/*** 
 * @Description: 
 * @Author: LeoTao
 * @Date: 2023-10-03 22:44:26
 * @LastEditTime: 2023-10-09 22:14:14
 */
#pragma once
#include "noncopyable.h"
#include "Timestamp.h"
#include "CurrentThread.h"
#include <functional>
#include <vector>
#include <memory>
#include <atomic>
#include <mutex>

class Channel;
class Poller;

/*事件循环类，主要包含两个模块 channel poller(epoll的抽象)*/

class EventLoop : noncopyable
{
public:
    using Functor = std::function<void()>;
    EventLoop();
    ~EventLoop();

    void loop();//开启事件循环
    void quit();//退出事件循环

    Timestamp pollReturnTime() const {return pollReturnTime_;}

    //在当前loop中执行cb
    void runInLoop(Functor cb);

    //把cb放入队列中，唤醒loop所在的线程，执行cb
    void queueInLoop(Functor cb);

    //唤醒loop所在的线程
    void wakeup();

    //eventLoop方法调用==》 poller的方法
    void updateChannel(Channel * channel);
    void removeChannel(Channel * channel);
    void hasChannel(Channel* channel);

    //判断evevntloop对象是否在自己的线程里面
    bool isInLoopThread() const {return threadId_ == CurrentThread::tid();}

    

private:

    void handleRead(); //wake up
    void dePendingFunctors();//执行回调
    using ChannelList = std::vector<Channel*>;

    std::atomic_bool looping_; //原子操作，通过CAS实现
    std::atomic_bool quit_;//标识退出loop循环
    
    const pid_t threadId_;//当前loop所在线程的id
    Timestamp pollReturnTime_;//poller返回发生事件的channels的时间点
    std::unique_ptr<Poller> poller_;

    int wakeupFd_;//主要作用：当mainLoop获取一个新用户的channel，通过轮询算法选择一个subloop，通过该成员来唤醒subloop来处理channel。
    std::unique_ptr<Channel> wakeupChannel_;

    ChannelList activeChannels_;
    Channel* currentActiveChannel_;

    std::atomic_bool callingPendingFunctors_; //标识当前loop是否有需要执行的回调操作
    std::mutex mutex_;//互斥锁，用来保护下面vector容器的线程安全操作
    std::vector<Functor> pendingFunctors_;//存储loop需要执行的所有回调操作
};