////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 1996-2024 The Octave Project Developers
//
// See the file COPYRIGHT.md in the top-level directory of this
// distribution or <https://octave.org/copyright/>.
//
// This file is part of Octave.
//
// Octave 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.
//
// Octave 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 Octave; see the file COPYING.  If not, see
// <https://www.gnu.org/licenses/>.
//
////////////////////////////////////////////////////////////////////////

#if ! defined (octave_ov_ref_h)
#define octave_ov_ref_h 1

#include "octave-config.h"

#if defined (OCTAVE_ENABLE_BYTECODE_EVALUATOR)

#include "ov-base.h"
#include "ovl.h"
#include "symscope.h"
#include "symrec.h"
#include "stack-frame.h"
#include <string>
#include <memory>

// octave_value_ref is to be used by the VM to implement
// global and persistent values.
//
// octave_value_ref need to overload any virtual call
// used by the assign and push slot op-codes.
//
// Any octave_value_ref should never leave the VM slots
// on the VM stack.

// Abstract type
class OCTINTERP_API
octave_value_ref : public octave_base_value
{
public:
    octave_value_ref () = default;
    ~octave_value_ref () = default;

    octave_value_ref * ref_rep () { return this; }
    bool is_ref () const { return true; }

    virtual octave_value deref () = 0;
    virtual void set_value (octave_value val) = 0;
    virtual octave_value & ref () = 0;
    virtual void maybe_save_state  () {};

    virtual bool is_global_ref () const { return false; }
    virtual bool is_persistent_ref () const { return false; }
    virtual bool is_ptr_ref () const { return false; }
    virtual bool is_local_ref () const { return false; }

    virtual octave::stack_frame::scope_flags get_scope_flag () = 0;
    virtual void mark_globalness_in_owning_frame (bool /* should_be_global */) {}

    void maybe_call_dtor ();
    octave_value simple_subsasgn (char type, octave_value_list& idx, const octave_value& rhs);
    octave_value subsasgn (const std::string& type, const std::list<octave_value_list>& idx, const octave_value& rhs);
    octave_base_value * unique_clone ();
    bool is_defined () const;
    bool is_maybe_function () const;
};

class OCTINTERP_API
octave_value_ref_global : public octave_value_ref
{
public:
    octave_value_ref_global () = default;
    ~octave_value_ref_global () = default;
    octave_value_ref_global (std::string name)
        : m_name (name) {};

    octave_value deref ();
    octave_value & ref ();
    void set_value (octave_value val);

    bool is_global_ref () const { return true; }

    octave::stack_frame::scope_flags get_scope_flag ()
    {
      return octave::stack_frame::scope_flags::GLOBAL;
    }

private:
    std::string m_name;

    DECLARE_OV_TYPEID_FUNCTIONS_AND_DATA
};

class OCTINTERP_API
octave_value_ref_persistent : public octave_value_ref
{
public:
    octave_value_ref_persistent () = default;
    ~octave_value_ref_persistent () = default;
    octave_value_ref_persistent (octave::symbol_scope scope, int offset)
        : m_offset (offset), m_scope (scope) {};

    octave_value deref ();
    octave_value & ref ();
    void set_value (octave_value val);

    bool is_persistent_ref () const { return true; }

    octave::stack_frame::scope_flags get_scope_flag ()
    {
      return octave::stack_frame::scope_flags::PERSISTENT;
    }

private:
    int m_offset;
    octave::symbol_scope m_scope = octave::symbol_scope::invalid ();

    DECLARE_OV_TYPEID_FUNCTIONS_AND_DATA
};

class OCTINTERP_API
octave_value_ref_vmlocal : public octave_value_ref
{
public:
    octave_value_ref_vmlocal () = default;
    ~octave_value_ref_vmlocal () = default;
    octave_value_ref_vmlocal (octave::symbol_record sym, octave::stack_frame *frame)
        : m_frame (frame), m_sym (sym) { }

    octave_value deref ();
    octave_value & ref ();
    void set_value (octave_value val);

    octave::stack_frame::scope_flags get_scope_flag ();

    void mark_globalness_in_owning_frame (bool should_be_global);

    bool is_local_ref () const { return true; }

private:
    octave::stack_frame *m_frame = nullptr;
    octave::symbol_record m_sym;

    DECLARE_OV_TYPEID_FUNCTIONS_AND_DATA
};

class OCTINTERP_API
octave_value_ref_ptr : public octave_value_ref
{
public:
    octave_value_ref_ptr () = default;
    ~octave_value_ref_ptr () = default;
    octave_value_ref_ptr (octave_value *pov)
        : m_pov (pov) { }

    octave_value deref ();
    octave_value & ref ();
    void set_value (octave_value val);

    octave::stack_frame::scope_flags get_scope_flag ()
    {
      if (m_pov->is_ref ())
        return m_pov->ref_rep ()->get_scope_flag ();
      return octave::stack_frame::scope_flags::LOCAL;
    }

    bool is_ptr_ref () const { return true; }
private:
    octave_value *m_pov;

    DECLARE_OV_TYPEID_FUNCTIONS_AND_DATA
};

#endif

#endif