/*
 * Created on Dec 1, 2004
 * Copyright (C) Andrea Schweer, 2004
 *
 * This file is part of the Greenstone Alerting Service.
 * Refer to the COPYING file in the base directory of this package
 * for licensing information.
 */
package org.greenstone.gsdlas.users;

import java.sql.*;
import java.util.Map;

import javax.servlet.http.HttpSession;

import org.greenstone.gsdlas.database.DatabaseManager;

/**
 * @author andrea
 *
 * TODO To change the template for this generated type comment go to
 * Window - Preferences - Java - Code Style - Code Templates
 */
public class UserManager {
    private static UserManager instance;
    
    private UserManager() {
        // hide constructor
    }
    
    static public UserManager getInstance() {
        if (instance == null) {
            instance = new UserManager();
        }
        return instance;
    }

    /**
     * @param session
     * @return
     */
    public boolean isLoggedIn(HttpSession session) {
        if (session.getCreationTime() - session.getLastAccessedTime() > session.getMaxInactiveInterval())
            return false;
        return session.getAttribute("username") != null;
    }

    /**
     * @param arguments
     * @param session
     * @throws PasswordMismatchException
     * @throws UserManagementException
     */
    public void createUser(Map arguments, HttpSession session) throws PasswordMismatchException, UserManagementException {
        if (!arguments.get("password").equals(arguments.get("password2"))) {
            throw new PasswordMismatchException("The passwords don't match");
        }
        String username = (String) arguments.get("username");
        
        byte[] password = ((String) arguments.get("password")).getBytes();
        
        byte[] pwdHash = password;
//        try {
//            pwdHash = MessageDigest.getInstance("MD5").digest(password);
//        } catch (NoSuchAlgorithmException e) {
//            e.printStackTrace();
//            throw new UserManagementException("could not create user", e);
//        }
        
        try {
            Connection conn = DatabaseManager.getInstance().getDatabaseConnection();
            Statement statement = conn.createStatement();
            statement.executeUpdate("INSERT INTO users (username, password) " +
            		"VALUES ('" + username + "','" + new String(pwdHash) + "')");
        } catch (Exception e) {
            e.printStackTrace();
            throw new UserManagementException("could not create user", e);
        }
        
    }

    /**
     * @param arguments
     * @param session
     * @throws UserManagementException
     */
    public void loginUser(Map arguments, HttpSession session) throws UserManagementException {
        String username = (String) arguments.get("username");
        
        if (isLoggedIn(session) && session.getAttribute("username").equals(username)) {
            return; // already logged in
        }
        
        byte[] password = ((String) arguments.get("password")).getBytes();
        
        byte[] pwdHash = password;
        try {
//            pwdHash = MessageDigest.getInstance("MD5").digest(password);
            
            Connection conn = DatabaseManager.getInstance().getDatabaseConnection();
            Statement statement = conn.createStatement();
            ResultSet results = statement.executeQuery("SELECT password " +
            		"FROM users WHERE username like '" + username + "';");
            String pwdFromDB = "";
            if(results.next()) {
                pwdFromDB = results.getString("password");
            }
            if (!pwdFromDB.equals(new String(pwdHash))) {
                throw new PasswordMismatchException("user " + username 
                        + " is unknown, or the passwords don't match");
            }
            session.setAttribute("username", username);
        } catch (Exception e) {
            e.printStackTrace();
            throw new UserManagementException("could not login user", e);
        }

    }
    
    
}