// Copyright (C) 2012-2015 ChaosForge Ltd
// http://chaosforge.org/
//
// This file is part of Nova libraries. 
// For conditions of distribution and use, see copying.txt file in root folder.

#include "nv/lua/lua_math.hh"

#include "nv/lua/lua_raw.hh"
#include "nv/lua/lua_aux.hh"
#include "nv/stl/type_traits/common.hh"

static size_t nlua_swizzel_lookup[256];

using nv::lua::detail::is_vec;
using nv::lua::detail::to_vec;
using nv::lua::detail::to_pvec;
using nv::lua::detail::push_vec;

inline bool nlua_is_swizzel( const unsigned char* str, size_t max )
{
	while (*str)
	{
		if (nlua_swizzel_lookup[*str] > max) return false;
		str++;
	}
	return true;
}

template < typename T, size_t k >
struct nlua_vec_constructor {
	static inline T unit() { return T(); }
	static inline T construct( lua_State*, int ) {
		return T();
	}
};

template < typename T > struct nlua_vec_constructor< T, 1 > {
	static inline T unit() { return T( 1 ); }
	static inline T construct( lua_State* L, int index ) {
		return T( lua_tonumber( L, index ) );
	}
};

template < typename T > struct nlua_vec_constructor< T, 2 > {
	static inline T unit() { return T( 1, 1 ); }
	static inline T construct( lua_State* L, int index ) {
		if ( lua_type( L, index ) == LUA_TUSERDATA )
			return to_vec<T>( L, index );
		else
			return T( lua_tonumber( L, index ), lua_tonumber( L, index + 1 ) );
	}
};

template < typename T > struct nlua_vec_constructor< T, 3 > {
	static inline T unit() { return T( 1, 1, 1 ); }
	static inline T construct( lua_State* L, int index ) {
		typedef nv::math::tvec2<typename T::value_type> vec2;
		if ( lua_type( L, index ) == LUA_TUSERDATA )
		{
			if ( is_vec<T>( L, index ) )
				return to_vec<T>( L, index );
			else
				return T( to_vec<vec2>( L, index ), lua_tonumber( L, index + 1 ) );
		}
		else
		{
			if ( lua_type( L, index+1 ) == LUA_TUSERDATA )
				return T( lua_tonumber( L, index ), to_vec<vec2>( L, index+1 ) );
			else
				return T( lua_tonumber( L, index ), lua_tonumber( L, index + 1 ), lua_tonumber( L, index + 2 ) );
		}
	}
};

template < typename T > struct nlua_vec_constructor< T, 4 > {
	static inline T unit() { return T( 1, 1, 1, 1 ); }
	static inline T construct( lua_State* L, int index ) {
		typedef nv::math::tvec2<typename T::value_type> vec2;
		typedef nv::math::tvec3<typename T::value_type> vec3;
		if ( lua_type( L, index ) == LUA_TUSERDATA )
		{
			if ( is_vec<T>( L, index ) )
				return to_vec<T>( L, index );
			else
			{
				if ( is_vec<vec3>( L, index ) )
					return T( to_vec<vec3>( L, index ), lua_tonumber( L, index + 1 ) );
				else
				{
					if ( lua_type( L, index+1 ) == LUA_TUSERDATA )
						return T( to_vec<vec2>( L, index ), to_vec<vec2>( L, index + 1 ) );
					else
						return T( to_vec<vec2>( L, index ), lua_tonumber( L, index + 1 ), lua_tonumber( L, index + 2 ) );
				}
			}
		}
		else
		{
			if ( lua_type( L, index+1 ) == LUA_TUSERDATA )
			{
				if ( is_vec<vec3>( L, index+1 ) )
					return T( lua_tonumber( L, index ), to_vec<vec3>( L, index+1 ) );
				else
					return T( lua_tonumber( L, index ), to_vec<vec2>( L, index+1 ), lua_tonumber( L, index + 2 ) );
			}
			else
			{
				if ( lua_type( L, index+2 ) == LUA_TUSERDATA )
					return T( lua_tonumber( L, index ), lua_tonumber( L, index + 1 ), to_vec<vec2>( L, index+2 ) );
				else
					return T( lua_tonumber( L, index ), lua_tonumber( L, index + 1 ), lua_tonumber( L, index + 2 ), lua_tonumber( L, index + 3 ) );
			}
		}
	}
};

template< typename T >
int nlua_vec_new( lua_State* L )
{
	push_vec<T>( L, nlua_vec_constructor<T,sizeof( T ) / sizeof( typename T::value_type )>::construct( L, 1 ) );
	return 1;
}

template< typename T >
int nlua_vec_random( lua_State* L )
{
	push_vec<T>( L, nv::lua::rng().range( to_vec<T>( L, 1 ), to_vec<T>( L, 2 ) ) );
	return 1;
}

