#include<sys/socket.h>
#include<sys/types.h>
#include<netinet/ip.h>
#include<arpa/inet.h>
#include<stdio.h>
#include<unistd.h>
#include<signal.h>
#include<stdlib.h>

int main(int argc, char ** argv){
	struct sockaddr_in sad;
	if(argc > 1)
		sad.sin_port = htons(atoi(argv[1]));
	else
		sad.sin_port = htons(5143);
	sad.sin_addr.s_addr = INADDR_ANY;
	sad.sin_family = AF_INET;

	int skt = socket(AF_INET, SOCK_STREAM, 0); // Step 1
	if(skt == -1){
		perror("socket");
		return 1;
	}
	if( bind(skt, (struct sockaddr*)(&sad), sizeof(struct sockaddr_in)) ){ // step 2
		perror("bind");
		return 1;
	}
	if( listen(skt, 5) ){ // step 3
		perror("listen");
		return 1;
	}	
	while(1){
		int client_fd;
		struct sockaddr_in client_address;
		socklen_t address_size = sizeof(struct sockaddr_in);
		client_fd = accept(skt, (struct sockaddr *)(&client_address), &address_size); // step 4
		printf("Connection made from address %s\n", inet_ntoa(client_address.sin_addr));

		int32_t from_client[2];
		from_client[0] = -999;
		from_client[1] = -999;
		ssize_t readlen = recv(client_fd, &from_client, 8, MSG_WAITALL);
		if(readlen == 8) {
			printf("Client sent:  %d and %d\n", from_client[0], from_client[1]);
			printf("As text, client sent %s\n", &from_client);
			int32_t result = from_client[0] + from_client[1];
			printf("The sum is %d\n", result);
			write(client_fd, &result, 4);
		}
		else 
			puts("Not enough data!  Giving up!");
		
		close(client_fd);
	}
	
	return 0;
}