/**
 * 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.cluster;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.security.NoSuchAlgorithmException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.storm.Config;
import org.apache.storm.assignments.ILocalAssignmentsBackend;
import org.apache.storm.assignments.LocalAssignmentsBackendFactory;
import org.apache.storm.generated.ClusterWorkerHeartbeat;
import org.apache.storm.generated.ExecutorInfo;
import org.apache.storm.generated.ExecutorStats;
import org.apache.storm.generated.ProfileAction;
import org.apache.storm.generated.WorkerTokenServiceType;
import org.apache.storm.shade.org.apache.zookeeper.ZooDefs;
import org.apache.storm.shade.org.apache.zookeeper.data.ACL;
import org.apache.storm.shade.org.apache.zookeeper.data.Id;
import org.apache.storm.shade.org.apache.zookeeper.server.auth.DigestAuthenticationProvider;
import org.apache.storm.utils.Utils;

public class ClusterUtils {

    public static final String ZK_SEPERATOR = "/";

    public static final String ASSIGNMENTS_ROOT = "assignments";
    public static final String STORMS_ROOT = "storms";
    public static final String SUPERVISORS_ROOT = "supervisors";
    public static final String WORKERBEATS_ROOT = "workerbeats";
    public static final String BACKPRESSURE_ROOT = "backpressure";
    public static final String LEADERINFO_ROOT = "leader-info";
    public static final String ERRORS_ROOT = "errors";
    public static final String BLOBSTORE_ROOT = "blobstore";
    public static final String BLOBSTORE_MAX_KEY_SEQUENCE_NUMBER_ROOT = "blobstoremaxkeysequencenumber";
    public static final String NIMBUSES_ROOT = "nimbuses";
    public static final String CREDENTIALS_ROOT = "credentials";
    public static final String LOGCONFIG_ROOT = "logconfigs";
    public static final String PROFILERCONFIG_ROOT = "profilerconfigs";
    public static final String SECRET_KEYS_ROOT = "secretkeys";

    public static final String ASSIGNMENTS_SUBTREE = ZK_SEPERATOR + ASSIGNMENTS_ROOT;
    public static final String STORMS_SUBTREE = ZK_SEPERATOR + STORMS_ROOT;
    public static final String SUPERVISORS_SUBTREE = ZK_SEPERATOR + SUPERVISORS_ROOT;
    public static final String WORKERBEATS_SUBTREE = ZK_SEPERATOR + WORKERBEATS_ROOT;
    public static final String BACKPRESSURE_SUBTREE = ZK_SEPERATOR + BACKPRESSURE_ROOT;
    public static final String LEADERINFO_SUBTREE = ZK_SEPERATOR + LEADERINFO_ROOT;
    public static final String ERRORS_SUBTREE = ZK_SEPERATOR + ERRORS_ROOT;
    public static final String BLOBSTORE_SUBTREE = ZK_SEPERATOR + BLOBSTORE_ROOT;
    public static final String BLOBSTORE_MAX_KEY_SEQUENCE_NUMBER_SUBTREE = ZK_SEPERATOR + BLOBSTORE_MAX_KEY_SEQUENCE_NUMBER_ROOT;
    public static final String NIMBUSES_SUBTREE = ZK_SEPERATOR + NIMBUSES_ROOT;
    public static final String CREDENTIALS_SUBTREE = ZK_SEPERATOR + CREDENTIALS_ROOT;
    public static final String LOGCONFIG_SUBTREE = ZK_SEPERATOR + LOGCONFIG_ROOT;
    public static final String PROFILERCONFIG_SUBTREE = ZK_SEPERATOR + PROFILERCONFIG_ROOT;
    public static final String SECRET_KEYS_SUBTREE = ZK_SEPERATOR + SECRET_KEYS_ROOT;

    // A singleton instance allows us to mock delegated static methods in our
    // tests by subclassing.
    private static final ClusterUtils INSTANCE = new ClusterUtils();
    private static ClusterUtils _instance = INSTANCE;

    /**
     * Provide an instance of this class for delegates to use. To mock out delegated methods, provide an instance of a subclass that
     * overrides the implementation of the delegated method.
     *
     * @param u a Cluster instance
     */
    public static void setInstance(ClusterUtils u) {
        _instance = u;
    }

    /**
     * Resets the singleton instance to the default. This is helpful to reset the class to its original functionality when mocking is no
     * longer desired.
     */
    public static void resetInstance() {
        _instance = INSTANCE;
    }