template< typename T >
int nlua_vec_clone( lua_State* L )
{
	push_vec<T>( L, to_vec<T>( L, 1 ) );
	return 1;
}

template< typename T >
int nlua_vec_sign( lua_State* L )
{
	push_vec<T>( L, nv::math::sign( to_vec<T>( L, 1 ) ) );
	return 1;
}

template< typename T >
int nlua_vec_call( lua_State* L )
{
	push_vec<T>( L, nlua_vec_constructor<T,sizeof( T ) / sizeof( typename T::value_type )>::construct( L, 2 ) );
	return 1;
}

template< typename T >
static int nlua_vec_unm( lua_State* L )
{
	push_vec<T>( L, -to_vec<T>( L, 1 ) );
	return 1;
}

template< typename T >
int nlua_vec_add( lua_State* L )
{
	T v;
	if ( lua_type( L, 1 ) == LUA_TNUMBER )
		v = static_cast<typename T::value_type>(lua_tonumber( L, 1 )) + to_vec<T>( L, 2 );
	else
		if ( lua_type( L, 2 ) == LUA_TNUMBER )
			v = to_vec<T>( L, 1 ) + static_cast<typename T::value_type>( lua_tonumber( L, 2 ) );
		else
			v = to_vec<T>( L, 1 ) + to_vec<T>( L, 2 );
	push_vec<T>( L, v );
	return 1;
}

template< typename T >
int nlua_vec_sub( lua_State* L )
{
	T v;
	if ( lua_type( L, 1 ) == LUA_TNUMBER )
		v = static_cast<typename T::value_type>(lua_tonumber( L, 1 )) - to_vec<T>( L, 2 );
	else
		if ( lua_type( L, 2 ) == LUA_TNUMBER )
			v = to_vec<T>( L, 1 ) - static_cast<typename T::value_type>(lua_tonumber( L, 2 ) );
		else
			v = to_vec<T>( L, 1 ) - to_vec<T>( L, 2 );
	push_vec<T>( L, v );
	return 1;
}

template< typename T >
int nlua_vec_mul( lua_State* L )
{
	T v;
	if ( lua_type( L, 1 ) == LUA_TNUMBER )
		v = static_cast<typename T::value_type>(lua_tonumber( L, 1 )) * to_vec<T>( L, 2 );
	else
		if ( lua_type( L, 2 ) == LUA_TNUMBER )
			v = to_vec<T>( L, 1 ) * static_cast<typename T::value_type>(lua_tonumber( L, 2 ));
		else
			v = to_vec<T>( L, 1 ) * to_vec<T>( L, 2 );
	push_vec<T>( L, v );
	return 1;
}

template< typename T >
int nlua_vec_div( lua_State* L )
{
	T v;
	if ( lua_type( L, 1 ) == LUA_TNUMBER )
		v = static_cast<typename T::value_type>(lua_tonumber( L, 1 )) / to_vec<T>( L, 2 );
	else
		if ( lua_type( L, 2 ) == LUA_TNUMBER )
			v = to_vec<T>( L, 1 ) / static_cast<typename T::value_type>(lua_tonumber( L, 2 ));
		else
			v = to_vec<T>( L, 1 ) / to_vec<T>( L, 2 );
	push_vec<T>( L, v );
	return 1;
}

template< typename T >
int nlua_vec_eq( lua_State* L )
{
	lua_pushboolean( L, to_vec<T>( L, 1 ) == to_vec<T>( L, 2 ) );
	return 1;
}

template< typename T >
int nlua_vec_get( lua_State* L )
{
	T v = to_vec<T>( L, 1 );
	for ( size_t i = 0; i < v.size(); ++i )
	{
		lua_pushnumber( L, v[i] );
	}
	return v.size();
}

template< typename T >
int nlua_vec_index( lua_State* L )
{
	T* v = to_pvec<T>( L, 1 );
	size_t len  = 0;
	size_t vlen = v->size();
	const unsigned char * key = reinterpret_cast<const unsigned char *>( lua_tolstring( L, 2, &len ) );
	size_t idx = 255;

	if ( len == 1 )
	{
		idx = nlua_swizzel_lookup[ key[ 0 ] ];
		if ( idx < vlen )
		{
			lua_pushnumber( L, (*v)[idx] );
			return 1;
		}
	}
	else if ( len < 4 && nlua_is_swizzel(key,vlen-1) )
	{
		switch (len) {
		case 2 : push_vec( L, nv::math::tvec2<typename T::value_type>( (*v)[nlua_swizzel_lookup[key[0]]], (*v)[nlua_swizzel_lookup[key[1]]] ) ); return 1;
		case 3 : push_vec( L, nv::math::tvec3<typename T::value_type>( (*v)[nlua_swizzel_lookup[key[0]]], (*v)[nlua_swizzel_lookup[key[1]]], (*v)[nlua_swizzel_lookup[key[2]]] ) ); return 1;
		case 4 : push_vec( L, nv::math::tvec4<typename T::value_type>( (*v)[nlua_swizzel_lookup[key[0]]], (*v)[nlua_swizzel_lookup[key[1]]], (*v)[nlua_swizzel_lookup[key[2]]], (*v)[nlua_swizzel_lookup[key[3]]] ) ); return 1;
		default: break;
		}
	}

