/**
 * TCP服务器通信基本流程
 * zhangyl 2018年12月13日
 */
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <iostream>
#include <string.h>
#include <vector>

int main(int argc, char* argv[])
{
 //1.创建一个侦听socket
 int listenfd = socket(AF_INET, SOCK_STREAM, 0);
 if (listenfd == -1)
 {
 std::cout << "create listen socket error." << std::endl;
 return -1;
 }

 //2.初始化服务器地址
 struct sockaddr_in bindaddr;
 bindaddr.sin_family = AF_INET;
 bindaddr.sin_addr.s_addr = htonl(INADDR_ANY);
 bindaddr.sin_port = htons(3000);
 if (bind(listenfd, (struct sockaddr *)&bindaddr, sizeof(bindaddr)) == -1)
 {
 std::cout << "bind listen socket error." << std::endl;
		close(listenfd);
 return -1;
 }

	//3.启动侦听
 if (listen(listenfd, SOMAXCONN) == -1)
 {
 std::cout << "listen error." << std::endl;
		close(listenfd);
 return -1;
 }
	
	//记录所有客户端连接的容器
	std::vector<int> clientfds;
 while (true)
 {
 struct sockaddr_in clientaddr;
 socklen_t clientaddrlen = sizeof(clientaddr);
		//4. 接受客户端连接
 int clientfd = accept(listenfd, (struct sockaddr *)&clientaddr, &clientaddrlen);
 if (clientfd != -1)
 { 	
			char recvBuf[32] = {0};
			//5. 从客户端接受数据
			int ret = recv(clientfd, recvBuf, 32, 0);
			if (ret > 0) 
			{
				std::cout << "recv data from client, data: " << recvBuf << std::endl;
				//6. 将收到的数据原封不动地发给客户端
				ret = send(clientfd, recvBuf, strlen(recvBuf), 0);
				if (ret != strlen(recvBuf))
					std::cout << "send data error." << std::endl;
				
				std::cout << "send data to client successfully, data: " << recvBuf << std::endl;
			} 
			else 
			{
				std::cout << "recv data error." << std::endl;
			}
			
			//close(clientfd);
			clientfds.push_back(clientfd);
 }
 }
	
	//7.关闭侦听socket
	close(listenfd);

 return 0;
}