/*
 * Copyright 2002-2019 the original author or authors.
 *
 * Licensed 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
 *
 *      https://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.springframework.web.socket.config;

import java.util.concurrent.Executor;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.messaging.simp.stomp.StompBrokerRelayMessageHandler;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler;
import org.springframework.web.socket.messaging.StompSubProtocolHandler;
import org.springframework.web.socket.messaging.SubProtocolHandler;
import org.springframework.web.socket.messaging.SubProtocolWebSocketHandler;

/**
 * A central class for aggregating information about internal state and counters
 * from key infrastructure components of the setup that comes with
 * {@code @EnableWebSocketMessageBroker} for Java config and
 * {@code <websocket:message-broker>} for XML.
 *
 * <p>By default aggregated information is logged every 30 minutes at INFO level.
 * The frequency of logging can be changed via {@link #setLoggingPeriod(long)}.
 *
 * <p>This class is declared as a Spring bean by the above configuration with the
 * name "webSocketMessageBrokerStats" and can be easily exported to JMX, e.g. with
 * the {@link org.springframework.jmx.export.MBeanExporter MBeanExporter}.
 *
 * @author Rossen Stoyanchev
 * @since 4.1
 */
public class WebSocketMessageBrokerStats {

        private static final Log logger = LogFactory.getLog(WebSocketMessageBrokerStats.class);


        private SubProtocolWebSocketHandler webSocketHandler;

        private StompSubProtocolHandler stompSubProtocolHandler;

        private StompBrokerRelayMessageHandler stompBrokerRelay;

        private ThreadPoolExecutor inboundChannelExecutor;

        private ThreadPoolExecutor outboundChannelExecutor;

        private ScheduledThreadPoolExecutor sockJsTaskScheduler;

        private ScheduledFuture<?> loggingTask;

        private long loggingPeriod = 30 * 60 * 1000;


        public void setSubProtocolWebSocketHandler(SubProtocolWebSocketHandler webSocketHandler) {
                this.webSocketHandler = webSocketHandler;
                this.stompSubProtocolHandler = initStompSubProtocolHandler();
        }

        private StompSubProtocolHandler initStompSubProtocolHandler() {
                for (SubProtocolHandler handler : this.webSocketHandler.getProtocolHandlers()) {
                        if (handler instanceof StompSubProtocolHandler) {
                                return (StompSubProtocolHandler) handler;
                        }
                }
                SubProtocolHandler defaultHandler = this.webSocketHandler.getDefaultProtocolHandler();
                if (defaultHandler != null && defaultHandler instanceof StompSubProtocolHandler) {
                        return (StompSubProtocolHandler) defaultHandler;
                }
                return null;
        }

        public void setStompBrokerRelay(StompBrokerRelayMessageHandler stompBrokerRelay) {
                this.stompBrokerRelay = stompBrokerRelay;
        }

        public void setInboundChannelExecutor(ThreadPoolTaskExecutor inboundChannelExecutor) {
                this.inboundChannelExecutor = inboundChannelExecutor.getThreadPoolExecutor();
        }

        public void setOutboundChannelExecutor(ThreadPoolTaskExecutor outboundChannelExecutor) {
                this.outboundChannelExecutor = outboundChannelExecutor.getThreadPoolExecutor();
        }

        public void setSockJsTaskScheduler(ThreadPoolTaskScheduler sockJsTaskScheduler) {
                this.sockJsTaskScheduler = sockJsTaskScheduler.getScheduledThreadPoolExecutor();
                this.loggingTask = initLoggingTask(1 * 60 * 1000);
        }

        private ScheduledFuture<?> initLoggingTask(long initialDelay) {
                if (this.loggingPeriod > 0 && logger.isInfoEnabled()) {
                        return this.sockJsTaskScheduler.scheduleAtFixedRate(new Runnable() {
                                @Override
                                public void run() {
                                        logger.info(WebSocketMessageBrokerStats.this);
                                }
                        }, initialDelay, this.loggingPeriod, TimeUnit.MILLISECONDS);
                }
                return null;
        }

        /**
         * Set the frequency for logging information at INFO level in milliseconds.
         * If set 0 or less than 0, the logging task is cancelled.
         * <p>By default this property is set to 30 minutes (30 * 60 * 1000).
         */
        public void setLoggingPeriod(long period) {
                if (this.loggingTask != null) {
                        this.loggingTask.cancel(true);
                }
                this.loggingPeriod = period;
                this.loggingTask = initLoggingTask(0);
        }

        /**
         * Return the configured logging period frequency in milliseconds.
         */
        public long getLoggingPeriod() {
                return this.loggingPeriod;
        }

        /**
         * Get stats about WebSocket sessions.
         */
        public String getWebSocketSessionStatsInfo() {
                return (this.webSocketHandler != null ? this.webSocketHandler.getStatsInfo() : "null");
        }

        /**
         * Get stats about STOMP-related WebSocket message processing.
         */
        public String getStompSubProtocolStatsInfo() {
                return (this.stompSubProtocolHandler != null ? this.stompSubProtocolHandler.getStatsInfo() : "null");
        }

        /**
         * Get stats about STOMP broker relay (when using a full-featured STOMP broker).
         */
        public String getStompBrokerRelayStatsInfo() {
                return (this.stompBrokerRelay != null ? this.stompBrokerRelay.getStatsInfo() : "null");
        }

        /**
         * Get stats about the executor processing incoming messages from WebSocket clients.
         */
        public String getClientInboundExecutorStatsInfo() {
                return (this.inboundChannelExecutor != null ? getExecutorStatsInfo(this.inboundChannelExecutor) : "null");
        }

        /**
         * Get stats about the executor processing outgoing messages to WebSocket clients.
         */
        public String getClientOutboundExecutorStatsInfo() {
                return (this.outboundChannelExecutor != null ? getExecutorStatsInfo(this.outboundChannelExecutor) : "null");
        }

        /**
         * Get stats about the SockJS task scheduler.
         */
        public String getSockJsTaskSchedulerStatsInfo() {
                return (this.sockJsTaskScheduler != null ? getExecutorStatsInfo(this.sockJsTaskScheduler) : "null");
        }

        private String getExecutorStatsInfo(Executor executor) {
                String str = executor.toString();
                return str.substring(str.indexOf("pool"), str.length() - 1);
        }

        public String toString() {
                return "WebSocketSession[" + getWebSocketSessionStatsInfo() + "]" +
                                ", stompSubProtocol[" + getStompSubProtocolStatsInfo() + "]" +
                                ", stompBrokerRelay[" + getStompBrokerRelayStatsInfo() + "]" +
                                ", inboundChannel[" + getClientInboundExecutorStatsInfo() + "]" +
                                ", outboundChannel[" + getClientOutboundExecutorStatsInfo() + "]" +
                                ", sockJsScheduler[" + getSockJsTaskSchedulerStatsInfo() + "]";
        }

}