/*
   Copyright 2003, 2002, 2001 Mike Burns, Sean Proctor

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

   The license is at <http://www.gnu.org/licenses/gpl.txt>.
   */

/* original version copyright Mike Burns, 2001.
 * updated version copyright Sean Proctor, 2002, 2003
 * original: 9/15/01
 * modified: 10/7/02 and again on 1/30/03 by Sean Proctor
 * Mike Burns <mike@mike-burns.com>
 * Sean Proctor <sproctor@ccs.neu.edu>
 */

#include <stdlib.h>
#include <stdio.h>
#include <time.h>

static const char *sneaker_colors[] = {"red", "orange", "yellow", "green",
	"blue", "khaki", "black"};
#define NUM_SNEAKERS (sizeof(sneaker_colors) / sizeof(const char *))

struct sneakers_t {
	int left;
	int right;
};

static int random_shoe(void)
{
	/* return a number from 0 to NUM_SNEAKERS - 1 */
	return (int)((double)NUM_SNEAKERS * rand() / (RAND_MAX + 1.0));
}

static struct sneakers_t make_sneakers(int date)
{
	struct sneakers_t sneakers;
	srand(date);

	sneakers.left = random_shoe();
	sneakers.right = random_shoe();

	if(sneakers.left == sneakers.right) {
		sneakers.left = random_shoe();
		sneakers.right = random_shoe();
	}

	return sneakers;
}

int current_date(void)
{
	time_t t;
	struct tm *time_tm;
	char date[9];

	if((t = time(NULL)) == -1 || !(time_tm = localtime(&t))) {
		printf("Really weird error.\n");
		exit(1);
	}

	sprintf(date, "%4d%02d%02d", time_tm->tm_year + 1900,
			time_tm->tm_mon + 1, time_tm->tm_mday);

	return atoi(date);
}

int make_date(int argc, char *argv[])
{
	// If we don't have a given date, use the current one
	if(argc == 1) return current_date();

	// If we don't have exactly one argument, or if our argument is longer
	// than 8 characters, we have an error
	if(argc != 2 || strlen(argv[1]) != 8) return 0;

	// return the value of the argument, 0 on error.
	return atoi(argv[1]);
}

int main (int argc, char *argv[])
{
	struct sneakers_t sneakers;
	int date;

	// make_date checks to make sure the input is valid and returns a
	// proper date depending on what the input was
	if(!(date = make_date(argc, argv))) {
		printf("usage: %s [YYYYMMDD]\n", argv[0]);
		exit(1);
	}

	sneakers = make_sneakers(date);

	printf("Sneakers for %08d:\nleft: %s\nright: %s\n",
			date,
			sneaker_colors[sneakers.left],
			sneaker_colors[sneakers.right]);

	return 0;
}