package com.test.distributed;


import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import org.apache.curator.framework.CuratorFramework;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

import com.alibaba.fastjson.JSONObject;
import com.alibaba.fastjson.parser.Feature;

/**
 * 负载均衡节点获取
 * @author 程就人生
 * @date 2020年1月13日
 */
@Component
public class ImLoadBalance {
	
	private static Logger log = LoggerFactory.getLogger(ImLoadBalance.class);

	@Value("${zookeeper.register.node}")
    private String managerPath;
    
    @Autowired
    private CuratorFramework zkClient;

    /**
     * 获取负载最小的IM节点
     *
     * @return
     */
    public ImNode getBestWorker() {
        List<ImNode> workers = getWorkers();
        log.info("全部节点如下：");
        workers.stream().forEach(node -> {
            log.info("节点信息：{}",JSONObject.toJSONString(node));
        });
        ImNode best = balance(workers);
        return best;
    }

    /**
     * 按照负载排序
     *
     * @param items 所有的节点
     * @return 负载最小的IM节点
     */
    protected ImNode balance(List<ImNode> items) {
        if (items.size() > 0) {
            // 根据balance值由小到大排序
            Collections.sort(items);

            // 返回balance值最小的那个
            ImNode node = items.get(0);

            log.info("最佳的节点为：{}",JSONObject.toJSONString(node));
            return node;
        } else {
            return null;
        }
    }


    /**
     * 从zookeeper中拿到所有IM节点
     */
    protected List<ImNode> getWorkers() {

        List<ImNode> workers = new ArrayList<ImNode>();

        List<String> children = null;
        try {
            children = zkClient.getChildren().forPath(managerPath);
        } catch (Exception e) {
            e.printStackTrace();
            return workers;
        }

        for (String child : children) {
            log.info("child:"+child);
            byte[] payload = null;
            try {
                payload = zkClient.getData().forPath(managerPath+"/"+child);

            } catch (Exception e) {
                e.printStackTrace();
            }
            if (null == payload) {
                continue;
            }
            ImNode worker = JSONObject.parseObject(payload, ImNode.class, Feature.AllowArbitraryCommas);
            workers.add(worker);
        }
        return workers;

    }
}