/*** 
 * @Description:
 * @Author: LeoTao
 * @Date: 2023-10-03 22:52:32
 * @LastEditTime: 2023-10-04 10:54:13
 */
#pragma once
#include "noncopyable.h"
#include "Timestamp.h"
#include <functional>
#include <memory>
/**
 * 类型的前置声明，
*/
class EventLoop;


/**
 * eventloop、channel、poller在reactor模型上对应Demultiplex多路事件分发器
 * Channel 理解为通道，封装了sockfd和其感兴趣的event，如EPOLLIN，EPOLLOUT事件
 * 还绑定了poller监听返回的具体事件
*/
class Channel : noncopyable
{
public:
    //回调函数命名
    using EventCallback = std::function<void()>;
    using ReadEventCallback = std::function<void(Timestamp)>;

    Channel(EventLoop * loop, int fd);
    ~Channel();

    //fd得到poller通知以后，处理相应的事件
    void handlerEvent(Timestamp receiveTime);

    //设置回调对象
    void setReadCallback(ReadEventCallback cb){ readCallback_ = std::move(cb);}
    void setWriteCallback(EventCallback cb){ writeCallback_ = std::move(cb);}
    void setCloseCallback(EventCallback cb){closeCallback_ = std::move(cb);}
    void setErrorCallback(EventCallback cb){errorCallback_ = std::move(cb);}

    //防止当channel被手动remove掉，channel还在执行回调操作
    void tie(const std::shared_ptr<void> &obj);

    int fd() const {return fd_;}
    int events() const {return events_;}
    void set_revents(int revt){revents_ = revt;}
    bool isNoneEvent() const {return events_ == kNoneEvent;}

    //设置fd相应的事件状态
    void enableReading(){events_ |= kReadEvent; update();}
    void disableReading(){events_ &= ~kReadEvent; update();}
    void enableWriteing(){events_ |= kWriteEvent; update();}
    void disableWriteing(){events_ &= ~kWriteEvent; update();}
    void disableAll(){events_ = kNoneEvent; update();}

    //返回fd当前的事件状态
    bool isNonEvent() const {return events_ == kNoneEvent;}
    bool isWrite() const {return events_ & kWriteEvent;}
    bool isReading() const {return events_ & kReadEvent;}

    //for poller
    int index() const {return index_;}
    void set_index(int idx) { index_ = idx;}

    EventLoop * ownerLoop(){return loop_;}
    void remove();


private:
    // 状态定义
    static const int kNoneEvent;
    static const int kReadEvent;
    static const int kWriteEvent;

    EventLoop *loop_;//事件循环
    const int fd_; //fd,poller监听的对象
    int events_; //注册fd感兴趣的事件
    int revents_; //poller返回的具体发生的事件
    int index_;

    //监听channel是否被释放
    std::weak_ptr<void> tie_;
    bool tied_;

    //回调函数
    /**
     * 因为channel通道里面能够获知fd最终发生的具体的事件revents，所以他负责调用具体事件的回调操作
    */
    ReadEventCallback readCallback_;
    EventCallback writeCallback_;
    EventCallback closeCallback_;
    EventCallback errorCallback_;

    void update();
    void handleEventWithGuard(Timestamp receiveTime);
};