#include<sys/socket.h>
#include<sys/types.h>
#include<netinet/ip.h>
#include<arpa/inet.h>
#include<stdio.h>
#include<unistd.h>
#include<fcntl.h>
#include<signal.h>
#include<stdlib.h>
#include<string.h>
#include "getoutput_demo/getoutput.h"

char debug_mode = 0;
int child(){
	int logfile_fd;
	if(!debug_mode){
		close(0);
		close(1);
		close(2);
		logfile_fd = open("daemon_log", O_WRONLY | O_CREAT | O_TRUNC, 0644);
		dup2(logfile_fd, 1);
		dup2(logfile_fd, 2);
	}
	chdir("/"); // Wikipedia points out a lot of daemons do this

	struct sockaddr_in sad;
	sad.sin_port = htons(5130);
	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
		char *usernames = getoutput("who | cut -d ' ' -f 1 | sort -u");	
		dprintf(1, "Client connected from IP %s\n", inet_ntoa(client_address.sin_addr)); 
		write(client_fd, usernames, strlen(usernames));
		free(usernames);
		close(client_fd);
	}
	// Won't run anyway
	close(logfile_fd);
	return 0;
}

int main(int argc, char ** argv){
	if(argc > 1 && !strcmp(argv[1], "--debug"))
		debug_mode = 1;

	if(debug_mode)
		child();
	else {
		pid_t pid = fork();
		if(pid) { // parent process
			return 0;
		} else { // child process
			child();
		}
	}
}