// 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_state.hh"

#include "nv/lua/lua_raw.hh"
#include "nv/lua/lua_nova.hh"
#include "nv/core/logging.hh"
#include "nv/stl/string.hh"

using namespace nv;

// stack_guard

#define NV_LUA_ABORT( func, ... ) \
	NV_LOG_CRITICAL( "lua::" func " : ", __VA_ARGS__ ) \
	NV_ABORT( "lua::" func " : critical error!" )


lua::stack_guard::stack_guard( lua::state* aL )
	: L(aL), m_level( lua_gettop(aL->m_state) )
{

}

lua::stack_guard::stack_guard( lua::state& aL )
	: L(&aL), m_level( lua_gettop(aL.m_state) )
{

}

lua::stack_guard::~stack_guard()
{
	lua_settop( L->m_state, m_level );
}

// stack_assert
nv::lua::stack_assert::stack_assert( lua::state* aL, int expected )
	: L(aL->get_raw()), m_expected( lua_gettop(aL->get_raw() ) + expected )
{

}

nv::lua::stack_assert::stack_assert( lua::state& aL, int expected )
	: L(aL.get_raw()), m_expected( lua_gettop(aL.get_raw() ) + expected )
{

}

nv::lua::stack_assert::stack_assert( lua_State* aL, int expected )
	: L(aL), m_expected( lua_gettop(aL) + expected )
{

}

lua::stack_assert::~stack_assert()
{
	NV_ASSERT( lua_gettop(L) == m_expected, "Lua stack corruption detected!" );
}


// state_wrapper

void nv::lua::state_wrapper::push_global_table()
{
	lua_pushglobaltable( m_state );
}

void nv::lua::state_wrapper::pop_global_table()
{
	lua_replace( m_state, -2 );
}

void lua::state_wrapper::call_get()
{
	lua_gettable( m_state, -2 );
}

void lua::state_wrapper::call_get_raw()
{
	lua_rawget( m_state, -2 );
}

void lua::state_wrapper::register_native_function( lfunction f, string_view name )
{
	if ( m_global ) push_global_table();
	lua_pushcfunction( m_state, f );
	lua_setfield( m_state, -2, name.data() );
	if ( m_global ) pop_global_table();
}

lua::state_wrapper::~state_wrapper()
{
	if (m_owner)
	{
		lua_close( m_state );
	}
}

bool nv::lua::state_wrapper::is_defined( const path& p, bool global )
{
	if ( !p.resolve( m_state, global ) )
	{
		return false;
	}
	bool result = !lua_isnil( m_state, -1 );
	lua_pop( m_state, 1 );
	return result;
}

bool nv::lua::state_wrapper::push_function( const path& p, bool global )
{
	if ( !p.resolve( m_state, global ) )
	{
		NV_LOG_ERROR( "Lua error : not a valid path - ", p.to_string() );
		return false;
	}

	if ( !lua_isfunction( m_state, -1 ) ) 
	{
		lua_pop( m_state, 1 );
		NV_LOG_ERROR( "Lua error : not a valid function - ", p.to_string() );
		return false;
	}
	return true;
}

int nv::lua::state_wrapper::call_function( int nargs, int nresults )
{
	int status = lua_pcall( m_state, nargs, nresults, 0 );
	if ( status != 0 )
	{
		NV_LOG_ERROR( "Lua error : ", lua_tostring( m_state, -1 ) );
		lua_pop( m_state, 1 );
	}
	return status;
}

// table_guard

lua::table_guard::table_guard( lua::state* lstate, const path& p, bool global )
	: state_wrapper( lstate->get_raw(), false ), m_level(0)
{
	m_global = false;
	m_level  = lua_gettop( m_state );
	if ( !p.resolve( m_state, global ) || lua_type(m_state, -1) != LUA_TTABLE )
	{
		NV_LOG_ERROR( "Could not resolve table!" );
		// TODO : error handling
	}
}

lua::table_guard::table_guard( const table_guard& parent, const path& p )
	: state_wrapper( parent.m_state, false ), m_level(0)
{
	m_global = false;
	m_level  = lua_gettop( m_state );
	if ( !p.resolve( m_state, false ) || lua_type(m_state, -1) != LUA_TTABLE )
	{
		NV_LOG_ERROR( "Could not resolve table!" );
		// TODO : error handling
	}
}

