// Copyright David Abrahams 2002. Permission to copy, use,
// modify, sell and distribute this software is granted provided this
// copyright notice appears in all copies. This software is provided
// "as is" without express or implied warranty, and with no claim as
// to its suitability for any purpose.
#ifndef CLASS_DWA200216_HPP
# define CLASS_DWA200216_HPP

# include <boost/python/class_fwd.hpp>
# include <boost/python/object/class.hpp>

# include <boost/python/bases.hpp>
# include <boost/python/object.hpp>
# include <boost/python/type_id.hpp>
# include <boost/python/data_members.hpp>
# include <boost/python/make_function.hpp>
# include <boost/python/signature.hpp>
# include <boost/python/init.hpp>
# include <boost/python/args_fwd.hpp>

# include <boost/type_traits/is_same.hpp>
# include <boost/type_traits/is_convertible.hpp>
# include <boost/type_traits/is_member_function_pointer.hpp>
# include <boost/type_traits/is_polymorphic.hpp>

# include <boost/mpl/size.hpp>
# include <boost/mpl/for_each.hpp>
# include <boost/mpl/bool.hpp>
# include <boost/mpl/not.hpp>
# include <boost/mpl/or.hpp>

# include <boost/python/object/select_holder.hpp>
# include <boost/python/object/class_wrapper.hpp>
# include <boost/python/object/make_instance.hpp>
# include <boost/python/object/pickle_support.hpp>
# include <boost/python/object/add_to_namespace.hpp>
# include <boost/python/object/class_converters.hpp>

# include <boost/python/detail/string_literal.hpp>
# include <boost/python/detail/overloads_fwd.hpp>
# include <boost/python/detail/operator_id.hpp>
# include <boost/python/detail/member_function_cast.hpp>
# include <boost/python/detail/def_helper.hpp>
# include <boost/python/detail/force_instantiate.hpp>

# include <boost/utility.hpp>
# include <boost/detail/workaround.hpp>

namespace boost { namespace python {

enum no_init_t { no_init };

namespace detail
{
  // This function object is used with mpl::for_each to write the id
  // of the type a pointer to which is passed as its 2nd compile-time
  // argument. into the iterator pointed to by its runtime argument
  struct write_type_id
  {
      write_type_id(type_info**p) : p(p) {}

      // Here's the runtime behavior
      template <class T>
      void operator()(T*) const
      {
          *(*p)++ = type_id<T>();
      }

      type_info** p;
  };

  template <class T, class Prev = detail::not_specified>
  struct select_held_type;

  template <class T1, class T2, class T3>
  struct has_noncopyable;

  template <detail::operator_id, class L, class R>
  struct operator_;

  // Register to_python converters for a class T.  The first argument
  // will be mpl::true_ unless noncopyable was specified as a
  // class_<...> template parameter. The 2nd argument is a pointer to
  // the type of holder that must be created. The 3rd argument is a
  // reference to the Python type object to be created.
  template <class T, class SelectHolder>
  inline void register_class_to_python(mpl::true_, SelectHolder, T* = 0)
  {
      typedef typename SelectHolder::type holder;
      force_instantiate(objects::class_cref_wrapper<T, objects::make_instance<T,holder> >());
      SelectHolder::register_();
  }

  template <class T, class SelectHolder>
  inline void register_class_to_python(mpl::false_, SelectHolder, T* = 0)
  {
      SelectHolder::register_();
  }

  namespace error
  {
    //
    // A meta-assertion mechanism which prints nice error messages and
    // backtraces on lots of compilers. Usage:
    //
    //      assertion<C>::failed
    //
    // where C is an MPL metafunction class
    //
    
    template <class C> struct assertion_failed { };
    template <class C> struct assertion_ok { typedef C failed; };

    template <class C>
    struct assertion
        : mpl::if_<C, assertion_ok<C>, assertion_failed<C> >::type
    {};

