/*
 * 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.
 */
/*
 * Copyright 2015 Cloudius Systems
 *
 * Modified by Cloudius Systems
 */
package org.apache.cassandra.net;

import static java.util.Collections.emptyMap;

import java.lang.management.ManagementFactory;
import java.net.UnknownHostException;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;

import javax.json.JsonArray;
import javax.json.JsonObject;
import javax.management.MBeanServer;
import javax.management.ObjectName;

import org.apache.cassandra.metrics.DroppedMessageMetrics;

import com.scylladb.jmx.api.APIClient;

public final class MessagingService implements MessagingServiceMBean {
    static final int INTERVAL = 1000; // update every 1second
    public static final String MBEAN_NAME = "org.apache.cassandra.net:type=MessagingService";
    private static final java.util.logging.Logger logger = java.util.logging.Logger
            .getLogger(MessagingService.class.getName());
    Map<String, DroppedMessageMetrics> dropped;
    private APIClient c = new APIClient();
    Map<String, Long> resent_timeout = new HashMap<String, Long>();
    private final ObjectName jmxObjectName;
    private long recentTimeoutCount;

    /* All verb handler identifiers */
    public enum Verb
    {
        MUTATION,
        @Deprecated BINARY,
        READ_REPAIR,
        READ,
        REQUEST_RESPONSE, // client-initiated reads and writes
        @Deprecated STREAM_INITIATE,
        @Deprecated STREAM_INITIATE_DONE,
        @Deprecated STREAM_REPLY,
        @Deprecated STREAM_REQUEST,
        RANGE_SLICE,
        @Deprecated BOOTSTRAP_TOKEN,
        @Deprecated TREE_REQUEST,
        @Deprecated TREE_RESPONSE,
        @Deprecated JOIN,
        GOSSIP_DIGEST_SYN,
        GOSSIP_DIGEST_ACK,
        GOSSIP_DIGEST_ACK2,
        @Deprecated DEFINITIONS_ANNOUNCE,
        DEFINITIONS_UPDATE,
        TRUNCATE,
        SCHEMA_CHECK,
        @Deprecated INDEX_SCAN,
        REPLICATION_FINISHED,
        INTERNAL_RESPONSE, // responses to internal calls
        COUNTER_MUTATION,
        @Deprecated STREAMING_REPAIR_REQUEST,
        @Deprecated STREAMING_REPAIR_RESPONSE,
        SNAPSHOT, // Similar to nt snapshot
        MIGRATION_REQUEST,
        GOSSIP_SHUTDOWN,
        _TRACE, // dummy verb so we can use MS.droppedMessages
        ECHO,
        REPAIR_MESSAGE,
        // use as padding for backwards compatability where a previous version needs to validate a verb from the future.
        PAXOS_PREPARE,
        PAXOS_PROPOSE,
        PAXOS_COMMIT,
        PAGED_RANGE,
        // remember to add new verbs at the end, since we serialize by ordinal
        UNUSED_1,
        UNUSED_2,
        UNUSED_3,
        ;
    }

    public void log(String str) {
        logger.finest(str);
    }

    public MessagingService() {
        MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
        try {
            jmxObjectName = new ObjectName(MBEAN_NAME);
            mbs.registerMBean(this, jmxObjectName);
            dropped = new HashMap<String, DroppedMessageMetrics>();
            for (Verb v : Verb.values()) {
                dropped.put(v.name(), new DroppedMessageMetrics(v));
            }
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    static MessagingService instance;

    public static MessagingService getInstance() {
        if (instance == null) {
            instance = new MessagingService();
        }
        return instance;
    }

    /**
     * Pending tasks for Command(Mutations, Read etc) TCP Connections
     */
    @Override
    public Map<String, Integer> getCommandPendingTasks() {
        log(" getCommandPendingTasks()");
        return c.getMapStringIntegerValue("/messaging_service/messages/pending");
    }

    /**
     * Completed tasks for Command(Mutations, Read etc) TCP Connections
     */
    @Override
    public Map<String, Long> getCommandCompletedTasks() {
        log("getCommandCompletedTasks()");
        Map<String, Long> res = c
                .getListMapStringLongValue("/messaging_service/messages/sent");
        return res;
    }

    /**
     * Dropped tasks for Command(Mutations, Read etc) TCP Connections
     */
    @Override
    public Map<String, Long> getCommandDroppedTasks() {
        log(" getCommandDroppedTasks()");
        return c.getMapStringLongValue("/messaging_service/messages/dropped");
    }