lua::table_guard::~table_guard()
{
	lua_settop( m_state, m_level );
}

nv::size_t lua::table_guard::get_size()
{
	return lua_rawlen( m_state, -1 );
}

bool lua::table_guard::has_field( string_view element )
{
	lua_getfield( m_state, -1, element.data() );
	bool result = !( lua_isnil( m_state, -1 ) );
	lua_pop( m_state, 1 );
	return result;
}

std::string lua::table_guard::get_std_string( string_view element, string_view defval /*= string_view() */ )
{
	lua_getfield( m_state, -1, element.data() );
	size_t l = 0;
	const char* str = nullptr;
	if ( lua_type( m_state, -1 ) == LUA_TSTRING )
	{
		str = lua_tolstring( m_state, -1, &l );
	}
	else
	{
		l = defval.size();
		str = defval.data();
	}
	std::string result( str, l );
	lua_pop( m_state, 1 );
	return result;
}

const_string lua::table_guard::get_string( string_view element, string_view defval /*= string_view() */ )
{
 	lua_getfield( m_state, -1, element.data() );
 	size_t l = 0;
 	const char* str = nullptr;
 	if ( lua_type( m_state, -1 ) == LUA_TSTRING )
 	{
 		str = lua_tolstring( m_state, -1, &l );
 	}
 	else
 	{
 		l = defval.size();
 		str = defval.data();
 	}
 	const_string result( str, l );
 	lua_pop( m_state, 1 );
 	return result;
}

char lua::table_guard::get_char( string_view element, char defval /*= "" */ )
{
	lua_getfield( m_state, -1, element.data() );
	char result = ( lua_type( m_state, -1 ) == LUA_TSTRING && lua_rawlen( m_state, -1 ) > 0 ) ? lua_tostring( m_state, -1 )[0] : defval;
	lua_pop( m_state, 1 );
	return result;
}

int lua::table_guard::get_integer( string_view element, int defval /*= "" */ )
{
	lua_getfield( m_state, -1, element.data() );
	lua_Integer result = lua_type( m_state, -1 ) == LUA_TNUMBER ? lua_tointeger( m_state, -1 ) : defval;
	lua_pop( m_state, 1 );
	return static_cast< int >( result );
}

unsigned lua::table_guard::get_unsigned( string_view element, unsigned defval /*= "" */ )
{
	lua_getfield( m_state, -1, element.data() );
	unsigned result = lua_type( m_state, -1 ) == LUA_TNUMBER ? lua_tounsigned( m_state, -1 ) : defval;
	lua_pop( m_state, 1 );
	return result;
}

double lua::table_guard::get_double( string_view element, double defval /*= "" */ )
{
	lua_getfield( m_state, -1, element.data() );
	double result = lua_type( m_state, -1 ) == LUA_TNUMBER ? lua_tonumber( m_state, -1 ) : defval;
	lua_pop( m_state, 1 );
	return result;
}


float nv::lua::table_guard::get_float( string_view element, float defval /*= 0.0 */ )
{
	lua_getfield( m_state, -1, element.data() );
	float result = lua_type( m_state, -1 ) == LUA_TNUMBER ? static_cast<float>( lua_tonumber( m_state, -1 ) ) : defval;
	lua_pop( m_state, 1 );
	return result;
}

bool lua::table_guard::get_boolean( string_view element, bool defval /*= "" */ )
{
	lua_getfield( m_state, -1, element.data() );
	bool result = lua_type( m_state, -1 ) == LUA_TBOOLEAN ? lua_toboolean( m_state, -1 ) != 0 : defval;
	lua_pop( m_state, 1 );
	return result;
}

bool nv::lua::table_guard::is_table( string_view element )
{
	lua_getfield( m_state, -1, element.data() );
	bool result = lua_type( m_state, -1 ) == LUA_TTABLE;
	lua_pop( m_state, 1 );
	return result;
}

bool nv::lua::table_guard::is_number( string_view element )
{
	lua_getfield( m_state, -1, element.data() );
	bool result = lua_type( m_state, -1 ) == LUA_TNUMBER;
	lua_pop( m_state, 1 );
	return result;
}

bool nv::lua::table_guard::is_boolean( string_view element )
{
	lua_getfield( m_state, -1, element.data() );
	bool result = lua_type( m_state, -1 ) == LUA_TBOOLEAN;
	lua_pop( m_state, 1 );
	return result;
}

bool nv::lua::table_guard::is_string( string_view element )
{
	lua_getfield( m_state, -1, element.data() );
	bool result = lua_type( m_state, -1 ) == LUA_TSTRING;
	lua_pop( m_state, 1 );
	return result;
}


