#include <errno.h>
#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include <pthread.h>
#include <unistd.h>
#include <poll.h>
#include <sys/epoll.h>
#include <errno.h>
#include <sys/time.h>
#include <sys/eventfd.h>

#include "server.h"


#define CONNECTION_SIZE			1024 // 1024 * 1024

#define MAX_PORTS			20

#define TIME_SUB_MS(tv1, tv2)  ((tv1.tv_sec - tv2.tv_sec) * 1000 + (tv1.tv_usec - tv2.tv_usec) / 1000)



#if ENABLE_KVSTORE

// typedef int (*msg_handler)(char *msg, int length, char *response);
// typedef int (*msg_handler)(char *request, int request_length, char *response, int *response_length);
typedef int (*msg_handler)(struct conn* conn);

extern int try_connect_master(char *ip, int port);

static msg_handler kvs_handler;

// 0 need more, -1 error, =1 suc
int kvs_request(struct conn *c) {
	// int consumed_out = kvs_handler(c->rbuffer, c->rlength, c->wbuffer, &c->wlength);
	int consumed_out = kvs_handler(c);
	return consumed_out; 
}

int kvs_response(struct conn *c) {

	

}


#endif



int accept_cb(int fd);
int recv_cb(int fd);
int send_cb(int fd);



int epfd = 0;
struct timeval begin;

int wakeup_fd = -1;


struct conn conn_list[CONNECTION_SIZE] = {0};
// fd


// 1 add, 0 mod
int set_event(int fd, int event, int flag) {

	if (flag) {  // non-zero add

		struct epoll_event ev;
		ev.events = event;
		ev.data.fd = fd;
		epoll_ctl(epfd, EPOLL_CTL_ADD, fd, &ev);

	} else {  // zero mod

		struct epoll_event ev;
		ev.events = event;
		ev.data.fd = fd;
		epoll_ctl(epfd, EPOLL_CTL_MOD, fd, &ev);
		
	}
	

}


int event_register(int fd, int event) {

	if (fd < 0) return -1;

	conn_list[fd].fd = fd;
	conn_list[fd].r_action.recv_callback = recv_cb;
	conn_list[fd].send_callback = send_cb;

	memset(conn_list[fd].rbuffer, 0, BUFFER_LENGTH);
	conn_list[fd].rlength = 0;

	memset(conn_list[fd].wbuffer, 0, BUFFER_LENGTH*2);
	conn_list[fd].wlength = 0;

	conn_list[fd].is_from_master = 0;
	
	set_event(fd, event, 1);
}


// listenfd(sockfd) --> EPOLLIN --> accept_cb
int accept_cb(int fd) {

	struct sockaddr_in  clientaddr;
	socklen_t len = sizeof(clientaddr);

	int clientfd = accept(fd, (struct sockaddr*)&clientaddr, &len);
	if (clientfd < 0) {
		printf("accept errno: %d --> %s\n", errno, strerror(errno));
		return -1;
	}
	
	event_register(clientfd, EPOLLIN);  // | EPOLLET

	if ((clientfd % 1000) == 0) {

		struct timeval current;
		gettimeofday(&current, NULL);

		int time_used = TIME_SUB_MS(current, begin);
		memcpy(&begin, &current, sizeof(struct timeval));
		

		//printf("accept finshed: %d, time_used: %d\n", clientfd, time_used);

	}

	return 0;
}


int recv_cb(int fd) {
	struct conn *c = &conn_list[fd];
	int avail = BUFFER_LENGTH - c->rlength;
	// printf("avail: %d\n", avail);
	if (avail <= 0) {
        // 缓冲满了还没解析出来：协议异常或包过大
        close(fd);
        epoll_ctl(epfd, EPOLL_CTL_DEL, fd, NULL);
        return 0;
    }

	int count = recv(fd, c->rbuffer + c->rlength, avail, 0);
	if (count == 0) { // disconnect
		//printf("client disconnect: %d\n", fd);
		close(fd);

		epoll_ctl(epfd, EPOLL_CTL_DEL, fd, NULL); // unfinished

		return 0;
	} else if (count < 0) { // 

		printf("count: %d, errno: %d, %s\n", count, errno, strerror(errno));
		close(fd);
		epoll_ctl(epfd, EPOLL_CTL_DEL, fd, NULL);

		return 0;
	}

	
	c->rlength += count;
	//printf("RECV: %s\n", conn_list[fd].rbuffer);

#if 0 // echo

	conn_list[fd].wlength = conn_list[fd].rlength;
	memcpy(conn_list[fd].wbuffer, conn_list[fd].rbuffer, conn_list[fd].wlength);

	printf("[%d]RECV: %s\n", conn_list[fd].rlength, conn_list[fd].rbuffer);

#elif ENABLE_HTTP

	http_request(&conn_list[fd]);

#elif ENABLE_WEBSOCKET

	ws_request(&conn_list[fd]);

#elif ENABLE_KVSTORE
	int consumed = kvs_request(c);
	if(consumed < 0){
		close(fd);
		epoll_ctl(epfd, EPOLL_CTL_DEL, fd, NULL);
		return 0;
	}

	// 清理 buffer 
	if (consumed > 0 && consumed < c->rlength) {
		// 有剩余未处理数据，搬移到 buffer 头部
		int left = c->rlength - consumed;
		if (left > 0) memmove(c->rbuffer, c->rbuffer + consumed, left);
		c->rlength = left;
		if (c->wlength > 0) set_event(fd, EPOLLOUT, 0);
		return count;

	}else{
		c->rlength = 0;
		if(c->wlength > 0) set_event(fd, EPOLLOUT, 0);
		return count;
	}

#endif


	set_event(fd, EPOLLOUT, 0);

	return count;
}


int send_cb(int fd) {

#if ENABLE_HTTP

	http_response(&conn_list[fd]);

