/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.openejb.core.security.jaas;

import org.apache.openejb.util.ConfUtils;
import org.apache.openejb.util.LogCategory;
import org.apache.openejb.util.Logger;

import javax.security.auth.Subject;
import javax.security.auth.callback.Callback;
import javax.security.auth.callback.CallbackHandler;
import javax.security.auth.callback.NameCallback;
import javax.security.auth.callback.PasswordCallback;
import javax.security.auth.callback.UnsupportedCallbackException;
import javax.security.auth.login.FailedLoginException;
import javax.security.auth.login.LoginException;
import javax.security.auth.spi.LoginModule;
import java.io.IOException;
import java.net.URL;
import java.util.Enumeration;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Properties;
import java.util.Set;

import static org.apache.openejb.loader.IO.readProperties;

/**
 * @version $Rev$ $Date$
 */
public class PropertiesLoginModule implements LoginModule {

    private static final String USER_FILE = "UsersFile";
    private static final String GROUP_FILE = "GroupsFile";

    private static Logger log = Logger.getInstance(LogCategory.OPENEJB_SECURITY, "org.apache.openejb.util.resources");

    private Subject subject;
    private CallbackHandler callbackHandler;

    private boolean debug;
    private Properties users = new Properties();
    private Properties groups = new Properties();
    private String user;
    private Set principals = new LinkedHashSet();

    private URL usersUrl;
    private URL groupsUrl;

    public void initialize(final Subject subject, final CallbackHandler callbackHandler, final Map sharedState, final Map options) {
        this.subject = subject;
        this.callbackHandler = callbackHandler;

        debug = log.isDebugEnabled() || "true".equalsIgnoreCase((String) options.get("Debug"));
        final String usersFile = String.valueOf(options.get(USER_FILE));
        final String groupsFile = String.valueOf(options.get(GROUP_FILE));

        usersUrl = ConfUtils.getConfResource(usersFile);
        groupsUrl = ConfUtils.getConfResource(groupsFile);

        if (debug) {
            log.debug("Users file: " + usersUrl.toExternalForm());
            log.debug("Groups file: " + groupsUrl.toExternalForm());
        }
    }

    public boolean login() throws LoginException {
        try {
            users = readProperties(usersUrl);
        } catch (final IOException ioe) {
            throw new LoginException("Unable to load user properties file " + usersUrl.getFile());
        }

        try {
            groups = readProperties(groupsUrl);
        } catch (final IOException ioe) {
            throw new LoginException("Unable to load group properties file " + groupsUrl.getFile());
        }

        final Callback[] callbacks = new Callback[2];

        callbacks[0] = new NameCallback("Username: ");
        callbacks[1] = new PasswordCallback("Password: ", false);
        try {
            callbackHandler.handle(callbacks);
        } catch (final IOException ioe) {
            throw new LoginException(ioe.getMessage());
        } catch (final UnsupportedCallbackException uce) {
            throw new LoginException(uce.getMessage() + " not available to obtain information from user");
        }

        user = ((NameCallback) callbacks[0]).getName();
        char[] tmpPassword = ((PasswordCallback) callbacks[1]).getPassword();
        if (tmpPassword == null) {
            tmpPassword = new char[0];
        }

        final String password = users.getProperty(user);

        if (password == null) {
            throw new FailedLoginException("User does not exist");
        }
        if (!password.equals(new String(tmpPassword))) {
            throw new FailedLoginException("Password does not match");
        }

        users.clear();

        if (debug) {
            log.debug("Logged in as '" + user + "'");
        }
        return true;
    }

    public boolean commit() throws LoginException {
        principals.add(new UserPrincipal(user));

        for (final Enumeration enumeration = groups.keys(); enumeration.hasMoreElements(); ) {
            final String name = (String) enumeration.nextElement();
            final String[] userList = String.valueOf(groups.getProperty(name)).split(",");
            for (int i = 0; i < userList.length; i++) {
                if (user.equals(userList[i])) {
                    principals.add(new GroupPrincipal(name));
                    break;
                }
            }
        }

        subject.getPrincipals().addAll(principals);

        clear();

        if (debug) {
            log.debug("commit");
        }
        return true;
    }

    public boolean abort() throws LoginException {
        clear();

        if (debug) {
            log.debug("abort");
        }
        return true;
    }

    public boolean logout() throws LoginException {
        subject.getPrincipals().removeAll(principals);
        principals.clear();

        if (debug) {
            log.debug("logout");
        }
        return true;
    }

    private void clear() {
        groups.clear();
        user = null;
    }

}