    /**
     * Pending tasks for Response(GOSSIP & RESPONSE) TCP Connections
     */
    @Override
    public Map<String, Integer> getResponsePendingTasks() {
        log(" getResponsePendingTasks()");
        return c.getMapStringIntegerValue("/messaging_service/messages/respond_pending");
    }

    /**
     * Completed tasks for Response(GOSSIP & RESPONSE) TCP Connections
     */
    @Override
    public Map<String, Long> getResponseCompletedTasks() {
        log(" getResponseCompletedTasks()");
        return c.getMapStringLongValue("/messaging_service/messages/respond_completed");
    }

    /**
     * dropped message counts for server lifetime
     */
    @Override
    public Map<String, Integer> getDroppedMessages() {
        log(" getDroppedMessages()");
        Map<String, Integer> res = new HashMap<String, Integer>();
        JsonArray arr = c.getJsonArray("/messaging_service/messages/dropped_by_ver");
        for (int i = 0; i < arr.size(); i++) {
            JsonObject obj = arr.getJsonObject(i);
            res.put(obj.getString("verb"), obj.getInt("count"));
        }
        return res;
    }

    /**
     * dropped message counts since last called
     */
    @SuppressWarnings("deprecation")
    @Override
    public Map<String, Integer> getRecentlyDroppedMessages() {
        log(" getRecentlyDroppedMessages()");
        Map<String, Integer> map = new HashMap<String, Integer>();
        for (Map.Entry<String, DroppedMessageMetrics> entry : dropped.entrySet())
            map.put(entry.getKey(), entry.getValue().getRecentlyDropped());
        return map;
    }

    /**
     * Total number of timeouts happened on this node
     */
    @Override
    public long getTotalTimeouts() {
        log(" getTotalTimeouts()");
        Map<String, Long> timeouts = getTimeoutsPerHost();
        long res = 0;
        for (Entry<String, Long> t : timeouts.entrySet()) {
            res += t.getValue();
        }
        return res;
    }

    /**
     * Number of timeouts per host
     */
    @Override
    public Map<String, Long> getTimeoutsPerHost() {
        log(" getTimeoutsPerHost()");
        return c.getMapStringLongValue("/messaging_service/messages/timeout");
    }

    /**
     * Number of timeouts since last check.
     */
    @Override
    public long getRecentTotalTimouts() {
        log(" getRecentTotalTimouts()");
        long timeoutCount = getTotalTimeouts();
        long recent = timeoutCount - recentTimeoutCount;
        recentTimeoutCount = timeoutCount;
        return recent;
    }

    /**
     * Number of timeouts since last check per host.
     */
    @Override
    public Map<String, Long> getRecentTimeoutsPerHost() {
        log(" getRecentTimeoutsPerHost()");
        Map<String, Long> timeouts = getTimeoutsPerHost();
        Map<String, Long> result = new HashMap<String, Long>();
        for ( Entry<String, Long> e : timeouts.entrySet()) {
            long res = e.getValue().longValue() -
                    ((resent_timeout.containsKey(e.getKey()))? (resent_timeout.get(e.getKey())).longValue()
                            : 0);
            resent_timeout.put(e.getKey(), e.getValue());
            result.put(e.getKey(),res);
        }
        return result;
    }

    @Override
    public int getVersion(String address) throws UnknownHostException {
        log(" getVersion(String address) throws UnknownHostException");
        return c.getIntValue("");
    }

    @Override
    public Map<String, Integer> getLargeMessagePendingTasks() {
        // TODO: implement for realsies
        return getCommandPendingTasks();
    }

    @Override
    public Map<String, Long> getLargeMessageCompletedTasks() {
        // TODO: implement for realsies
        return getCommandCompletedTasks();
    }

    @Override
    public Map<String, Long> getLargeMessageDroppedTasks() {
        // TODO: implement for realsies
        return getCommandDroppedTasks();
    }

    @Override
    public Map<String, Integer> getSmallMessagePendingTasks() {
        // TODO: implement for realsies
        return getResponsePendingTasks();
    }

    @Override
    public Map<String, Long> getSmallMessageCompletedTasks() {
        // TODO: implement for realsies
        return getResponseCompletedTasks();
    }

    @Override
    public Map<String, Long> getSmallMessageDroppedTasks() {
        // TODO: implement for realsies
        return emptyMap();
    }

    @Override
    public Map<String, Integer> getGossipMessagePendingTasks() {
        // TODO: implement for realsies
        return emptyMap();
    }

    @Override
    public Map<String, Long> getGossipMessageCompletedTasks() {
        // TODO: implement for realsies
        return emptyMap();
    }

    @Override
    public Map<String, Long> getGossipMessageDroppedTasks() {
        // TODO: implement for realsies
        return emptyMap();
    }
}