#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>

void handle_arguments(int argc, char *argv[]) {
    if (argc != 2) {
        fprintf(stderr, "Usage: %s PORT\n", argv[0]);
        exit(EXIT_FAILURE);
    }
}

void run_server(int port) {
	// create a socket using Internet protocol
	int sockfd = socket(AF_INET, SOCK_STREAM, 0);
	if (sockfd == -1) {
		perror("socket");
		exit(EXIT_FAILURE);
	}


	struct sockaddr_in serv_addr, client_addr;
	socklen_t client_addr_len = sizeof(client_addr);
	memset(&serv_addr, 0, sizeof(serv_addr));
	memset(&client_addr, 0, sizeof(client_addr));
	serv_addr.sin_family = AF_INET;
	serv_addr.sin_port = htons(port);
	serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);

	// bind sockfd to serv_addr
	int rv = bind(sockfd, (const struct sockaddr *)&serv_addr, sizeof(serv_addr));
	if (rv == -1) {
		perror("bind");
		exit(EXIT_FAILURE);
	}

	rv = listen(sockfd, 5);
	if (rv == -1) {
		perror("listen");
		exit(EXIT_FAILURE);
	}

	int accfd = accept(sockfd, (struct sockaddr *)&client_addr, &client_addr_len);
	if (accfd == -1) {
		perror("accept");
		exit(EXIT_FAILURE);
	}

	size_t buffer_size = sizeof(uint32_t);
	union {
        uint32_t number;
        char array[buffer_size];
    } buffer;
	memset(&buffer, 0, buffer_size);

	while (1) {
		read(accfd, buffer.array, buffer_size);
		printf("%d\n", ntohl(buffer.number));
		write(accfd, buffer.array, buffer_size);
		memset(&buffer, 0, buffer_size);
	}
}

int main(int argc, char *argv[]) {
	handle_arguments(argc, argv);
	run_server(strtol(argv[1], NULL, 10));

	return 0;
}