/******************************************************************************/
/* SETS ***********************************************************************/
/******************************************************************************/

#ifndef _H_EBCL_SETS
#define _H_EBCL_SETS
#include <ebcl/Arrays.hh>
namespace ebcl {

// FIXME move this to utilities \/

// Define a structure that can be used as a tag
#define M_DEFINE_TAG( NAME ) \
	struct NAME { }
// Define a tag structure that can carry arguments
#define M_DEFINE_TEMPLATE_TAG( NAME , ARGS... ) \
	template< ARGS > \
	M_DEFINE_TAG( NAME )

// A structure that can be used to carry a tag structure instance
template< typename Tag >
struct UseTag
{
	const Tag tag;

	template< typename ... ArgTypes >
	constexpr UseTag( ArgTypes&&... args ) noexcept
		: tag( std::forward< ArgTypes >( args ) ... ) { }
};


// Implementation of a set of type Type. The actual implementation is
// determined by the ImplTag type
template< typename Type , typename ImplTag >
	class T_SetImplementation;


// ArrayBacked implementation tag. InPlace is the amount of items to
// store in-place (0 will cause a T_Array to be used
M_DEFINE_TEMPLATE_TAG( ArrayBacked ,
	uint32_t InPlace ,
	uint32_t Growth = 0
);
//M_DEFINE_TAG( IndexBacked );


// Templated horrors used by the main T_Set class.
struct T_SetHelper
{
	// Default implementation to use; also determines the in-place
	// storage size
	using DefaultImplementation = ArrayBacked< 8 >; // FIXME should use Index by default

	// Default implementation class
	template< typename Type
	> using DefaultType = T_SetImplementation<
			Type , DefaultImplementation >;

	// ---------------------------------------------------------------------

	// In-place storage size
	template< typename Type
	> static constexpr auto DefaultSize{
		sizeof( DefaultType< Type > ) };
	// In-place storage alignment
	template< typename Type
	> static constexpr auto DefaultAlign{
		alignof( DefaultType< Type > ) };

	// ---------------------------------------------------------------------

	// Implementation handler operations
	enum E_Operation
	{
		// New instance; output = storage
		INIT ,
		// Copy instance; output = storage, rArg = source
		INIT_COPY ,
		// Move instance; output = storage, wArg = source
		INIT_MOVE ,
		// Destroy instance; wArg = storage
		DESTROY ,

		// Get size; rArg = storage, output = result
		SIZE ,
		// Get index of element; wArg = storage, rArg = element, output = result
		INDEX_OF ,

		// Add copy of element; wArg = storage, rArg = element, output = result
		ADD_COPY ,
		// Move & add element; wArg = storage, rArg = element, output = result
		ADD_MOVE ,
		// Delete element; wArg = storage, rArg = element, output = result
		REMOVE ,
	};

	// Handler function type
	using F_Handler = std::function<
		void( E_Operation , void* , void const* , void* ) >;

	// ---------------------------------------------------------------------

	// Handler for in-place implementations
	template< typename Type , typename Impl
	> struct T_InPlaceHandler
	{
		static void shdl( E_Operation operation ,
				void* wArg ,
				void const* rArg ,
				void* output );
	};

	// Handler for heap-allocated implementations
	template< typename Type , typename Impl
	> struct T_HeapHandler
	{
		static void shdl( E_Operation operation ,
				void* wArg ,
				void const* rArg ,
				void* output );
	};

	// Use the in-place handler if the implementation data can fit into the
	// in-place storage; otherwise use the heap-allocated handler.
	template<
		typename Type , typename ImplTag ,
		typename Impl = T_SetImplementation< Type , ImplTag >
	> using T_Handler = std::conditional_t<
		sizeof( Impl ) <= DefaultSize< Type > ,
		T_InPlaceHandler< Type , ImplTag > ,
		T_HeapHandler< Type , ImplTag >
	>;
};

template< typename Type >
class T_Set
{
    private:

	// Storage area for the implementation's data
	std::aligned_storage_t<
		T_SetHelper::DefaultSize< Type > ,
		T_SetHelper::DefaultAlign< Type >
	> storage_;

	// Handler
	T_SetHelper::F_Handler handler_;

    public:
	// Default constructor, using the default implementation
	T_Set( ) noexcept;
	// Create a set with a specific implementation
	template< typename Tag
	> T_Set( UseTag< Tag > impl ) noexcept;

	// Copy constructor / assignment
	T_Set( T_Set const& other ) noexcept;
	T_Set& operator =( T_Set const& other ) noexcept;

	// Move constructor / assignment
	T_Set( T_Set&& other ) noexcept;
	T_Set& operator =( T_Set&& other ) noexcept;

	~T_Set( );

	// ---------------------------------------------------------------------

	// Returns amount of elements
	uint32_t size( ) const noexcept;
	// Checks if item is in the set
	bool contains( Type const& item ) const noexcept;
	// Returns underlying index of item, or -1 if not in the set
	int32_t indexOf( Type const& item ) const noexcept;

	// ---------------------------------------------------------------------

	// Add copy of item, returns true if added
	bool add( Type const& item ) noexcept;
	// Add moved item, returns true if added
	bool add( Type&& item ) noexcept;
	// Remove item, returns true if removed
	bool remove( Type const& item ) noexcept;
};


}
#endif // _H_EBCL_SETS
// XXX #include <ebcl/inline/Sets.hh>
#include "Sets-inline.hh"