    /**
     * Get ZK ACLs for a topology to have read/write access.
     *
     * @param topoConf the topology config.
     * @return the ACLs.
     */
    public static List<ACL> mkTopoReadWriteAcls(Map<String, Object> topoConf) {
        return mkTopoAcls(topoConf, ZooDefs.Perms.ALL);
    }

    /**
     * Get ZK ACLs for a topology to have read only access.
     *
     * @param topoConf the topology config.
     * @return the ACLs.
     */
    public static List<ACL> mkTopoReadOnlyAcls(Map<String, Object> topoConf) {
        return mkTopoAcls(topoConf, ZooDefs.Perms.READ);
    }

    private static List<ACL> mkTopoAcls(Map<String, Object> topoConf, int perms) {
        List<ACL> aclList = null;
        String payload = (String) topoConf.get(Config.STORM_ZOOKEEPER_TOPOLOGY_AUTH_PAYLOAD);
        if (Utils.isZkAuthenticationConfiguredTopology(topoConf)) {
            aclList = new ArrayList<>();
            ACL acl1 = ZooDefs.Ids.CREATOR_ALL_ACL.get(0);
            aclList.add(acl1);
            try {
                ACL acl2 = new ACL(perms, new Id("digest", DigestAuthenticationProvider.generateDigest(payload)));
                aclList.add(acl2);
            } catch (NoSuchAlgorithmException e) {
                //Should only happen on a badly configured system
                throw new RuntimeException(e);
            }
        }
        return aclList;
    }

    public static String supervisorPath(String id) {
        return SUPERVISORS_SUBTREE + ZK_SEPERATOR + id;
    }

    public static String assignmentPath(String id) {
        return ASSIGNMENTS_SUBTREE + ZK_SEPERATOR + id;
    }

    public static String blobstorePath(String key) {
        return BLOBSTORE_SUBTREE + ZK_SEPERATOR + key;
    }

    public static String blobstoreMaxKeySequenceNumberPath(String key) {
        return BLOBSTORE_MAX_KEY_SEQUENCE_NUMBER_SUBTREE + ZK_SEPERATOR + key;
    }

    public static String nimbusPath(String id) {
        return NIMBUSES_SUBTREE + ZK_SEPERATOR + id;
    }

    public static String stormPath(String id) {
        return STORMS_SUBTREE + ZK_SEPERATOR + id;
    }

    public static String workerbeatStormRoot(String stormId) {
        return WORKERBEATS_SUBTREE + ZK_SEPERATOR + stormId;
    }

    public static String workerbeatPath(String stormId, String node, Long port) {
        return workerbeatStormRoot(stormId) + ZK_SEPERATOR + node + "-" + port;
    }

    public static String backpressureStormRoot(String stormId) {
        return BACKPRESSURE_SUBTREE + ZK_SEPERATOR + stormId;
    }

    public static String backpressurePath(String stormId, String node, Long port) {
        return backpressureStormRoot(stormId) + ZK_SEPERATOR + node + "-" + port;
    }

    /**
     * Get the backpressure znode full path.
     *
     * @param stormId   The topology id
     * @param shortPath A string in the form of "node-port"
     * @return The backpressure znode path
     */
    public static String backpressurePath(String stormId, String shortPath) {
        return backpressureStormRoot(stormId) + ZK_SEPERATOR + shortPath;
    }

    public static String errorStormRoot(String stormId) {
        return ERRORS_SUBTREE + ZK_SEPERATOR + stormId;
    }

    public static String errorPath(String stormId, String componentId) {
        return errorStormRoot(stormId) + ZK_SEPERATOR + Utils.urlEncodeUtf8(componentId);
    }

    public static String lastErrorPath(String stormId, String componentId) {
        return errorPath(stormId, componentId) + "-last-error";
    }

    public static String credentialsPath(String stormId) {
        return CREDENTIALS_SUBTREE + ZK_SEPERATOR + stormId;
    }

    /**
     * Get the path to the log config for a topology.
     *
     * @param stormId the topology id.
     * @return the path to the config.
     */
    public static String logConfigPath(String stormId) {
        return LOGCONFIG_SUBTREE + ZK_SEPERATOR + stormId;
    }

    public static String profilerConfigPath(String stormId) {
        return PROFILERCONFIG_SUBTREE + ZK_SEPERATOR + stormId;
    }

    public static String profilerConfigPath(String stormId, String host, Long port, ProfileAction requestType) {
        return profilerConfigPath(stormId) + ZK_SEPERATOR + host + "_" + port + "_" + requestType;
    }