#elif ENABLE_WEBSOCKET

	ws_response(&conn_list[fd]);

#elif ENABLE_KVSTORE

	kvs_response(&conn_list[fd]);

#endif

	struct conn *c = &conn_list[fd];
    int sent_total = 0;

	pthread_mutex_lock(&c->g_sync_lock);

	while (c->wlength > 0) {
		ssize_t n = send(fd, c->wbuffer, (size_t)c->wlength, MSG_NOSIGNAL);
		if (n > 0) {
            sent_total += (int)n;

			if (n == c->wlength) {
                /* 全部发完 */
                c->wlength = 0;
                break;
            }
			
			/* 只发了一部分：把剩余数据搬到 buffer 头部 */
            int left = c->wlength - (int)n;
            memmove(c->wbuffer, c->wbuffer + n, (size_t)left);
            c->wlength = left;

            /* 不要在这里死循环占用 CPU，交给下一次 EPOLLOUT */
            break;
        }

		if (n < 0) {
            if (errno == EAGAIN || errno == EWOULDBLOCK) {
                /* 暂时发不出去，等下一次可写事件 */
                pthread_mutex_unlock(&c->g_sync_lock);
                set_event(fd, EPOLLOUT, 0);
                return sent_total;
            }

            /* 对端断开 / 其他错误 */
            int e = errno;
            pthread_mutex_unlock(&c->g_sync_lock);

            printf("send fd=%d errno=%d %s\n", fd, e, strerror(e));
            close(fd);
            epoll_ctl(epfd, EPOLL_CTL_DEL, fd, NULL);
            return 0;
        }

        break;
	}
	pthread_mutex_unlock(&c->g_sync_lock);

    if (c->wlength > 0) {
        /* 还有没发完，继续监听可写 */
        set_event(fd, EPOLLOUT, 0);
    } else {
        /* 发完了，回到读 */
        set_event(fd, EPOLLIN, 0);
    }

    return sent_total;
}

// wakup fd

int handle_wakeup_fd_cb(int fd);

int init_wakeup_fd(void) {
    wakeup_fd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
    if (wakeup_fd < 0) {
        printf("eventfd failed: errno=%d %s\n", errno, strerror(errno));
        return -1;
    }

	conn_list[wakeup_fd].fd = wakeup_fd;
	conn_list[wakeup_fd].r_action.recv_callback = handle_wakeup_fd_cb;
	set_event(wakeup_fd, EPOLLIN, 1);

    return 0;
}

// EPOLLOUT 
void sync_wakeup(int fd) {
	if (wakeup_fd < 0) return;
	set_event(fd, EPOLLOUT, 0);

    uint64_t one = 1;
    ssize_t n = write(wakeup_fd, &one, sizeof(one));
}

int handle_wakeup_fd_cb(int fd) {
    uint64_t v;
    while (1) {
        ssize_t n = read(wakeup_fd, &v, sizeof(v));
        if (n == sizeof(v)) continue;
        if (n < 0 && errno == EAGAIN) break;   // 已经读空
        break;
    }
	return 0;
}

int r_init_server(unsigned short port) {

	int sockfd = socket(AF_INET, SOCK_STREAM, 0);

	struct sockaddr_in servaddr;
	servaddr.sin_family = AF_INET;
	servaddr.sin_addr.s_addr = htonl(INADDR_ANY); // 0.0.0.0
	servaddr.sin_port = htons(port); // 0-1023, 

	if (-1 == bind(sockfd, (struct sockaddr*)&servaddr, sizeof(struct sockaddr))) {
		printf("bind failed: %s\n", strerror(errno));
	}

	listen(sockfd, 10);
	//printf("listen finshed: %d\n", sockfd); // 3 

	return sockfd;

}

int reactor_start(unsigned short port, msg_handler handler, char *m_ip, int m_port) {

	//unsigned short port = 2000;
	kvs_handler = handler;

	epfd = epoll_create(1);

	if(init_wakeup_fd() < 0){
		close(epfd);
		return -1;
	}

	// slave
	if(m_ip != NULL){
		int masterfd = try_connect_master(m_ip, m_port);
		event_register(masterfd, EPOLLIN);
		conn_list[masterfd].is_from_master = 1;
	}

	int i = 0;

	for (i = 0;i < MAX_PORTS;i ++) {
		
		int sockfd = r_init_server(port + i);
		
		conn_list[sockfd].fd = sockfd;
		conn_list[sockfd].r_action.recv_callback = accept_cb;
		conn_list[sockfd].is_from_master = 0;

		set_event(sockfd, EPOLLIN, 1);
	}

	gettimeofday(&begin, NULL);

	while (1) { // mainloop

		struct epoll_event events[1024] = {0};
		int nready = epoll_wait(epfd, events, 1024, -1);

		int i = 0;
		for (i = 0;i < nready;i ++) {

			int connfd = events[i].data.fd;

#if 0
			if (events[i].events & EPOLLIN) {
				conn_list[connfd].r_action.recv_callback(connfd);
			} else if (events[i].events & EPOLLOUT) {
				conn_list[connfd].send_callback(connfd);
			}

#else 
			if (events[i].events & EPOLLIN) {
				// printf("connlist:%p, r_action:%p, recv_callaback:%p\n", &conn_list[connfd], &conn_list[connfd].r_action, conn_list[connfd].r_action.recv_callback);
				conn_list[connfd].r_action.recv_callback(connfd);
			} 

			if (events[i].events & EPOLLOUT) {
				conn_list[connfd].send_callback(connfd);
			}
#endif
		}

	}
	
	if (wakeup_fd >= 0) close(wakeup_fd);
	if (epfd >= 0) close(epfd);
	return 0;
}