#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <netdb.h>
#include <unistd.h>
#include <netinet/in.h>
#include "server.h"

//
// parseArguments
//
// Returns the first command-line argument of the program, converted
// to an integer. If there is not exactly one command-line argument,
// or if the argument does not represent an integer, then it prints
// an error message and exits the program.
//
int parseArguments(int argc, char **argv) {
	if(argc != 2 || strcmp(argv[1], "") == 0) {
		fprintf(stderr, "usage: %s #\n", argv[0]);
		exit(-1);
	}
	int ret = atoi(argv[1]);
	if(ret <= 0) {
		fprintf(stderr, "usage: %s #\n", argv[0]);
		exit(-1);
	}
	return ret;
}

//
// getServerSocket
//
// Opens a server socket bound to port !portnum!, returning the
// file descriptor of the socket. If any errors are encountered,
// the function prints a function and exits the program.
//
int getServerSocket(int portnum) {
	struct hostent *hp;
	int sock;
	int err;
	struct sockaddr_in sa;

	// see who I am
	/*
	gethostname(myname, MAXHOSTNAMELEN);
	hp = gethostbyname(myname);
	if(hp == NULL) {
		perror("gethostname");
		exit(-1);
	}
	*/

	// create a Internet socket with which to work
	sock = socket(PF_INET, SOCK_STREAM, 0);
	if(sock == -1) {
		perror("socket");
		exit(-1);
	}

	// initialize the socket's port number
	memset(&sa, 0, sizeof(struct sockaddr_in));
	sa.sin_family = AF_INET;
	sa.sin_addr.s_addr = htonl(INADDR_ANY);
	sa.sin_port = htons((unsigned short) portnum);
	err = bind(sock, (struct sockaddr*) &sa, sizeof(struct sockaddr_in));
	if(err < 0) {
		perror("bind");
		exit(-1);
	}

	// set up socket as a listener (willing to queue up to five
	// connection requests)
	err = listen(sock, 5);
	if(err < 0) {
		perror("listen");
		exit(-1);
	}

	return sock;
}

//
// splitLine
//
// Breaks the string to which !buf! points into a sequence of
// words. The pointer to each successive word is placed into
// the !argv! array, stopping at !max_args! words. The function
// returns the number of words found in !buf! (up to !max_args!).
//
int splitLine(char *buf, char **argv, int max_args) {
	int arg;
	while(isspace(*buf)) ++buf;              // skip over initial spaces
	for(arg = 0; arg < max_args && *buf != '\0'; arg++) {
		argv[arg] = buf;                     // save word in array
		while(*buf != '\0' && !isspace(*buf)) ++buf; // skip past word
		if(*buf != '\0') {                 // if spaces follow word:
			*buf = '\0';                     // replace space with NUL
			do ++buf; while(isspace(*buf));  // skip following spaces
		}
	}
	return arg; // the array has been filled with words
}