/**
 * 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.storm.security.auth.authorizer;

import java.util.Collection;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import org.apache.storm.security.auth.IAuthorizer;
import org.apache.storm.security.auth.ReqContext;

/**
 * An authorization implementation that simply checks a whitelist of users that are allowed to use the cluster.
 */
public class SimpleWhitelistAuthorizer implements IAuthorizer {
    public static final String WHITELIST_USERS_CONF = "storm.auth.simple-white-list.users";
    protected Set<String> users;

    /**
     * Invoked once immediately after construction.
     *
     * @param conf Storm configuration
     */
    @Override
    public void prepare(Map<String, Object> conf) {
        users = new HashSet<>();
        if (conf.containsKey(WHITELIST_USERS_CONF)) {
            users.addAll((Collection<String>) conf.get(WHITELIST_USERS_CONF));
        }
    }

    /**
     * `permit()` method is invoked for each incoming Thrift request.
     *
     * @param context   request context includes info about
     * @param operation operation name
     * @param topoConf  configuration of targeted topology
     * @return true if the request is authorized, false if reject
     */
    @Override
    public boolean permit(ReqContext context, String operation, Map<String, Object> topoConf) {
        return context.principal() != null ? users.contains(context.principal().getName()) : false;
    }
}