// -*- coding: utf-8 -*-
// Copyright (C) by the Spot authors, see the AUTHORS file for details.
//
// 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/>.

#pragma once

#include <spot/twa/twagraph.hh>

namespace spot
{
  /// \ingroup twa_reduction
  /// \brief Attempt to synthetize an equivalent deterministic TBA
  /// with a SAT solver.
  ///
  /// \param a the input TGA.  It should have only one acceptance
  /// set and be deterministic.  I.e., it should be a deterministic TBA.
  ///
  /// \param target_state_number the desired number of states wanted
  /// in the resulting automaton.  The result may have less than \a
  /// target_state_number reachable states.
  ///
  /// \param state_based set to true to force all outgoing transitions
  /// of a state to share the same acceptance condition, effectively
  /// turning the TBA into a BA.
  ///
  /// If no equivalent deterministic TBA with \a target_state_number
  /// states is found, this returns a null pointer.
  SPOT_API twa_graph_ptr
  dtba_sat_synthetize(const const_twa_graph_ptr& a,
                      int target_state_number,
                      bool state_based = false);

  /// \ingroup twa_reduction
  /// \brief Attempt to minimize a deterministic TBA with a SAT solver.
  ///
  /// This calls dtba_sat_synthetize() in a loop, with a decreasing
  /// number of states, and returns the last successfully built TBA.
  ///
  /// If no smaller TBA exist, this returns a null pointer.
  SPOT_API twa_graph_ptr
  dtba_sat_minimize(const const_twa_graph_ptr& a,
                    bool state_based = false,
                    int max_states = -1);

  /// \brief Attempt to minimize a deterministic TBA with a SAT solver.
  ///
  /// This calls dtba_sat_synthetize() in a loop, but attempting to
  /// find the minimum number of states using a binary search.
  //
  /// If no smaller TBA exist, this returns a null pointer.
  SPOT_API twa_graph_ptr
  dtba_sat_minimize_dichotomy(const const_twa_graph_ptr& a,
                              bool state_based = false,
                              bool langmap = false,
                              int max_states = -1);

  /// \brief Attempt to minimize a det. TBA with a SAT solver.
  ///
  /// This acts like dtba_sat_synthetize() and obtains a first minimized
  /// automaton. Then, incrementally, it encodes the deletion of one state
  /// and solves it as many time as param value.
  /// If param >= 0, this process is fully repeated until the minimal automaton
  /// is found. Otherwise, it continues to delete states one by one
  /// incrementally until the minimal automaton is found.
  ///
  /// If no smaller TBA exist, this returns a null pointer.
  SPOT_API twa_graph_ptr
  dtba_sat_minimize_incr(const const_twa_graph_ptr& a,
                         bool state_based = false,
                         int max_states = -1,
                         int param = 2);

  /// \brief Attempt to minimize a deterministic TBA incrementally with a SAT
  /// solver.
  ///
  /// This acts like dtba_sat_synthetize() and obtains a first minimized
  /// automaton. Then, it adds <param> assumptions, such that each assumption
  /// removes a new state and implies the previous assumptions. A first
  /// resolution is attempted assuming the last assumption (thus involving all
  /// the previous ones). If the problem is SAT several stages have just been
  /// won and all this process is restarted. Otherwise, we know that the
  /// minimal automaton can be obtained with fewer assumption. This
  /// automaton is found dichotomously.
  ///
  /// If no smaller TBA exist, this returns a null pointer.
  SPOT_API twa_graph_ptr
  dtba_sat_minimize_assume(const const_twa_graph_ptr& a,
                    bool state_based = false,
                    int max_states = -1,
                    int param = 6);
}
