2.id = i1.word " +
		    "AND w1.word=" + formatString((String) terms.get(0)) +
		    " AND w2.word=" + formatString((String) terms.get(1));
		terms.remove(0);
		terms.remove(0);
		rs = stmt.executeQuery(query);
		while(rs.next()) tmp.add(rs.getString(1));
		if (result == null) result = tmp;
		else result = ListOps.intersect(tmp, result);
		offset += 2;
	    }
	    wrapper.checkIn();
	    return result;

	} catch (Exception e) {
	    wrapper.checkIn();
	    throw e;
	}
    }
}