//TCP服務端
#include"myhead.h"

struct client *head = NULL;
struct sockaddr_in saddr;
struct sockaddr_in caddr;

struct client
{
	int sock;
	struct client *next;
};

struct client *init_list()               //建立客戶端佇列頭，為了讓客戶端“群聊”
{
	struct client *head = malloc(sizeof(struct client));
	head->next = NULL;
	return head;
}

int add_node(struct client*head,int new_sockfd)
{
	struct client *new = malloc(sizeof(struct client));
	struct client *p = head;

	new->sock = new_sockfd;
	new->next = NULL;

	while(p->next!=NULL)
	{
		p = p->next;
	}
	p->next = new;
	new->next = NULL;
	return 0;
}

int del_node(struct client*head,int sockfd)
{
	struct client *q = head;
	struct client *p = q->next;

	while(p->sock !=sockfd)
	{
		if(p->next !=NULL)
		{
			p = p->next;
			q = q->next;
		}
		else if(p->next == NULL)    //cannot find the sockfd
		{
			printf("can not find sockfd to del\n");
			return -1;
		}
	}
	q->next = p->next;
	free(p);
	return 0;
}

int broadcast_client(struct client*head,int sockfd,char *buf)
{
	struct client *p = head->next;
	while(p!=NULL)
	{
		if(p->sock != sockfd)
		{
			write(p->sock,buf,50);
		}
		else if(p->sock == sockfd)
		{
			p = p->next;
			continue;
		}
		p = p->next;
	}
	return 0;
}

void* thread(void* arg)
{
	pthread_detach(pthread_self());              //設定該執行緒為分離狀態，不需要主執行緒回收其系統資源。
	char buf[50];
	char ipbuf[50];
	bzero(ipbuf,50);
	bzero(buf,50);
	int port;
	int sockfd = *((int*)arg);
	while(1)                                     //迴圈接收客戶端發來的資訊
	{
		read(sockfd,buf,50);
		if(strcmp(buf,"quit")==0)            //當客戶端發來的資訊為 quit，則退出執行緒，並刪除該結點
		{
			del_node(head,sockfd);
			pthread_exit(NULL);
		}	
		inet_ntop(AF_INET,(void*)&caddr.sin_addr.s_addr,ipbuf,50);	//把客戶端的ip資訊放到ipbuf中
		port = ntohs(caddr.sin_port);                                   //把客戶端的埠號放到變數port中
		printf("read from ip:%s,port:%hu\n",ipbuf,port);
		printf("message:%s\n",buf);
		broadcast_client(head,sockfd,buf);                              //把一個客戶端發來的資訊轉發給其他客戶端
		bzero(buf,50);
	}
}

int main()
{
	
	int sockfd,new_sockfd;
	int size,ret;
	

	pthread_t tid;

	size = sizeof(struct sockaddr_in);
	head = init_list();

	bzero(&saddr,size);
	saddr.sin_family = AF_INET;                 //繫結協議域為 IPv4
	saddr.sin_port = htons(7777);               //繫結埠號為7777
	saddr.sin_addr.s_addr = htonl(INADDR_ANY);  //繫結ip地址為本機的一個隨機IP

	sockfd = socket(AF_INET,SOCK_STREAM,0);     //建立socket套接字
	ret = bind(sockfd,(struct sockaddr*)&saddr,size);          //socket套接字和sockaddr_in結構體繫結在一起，賦予socket屬性
	listen(sockfd,5);                               //開始監聽有沒有客戶端連線

	while(1)                   //迴圈監聽有沒有客戶端連線進來，就像一個接待人員等待客人，有客人來了就服務他
	{
		new_sockfd = accept(sockfd,(struct sockaddr*)&caddr,&size);      //等待客戶端連線，並返回該客戶端的描述符
		add_node(head,new_sockfd);                                       //若有客戶端連線，則把該客戶端加入到客戶端佇列中

		pthread_create(&tid,NULL,thread,(void*)&new_sockfd);            //建立一個執行緒服務新連線進來的客戶端

	}
	pthread_exit(NULL);
	return 0;
}
 

//TCP客戶端
#include"myhead.h"

void* thread(void* arg)             //讀取從伺服器轉發過來的資訊，這些資訊是其他客戶端發到伺服器上，伺服器再轉發過來的
{
	char buf[50];
	int sockfd = *((int*)arg);
	while(1)                      //迴圈等待伺服器有沒有資訊發過來，有就打印出來，沒就阻塞等待
	{
		read(sockfd,buf,50);
		printf("%s\n",buf);
	}
}

int main()
{
	int sockfd;
	int size;
	char buf[50]={0};
	pthread_t tid;
	struct sockaddr_in saddr;
	size = sizeof(saddr);
	bzero(&saddr,size);

	saddr.sin_family = AF_INET;
	saddr.sin_port = htons(7777);
	saddr.sin_addr.s_addr = inet_addr("192.168.152.128");   //這裡的IP是服務端的IP

	sockfd = socket(AF_INET,SOCK_STREAM,0);
	connect(sockfd,(struct sockaddr*)&saddr,size);            //連線服務端

	pthread_create(&tid,NULL,thread,(void*)&sockfd);          //連線成功後，建立一條執行緒用於迴圈讀取服務端發來的資訊
	while(1)                                                  //主執行緒用於給服務端發信息。
	{
		scanf("%s",buf);
		write(sockfd,buf,50);
		bzero(buf,50);
	}
	return 0;
}