// -*- coding: utf-8 -*-
// Copyright (C) 2011, 2012, 2013, 2014, 2015 Laboratoire de Recherche
// et Développement de l'Epita (LRDE).
// Copyright (C) 2003, 2004, 2005 Laboratoire d'Informatique de Paris
// 6 (LIP6), département Systèmes Répartis Coopératifs (SRC),
// Université Pierre et Marie Curie.
//
// 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 "lbtt.hh"
#include <map>
#include <string>
#include <ostream>
#include "twa/formula2bdd.hh"
#include "reachiter.hh"
#include "misc/bddlt.hh"
#include "priv/accmap.hh"
#include "tl/print.hh"

namespace spot
{
  namespace
  {
    class lbtt_bfs : public tgba_reachable_iterator_breadth_first
    {
    public:
      lbtt_bfs(const const_twa_ptr& a, std::ostream& os, bool sba_format)
	: tgba_reachable_iterator_breadth_first(a),
	  os_(os),
	  sba_format_(sba_format),
	  sba_(nullptr)
      {
	// Check if the automaton can be converted into a
	// twa_graph. This makes the state_is_accepting() function
	// more efficient.
	if (a->is_sba())
	  sba_ = std::dynamic_pointer_cast<const twa_graph>(a);
      }

      acc_cond::mark_t
      state_acc_sets(const state *s) const
      {
	// If the automaton has a SBA type, it's easier to just query the
	// state_is_accepting() method.
	if (sba_)
	  return sba_->state_acc_sets(sba_->state_number(s));

	// Otherwise, since we are dealing with a degeneralized
	// automaton nonetheless, the transitions leaving an accepting
	// state are either all accepting, or all non-accepting.  So
	// we just check the acceptance of the first transition.  This
	// is not terribly efficient since we have to create the
	// iterator.
	twa_succ_iterator* it = aut_->succ_iter(s);
	if (!it->first())
	  return {};
	auto res = it->acc();
	aut_->release_iter(it);
	return res;
      }


      void
      process_state(const state* s, int n, twa_succ_iterator*)
      {
	--n;
	if (n == 0)
	  body_ << "0 1";
	else
	  body_ << "-1\n" << n << " 0";
	// Do we have state-based acceptance?
	if (sba_format_)
	  {
	    for (auto i: state_acc_sets(s).sets())
	      body_ << ' ' << i;
	    body_ << " -1";
	  }
	body_ << '\n';
      }

      void
      process_link(const state*, int,
		   const state*, int out, const twa_succ_iterator* si)
      {
	body_ << out - 1 << ' ';
	if (!sba_format_)
	  {
	    for (auto s: aut_->acc().sets(si->acc()))
	      body_ << s << ' ';
	    body_ << "-1 ";
	  }
	print_lbt_ltl(body_, bdd_to_formula(si->cond(),
					    aut_->get_dict())) << '\n';
      }

      void
      end()
      {
	os_ << seen.size() << ' ';
	if (sba_format_)
	  os_ << aut_->num_sets();
	else
	  os_ << aut_->num_sets() << 't';
	os_ << '\n' << body_.str() << "-1" << std::endl;
      }

    private:
      std::ostream& os_;
      std::ostringstream body_;
      bdd all_acc_conds_;
      bool sba_format_;
      const_twa_graph_ptr sba_;
    };
  }

  std::ostream&
  print_lbtt(std::ostream& os, const const_twa_ptr& g, const char* opt)
  {
    if (!g->acc().is_generalized_buchi())
      throw std::runtime_error
	("LBTT only supports generalized Büchi acceptance");

    bool sba = g->prop_state_acc();
    if (opt)
      switch (char c = *opt++)
	{
	case 't':
	  sba = false;
	  break;
	default:
	  throw std::runtime_error
	    (std::string("unknown option for print_lbtt(): ") + c);
	}

    lbtt_bfs b(g, os, sba);
    b.run();
    return os;
  }
}