    //
    // Checks for validity of arguments used to define virtual
    // functions with default implementations.
    //
    
    template <class Default>
    void not_a_derived_class_member(Default) {}
    
    template <class T, class Fn>
    struct virtual_function_default
    {
        template <class Default>
        static void
        must_be_derived_class_member(Default const&)
        {
            typedef typename assertion<mpl::not_<is_same<Default,Fn> > >::failed test0;
# if !BOOST_WORKAROUND(__MWERKS__, <= 0x2407)
            typedef typename assertion<is_polymorphic<T> >::failed test1;
# endif 
            typedef typename assertion<is_member_function_pointer<Fn> >::failed test2;
            not_a_derived_class_member<Default>(Fn());
        }
    };
  }
}

// This is the primary mechanism through which users will expose
// C++ classes to Python.
template <
    class T // class being wrapped
    , class X1 // = detail::not_specified
    , class X2 // = detail::not_specified
    , class X3 // = detail::not_specified
    >
class class_ : public objects::class_base
{
 public: // types
    typedef objects::class_base base;
    typedef T wrapped_type;
    
    typedef class_<T,X1,X2,X3> self;
    BOOST_STATIC_CONSTANT(bool, is_copyable = (!detail::has_noncopyable<X1,X2,X3>::value));

    typedef typename detail::select_held_type<
        X1, typename detail::select_held_type<
        X2, typename detail::select_held_type<
        X3
    >::type>::type>::type held_type;

    typedef objects::select_holder<T,held_type> holder_selector;

 private: // types

    typedef typename detail::select_bases<X1
            , typename detail::select_bases<X2
              , typename boost::python::detail::select_bases<X3>::type
              >::type
            >::type bases;


    // A helper class which will contain an array of id objects to be
    // passed to the base class constructor
    struct id_vector
    {
        id_vector()
        {
            // Stick the derived class id into the first element of the array
            ids[0] = type_id<T>();

            // Write the rest of the elements into succeeding positions.
            type_info* p = ids + 1;
            mpl::for_each(detail::write_type_id(&p), (bases*)0, (add_pointer<mpl::_>*)0);
        }

        BOOST_STATIC_CONSTANT(
            std::size_t, size = mpl::size<bases>::value + 1);
        type_info ids[size];
    };
    friend struct id_vector;

 public: // constructors
    
    // Construct with the class name, with or without docstring, and default __init__() function
    class_(char const* name, char const* doc = 0);

    // Construct with class name, no docstring, and an uncallable __init__ function
    class_(char const* name, no_init_t);

    // Construct with class name, docstring, and an uncallable __init__ function
    class_(char const* name, char const* doc, no_init_t);

    // Construct with class name and init<> function
    template <class DerivedT>
    inline class_(char const* name, init_base<DerivedT> const& i)
        : base(name, id_vector::size, id_vector().ids)
    {
        this->register_();
        define_init(*this, i.derived());
        this->set_instance_size(holder_selector::additional_size());
    }

    // Construct with class name, docstring and init<> function
    template <class DerivedT>
    inline class_(char const* name, char const* doc, init_base<DerivedT> const& i)
        : base(name, id_vector::size, id_vector().ids, doc)
    {
        this->register_();
        define_init(*this, i.derived());
        this->set_instance_size(holder_selector::additional_size());
    }

 public: // member functions
    
    // Define additional constructors
    template <class DerivedT>
    self& def(init_base<DerivedT> const& i)
    {
        define_init(*this, i.derived());
        return *this;
    }

