#pragma once
// IWYU pragma: private, include "PassVisitor.h"

template<typename pass_type>
class PassVisitor;

typedef std::function<void( void * )> cleanup_func_t;
typedef std::function< void( cleanup_func_t, void * ) > at_cleanup_t;

class guard_value_impl {
public:
	guard_value_impl( at_cleanup_t * at_cleanup ) {
		if( at_cleanup ) {
			*at_cleanup = [this]( cleanup_func_t && func, void* val ) {
				push( std::move( func ), val );
			};
		}
	}

	~guard_value_impl() {
		while( !cleanups.empty() ) {
			auto& cleanup = cleanups.top();
			cleanup.func( cleanup.val );
			cleanups.pop();
		}
	}

	void push( cleanup_func_t && func, void* val ) {
		cleanups.emplace( std::move(func), val );
	}

private:
	struct cleanup_t {
		cleanup_func_t func;
		void * val;

		cleanup_t( cleanup_func_t&& func, void * val ) : func(func), val(val) {}
	};

	std::stack< cleanup_t > cleanups;
};

class bool_ref {
public:
	bool_ref() = default;
	~bool_ref() = default;

	operator bool() { return *m_ref; }
	bool operator=( bool val ) { return *m_ref = val; }

private:

	template<typename pass>
	friend class PassVisitor;

	void set( bool & val ) { m_ref = &val; };

	bool * m_ref;
};

template< typename TreeType, typename VisitorType >
inline void indexerScopedAccept( TreeType * tree, VisitorType & visitor ) {
	auto guard = makeFuncGuard(
		[&visitor]() { visitor.indexerScopeEnter(); },
		[&visitor]() { visitor.indexerScopeLeave(); }
	);
	maybeAccept( tree, visitor );
}

template< typename TreeType, typename MutatorType >
inline void indexerScopedMutate( TreeType *& tree, MutatorType & mutator ) {
	auto guard = makeFuncGuard(
		[&mutator]() { mutator.indexerScopeEnter(); },
		[&mutator]() { mutator.indexerScopeLeave(); }
	);
	tree = maybeMutate( tree, mutator );
}

template< typename TreeType, typename MutatorType >
inline void maybeMutateRef( TreeType *& tree, MutatorType & mutator ) {
	tree = maybeMutate( tree, mutator );
}

//-------------------------------------------------------------------------------------------------------------------------------------------------------------------------
// Deep magic (a.k.a template meta programming) to make the templated visitor work
// Basically the goal is to make 2 previsit_impl
// 1 - Use when a pass implements a valid previsit. This uses overloading which means the any overload of
//     'pass.previsit( node )' that compiles will be used for that node for that type
//     This requires that this option only compile for passes that actually define an appropriate visit.
//     SFINAE will make sure the compilation errors in this function don't halt the build.
//     See http://en.cppreference.com/w/cpp/language/sfinae for details on SFINAE
// 2 - Since the first implementation might not be specilizable, the second implementation exists and does nothing.
//     This is needed only to eliminate the need for passes to specify any kind of handlers.
//     The second implementation only works because it has a lower priority. This is due to the bogus last parameter.
//     The second implementation takes a long while the first takes an int. Since the caller always passes an literal 0
//     the first implementation takes priority in regards to overloading.
// Mutator functions work along the same principal
//-------------------------------------------------------------------------------------------------------------------------------------------------------------------------
// Visit
template<typename pass_type, typename node_type>
static inline auto previsit_impl( pass_type& pass, node_type * node, __attribute__((unused)) int unused ) -> decltype( pass.previsit( node ), void() ) {
	pass.previsit( node );
}

template<typename pass_type, typename node_type>
static inline void previsit_impl( __attribute__((unused)) pass_type& pass, __attribute__((unused)) node_type * node, __attribute__((unused)) long unused ) {}


template<typename pass_type, typename node_type>
static inline auto postvisit_impl( pass_type& pass, node_type * node, __attribute__((unused)) int unused ) -> decltype( pass.postvisit( node ), void() ) {
	pass.postvisit( node );
}

template<typename pass_type, typename node_type>
static inline void postvisit_impl( __attribute__((unused)) pass_type& pass, __attribute__((unused)) node_type * node, __attribute__((unused)) long unused ) {}

//---------------------------------------------------------
// Mutate
template<typename pass_type, typename node_type>
static inline auto premutate_impl( pass_type& pass, node_type * node, __attribute__((unused)) int unused ) -> decltype( pass.premutate( node ), void() ) {
	return pass.premutate( node );
}

template<typename pass_type, typename node_type>
static inline void premutate_impl( __attribute__((unused)) pass_type& pass, __attribute__((unused)) node_type * node, __attribute__((unused)) long unused ) {}


template<typename return_type, typename pass_type, typename node_type>
static inline auto postmutate_impl( pass_type& pass, node_type * node, __attribute__((unused)) int unused ) -> decltype( pass.postmutate( node ) ) {
	return pass.postmutate( node );
}

template<typename return_type, typename pass_type, typename node_type>
static inline return_type postmutate_impl( __attribute__((unused)) pass_type& pass, node_type * node, __attribute__((unused)) long unused ) { return node; }

