#include "LuaVM.hpp"
#include "StringUtils.hpp"

#ifdef _WIN32
#define snprintf _snprintf
#endif
#define __STDC_FORMAT_MACROS
#include "util/IntTypes.hpp"

#include <stdexcept>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <string>

using namespace std;

LuaVM::LuaVM( ) : m_lua( 0 )
{
	initialize( );
}

LuaVM::~LuaVM( )
{
	lua_close( m_lua );
}

lua_State *LuaVM::handle( )
{
	return m_lua;
}

void LuaVM::initialize( )
{
	m_lua = luaL_newstate( );
	
	luaL_openlibs( m_lua );
}

void LuaVM::fullGarbageCollect( )
{
	lua_gc( m_lua, LUA_GCCOLLECT, 0 );
}

void LuaVM::loadSource( const char *sourceFilename )
{
	int res;
	
	m_sourceFilename.assign( sourceFilename );
	
	res = luaL_loadfile( m_lua, m_sourceFilename.c_str( ) );
	if( res != 0 ) {
		ostringstream ss;
		ss << "Can't read Lua source file from file '" << m_sourceFilename << "': " << lua_tostring( m_lua, -1 );
		lua_pop( m_lua, 1 );
		throw std::runtime_error( ss.str( ) );
	}
}

void LuaVM::executeMain( )
{
	int res = lua_pcall( m_lua, 0, 0, 0 );
	if( res != 0 ) {
		ostringstream ss;
		ss << "Can't execute main body of Lua source file '" << m_sourceFilename << "': " << lua_tostring( m_lua, -1 );
		lua_pop( m_lua, 1 );
		throw std::runtime_error( ss.str( ) );
	}
}

void LuaVM::executeFunction( const string &f )
{
	//int top = lua_gettop( m_lua );
	lua_getglobal( m_lua, f.c_str( ) );	
	int res = lua_pcall( m_lua, 0, LUA_MULTRET, 0 );
	if( res != 0 ) {
		ostringstream ss;
		ss << "Unable to call Lua function '" << f << "': " << lua_tostring( m_lua, -1 );
		lua_pop( m_lua, 1 );
		throw std::runtime_error( ss.str( ) );
	}
	//int nresults = lua_gettop( m_lua ) - top;
	
	// TODO: return results
}

void LuaVM::dumpGlobals( )
{
	lua_rawgeti( m_lua, LUA_REGISTRYINDEX, LUA_RIDX_GLOBALS );
	lua_pushnil( m_lua );
	while( lua_next( m_lua, -2 ) ) {
		if( lua_type( m_lua, -2 ) == LUA_TSTRING ) {
			cout << lua_tostring( m_lua, -2 ) << endl;
		}
		lua_pop( m_lua, 1 );
	}
}

void LuaVM::dumpStackElement( lua_State *l, int i, int indent )
{
	int type = lua_type( l, i );

	if( indent == 0 ) {
		cout << setfill( '0' ) << setw( 2 ) << i << ": ";
	}
		
	switch( type ) {
		case LUA_TNIL:
			cout << "LUA_TNIL nil";
			break;
			
		case LUA_TBOOLEAN:
			cout << "LUA_TBOOLEAN " << ( lua_toboolean( l, i ) ? "true" : "false" );
			break;

		case LUA_TNUMBER:
			cout << "LUA_TNUMBER " << lua_tonumber( l, i ) << "";
			break;

		case LUA_TSTRING:
			cout << "LUA_TSTRING '" << lua_tostring( l, i ) << "'";
			break;
		
		case LUA_TTABLE:
			cout << "LUA_TTABLE { ";
			
			lua_pushvalue( l, i );
			lua_pushnil( l );
			while( lua_next( l, -2 ) ) {
				lua_pushvalue( l, -2 );
				if( lua_isstring( l, -1 ) ) {
					cout << lua_tostring( l, -1 );
				} else {
					cout << "<unknown key type "
						<< lua_typename( l, lua_type( l, -1 ) ) << ">";
				}
				