    // Wrap a member function or a non-member function which can take
    // a T, T cv&, or T cv* as its first parameter, or a callable
    // python object.
    template <class F>
    self& def(char const* name, F f)
    {
        this->def_impl(name, f, detail::def_helper<char const*>(0), &f);
        return *this;
    }

    template <class A1, class A2>
    self& def(char const* name, A1 a1, A2 const& a2)
    {
        this->def_maybe_overloads(name, a1, a2, &a2);
        return *this;
    }

    template <class Fn, class A1, class A2>
    self& def(char const* name, Fn fn, A1 const& a1, A2 const& a2)
    {
        //  The arguments are definitely:
        //      def(name, function, policy, doc_string)
        //      def(name, function, doc_string, policy)

        this->def_impl(
            name, fn
            , detail::def_helper<A1,A2>(a1,a2)
            , &fn);

        return *this;
    }

    template <class Fn, class A1, class A2, class A3>
    self& def(char const* name, Fn fn, A1 const& a1, A2 const& a2, A3 const& a3)
    {
        this->def_impl(
            name, fn
            , detail::def_helper<A1,A2,A3>(a1,a2,a3)
            , &fn);

        return *this;
    }

    template <detail::operator_id id, class L, class R>
    self& def(detail::operator_<id,L,R> const& op)
    {
        typedef detail::operator_<id,L,R> op_t;
        return this->def(op.name(), &op_t::template apply<T>::execute);
    }

    //
    // Data member access
    //
    template <class D, class B>
    self& def_readonly(char const* name, D B::*pm_)
    {
        D T::*pm = pm_;
        this->add_property(name, make_getter(pm));
        return *this;
    }

    template <class D, class B>
    self& def_readwrite(char const* name, D B::*pm_)
    {
        D T::*pm = pm_;
        return this->add_property(name, make_getter(pm), make_setter(pm));
    }

    // Property creation
    template <class Get>
    self& add_property(char const* name, Get fget)
    {
        base::add_property(
            name
            , object(
                detail::member_function_cast<T,Get>::stage1(fget).stage2((T*)0).stage3(fget)
                )
            );
        
        return *this;
    }

    template <class Get, class Set>
    self& add_property(char const* name, Get fget, Set fset)
    {
        base::add_property(
            name
            , object(
                detail::member_function_cast<T,Get>::stage1(fget).stage2((T*)0).stage3(fget)
                )
            , object(
                detail::member_function_cast<T,Set>::stage1(fset).stage2((T*)0).stage3(fset)
                )
            );
        return *this;
    }
        
    template <class U>
    self& setattr(char const* name, U const& x)
    {
        this->base::setattr(name, object(x));
        return *this;
    }

    // Pickle support
    template <typename PickleSuiteType>
    self& def_pickle(PickleSuiteType const& x)
    {
      error_messages::must_be_derived_from_pickle_suite(x);
      detail::pickle_suite_finalize<PickleSuiteType>::register_(
        *this,
        &PickleSuiteType::getinitargs,
        &PickleSuiteType::getstate,
        &PickleSuiteType::setstate,
        PickleSuiteType::getstate_manages_dict());
      return *this;
    }

    self& staticmethod(char const* name)
    {
        this->make_method_static(name);
        return *this;
    }
 private: // helper functions

    inline void register_() const;

    //
    // These two overloads discriminate between def() as applied to
    // things which are already wrapped into callable python::object
    // instances and everything else.
    //
    template <class F, class A1>
    inline void def_impl(
        char const* name
        , F f
        , detail::def_helper<A1> const& helper
        , object const*)
    {
        // It's too late to specify anything other than docstrings, if
        // the callable object is already wrapped.
        BOOST_STATIC_ASSERT(
            (is_same<char const*,A1>::value
             || detail::is_string_literal<A1>::value));
        
        objects::add_to_namespace(*this, name, f, helper.doc());
    }

    template <class Fn, class Helper>
    inline void def_impl(
        char const* name
        , Fn fn
        , Helper const& helper
        , ...)
    {
        objects::add_to_namespace(
            *this, name,
            make_function(
                // This bit of nastiness casts F to a member function of T if possible.
                detail::member_function_cast<T,Fn>::stage1(fn).stage2((T*)0).stage3(fn)
                , helper.policies(), helper.keywords())
            , helper.doc());

        this->def_default(name, fn, helper, mpl::bool_<Helper::has_default_implementation>());
    }

