#include <winsock2.h>
#include <windows.h>
#include <Stdio.h>
#include <stdlib.h>

int main(int argc, char * argv[]) {
	SOCKET sock;
	srand(GetTickCount());
	printf("UDP test program\nListens on port 8888, transmits data as a response to received data.\n");

	{
		WSADATA d;
		int i;
		i=WSAStartup(0x0002,&d);
		if(i==0) {
			printf("Winsock 2.0 initialized correctly...\n");
		} else {
			printf("Winsock failed to init.\n");
			return 0;
		}
	}

	sock=socket(AF_INET,SOCK_DGRAM,0);
	sockaddr_in sain;
	sain.sin_family=AF_INET;
	sain.sin_addr.S_un.S_addr=ADDR_ANY;
	sain.sin_port=htons(8888);
	if(bind(sock,(sockaddr *)&sain,sizeof(sain))) {
		printf("bind() error!\n");
		closesocket(sock);
		return 0;
	}

	char incomingbuf[1024];
	char outgoingbuf[1024];
	int datalen;
	int sain_len;
	sockaddr_in sender;
	DWORD err;
	while(1) {
		sain_len=sizeof(sender);
		datalen=recvfrom(sock,incomingbuf,1023,0,(sockaddr *)&sender,&sain_len);
		if(datalen>0) {
			incomingbuf[datalen]=0;
			printf("UDP Datagram from %i.%i.%i.%i:%i\n",sender.sin_addr.S_un.S_un_b.s_b1,sender.sin_addr.S_un.S_un_b.s_b2,sender.sin_addr.S_un.S_un_b.s_b3,sender.sin_addr.S_un.S_un_b.s_b4,ntohs(sender.sin_port));
			printf("Received '%s' [%i]\n",incomingbuf,datalen);
			wsprintf(outgoingbuf,"%s|rnd=%i",incomingbuf,rand()&0xFF);
			printf("Sent back: '%s' [%i]\n",outgoingbuf,strlen(outgoingbuf));
			sendto(sock,outgoingbuf,strlen(outgoingbuf)+1,0,(sockaddr *)&sender,sizeof(sender));
		} else {
			err=WSAGetLastError();
			Sleep(1);
		}
	}



	closesocket(sock);

	return 0;
}