////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2012-2021 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 (HAVE_CONFIG_H)
#  include "config.h"
#endif

#include "cdef-class.h"
#include "cdef-manager.h"
#include "cdef-method.h"
#include "cdef-package.h"
#include "cdef-property.h"
#include "cdef-utils.h"
#include "interpreter-private.h"
#include "ov-classdef.h"
#include "ov-usr-fcn.h"
#include "pt-eval.h"

namespace octave
{
  std::string
  get_base_name (const std::string& nm)
  {
    std::string::size_type pos = nm.find_last_of ('.');

    if (pos != std::string::npos)
      return nm.substr (pos + 1);

    return nm;
  }

  void
  make_function_of_class (const std::string& class_name,
                          const octave_value& fcn)
  {
    octave_function *of = fcn.function_value ();

    of->stash_dispatch_class (class_name);

    octave_user_function *uf = of->user_function_value (true);

    if (uf)
      {
        if (get_base_name (class_name) == uf->name ())
          uf->mark_as_classdef_constructor ();
        else
          uf->mark_as_classdef_method ();
      }
  }

  void
  make_function_of_class (const cdef_class& cls, const octave_value& fcn)
  {
    make_function_of_class (cls.get_name (), fcn);
  }

  cdef_class
  lookup_class (const std::string& name, bool error_if_not_found,
                bool load_if_not_found)
  {
    cdef_manager& cdm = __get_cdef_manager__ ("lookup_class");

    return cdm.find_class (name, error_if_not_found, load_if_not_found);
  }

  cdef_class
  lookup_class (const cdef_class& cls)
  {
    // FIXME: placeholder for the time being, the purpose
    //        is to centralized any class update activity here.

    return cls;
  }

  cdef_class
  lookup_class (const octave_value& ov)
  {
    if (ov.is_string())
      return lookup_class (ov.string_value ());
    else
      {
        cdef_class cls (to_cdef (ov));

        return lookup_class (cls);
      }

    return cdef_class ();
  }

  std::list<cdef_class>
  lookup_classes (const Cell& cls_list)
  {
    std::list<cdef_class> retval;

    for (int i = 0; i < cls_list.numel (); i++)
      {
        cdef_class c = lookup_class (cls_list(i));

        retval.push_back (c);
      }

    return retval;
  }

  octave_value
  to_ov (const cdef_object& obj)
  {
    if (obj.ok ())
      return octave_value (new octave_classdef (obj));
    else
      return octave_value (Matrix ());
  }

  octave_value
  to_ov (const octave_value& ov)
  {
    return ov;
  }

  cdef_object
  to_cdef (const octave_value& val)
  {
    if (val.type_name () != "object")
      error ("cannot convert '%s' into 'object'", val.type_name().c_str ());

    return dynamic_cast<octave_classdef *> (val.internal_rep ())->get_object ();
  }

  cdef_object&
  to_cdef_ref (const octave_value& val)
  {
    if (val.type_name () != "object")
      error ("cannot convert '%s' into 'object'", val.type_name().c_str ());

    return dynamic_cast<octave_classdef *> (val.internal_rep ())->get_object_ref ();
  }

  cdef_object
  to_cdef (const cdef_object& obj)
  {
    return obj;
  }

  octave_value
  to_ov (const std::list<cdef_class>& class_list)
  {
    Cell cls (class_list.size (), 1);
    int i = 0;

    for (const auto& cdef_cls : class_list)
      cls(i++) = to_ov (cdef_cls);

    return octave_value (cls);
  }

  bool
  is_dummy_method (const octave_value& fcn)
  {
    bool retval = false;

    if (fcn.is_defined ())
      {
        if (fcn.is_user_function ())
          {
            octave_user_function *uf = fcn.user_function_value (true);

            if (! uf || ! uf->body ())
              retval = true;
          }
      }
    else
      retval = true;

    return retval;
  }

  bool
  is_superclass (const cdef_class& clsa, const cdef_class& clsb,
                 bool allow_equal, int max_depth)
  {
    bool retval = false;

    if (allow_equal && clsa == clsb)
      retval = true;
    else if (max_depth != 0)
      {
        Cell c = clsb.get ("SuperClasses").cell_value ();

        for (int i = 0; ! retval && i < c.numel (); i++)
          {
            octave_classdef *metacls = c(i).classdef_object_value ();
            std::string clsname = metacls->get_property (0, "Name").string_value ();
            cdef_class cls = lookup_class (clsname);

