#include <stdio.h>
#include <string.h>

#include <winsock2.h> 

#define PORT 8888
#define  BUFFER_SIZE 4196

const char* kExitFlag = "exit";

int main() {
	WORD winsock_version = MAKEWORD(2,2);
	WSADATA wsa_data;
	if (WSAStartup(winsock_version, &wsa_data) != 0) {
		printf("Failed to init socket dll!\n");
		return 1;
	}
	
	SOCKET server_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	if (server_socket == INVALID_SOCKET) {
		printf("Failed to create server socket!\n");
		return 2;
	}
	
	sockaddr_in server_addr;
	server_addr.sin_family = AF_INET;
	server_addr.sin_port = htons(PORT);
	server_addr.sin_addr.S_un.S_addr = INADDR_ANY;
	
	if (bind(server_socket, (LPSOCKADDR)&server_addr, sizeof(server_addr)) == SOCKET_ERROR) {
		printf("Failed to bind port!\n");
		return 3;
	}
	
	if (listen(server_socket, 10)) {
		printf("Failed to listen!\n");
		return 4;
	}
	
	sockaddr_in client_addr;
	int client_addr_len = sizeof(client_addr);
	printf("Wait for connecting...\n");
	
	SOCKET client_socket = accept(server_socket, (SOCKADDR*)&client_addr, &client_addr_len);
	if (client_socket == INVALID_SOCKET) {
		printf("Failed to accept!\n");
		return 5;
	}
	
	printf("Succeed to receive a connection: %s\n" , inet_ntoa(client_addr.sin_addr));
	
	char recv_buf[BUFFER_SIZE+1];
	while (true) {
		int ret = recv(client_socket, recv_buf, BUFFER_SIZE, 0);
		if (ret < 0) {
			printf("Failed to receive data!\n");
			break;
		}
		recv_buf[ret]=0; // correctly ends received string
		
		printf("Receive from Client: \"%s\" \n", recv_buf);
		if (strcmp(kExitFlag,recv_buf)==0) {
			send(client_socket, kExitFlag, sizeof(kExitFlag), 0);			
			printf("Exit!\n");
			break;
		}
		
		const char* send_data = "Hello, Tcp Client!\n";
		send(client_socket, send_data, strlen(send_data), 0);
	}
	
	closesocket(client_socket);
	closesocket(server_socket);
	
	WSACleanup();
	
	return 0;
}