/*
 * 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 cn.escheduler.server.worker.runner;

import cn.escheduler.common.Constants;
import cn.escheduler.common.queue.ITaskQueue;
import cn.escheduler.common.thread.Stopper;
import cn.escheduler.common.thread.ThreadUtils;
import cn.escheduler.common.utils.FileUtils;
import cn.escheduler.common.utils.OSUtils;
import cn.escheduler.dao.ProcessDao;
import cn.escheduler.dao.model.*;
import cn.escheduler.server.zk.ZKWorkerClient;
import org.apache.commons.configuration.Configuration;
import org.apache.commons.lang3.StringUtils;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.recipes.locks.InterProcessMutex;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Arrays;
import java.util.Date;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.ThreadPoolExecutor;

/**
 *  fetch task thread
 */
public class FetchTaskThread implements Runnable{

    private static final Logger logger = LoggerFactory.getLogger(FetchTaskThread.class);
    /**
     *  set worker concurrent tasks
     */
    private final int taskNum;

    /**
     *  zkWorkerClient
     */
    private final ZKWorkerClient zkWorkerClient;

    /**
     * task queue impl
     */
    protected ITaskQueue taskQueue;

    /**
     *  process database access
     */
    private final ProcessDao processDao;

    /**
     *  worker thread pool executor
     */
    private final ExecutorService workerExecService;

    /**
     *  worker exec nums
     */
    private int workerExecNums;

    private Configuration conf;


    public FetchTaskThread(int taskNum, ZKWorkerClient zkWorkerClient,
                           ProcessDao processDao, Configuration conf,
                           ITaskQueue taskQueue){
        this.taskNum = taskNum;
        this.zkWorkerClient = zkWorkerClient;
        this.processDao = processDao;
        this.workerExecNums = conf.getInt(Constants.WORKER_EXEC_THREADS,
                Constants.defaultWorkerExecThreadNum);
        // worker thread pool executor
        this.workerExecService = ThreadUtils.newDaemonFixedThreadExecutor("Worker-Fetch-Task-Thread",workerExecNums);
        this.conf = conf;
        this.taskQueue = taskQueue;
    }

    /**
     * Check if the task runs on this worker
     * @param taskInstance
     * @param host
     * @return
     */
    private boolean checkWorkerGroup(TaskInstance taskInstance, String host){

        int taskWorkerGroupId = processDao.getTaskWorkerGroupId(taskInstance);

        if(taskWorkerGroupId <= 0){
            return true;
        }
        WorkerGroup workerGroup = processDao.queryWorkerGroupById(taskWorkerGroupId);
        if(workerGroup == null ){
            logger.info("task {} cannot find the worker group, use all worker instead.", taskInstance.getId());
            return true;
        }
        String ips = workerGroup.getIpList();
        if(StringUtils.isBlank(ips)){
            logger.error("task:{} worker group:{} parameters(ip_list) is null, this task would be running on all workers",
                    taskInstance.getId(), workerGroup.getId());
        }
        String[] ipArray = ips.split(Constants.COMMA);
        List<String> ipList =  Arrays.asList(ipArray);
        return ipList.contains(host);
    }




    @Override
    public void run() {

        while (Stopper.isRunning()){
            InterProcessMutex mutex = null;
            try {

                ThreadPoolExecutor poolExecutor = (ThreadPoolExecutor) workerExecService;

                //check memory and cpu usage and threads
                if(OSUtils.checkResource(this.conf, false) && checkThreadCount(poolExecutor)) {

                    //whether have tasks, if no tasks , no need lock  //get all tasks
                    List<String> tasksQueueList = taskQueue.getAllTasks(Constants.SCHEDULER_TASKS_QUEUE);
                    if(tasksQueueList.size() > 0){
                        // creating distributed locks, lock path /escheduler/lock/worker
                        String zNodeLockPath = zkWorkerClient.getWorkerLockPath();
                        mutex = new InterProcessMutex(zkWorkerClient.getZkClient(), zNodeLockPath);
                        mutex.acquire();

                        // task instance id str
                        List<String> taskQueueStrArr = taskQueue.poll(Constants.SCHEDULER_TASKS_QUEUE, taskNum);

