// -*- coding: utf-8 -*-
// Copyright (C) 2014, 2015 Laboratoire de Recherche et Développement
// de l'Epita (LRDE).
//
// This file is part of Spot, a model checking library.
//
// Spot 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 3 of the License, or
// (at your option) any later version.
//
// Spot 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, see <http://www.gnu.org/licenses/>.

#include <algorithm>
#include <numeric>
#include <random>
#include "randomize.hh"
#include "misc/random.hh"

namespace spot
{
  void
  randomize(tgba_digraph_ptr& aut, bool randomize_states,
	    bool randomize_transitions)
  {
    if (!randomize_states && !randomize_transitions)
      return;
    auto& g = aut->get_graph();
    if (randomize_states)
      {
	unsigned n = g.num_states();
	std::vector<unsigned> nums(n);
	std::iota(nums.begin(), nums.end(), 0);
	mrandom_shuffle(nums.begin(), nums.end());
	g.rename_states_(nums);
	aut->set_init_state(nums[aut->get_init_state_number()]);

	if (auto sn =
	    aut->get_named_prop<std::vector<std::string>>("state-names"))
	  {
	    unsigned sns = sn->size(); // Might be != n.
	    auto nn = new std::vector<std::string>(n);
	    for (unsigned i = 0; i < sns && i < n; ++i)
	      (*nn)[nums[i]] = (*sn)[i];
	    aut->set_named_prop("state-names", nn);
	  }
      }
    if (randomize_transitions)
      {
	g.remove_dead_transitions_();
	auto& v = g.transition_vector();
	mrandom_shuffle(v.begin() + 1, v.end());
      }

    typedef tgba_digraph::graph_t::trans_storage_t tr_t;
    g.sort_transitions_([](const tr_t& lhs, const tr_t& rhs)
			{ return lhs.src < rhs.src; });
    g.chain_transitions_();
  }
}