/** \file
  * Implement _NewEnum style classes and iterators.
  */
/*
 * Copyright © 2000 Sofus Mortensen
 *
 * This material is provided "as is", with absolutely no warranty
 * expressed or implied. Any use is at your own risk. Permission to
 * use or copy this software for any purpose is hereby granted without
 * fee, provided the above notices are retained on all copies.
 * Permission to modify the code and to distribute modified code is
 * granted, provided the above notices are retained, and a notice that
 * the code was modified is included with the above copyright notice.
 *
 * This header is part of Comet version 2.
 * https://github.com/alamaison/comet
 */

#ifndef COMET_STL_ENUM_H
#define COMET_STL_ENUM_H

#include <comet/config.h>

#include <comet/enum_common.h>
#include <comet/server.h>
#include <comet/stl.h>
#include <comet/variant.h>

namespace comet {

    namespace impl {

        template<typename Collection, typename Outer>
        class stl_enum_source
        {
        public:
            typedef typename Collection::const_iterator const_iterator;

            explicit stl_enum_source(
                const Collection& container, com_ptr<Outer> outer)
                : outer_(outer), container_(container), it_(begin()) {}

            const_iterator begin()
            {
                return container_.begin();
            }

            const_iterator end()
            {
                return container_.end();
            }

            const_iterator& current()
            {
                return it_;
            }

        private:

            // Not copy-assignable
            stl_enum_source& operator=(const stl_enum_source&);

            com_ptr<Outer> outer_;
            const Collection& container_;
            const_iterator it_;
        };

    }

    /** \class stl_enumeration_t  enum.h comet/enum.h
      * Implements _NewEnum style COM object.
      * \param Itf Enumeration Interface.
      * \param C STL Style container.
      * \param T Iteration Element type (VARIANT)
      * \param CONVERTER Converts container element to \p T type. (std::identity<C::value_type>)
      * \sa stl_enumeration create_enum
      */
    template<
        typename Itf, typename C, typename T=VARIANT,
        typename CONVERTER=std::identity<COMET_STRICT_TYPENAME C::value_type>,
        typename TH=::IUnknown>
    class stl_enumeration_t :
        public impl::enumeration<
            Itf, T, CONVERTER, impl::stl_enum_source<C, TH> >
    {
    public:

        stl_enumeration_t(
            const C& container, TH* outer=0,
            const CONVERTER& converter=CONVERTER())
            : enumeration(
                impl::stl_enum_source<C, TH>(container, outer), converter) {}

    private:
        stl_enumeration_t(const stl_enumeration_t&);
        stl_enumeration_t& operator=(const stl_enumeration_t&);
    };

    /**
     * STL Enumeration creation helper.
     *
     * Creates the enumeration with the element type specified by the
     * enumerated_type_of policy.  To specify the element type directly, use
     * stl_enumeration_t.
     *
     * \param ET Enumeration Type e.g. IEnumUnknown.
     */
    template<typename ET>
    struct stl_enumeration
    {

        /** Auto-Create a _NewEnum enumerator from an STL container.
          * No contained object.
          * \param container STL Container.
          */
        template<typename C>
        static com_ptr<ET> create(const C& container)
        {
            typedef typename enumerated_type_of<ET>::is T;
            typedef std::identity<COMET_STRICT_TYPENAME C::value_type>
                CONVERTER;
            return new stl_enumeration_t<ET, C, T, CONVERTER, IUnknown>(
                container, 0);
        }

        /** Auto-Create a _NewEnum enumerator from an STL container.
          * \param container STL Container.
          * \param th Outer or \e this pointer.
          */
        template<typename C, typename TH>
        static com_ptr<ET> create(const C& container, TH* th)
        {
            typedef typename enumerated_type_of<ET>::is T;
            typedef std::identity<COMET_STRICT_TYPENAME C::value_type>
                CONVERTER;
            return new stl_enumeration_t<ET, C, T, CONVERTER, TH>(
                container, th);
        }

        /** Auto-Create a _NewEnum enumerator from an STL container, specifying
          * a converter.
          * \param container STL Container.
          * \param th Outer or \e this pointer.
          * \param converter Converter type (convert Container element to
          * iterator interface element types).
          */
        template<typename C, typename TH, typename CONVERTER>
        static com_ptr<ET> create(
            const C& container, TH* th, const CONVERTER& converter)
        {
            typedef typename enumerated_type_of<ET>::is T;
            return new stl_enumeration_t<ET, C, T, CONVERTER, TH>(
                container, th, converter);
        }
    };

    /*! Creates IEnumVARIANT enumeration of a STL container.
     * \param container STL Container.
     * \param th Outer or \e this pointer.
        \code
            com_ptr<IEnumVARIANT> get__NewEnum() {
                return create_enum( collection_, this );
            }
        \endcode
      * \relates stl_enumeration
    */
    template<typename C, typename TH>
    com_ptr<IEnumVARIANT> create_enum(const C& container, TH* th = 0)
    {
        return stl_enumeration<IEnumVARIANT>::create(container, th);
    }

    //! Creates IEnumVARIANT enumeration of a STL container with a converter.
    /*! \param container STL Container.
      * \param th Outer or \e this pointer.
      * \param converter Converter type (convert Container element to VARIANT)
      * \sa ptr_converter ptr_converter_select1st ptr_converter_select2nd
      * \relates stl_enumeration
      */
    template<typename C, typename TH, typename CONVERTER>
    com_ptr<IEnumVARIANT> create_enum(const C& container, TH* th, CONVERTER converter)
    {
        return stl_enumeration<IEnumVARIANT>::create(container, th, converter);
    }

}

#endif