// state

lua::state::state( lua_State* state ) : state_wrapper( state, false )
{

}

lua::state::state( bool load_libs /*= false*/ ) : state_wrapper( nullptr, true )
{
	load_lua_library();
	m_owner = true;
	m_state = luaL_newstate( );

	lua_pushcfunction(m_state, luaopen_base);
	lua_pushliteral(m_state, LUA_TABLIBNAME);
	lua_call(m_state, 1, 0);

	{
		// Preregister 8 references for Handle registry
		lua_newtable(m_state);
		NV_ASSERT( luaL_ref( m_state, LUA_REGISTRYINDEX ) == 1, "First reference not 1!" );
		for ( uint32 i = 1; i < 8; ++i )
		{
			lua_newtable(m_state);
			luaL_ref( m_state, LUA_REGISTRYINDEX );
		}
	}

	if ( load_libs )
	{
		stack_guard guard( this );
		static const luaL_Reg lualibs[] =
		{
			{ "string", luaopen_string },
			{ "table",  luaopen_table },
			{ "math",   luaopen_math },
			{ NULL, NULL}
		};
		const luaL_Reg *lib = lualibs;
		for(; lib->func != NULL; lib++)
		{
			lua_pushcfunction( m_state, lib->func );
			lua_call(m_state, 0, 1);
			lua_setglobal( m_state, lib->name );
		}
		register_nova( this );
	}

	NV_LOG_TRACE( "Lua state created" );
}

int lua::state::load_string( string_view code, string_view name )
{
	NV_LOG_TRACE( "Loading Lua string '", name, "'");
	return luaL_loadbuffer( m_state, code.data(), code.length(), name.data() );
}

int lua::state::load_file( string_view filename )
{
	NV_LOG_NOTICE( "Loading Lua file '", filename, "'");
	return luaL_loadfile( m_state, filename.data() );
}

bool lua::state::do_string( string_view code, string_view name, int rvalues )
{
	lua::stack_guard( this );
	int result = load_string(code,name);
	if (result)
	{
		NV_LOG_WARNING( "Failed to load string ", name, ": ", lua_tostring(m_state, -1));
		return false;
	}
	return do_current( name, rvalues ) == 0;
}

bool lua::state::do_file( string_view filename )
{
	lua::stack_guard( this );
	int result = load_file(filename);
	if (result) 
	{
		NV_LOG_WARNING( "Failed to open file ", filename, ": ", lua_tostring( m_state, -1 ) );
		return false;
	}
	return do_current( filename ) == 0;
}

int lua::state::do_current( string_view name, int rvalues )
{
	int result = lua_pcall(m_state, 0, rvalues, 0);
	if (result) 
	{
		NV_LOG_WARNING( "Failed to run script ", name, ": ", lua_tostring( m_state, -1 ) );
		lua_pop( m_state, 1 );
	}
	return result;
}

int lua::state::get_stack_size()
{
	return lua_gettop( m_state );
}

void lua::state::log_stack()
{
	int top = lua_gettop(m_state);
	NV_LOG_DEBUG( "Stack dump (", top, ")");
	for ( int i = 0; i < top; ++i )
	{
		NV_LOG_DEBUG( "#", i+1, " - ", lua_typename(m_state, lua_type(m_state, i+1) ), " = ", nlua_typecontent(m_state, i+1) );
	}
}

lua_State* lua::state::get_raw()
{
	return m_state;
}

lua::ref lua::state::register_object( void* o, string_view lua_name )
{
	if ( o == nullptr ) return lua::ref( lua::ref::none );
	stack_guard guard( this );
	lua_getglobal( m_state, lua_name.data() );
	if ( lua_isnil( m_state, -1 ) )
	{
		NV_LUA_ABORT( "state::register_object", lua_name, " type not registered!" );
	}
	deep_pointer_copy( -1, o );
	return lua::ref( luaL_ref( m_state, LUA_REGISTRYINDEX ) );
}

lua::ref lua::state::register_proto( string_view id, string_view storage )
{
	stack_guard guard( this );
	lua_getglobal( m_state, storage.data() );
	if ( lua_isnil( m_state, -1 ) )
	{
		NV_LUA_ABORT( "state::register_proto", "\"", storage, "\" storage not registered!" );
	}
	lua_getfield( m_state, -1, id.data() );
	if ( lua_isnil( m_state, -1 ) )
	{
		NV_LUA_ABORT( "state::register_proto", "\"", id, "\" not found in \"", storage, "\"!" );
	}
	return lua::ref( luaL_ref( m_state, LUA_REGISTRYINDEX ) );
}

