/*
 * Copyright 2006 Hippo
 *
 * Licensed under the Apache License, Version 2.0 (the  "License"); 
 * you may not use this file except in compliance with the License. 
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" 
 * BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
 * See the License for the specific language governing permissions and 
 * limitations under the License.
 */
package nl.hippo.webdav.utils;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileReader;
import java.util.Properties;

import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.CommandLineParser;
import org.apache.commons.cli.HelpFormatter;
import org.apache.commons.cli.Options;
import org.apache.commons.cli.PosixParser;

/**
 * <p>
 * Example of how to use the Hippo WebDAV search utility class for querying the Hippo repository (or any other WebDAV compliant server)
 * </p><p>
 * Implements a commandline frontend for use as a standalone application, it: 
 * <ol>
 *  <li>Reads a configuration file and a DASL query file</li>
 *  <li>Creates and initializes a Search Object</li>
 *  <li>Executes the DASL query and sends the results (an XML String) to stdout</li>
 * </ol>
 * </p><p>
 * These are the supported commandline options (all optional):
 * <pre>
 * -c,--config    Configuration file (defaults to 'etc/search.properties')
 * -d,--dasl      Dasl query file (defaults to 'etc/dasl.xml')
 * -h,--help      Print usage information
 * </pre> 
 * </p>
 * 
 * @author wgrevink
 */
public class SearchMain {

    private static final String DEFAULT_CONFIG = "etc/search.properties";
    private static final String DEFAULT_DASL = "etc/dasl.xml"; 
    
    static String configFile;
    static String daslFile;
    
    /**
     * Main entry point: Parses the commandline, creates and initializes a Search object and executes it.
     * The result of the query is sent to standard out.
     *     
     * @param args Commandline arguments.
     */
    public static void main(String[] args) {

        parseCommandLine(args);
        Properties config = loadConfigFile();
        String dasl = loadDaslfile();

        try {
            // Create a Search object and initialize it.
            Search search = new Search();
            search.setConfig(config);
            search.setDasl(dasl);

            // Do the actual query
            String result = search.execute();

            // Print the result to stdout
            System.out.println(result);
        }
        catch (RuntimeException e) {
            System.err.println(e.getMessage());
        }
    }

    /**
     * Parse the commandline arguments to locate the
     * configuration propertiesfile and dasl query file.
     */    
    private static void parseCommandLine(String[] args) {
        try {
            Options options = new Options();
            options.addOption("c", "config", true, "Configuration file (default '" +DEFAULT_CONFIG+ "')");
            options.addOption("d", "dasl", true, "Dasl query file (default '" +DEFAULT_DASL+ "')");
            options.addOption("h", "help", false, "Print usage information");

            CommandLineParser parser = new PosixParser();
            CommandLine cmd = parser.parse(options, args);

            if (cmd.hasOption("h")) {
                HelpFormatter formatter = new HelpFormatter();
                formatter.printHelp("SearchMain", options);
                System.exit(0);
            }

            configFile = cmd.getOptionValue("c", DEFAULT_CONFIG);
            daslFile = cmd.getOptionValue("d", DEFAULT_DASL);

        }
        catch (Exception e) {
            System.err.println("Error while parsing commandline: " + e.getMessage());
            System.exit(-1);
        }
    }
    
    
    /**
     *  Load the configuration file
     */
    private static Properties loadConfigFile() {
        Properties properties = new Properties();
        try {
            properties.load(new BufferedInputStream(new FileInputStream(configFile)));
        }
        catch (Exception e) {
            System.err.println("Error while loading configuration file: " + e.getMessage());
            System.exit(-1);
        }
        return properties;
    }


    /**
     * Load a DASL query file
     */
    private static String loadDaslfile() { 
        final String linesep = System.getProperty("line.separator");
        StringBuffer dasl = new StringBuffer();
        try {
            BufferedReader br = new BufferedReader(new FileReader(daslFile));
            String line;
            while ((line = br.readLine()) != null) {
                dasl.append(line).append(linesep);
            }
        }
        catch (Exception e) {
            System.err.println("Error while loading DASL file '" + daslFile + "': " + e.getMessage());
            System.exit(-1);
        }
        return dasl.toString();
    }
}