/**
 * 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
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * 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.hive.common;

import java.io.File;
import java.io.IOException;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import org.apache.hadoop.security.SecurityUtil;
import org.apache.hadoop.security.UserGroupInformation;
import org.apache.hive.hcatalog.streaming.ConnectionError;
import org.apache.hive.hcatalog.streaming.HiveEndPoint;
import org.apache.storm.hive.security.AutoHive;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import static org.apache.storm.Config.TOPOLOGY_AUTO_CREDENTIALS;

public class HiveUtils {
    private static final Logger LOG = LoggerFactory.getLogger(HiveUtils.class);

    public static HiveEndPoint makeEndPoint(List<String> partitionVals, HiveOptions options) throws ConnectionError {
        if (partitionVals == null) {
            return new HiveEndPoint(options.getMetaStoreURI(), options.getDatabaseName(), options.getTableName(), null);
        }
        return new HiveEndPoint(options.getMetaStoreURI(), options.getDatabaseName(), options.getTableName(), partitionVals);
    }

    public static HiveWriter makeHiveWriter(HiveEndPoint endPoint, ExecutorService callTimeoutPool, UserGroupInformation ugi,
                                            HiveOptions options, boolean tokenAuthEnabled)
        throws HiveWriter.ConnectFailure, InterruptedException {
        return new HiveWriter(endPoint, options.getTxnsPerBatch(), options.getAutoCreatePartitions(),
                              options.getCallTimeOut(), callTimeoutPool, options.getMapper(), ugi, tokenAuthEnabled);
    }

    public static synchronized UserGroupInformation authenticate(boolean isTokenAuthEnabled, String keytab, String principal) throws
        AuthenticationFailed {

        if (isTokenAuthEnabled) {
            return getCurrentUser(principal);
        }

        boolean kerberosEnabled = false;

        if (principal == null && keytab == null) {
            kerberosEnabled = false;
        } else if (principal != null && keytab != null) {
            kerberosEnabled = true;
        } else {
            throw new IllegalArgumentException("To enable Kerberos, need to set both KerberosPrincipal and  KerberosKeytab");
        }

        if (kerberosEnabled) {
            File kfile = new File(keytab);

            if (!(kfile.isFile() && kfile.canRead())) {
                throw new IllegalArgumentException("The keyTab file: " + keytab + " is nonexistent or can't read. "
                                                   + "Please specify a readable keytab file for Kerberos auth.");
            }

            try {
                principal = SecurityUtil.getServerPrincipal(principal, "");
            } catch (Exception e) {
                throw new AuthenticationFailed("Host lookup error when resolving principal " + principal, e);
            }

            try {
                UserGroupInformation.loginUserFromKeytab(principal, keytab);
                return UserGroupInformation.getLoginUser();
            } catch (IOException e) {
                throw new AuthenticationFailed("Login failed for principal " + principal, e);
            }
        }

        return null;

    }

    public static void logAllHiveEndPoints(Map<HiveEndPoint, HiveWriter> allWriters) {
        for (Map.Entry<HiveEndPoint, HiveWriter> entry : allWriters.entrySet()) {
            LOG.info("cached writers {} ", entry.getValue());
        }
    }

    public static boolean isTokenAuthEnabled(Map<String, Object> conf) {
        return conf.get(TOPOLOGY_AUTO_CREDENTIALS) != null &&
               (((List) conf.get(TOPOLOGY_AUTO_CREDENTIALS)).contains(AutoHive.class.getName()));
    }

    private static UserGroupInformation getCurrentUser(String principal) throws AuthenticationFailed {
        try {
            return UserGroupInformation.getCurrentUser();
        } catch (IOException e) {
            throw new AuthenticationFailed("Login failed for principal " + principal, e);
        }
    }

    public static class AuthenticationFailed extends Exception {
        public AuthenticationFailed(String reason, Exception cause) {
            super("Kerberos Authentication Failed. " + reason, cause);
        }
    }
}