	luaL_getmetafield( L, 1, "__functions" );
	lua_pushvalue( L, 2 );
	lua_rawget( L, -2 );
	return 1;
}

template< typename T >
int nlua_vec_newindex( lua_State* L )
{
	typedef nv::math::tvec2<typename T::value_type> vec2;
	typedef nv::math::tvec3<typename T::value_type> vec3;
	typedef nv::math::tvec4<typename T::value_type> vec4;

	T* v = to_pvec<T>( L, 1 );
	size_t len  = 0;
	size_t vlen = v->size();
	const unsigned char * key = reinterpret_cast<const unsigned char *>( lua_tolstring( L, 2, &len ) );
	size_t idx = 255;
	if( len == 1 )
	{
		idx = nlua_swizzel_lookup[ key[ 0 ] ];
		if ( idx < vlen )
		{
			(*v)[idx] = static_cast<typename T::value_type>( luaL_checknumber( L, 3 ) );
			return 0;
		}
	}
	else if ( len < 4 && nlua_is_swizzel(key,vlen-1) )
	{
 		switch (len) {
		case 2 : { vec2 v2 = to_vec<vec2>(L,3); for ( size_t i = 0; i< len; ++i) (*v)[nlua_swizzel_lookup[key[i]]] = v2[i]; } return 0;
		case 3 : { vec3 v3 = to_vec<vec3>(L,3); for ( size_t i = 0; i< len; ++i) (*v)[nlua_swizzel_lookup[key[i]]] = v3[i]; } return 0;
		case 4 : { vec4 v4 = to_vec<vec4>(L,3); for ( size_t i = 0; i< len; ++i) (*v)[nlua_swizzel_lookup[key[i]]] = v4[i]; } return 0;
 		default: break;
		}
	}
	return 0;
}

template< typename T >
static int nlua_vec_tostring( lua_State* L )
{
	T v = to_vec<T>( L, 1 );
	bool fl = nv::is_floating_point<typename T::value_type>::value;
	switch ( v.size() )
	{
	case 1: lua_pushfstring( L, ( fl ? "(%f)"          : "(%d)" ),          v[0] ); break;
	case 2: lua_pushfstring( L, ( fl ? "(%f,%f)"       : "(%d,%d)" ),       v[0], v[1] ); break;
	case 3: lua_pushfstring( L, ( fl ? "(%f,%f,%f)"    : "(%d,%d,%d)" ),    v[0], v[1], v[2] ); break;
	case 4: lua_pushfstring( L, ( fl ? "(%f,%f,%f,%f)" : "(%d,%d,%d,%d)" ), v[0], v[1], v[2], v[3] ); break;
	default:
		lua_pushliteral( L, "(vector?)" ); break;
	}
	return 1;
}

template< typename T >
int luaopen_vec( lua_State * L )
{
	static const struct luaL_Reg nlua_vec_sf [] = {
		{ "new",            nlua_vec_new<T> },
		{ "random",         nlua_vec_random<T> },
		{NULL, NULL}
	};

	static const struct luaL_Reg nlua_vec_f [] = {
		{ "clone",          nlua_vec_clone<T> },
		{ "sign",           nlua_vec_sign<T> },
		{ "get",            nlua_vec_get<T> },
		{ "tostring",       nlua_vec_tostring<T> },
		{NULL, NULL}
	};

	static const struct luaL_Reg nlua_vec_sm [] = {
		{ "__call",         nlua_vec_call<T> },
		{NULL, NULL}
	};

	static const struct luaL_Reg nlua_vec_m [] = {
		{ "__add",      nlua_vec_add<T> },
		{ "__sub",      nlua_vec_sub<T> },
		{ "__unm",      nlua_vec_unm<T> },
		{ "__mul",      nlua_vec_mul<T> },
		{ "__div",      nlua_vec_div<T> },
		{ "__eq",       nlua_vec_eq<T> },
		{ "__index",    nlua_vec_index<T> },
		{ "__newindex", nlua_vec_newindex<T> },
		{ "__tostring", nlua_vec_tostring<T> },
		{NULL, NULL}
	};

