/* -*- mode: C -*-  */
/* 
   IGraph library.
   Copyright (C) 2006  Gabor Csardi <csardi@rmki.kfki.hu>
   MTA RMKI, Konkoly-Thege Miklos st. 29-33, Budapest 1121, Hungary
   
   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.,  51 Franklin Street, Fifth Floor, Boston, MA 
   02110-1301 USA

*/

#include <igraph.h>

void print_vector(igraph_vector_t *v, FILE *f) {
  long int i;
  for (i=0; i<igraph_vector_size(v); i++) {
    fprintf(f, " %d", (int)VECTOR(*v)[i]);
  }
  fprintf(f, "\n");
}

void igraph_warning_handler_print_stdout(const char *reason, const char *file,
					 int line, int igraph_errno) {
  fprintf(stdout, "Warning: %s\n", reason);
}


int main() {

  igraph_t g;
  igraph_vector_t v, res;
  int ret;

  igraph_set_warning_handler(igraph_warning_handler_print_stdout);

  /* Test graph taken from http://en.wikipedia.org/wiki/Topological_sorting
   * @ 05.03.2006 */
  igraph_small(&g, 8, 1, 0, 3, 0, 4, 1, 3, 2, 4, 2, 7, \
	       3, 5, 3, 6, 3, 7, 4, 6, -1);

  igraph_vector_init(&res, 0);

  igraph_topological_sorting(&g, &res, IGRAPH_OUT);
  print_vector(&res, stdout);
  igraph_topological_sorting(&g, &res, IGRAPH_IN);
  print_vector(&res, stdout);

  /* Add a circle: 5 -> 0 */
  igraph_vector_init_int(&v, 2, 5, 0);
  igraph_add_edges(&g, &v, 0);
  igraph_topological_sorting(&g, &res, IGRAPH_OUT);
  print_vector(&res, stdout);
  igraph_vector_destroy(&v);
  igraph_destroy(&g);

  /* Error handling */
  igraph_set_error_handler(igraph_error_handler_ignore);

  /* This graph is the same but undirected */
  igraph_small(&g, 8, 0, 0, 3, 0, 4, 1, 3, 2, 4, 2, 7, \
	       3, 5, 3, 6, 3, 7, 4, 6, -1);
  ret=igraph_topological_sorting(&g, &res, IGRAPH_ALL);
  if (ret != IGRAPH_EINVAL) {
    return 1;
  }
  ret=igraph_topological_sorting(&g, &res, IGRAPH_OUT);
  if (ret != IGRAPH_EINVAL) {
    return 1;
  }  
  igraph_destroy(&g);

  igraph_vector_destroy(&res);  
  return 0;
}