//---------------------------------------------------------
// Begin/End scope
template<typename pass_type>
static inline auto begin_scope_impl( pass_type& pass, __attribute__((unused)) int unused ) -> decltype( pass.beginScope(), void() ) {
	pass.beginScope();
}

template<typename pass_type>
static inline void begin_scope_impl( __attribute__((unused)) pass_type& pass, __attribute__((unused)) long unused ) {}


template<typename pass_type>
static inline auto end_scope_impl( pass_type& pass, __attribute__((unused)) int unused ) -> decltype( pass.endScope(), void() ) {
	pass.endScope();
}

template<typename pass_type>
static inline void end_scope_impl( __attribute__((unused)) pass_type& pass, __attribute__((unused)) long unused ) {}

//---------------------------------------------------------
// Fields
#define FIELD_PTR( type, name )                                                                                                        \
template<typename pass_type>                                                                                                           \
static inline auto name##_impl( pass_type& pass, __attribute__((unused)) int unused ) -> decltype( &pass.name ) { return &pass.name; } \
                                                                                                                                       \
template<typename pass_type>                                                                                                           \
static inline type * name##_impl( __attribute__((unused)) pass_type& pass, __attribute__((unused)) long unused ) { return nullptr;}    \

FIELD_PTR( TypeSubstitution *, env )
FIELD_PTR( std::list< Statement* >, stmtsToAddBefore )
FIELD_PTR( std::list< Statement* >, stmtsToAddAfter  )
FIELD_PTR( std::list< Declaration* >, declsToAddBefore )
FIELD_PTR( std::list< Declaration* >, declsToAddAfter  )
FIELD_PTR( bool_ref, visit_children )
FIELD_PTR( at_cleanup_t, at_cleanup )
FIELD_PTR( PassVisitor<pass_type> * const, visitor )

//---------------------------------------------------------
// Indexer
template<typename pass_type>
static inline auto indexer_impl_enterScope( pass_type & pass, int ) -> decltype( pass.indexer.enterScope(), void() ) {
	pass.indexer.enterScope();
}

template<typename pass_type>
static inline auto indexer_impl_enterScope( pass_type &, int ) {}

template<typename pass_type>
static inline auto indexer_impl_leaveScope( pass_type & pass, int ) -> decltype( pass.indexer.leaveScope(), void() ) {
	pass.indexer.leaveScope();
}

template<typename pass_type>
static inline auto indexer_impl_leaveScope( pass_type &, int ) {}


#define INDEXER_FUNC( func, type )                                                                                             \
template<typename pass_type>                                                                                                   \
static inline auto indexer_impl_##func ( pass_type & pass, int, type arg ) -> decltype( pass.indexer.func( arg ), void() ) {   \
	pass.indexer.func( arg );                                                                                                \
}                                                                                                                              \
                                                                                                                               \
template<typename pass_type>                                                                                                   \
static inline void indexer_impl_##func ( pass_type &, long, type ) {}                                                          \

INDEXER_FUNC( addId     , DeclarationWithType * );
INDEXER_FUNC( addType   , NamedTypeDecl *       );
INDEXER_FUNC( addStruct , StructDecl *          );
INDEXER_FUNC( addEnum   , EnumDecl *            );
INDEXER_FUNC( addUnion  , UnionDecl *           );
INDEXER_FUNC( addTrait  , TraitDecl *           );


template<typename pass_type>
static inline auto indexer_impl_addStructFwd( pass_type & pass, int, StructDecl * decl ) -> decltype( pass.indexer.addStruct( decl ), void() ) {
	StructDecl * fwd = new StructDecl( decl->name );
	cloneAll( decl->parameters, fwd->parameters );
	pass.indexer.addStruct( fwd );
}

template<typename pass_type>
static inline auto indexer_impl_addStructFwd( pass_type &, int, StructDecl * ) {}

template<typename pass_type>
static inline auto indexer_impl_addUnionFwd( pass_type & pass, int, UnionDecl * decl ) -> decltype( pass.indexer.addUnion( decl ), void() ) {
	UnionDecl * fwd = new UnionDecl( decl->name );
	cloneAll( decl->parameters, fwd->parameters );
	pass.indexer.addUnion( fwd );
}

template<typename pass_type>
static inline auto indexer_impl_addUnionFwd( pass_type &, int, UnionDecl * ) {}

template<typename pass_type>
static inline auto indexer_impl_addStruct( pass_type & pass, int, const std::string & str ) -> decltype( pass.indexer.addStruct( str ), void() ) {
	if ( ! pass.indexer.lookupStruct( str ) ) {
		pass.indexer.addStruct( str );
	}
}

template<typename pass_type>
static inline auto indexer_impl_addStruct( pass_type &, int, const std::string & ) {}

template<typename pass_type>
static inline auto indexer_impl_addUnion( pass_type & pass, int, const std::string & str ) -> decltype( pass.indexer.addUnion( str ), void() ) {
	if ( ! pass.indexer.lookupUnion( str ) ) {
		pass.indexer.addUnion( str );
	}
}

template<typename pass_type>
static inline auto indexer_impl_addUnion( pass_type &, int, const std::string & ) {}