#include<stdio.h>
#include<arpa/inet.h>
#include<sys/socket.h>
#include<pthread.h>
#include<unistd.h>

int32_t sqw;
int32_t sqc;

void* client_interaction(int cfd){
		char type;
		for(;;){
			if(read(cfd, &type, 1) != 1)
				break;
			if(type == 'N'){
				int32_t weight;
				read(cfd, &weight, 4);
				sqc++;
				sqw += weight;
				type = 'A';
				write(cfd, &type, 1);
				// This is tempting, but doesn't work:
				// write(cfd, 65, 1);
				// This does:
				// write(cfd, "A", 1);
			} else if(type == 'Q') {
				type = 83;
				write(cfd, &type, 1);
				write(cfd, &sqc, 4);
				int32_t average = sqw / sqc;
				write(cfd, &average, 4);
			} else 
				break;
		}
		close(cfd);

}

int main(){
	int skt = socket(AF_INET, SOCK_STREAM, 0);
	struct sockaddr_in sad;
	sad.sin_port = htons(5100);
	sad.sin_family = AF_INET;
	sad.sin_addr.s_addr = 0;
	bind(skt, (struct sockaddr*)&sad, sizeof(sad));
	listen(skt, 5);
	for(;;){
		int cfd = accept(skt, 0, 0);
		// start the client's thread
		pthread_t t;
		pthread_create(&t, 0, (void*(*)(void*)) client_interaction, (void*)(long int)cfd);
	}
	close(skt);
	return 0;
}