                        for(String taskQueueStr : taskQueueStrArr){
                            if (StringUtils.isNotBlank(taskQueueStr )) {

                                if (!checkThreadCount(poolExecutor)) {
                                    break;
                                }

                                String[] taskStringArray = taskQueueStr.split(Constants.UNDERLINE);
                                String taskInstIdStr = taskStringArray[3];
                                Date now = new Date();
                                Integer taskId = Integer.parseInt(taskInstIdStr);

                                // find task instance by task id
                                TaskInstance taskInstance = processDao.findTaskInstanceById(taskId);

                                logger.info("worker fetch taskId : {} from queue ", taskId);

                                int retryTimes = 30;
                                // mainly to wait for the master insert task to succeed
                                while (taskInstance == null && retryTimes > 0) {
                                    Thread.sleep(Constants.SLEEP_TIME_MILLIS);
                                    taskInstance = processDao.findTaskInstanceById(taskId);
                                    retryTimes--;
                                }

                                if (taskInstance == null ) {
                                    logger.error("task instance is null. task id : {} ", taskId);
                                    continue;
                                }

                                if(!checkWorkerGroup(taskInstance, OSUtils.getHost())){
                                    continue;
                                }
                                taskQueue.removeNode(Constants.SCHEDULER_TASKS_QUEUE, taskQueueStr);
                                logger.info("remove task:{} from queue", taskQueueStr);

                                // set execute task worker host
                                taskInstance.setHost(OSUtils.getHost());
                                taskInstance.setStartTime(now);


                                // get process instance
                                ProcessInstance processInstance = processDao.findProcessInstanceDetailById(taskInstance.getProcessInstanceId());

                                // get process define
                                ProcessDefinition processDefine = processDao.findProcessDefineById(taskInstance.getProcessDefinitionId());


                                taskInstance.setProcessInstance(processInstance);
                                taskInstance.setProcessDefine(processDefine);


                                // get local execute path
                                String execLocalPath = FileUtils.getProcessExecDir(processDefine.getProjectId(),
                                        processDefine.getId(),
                                        processInstance.getId(),
                                        taskInstance.getId());
                                logger.info("task instance  local execute path : {} ", execLocalPath);


                                // set task execute path
                                taskInstance.setExecutePath(execLocalPath);

                            Tenant tenant = processDao.getTenantForProcess(processInstance.getTenantId(),
                                    processDefine.getUserId());
                            if(tenant == null){
                                logger.error("cannot find suitable tenant for the task:{}, process instance tenant:{}, process definition tenant:{}",
                                        taskInstance.getName(),processInstance.getTenantId(), processDefine.getTenantId());
                                continue;
                            }

                            // check and create Linux users
                            FileUtils.createWorkDirAndUserIfAbsent(execLocalPath,
                                    tenant.getTenantCode(), logger);

                                logger.info("task : {} ready to submit to task scheduler thread",taskId);
                                // submit task
                                workerExecService.submit(new TaskScheduleThread(taskInstance, processDao));

                            }
                        }

                    }

                }

                Thread.sleep(Constants.SLEEP_TIME_MILLIS);

            }catch (Exception e){
                logger.error("fetch task thread exception : " + e.getMessage(),e);
            }finally {
                if (mutex != null){
                    try {
                        mutex.release();
                    } catch (Exception e) {
                        if(e.getMessage().equals("instance must be started before calling this method")){
                            logger.warn("fetch task lock release");
                        }else{
                            logger.error("fetch task lock release failed : " + e.getMessage(),e);
                        }
                    }
                }
            }
        }
    }

    /**
     *
     * @param poolExecutor
     * @return
     */
    private boolean checkThreadCount(ThreadPoolExecutor poolExecutor) {
        int activeCount = poolExecutor.getActiveCount();
        if (activeCount >= workerExecNums) {
            logger.info("thread insufficient , activeCount : {} , workerExecNums : {}, will sleep : {} millis for thread resource", activeCount, workerExecNums, Constants.SLEEP_TIME_MILLIS);
            return false;
        }
        return true;
    }
}