/* quickstartexpand.cc: Simplest possible query expansion
 *
 * Copyright 2003,2004 Olly Betts
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
 * USA
 */

#include <xapian.h>
#include <iostream>
using namespace std;

int main(int argc, char **argv)
{
    // Simplest possible options parsing: we just require two or more
    // parameters.
    if (argc < 3) {
        cout << "usage: " << argv[0] <<
                " <path to database> <search terms> -- <relevant docids>" <<
                endl;
        exit(1);
    }

    // Catch any Xapian::Error exceptions thrown
    try {
        // Open the database
        Xapian::Database database(argv[1]);

        // Start an enquire session
        Xapian::Enquire enquire(database);

        // Prepare the query terms
        vector<string> queryterms;
        int optpos;
        for (optpos = 2; optpos < argc; optpos++) {
            if(string(argv[optpos]) == "--") {
                optpos++;
                break;
            }
            queryterms.push_back(argv[optpos]);
        }

        // Prepare the relevant document list
        Xapian::RSet reldocs;
        for (; optpos < argc; optpos++) {
            Xapian::docid rdid = atoi(argv[optpos]);
            if (rdid != 0) {
                reldocs.add_document(rdid);
            }
        }

        // Build the query object
        Xapian::Query query(Xapian::Query::OP_OR, queryterms.begin(), queryterms.end());

        Xapian::MSet matches;
        if (query.is_defined()) {
            cout << "Performing query '" << query.get_description() <<
                    "'" << endl;

            // Give the query object to the enquire session
            enquire.set_query(query);

            // Get the top 10 results of the query
            matches = enquire.get_mset(0, 10);

            // Display the results
            cout << matches.items.size() << " results found" << endl;

            for (Xapian::MSetIterator i = matches.begin();
                 i != matches.end();
                 ++i) {
                Xapian::Document doc = i.get_document();
                cout << "Document ID " << *i << "\t" <<
                        i.get_weight() << " [" <<
                        doc.get_data() << "]" << endl;
            }
        }

        // Put the top 5 into the rset if rset is empty
        if (reldocs.empty()) {
            Xapian::MSetIterator i;
            int j;
            for (i = matches.begin(),
                 j = 0;
                 (i != matches.end()) && (j < 5);
                 ++i, ++j) {
                reldocs.add_document(*i);
            }
        }
        
        // Get the suggested expand terms
        Xapian::ESet eterms = enquire.get_eset(10, reldocs);

        // Display the expand terms
        cout << eterms.size() << " suggested additional terms" << endl;

        for (Xapian::ESetIterator k = eterms.begin();
             k != eterms.end();
             ++k) {
            cout << "Term '" << *k << "'\t " <<
                    "(weight " << k.get_weight() << ")" << endl;
        }
    } catch(const Xapian::Error &error) {
        cout << "Exception: "  << error.get_msg() << endl;
    }
}