#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.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) {
	int sockfd = socket(AF_INET, SOCK_STREAM, 0);
	if (sockfd < 0) {
		fprintf(stderr, "socket: ");
		exit(EXIT_FAILURE);
	}

	struct sockaddr_in serv_addr, client_addr;
	socklen_t client_addr_len;
	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);

	int rv = bind(sockfd, (const struct sockaddr *)&serv_addr, sizeof(serv_addr));
	if (rv < 0) {
		fprintf(stderr, "bind: ");
		exit(EXIT_FAILURE);
	}

	rv = listen(sockfd, 5);
	if (rv < 0) {
		fprintf(stderr, "listen: ");
		exit(EXIT_FAILURE);
	}

	int accfd = accept(sockfd, (struct sockaddr *)&client_addr, &client_addr_len);
	if (accfd < 0) {
		fprintf(stderr, "accept: ");
		exit(EXIT_FAILURE);
	}


	size_t buffer_size = 100;
	char buffer[buffer_size];
	memset(&buffer, 0, buffer_size);

	while (1) {
		read(accfd, buffer, buffer_size);
		write(accfd, buffer, buffer_size);
		memset(&buffer, 0, buffer_size);
	}
}

int main(int argc, char *argv[]) {
	// Socket
	// setsockopt
	// Bind
	// listen()
	// accept
	// send/recv
	handle_arguments(argc, argv);
	run_server(strtol(argv[1], NULL, 10));

	return 0;
}