void lua::state::register_native_object_method( string_view lua_name, string_view name, lfunction f )
{
	stack_guard guard( this );
	lua_getglobal( m_state, lua_name.data() );
	if ( lua_isnil( m_state, -1 ) )
	{
		NV_LUA_ABORT( "state::register_native_object_method", "\"", lua_name, "\" type not registered!" );
	}
	lua_pushcfunction( m_state, f );
	lua_setfield( m_state, -2, name.data() );
}

void lua::state::unregister_object( ref object_index )
{
	if ( !object_index.is_valid() ) return;
	stack_guard guard( this );
	lua_rawgeti( m_state, LUA_REGISTRYINDEX, object_index.get() );
	lua_pushliteral( m_state, "__ptr" );
	lua_pushboolean( m_state, false );
	lua_rawset( m_state, -3 );
	lua_pop( m_state, 1 );
	luaL_unref( m_state, LUA_REGISTRYINDEX, object_index.get() );
}


void lua::state::deep_pointer_copy( int index, void* obj )
{
	index = lua_absindex( m_state, index );
	lua_newtable( m_state );
	lua_pushnil( m_state );
	bool has_functions = false;
	bool has_metatable = false;

	while ( lua_next( m_state, index ) != 0 )
	{
		if ( lua_isfunction( m_state, -1 ) ) 
			has_functions = true;
		else if ( lua_istable( m_state, -1 ) )
		{
			deep_pointer_copy( -1, obj );
			lua_insert( m_state, -2 );
			lua_pop( m_state, 1 );
		}
		lua_pushvalue( m_state, -2 );
		lua_insert( m_state, -2 );
		lua_settable( m_state, -4 );
	}

	if ( lua_getmetatable( m_state, -2 ) )
	{
		lua_setmetatable( m_state, -2 );
		has_metatable = true;
	}

	if ( has_functions || has_metatable )
	{
		lua_pushliteral( m_state, "__ptr" );
		lua_pushlightuserdata( m_state, obj );
		lua_rawset( m_state, -3 );
	}
}

void nv::lua::state::store_metadata( ref object_index, string_view metaname, void* pointer )
{
	if ( !object_index.is_valid() ) return;
	lua_rawgeti( m_state, LUA_REGISTRYINDEX, object_index.get() );
	lua_pushlstring( m_state, metaname.data(), metaname.size() );
	lua_pushlightuserdata( m_state, pointer );
	lua_rawset( m_state, -3 );
	lua_pop( m_state, 1 );
}

void nv::lua::state::register_enum( string_view name, int value )
{
	lua_pushinteger( m_state, value );
	lua_setglobal( m_state, name.data() );
}

nv::lua::ref nv::lua::state::register_handle_component_impl( string_view id, bool empty )
{
	int args = empty ? 1 : 2;
	NV_LUA_STACK_ASSERT( m_state, -args );

	if ( lua_isnil( m_state, -1 ) || (!empty && lua_isnil( m_state, -2 )) )
	{
		lua_pop( m_state, args );
		return ref();
	}
	if (empty)
		lua_createtable( m_state, 0, 0 );
	else
		nlua_deepcopy( m_state, -2 );
	lua_pushlstring( m_state, id.data(), id.size() );
	lua_pushvalue( m_state, -2 );
	lua_rawset( m_state, -4 );
	lua_replace( m_state, -2 );
	ref result = lua::ref( luaL_ref( m_state, LUA_REGISTRYINDEX ) );
	if (!empty) lua_pop( m_state, 1 );
	return result;
}

void nv::lua::state::unregister_handle_component_impl( string_view id )
{
	NV_LUA_STACK_ASSERT( m_state, -1 );

	if ( lua_isnil( m_state, -1 ) )
	{
		lua_pop( m_state, 1 );
		return;
	}
	lua_pushlstring( m_state, id.data(), id.size() );
	lua_pushnil( m_state );
	lua_rawset( m_state, -3 );
	lua_pop( m_state, 1 );
}

void nv::lua::state::register_singleton( string_view name, void* o )
{
	if ( o == nullptr ) return;
	stack_guard guard( this );
	lua_getglobal( m_state, name.data() );
	if ( lua_isnil( m_state, -1 ) )
	{
		NV_LUA_ABORT( "state::register_singleton", "\"", name, "\" type not registered!" );
	}
	deep_pointer_copy( -1, o );
	lua_setglobal( m_state, name.data() );
}