    /**
     * Get the base path where secret keys are stored for a given service.
     *
     * @param type the service we are interested in.
     * @return the path to that service root.
     */
    public static String secretKeysPath(WorkerTokenServiceType type) {
        return SECRET_KEYS_SUBTREE + ZK_SEPERATOR + type.name();
    }

    /**
     * Get the path to secret keys for a specific topology.
     *
     * @param type       the service the secret is for.
     * @param topologyId the topology the secret is for.
     * @return the path to the list of secret keys.
     */
    public static String secretKeysPath(WorkerTokenServiceType type, String topologyId) {
        return secretKeysPath(type) + ZK_SEPERATOR + topologyId;
    }

    /**
     * Get the path to a specific secret key.
     *
     * @param type       the service the secret is for.
     * @param topologyId the topology the secret is for.
     * @param version    the version the secret is for.
     * @return the path to the secret.
     */
    public static String secretKeysPath(WorkerTokenServiceType type, String topologyId, long version) {
        return secretKeysPath(type, topologyId) + ZK_SEPERATOR + version;
    }

    public static <T> T maybeDeserialize(byte[] serialized, Class<T> clazz) {
        if (serialized != null) {
            return Utils.deserialize(serialized, clazz);
        }
        return null;
    }

    /**
     * Ensures that we only return heartbeats for executors assigned to this worker.
     */
    public static Map<ExecutorInfo, ExecutorBeat> convertExecutorBeats(List<ExecutorInfo> executors,
                                                                       ClusterWorkerHeartbeat workerHeartbeat) {
        Map<ExecutorInfo, ExecutorBeat> executorWhb = new HashMap<>();
        Map<ExecutorInfo, ExecutorStats> executorStatsMap = workerHeartbeat.get_executor_stats();
        for (ExecutorInfo executor : executors) {
            if (executorStatsMap.containsKey(executor)) {
                long time = workerHeartbeat.get_time_secs();
                int uptime = workerHeartbeat.get_uptime_secs();
                ExecutorStats executorStats = workerHeartbeat.get_executor_stats().get(executor);
                ExecutorBeat executorBeat = new ExecutorBeat(time, uptime, executorStats);
                executorWhb.put(executor, executorBeat);
            }
        }
        return executorWhb;
    }

    public static IStateStorage mkStateStorage(Map<String, Object> config, Map<String, Object> authConf,
                                               ClusterStateContext context) throws Exception {
        return _instance.mkStateStorageImpl(config, authConf, context);
    }

    public static IStormClusterState mkStormClusterState(Object stateStorage, ILocalAssignmentsBackend backend,
                                                         ClusterStateContext context) throws Exception {
        return _instance.mkStormClusterStateImpl(stateStorage, backend, context);
    }

    public static IStormClusterState mkStormClusterState(Object stateStorage, ClusterStateContext context) throws Exception {
        return _instance.mkStormClusterStateImpl(stateStorage, LocalAssignmentsBackendFactory.getDefault(), context);
    }

    public static String stringifyError(Throwable error) {
        StringWriter result = new StringWriter();
        PrintWriter printWriter = new PrintWriter(result);
        error.printStackTrace(printWriter);
        return result.toString();
    }

    public IStormClusterState mkStormClusterStateImpl(Object stateStorage, ILocalAssignmentsBackend backend,
                                                      ClusterStateContext context) throws Exception {
        if (stateStorage instanceof IStateStorage) {
            return new StormClusterStateImpl((IStateStorage) stateStorage, backend, context, false);
        } else {
            IStateStorage storage = _instance.mkStateStorageImpl((Map<String, Object>) stateStorage,
                                                                 (Map<String, Object>) stateStorage, context);
            return new StormClusterStateImpl(storage, backend, context, true);
        }
    }

    public IStateStorage mkStateStorageImpl(Map<String, Object> config, Map<String, Object> authConf, ClusterStateContext context) throws
        Exception {
        String className = null;
        IStateStorage stateStorage = null;
        if (config.get(Config.STORM_CLUSTER_STATE_STORE) != null) {
            className = (String) config.get(Config.STORM_CLUSTER_STATE_STORE);
        } else {
            className = "org.apache.storm.cluster.ZKStateStorageFactory";
        }
        Class clazz = Class.forName(className);
        StateStorageFactory storageFactory = (StateStorageFactory) clazz.newInstance();
        stateStorage = storageFactory.mkStore(config, authConf, context);
        return stateStorage;
    }
}
