#  Copyright (c) 2017
#  by authors as mentioned on:
#  https://github.com/lkastner/polymake_toric/wiki/Authors
#  
#  Project home:
#  https://github.com/lkastner/polymake_toric
#
#  For licensing we cite the original Polymake code:
#
#  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, or (at your option) any
#  later version: http://www.gnu.org/licenses/gpl.txt.
#
#  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.

REQUIRE polytope::_4ti2.rules


declare object BinomialIdeal : Ideal {
   
   property BINOMIAL_GENERATORS : Matrix<Int>;

   rule N_VARIABLES : BINOMIAL_GENERATORS {
      $this->N_VARIABLES = $this->BINOMIAL_GENERATORS->cols;
   }

   rule GENERATORS : BINOMIAL_GENERATORS {
      my $binomials = $this->BINOMIAL_GENERATORS;
      my @gens;
      my $coef = new Vector<Rational>(1, -1);
      foreach my $binomial (@$binomials){
         my $positivePart = new Vector<Int>(map($_>0 ? $_ : 0, @$binomial));
         my $negativePart = new Vector<Int>(map($_<0 ? -$_ : 0, @$binomial));
         my $expmat = new Matrix<Int>([$positivePart, $negativePart]);
         push @gens, new Polynomial($coef, $expmat);
      }
      $this->GENERATORS = \@gens;
   }

}

object polytope::Cone<Rational> {

   # @category Algebraic Geometry
   # The matrix containing the exponent vectors of the binomials whose
   # vanishing set is the affine toric variety given by the cone.
   # In other words the rows of this matrix give the relations between the
   # Hilbert basis elements.
   # @depends 4ti2
   property TORIC_IDEAL : BinomialIdeal;

   rule _4ti2.toric_ideal : TORIC_IDEAL.BINOMIAL_GENERATORS : HILBERT_BASIS_GENERATORS {
      my $H = $this->HILBERT_BASIS_GENERATORS->[0];
      
      # Creating temporary file for input.
      my $temp = new Tempfile;
      open(my $input, ">$temp.mat")
         or die "Kill all humans.";

      # Printing Hilbert basis to file.
      print $input $H->cols, " ", $H->rows, "\n";
      print $input new Matrix<Integer>(transpose($H));
      close $input;

      # Running 4ti2.
      open(my $P, "$groebner $temp 2>&1 |")
         or die "couldn't run 4ti2's 'groebner': $!";
      local $_;
      while(<$P>) {
         # print $_;
      }
      close $P;

      # Parsing output.
      open(my $output, "<$temp.gro")
         or die "Humans not found.";
      local $_;
      my @ti = ();
      while(<$output>) {   
         if(/^$/) {
            next;
         }
         # print "line: ".$_;
         my @p = split;
         push @ti, \@p;
      }
      my $size = @ti;
      @ti = @ti[1..($size-1)];

      close $output;
      $this->TORIC_IDEAL->BINOMIAL_GENERATORS = scalar(@ti) ? new Matrix<Integer>(\@ti) : new Matrix<Integer>(0, $H->cols());
   }

}

