// -*- coding: utf-8 -*-
// Copyright (C) 2011, 2013, 2014, 2015 Laboratoire de Recherche et
// Développement de l'Epita (LRDE).
// Copyright (C) 2003, 2004, 2006 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/>.

#pragma once

#include "tgba.hh"
#include "misc/fixpool.hh"

namespace spot
{

  /// \ingroup tgba_on_the_fly_algorithms
  /// \brief A state for spot::tgba_product.
  ///
  /// This state is in fact a pair of state: the state from the left
  /// automaton and that of the right.
  class SPOT_API state_product final: public state
  {
  public:
    /// \brief Constructor
    /// \param left The state from the left automaton.
    /// \param right The state from the right automaton.
    /// \param pool The pool from which the state was allocated.
    /// These states are acquired by spot::state_product, and will
    /// be destroyed on destruction.
    state_product(state* left, state* right, fixed_size_pool* pool)
      :	left_(left), right_(right), count_(1), pool_(pool)
    {
    }

    virtual void destroy() const;

    state*
    left() const
    {
      return left_;
    }

    state*
    right() const
    {
      return right_;
    }

    virtual int compare(const state* other) const;
    virtual size_t hash() const;
    virtual state_product* clone() const;

  private:
    state* left_;		///< State from the left automaton.
    state* right_;		///< State from the right automaton.
    mutable unsigned count_;
    fixed_size_pool* pool_;

    virtual ~state_product();
    state_product(const state_product& o); // No implementation.
  };


  /// \brief A lazy product.  (States are computed on the fly.)
  class SPOT_API tgba_product: public tgba
  {
  public:
    /// \brief Constructor.
    /// \param left The left automata in the product.
    /// \param right The right automata in the product.
    /// Do not be fooled by these arguments: a product is commutative.
    tgba_product(const const_tgba_ptr& left, const const_tgba_ptr& right);

    virtual ~tgba_product();

    virtual state* get_init_state() const;

    virtual tgba_succ_iterator*
    succ_iter(const state* state) const;

    virtual std::string format_state(const state* state) const;

    virtual std::string
    transition_annotation(const tgba_succ_iterator* t) const;

    virtual state* project_state(const state* s, const const_tgba_ptr& t) const;

    const acc_cond& left_acc() const;
    const acc_cond& right_acc() const;

  protected:
    virtual bdd compute_support_conditions(const state* state) const;

  protected:
    const_tgba_ptr left_;
    const_tgba_ptr right_;
    bool left_kripke_;
    fixed_size_pool pool_;

  private:
    // Disallow copy.
    tgba_product(const tgba_product&) SPOT_DELETED;
    tgba_product& operator=(const tgba_product&) SPOT_DELETED;
  };

  /// \brief A lazy product with different initial states.
  class SPOT_API tgba_product_init final: public tgba_product
  {
  public:
    tgba_product_init(const const_tgba_ptr& left, const const_tgba_ptr& right,
		      const state* left_init, const state* right_init);
    virtual state* get_init_state() const;
  protected:
    const state* left_init_;
    const state* right_init_;
  };

  /// \brief on-the-fly TGBA product
  inline tgba_product_ptr otf_product(const const_tgba_ptr& left,
				      const const_tgba_ptr& right)
  {
    return std::make_shared<tgba_product>(left, right);
  }

  /// \brief on-the-fly TGBA product with forced initial states
  inline tgba_product_ptr otf_product_at(const const_tgba_ptr& left,
					 const const_tgba_ptr& right,
					 const state* left_init,
					 const state* right_init)
  {
    return std::make_shared<tgba_product_init>(left, right,
					       left_init, right_init);
  }
}