            retval = is_superclass (clsa, cls, true,
                                    max_depth < 0 ? max_depth : max_depth-1);
          }
      }

    return retval;
  }

  bool
  is_strict_superclass (const cdef_class& clsa, const cdef_class& clsb)
  {
    return is_superclass (clsa, clsb, false);
  }

  bool
  is_direct_superclass (const cdef_class& clsa, const cdef_class& clsb)
  {
    return is_superclass (clsa, clsb, false, 1);
  }

  cdef_package
  lookup_package (const std::string& name, bool error_if_not_found,
                  bool load_if_not_found)
  {
    cdef_manager& cdm = __get_cdef_manager__ ("lookup_package");

    return cdm.find_package (name, error_if_not_found, load_if_not_found);
  }

  cdef_class
  get_class_context (std::string& name, bool& in_constructor)
  {
    name = "";
    in_constructor = false;

    cdef_class cls;

    // If the dispatch class is set in the current stack frame it
    // overrides whatever dispatch class there is for the currently
    // executing function so that function handles returned from class
    // methods will use the dispatch class of the class in which they
    // are defined instead of the class in which they are executing.

    tree_evaluator& tw = __get_evaluator__ ("get_class_context");

    std::string dispatch_class = tw.get_dispatch_class ();

    if (! dispatch_class.empty ())
      return lookup_class (dispatch_class);

    octave_function *fcn = tw.current_function ();

    if (fcn && (fcn->is_class_method ()
                || fcn->is_classdef_constructor ()
                || fcn->is_anonymous_function_of_class ()
                || (fcn->is_private_function ()
                    && ! fcn->dispatch_class ().empty ())))
      {
        cls = lookup_class (fcn->dispatch_class ());

        name = fcn->name ();
        in_constructor = fcn->is_classdef_constructor ();
      }

    return cls;
  }

  cdef_class
  get_class_context (void)
  {
    std::string dummy_string;
    bool dummy_bool;

    return get_class_context (dummy_string, dummy_bool);
  }

  bool
  check_access (const cdef_class& cls, const octave_value& acc,
                const std::string& meth_name, const std::string& prop_name,
                bool is_prop_set)
  {
    if (acc.is_string ())
      {
        std::string acc_s = acc.string_value ();

        if (acc_s == "public")
          return true;

        cdef_class ctx = get_class_context ();

        // The access is private or protected, this requires a
        // valid class context.

        if (ctx.ok ())
          {
            if (acc_s == "private")
              return (ctx == cls);
            else if (acc_s == "protected")
              {
                if (is_superclass (cls, ctx))
                  // Calling a protected method in a superclass.
                  return true;
                else if (is_strict_superclass (ctx, cls))
                  {
                    // Calling a protected method or property in a derived class.
                    // This is only allowed if the context class knows about it
                    // and has access to it.

                    if (! meth_name.empty ())
                      {
                        cdef_method m = ctx.find_method (meth_name);

                        if (m.ok ())
                          return check_access (ctx, m.get ("Access"), meth_name);

                        return false;
                      }
                    else if (! prop_name.empty ())
                      {
                        cdef_property p = ctx.find_property (prop_name);

                        if (p.ok ())
                          {
                            octave_value p_access = p.get (is_prop_set ?
                                                           "SetAccess" :
                                                           "GetAccess");

                            return check_access (ctx, p_access, meth_name,
                                                 prop_name, is_prop_set);
                          }

                        return false;
                      }
                    else
                      panic_impossible ();
                  }

                return false;
              }
            else
              panic_impossible ();
          }
      }
    else if (acc.isobject ())
      {
        cdef_class ctx = get_class_context ();

        // At this point, a class context is always required.
        if (ctx.ok ())
          {
            if (ctx == cls)
              return true;

            cdef_class acc_cls (to_cdef (acc));

            if (is_superclass (acc_cls, ctx))
              return true;
          }
      }
    else if (acc.iscell ())
      {
        Cell acc_c = acc.cell_value ();

        cdef_class ctx = get_class_context ();

        // At this point, a class context is always required.

        if (ctx.ok ())
          {
            if (ctx == cls)
              return true;

            for (int i = 0; i < acc.numel (); i++)
              {
                cdef_class acc_cls (to_cdef (acc_c(i)));

                if (is_superclass (acc_cls, ctx))
                  return true;
              }
          }
      }
    else
      error ("invalid property/method access in class '%s'",
             cls.get_name ().c_str ());

    return false;
  }
}