/**

 * clplaner.c

 * Copyright (C) 2008 Markus Broeker

 */

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <time.h>

#include <limits.h>

#define MAXLOOP 25

#define MAXLINE 80

#ifndef MAXTEAM

#define MAXTEAM 32

#endif

#define getrandom(max) (1+(int)((float)(max)*rand()/RAND_MAX))

void swap (int *v, int i, int j)

{

    int temp;

    if (i == j)

        return;

    temp = v[i];

    v[i] = v[j];

    v[j] = temp;

}

void cleanup (char **first, char **second)

{

    int i;

    i = 0;

    while (first[i] != NULL)

        free (first[i++]);

    i = 0;

    while (second[i] != NULL)

        free (second[i++]);

}

unsigned int time_seed ()

{

    time_t now = time (NULL);

    unsigned char *p = (unsigned char *)&now;

    unsigned int seed = 0;

    size_t i;

    for (i = 0; i < sizeof (now); i++)

        seed = seed * (UCHAR_MAX + 2U) + p[i];

    return seed;

}

int getTeams (FILE * f, char **first, int *first_idx, char **second, int *second_idx)

{

    int i;

    char buffer[MAXLINE + 1];

    char *ptr;

    i = 0;

    while ((i < MAXTEAM) && fgets (buffer, MAXLINE, f) != NULL) {

        if ((first[i] = malloc (MAXLINE + 1)) == NULL) {

            perror ("malloc");

            break;

        }

        if ((ptr = strchr (buffer, '\n')))

            *ptr = '\0';

        strncpy (first[i], buffer, MAXLINE);

        first_idx[i] = i;

        if (fgets (buffer, MAXLINE, f) == NULL) {

            printf ("You need 2, 4, 6, ..., or %d teams in your file\n", 2 * MAXTEAM);

            second[i] = first[i + 1] = NULL;

            cleanup (first, second);

            fclose (f);

            exit (EXIT_FAILURE);

        }

        if ((second[i] = malloc (MAXLINE + 1)) == NULL) {

            perror ("malloc");

            break;

        }

        if ((ptr = strchr (buffer, '\n')))

            *ptr = '\0';

        strncpy (second[i], buffer, MAXLINE);

        second_idx[i] = i;

        i++;

    }

    first[i] = second[i] = NULL;

    return i;

}

void shakeTeamIdx (int *first_idx, int *second_idx, int teams)

{

    int i, j, k;

    /*

     * Who wins the Title?

     */

    if (teams == 1)

        return;

    /*

     * swap the index MAXLOOP times...

     */

    for (i = 0; i < MAXLOOP; i++) {

        for (j = 0; j < teams; j++) {

            k = getrandom (teams - 1);

            swap (second_idx, j, k);

            k = getrandom (teams - 1);

            swap (first_idx, j, k);

        }

    }

    /*

     * avoid group clashes

     */

    for (i = 0; i < teams - 1; i++) {

        if (first_idx[i] == second_idx[i])

            swap (first_idx, i, i + 1);

    }

    if (first_idx[i] == second_idx[i])

        swap (first_idx, i, i - 1);

}

int main (int argc, char **argv)

{

    FILE *f;

    char *first[MAXTEAM + 1];

    char *second[MAXTEAM + 1];

    int first_idx[MAXTEAM];

    int second_idx[MAXTEAM];

    int i, teams;

    if (argc != 2) {

        printf ("Usage: %s FILE\n\n", argv[0]);

        printf ("One Team per line, seperated by newline, n=2, 4, ..., or %d\n", 2 * MAXTEAM);

        printf ("Team n is the Groupwinner, n+1 is the Runners Up\n");

        printf ("Report bugs to mbroeker@largo.homelinux.org\n");

        return EXIT_FAILURE;

    }

    if ((f = fopen (argv[1], "r")) == NULL) {

        perror ("fopen");

        return EXIT_FAILURE;

    }

    srand (time_seed ());

    teams = getTeams (f, first, first_idx, second, second_idx);

    shakeTeamIdx (first_idx, second_idx, teams);

    for (i = 0; i < teams; i++)

        printf ("%30s vs %s\n", second[second_idx[i]], first[first_idx[i]]);

    cleanup (first, second);

    if (f != NULL)

        fclose (f);

    return EXIT_SUCCESS;

}