    //
    // These two overloads handle the definition of default
    // implementation overloads for virtual functions. The second one
    // handles the case where no default implementation was specified.
    //
    template <class Fn, class Helper>
    inline void def_default(
        char const* name
        , Fn fn
        , Helper const& helper
        , mpl::bool_<true>)
    {
        detail::error::virtual_function_default<T,Fn>::must_be_derived_class_member(
            helper.default_implementation());
            
        objects::add_to_namespace(
            *this, name,
            make_function(
                helper.default_implementation(), helper.policies(), helper.keywords())
            );
    }
    
    template <class Fn, class Helper>
    inline void def_default(char const*, Fn, Helper const&, mpl::bool_<false>)
    { }
    
    //
    // These two overloads discriminate between def() as applied to
    // regular functions and def() as applied to the result of
    // BOOST_PYTHON_FUNCTION_OVERLOADS(). The final argument is used to
    // discriminate.
    //
    template <class OverloadsT, class SigT>
    void def_maybe_overloads(
        char const* name
        , SigT sig
        , OverloadsT const& overloads
        , detail::overloads_base const*)

    {
        //  convert sig to a type_list (see detail::get_signature in signature.hpp)
        //  before calling detail::define_with_defaults.
        detail::define_with_defaults(
            name, overloads, *this, detail::get_signature(sig));
    }

    template <class Fn, class A1>
    void def_maybe_overloads(
        char const* name
        , Fn fn
        , A1 const& a1
        , ...)
    {
        this->def_impl(
            name, fn
            , detail::def_helper<A1>(a1)
            , &fn);

    }
};


//
// implementations
//

// register converters
template <class T, class X1, class X2, class X3>
inline void class_<T,X1,X2,X3>::register_() const
{
    objects::register_class_from_python<T,bases>();

    detail::register_class_to_python<T>(
        mpl::bool_<is_copyable>()
# if BOOST_WORKAROUND(__MWERKS__, <= 0x2407)
        , holder_selector::execute((held_type*)0)
# elif BOOST_WORKAROUND(BOOST_MSVC, <= 1300)
        , holder_selector::type()
# else 
        , typename holder_selector::type()
# endif 
        );
}

template <class T, class X1, class X2, class X3>
inline class_<T,X1,X2,X3>::class_(char const* name, char const* doc)
    : base(name, id_vector::size, id_vector().ids, doc)
{
    this->register_();
    this->set_instance_size(holder_selector::additional_size());
# if BOOST_WORKAROUND(__MWERKS__, <= 0x2407)
    holder_selector::execute((held_type*)0).assert_default_constructible();
# else 
    holder_selector::type::assert_default_constructible();
# endif 
    this->def(init<>());
}

template <class T, class X1, class X2, class X3>
inline class_<T,X1,X2,X3>::class_(char const* name, no_init_t)
    : base(name, id_vector::size, id_vector().ids)
{
    this->register_();
    this->def_no_init();
}

template <class T, class X1, class X2, class X3>
inline class_<T,X1,X2,X3>::class_(char const* name, char const* doc, no_init_t)
    : base(name, id_vector::size, id_vector().ids, doc)
{
    this->register_();
    this->def_no_init();
}

namespace detail
{
  template <class T1, class T2, class T3>
  struct has_noncopyable
      : mpl::or_<
          is_same<T1,noncopyable>
        , is_same<T2,noncopyable>
        , is_same<T3,noncopyable>
      >
  {};


    template <class T, class Prev>
    struct select_held_type
        : mpl::if_<
             mpl::or_<
                 specifies_bases<T>
               , is_same<T,noncopyable>
            >
            , Prev
            , T
          >
    {
    };
}

}} // namespace boost::python

#endif // CLASS_DWA200216_HPP