	luaL_newmetatable( L, nv::lua::pass_traits<T>::metatable() );
	nlua_register( L, nlua_vec_m, -1 );
	lua_createtable( L, 0, 0 );
	nlua_register( L, nlua_vec_f, -1 );
	lua_setfield(L, -2, "__functions" );
	lua_pop( L, 1 );

	lua_createtable( L, 0, 0 );
	nlua_register( L, nlua_vec_sf, -1 );
	lua_createtable( L, 0, 0 );
	nlua_register( L, nlua_vec_sm, -1 );
	lua_setmetatable( L, -2 );

	nv::lua::detail::push_vec( L, T() );
	lua_setfield( L, -2, "ZERO" );
	nv::lua::detail::push_vec( L, nlua_vec_constructor<T,sizeof( T ) / sizeof( typename T::value_type )>::unit() );
	lua_setfield( L, -2, "UNIT" );
	return 1;
}

template < typename T >
void nlua_rtti_vec_push( nv::lua::state* state, const nv::type_entry*, void* object )
{
	T* value = reinterpret_cast<T*>( object );
	push_vec<T>( state->get_raw(), *value );
}

template < typename T >
bool nlua_rtti_vec_read( nv::lua::state* state, const nv::type_entry*, void* object, int index )
{
	T* value = reinterpret_cast<T*>( object );
	int type = lua_type( state->get_raw(), index );
	if ( type == LUA_TUSERDATA )
	{
		T* from = to_pvec<T>( state->get_raw(), index );
		if ( !from ) return false;
		*value = *from;
	}
// 	else if ( type == LUA_TTABLE )
// 	{
// 
// 	}
	else
		return false;
	int todo; int table_constructor;
	return true;
}

void nv::lua::register_math( lua::state* state )
{ 
	for (size_t i = 0; i < 256; ++i ) nlua_swizzel_lookup[i] = 255;
	using nv::uchar8;
	nlua_swizzel_lookup[uchar8( 'x' )] = 0;
	nlua_swizzel_lookup[uchar8( 'r' )] = 0;
	nlua_swizzel_lookup[uchar8( 's' )] = 0;
	nlua_swizzel_lookup[uchar8( '0' )] = 0;
	nlua_swizzel_lookup[uchar8( 'y' )] = 1;
	nlua_swizzel_lookup[uchar8( 'g' )] = 1;
	nlua_swizzel_lookup[uchar8( 't' )] = 0;
	nlua_swizzel_lookup[uchar8( '1' )] = 1;
	nlua_swizzel_lookup[uchar8( 'z' )] = 2;
	nlua_swizzel_lookup[uchar8( 'b' )] = 2;
	nlua_swizzel_lookup[uchar8( 'u' )] = 0;
	nlua_swizzel_lookup[uchar8( '2' )] = 2;
	nlua_swizzel_lookup[uchar8( 'w' )] = 3;
	nlua_swizzel_lookup[uchar8( 'a' )] = 3;
	nlua_swizzel_lookup[uchar8( 'v' )] = 0;
	nlua_swizzel_lookup[uchar8( '3' )] = 3;

	lua_State* L = state->get_raw();
	int stack = lua_gettop( L );

	nlua_requiref(L, "coord", luaopen_vec<nv::ivec2>, 1);
	nlua_requiref(L, "ivec2", luaopen_vec<nv::ivec2>, 1);
	nlua_requiref(L, "ivec3", luaopen_vec<nv::ivec3>, 1);
	nlua_requiref(L, "ivec4", luaopen_vec<nv::ivec4>, 1);
	nlua_requiref(L, "vec2", luaopen_vec<nv::vec2>, 1);
	nlua_requiref(L, "vec3", luaopen_vec<nv::vec3>, 1);
	nlua_requiref(L, "vec4", luaopen_vec<nv::vec4>, 1);
	lua_settop( L, stack );

	state->register_rtti_type< nv::ivec2 >( nlua_rtti_vec_push<nv::ivec2>, nlua_rtti_vec_read<nv::ivec2> );
	state->register_rtti_type< nv::ivec3 >( nlua_rtti_vec_push<nv::ivec3>, nlua_rtti_vec_read<nv::ivec3> );
	state->register_rtti_type< nv::ivec4 >( nlua_rtti_vec_push<nv::ivec4>, nlua_rtti_vec_read<nv::ivec4> );
	state->register_rtti_type< nv::vec2 > ( nlua_rtti_vec_push<nv::vec2>,  nlua_rtti_vec_read<nv::vec2> );
	state->register_rtti_type< nv::vec3 > ( nlua_rtti_vec_push<nv::vec3>,  nlua_rtti_vec_read<nv::vec3> );
	state->register_rtti_type< nv::vec4 > ( nlua_rtti_vec_push<nv::vec4>,  nlua_rtti_vec_read<nv::vec4> );
}