				cout << " = ";
				
				dumpStackElement( l, -2, indent + 1 );
				
				cout << ", ";
				
				lua_pop( l, 2 );
			}
			lua_pop( l, 1 );
				
			cout << " }";
			
			break;
			
		case LUA_TFUNCTION: {
			lua_CFunction f = lua_tocfunction( l, i );
			char buf[33];
			snprintf( buf, 32, "function[%016" PRIxPTR "]", (uintptr_t)f );
			// TODO: int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar);
			cout << "LUA_TFUNCTION " << buf;
			break;
		}
		
		case LUA_TLIGHTUSERDATA: {
			void *p = lua_touserdata( l, i );
			char buf[33];
			snprintf( buf, 32, "void *[%016" PRIxPTR "]", (uintptr_t)p );
			cout << "LUA_TLIGHTUSERDATA " << buf;
			break;
		}
		
		case LUA_TUSERDATA: {
			void *p = lua_touserdata( l, i );
			char buf[33];
			snprintf( buf, 32, "void *[%016" PRIxPTR "]", (uintptr_t)p );
			// TODO: is there a tostring entry in the metatable?
			cout << "LUA_TUSERDATA " << buf;
			break;
		}
			
		case LUA_TTHREAD: {
			//lua_State *thread = lua_tothread( l, i );
			// TODO: more information like status of the thread?
			cout << "LUA_TTHREAD ";
			break;
		}
								
		default:
			cout << lua_typename( l, type ) << " <unknown>";
			break;
	}
	
	if( indent == 0 ) {
		cout << endl;
	}
}

void LuaVM::dumpStack( )
{
	cout << "-- stack --" << endl;
	
	int top = lua_gettop( m_lua );
	for( int i = 1; i <= top; i++ ) {
		dumpStackElement( m_lua, i );		
	}

	cout << "-- end of stack --" << endl;
}

void LuaVM::dumpState( )
{
	cout << "globals:" << endl;
	dumpGlobals( );
	cout << "stack:" << endl;
	dumpStack( );
}
    
int LuaVM::findValue( const string &key )
{
	vector<string> parts = split( key, "." );

	if( parts.size( ) == 1 ) {
		lua_getglobal( m_lua, parts[0].c_str( ) );

		if( lua_isnil( m_lua, -1 ) ) {
			lua_pop( m_lua, 1 );
			ostringstream ss;
			ss << "key '" << key << "' refers to an empty element";
			throw runtime_error( ss.str( ) );
		}

		return 1;
	}
	
	lua_getglobal( m_lua, parts[0].c_str( ) );
	for( int i = 1; i <= (int)parts.size( ) - 1; i++ ) {
		if( !lua_istable( m_lua, -1 ) ) {
			lua_pop( m_lua, i );
			ostringstream ss;
			ss << "table expected in '" << key << "' when derefencing field '" << parts[i] << "'";
			throw runtime_error( ss.str( ) );
		}
		lua_getfield( m_lua, -1, parts[i].c_str( ) );
	}
	
	if( lua_isnil( m_lua, -1 ) ) {
		lua_pop( m_lua, (int)parts.size( ) );
		ostringstream ss;
		ss << "key '" << key << "' refers to an empty element";
		throw runtime_error( ss.str( ) );
	}
	
	return parts.size( );
}

string LuaVM::getString( const string &key )
{
	int n = findValue( key );	

	string res = lua_tostring( m_lua, -1 );
	lua_pop( m_lua, n );	

	//dumpStack( );
	
	return res;
}

int LuaVM::getInt( const std::string &key )
{
	int n = findValue( key );	

	int res = lua_tointeger( m_lua, -1 );
	lua_pop( m_lua, n );	

	//dumpStack( );
	
	return res;
}

bool LuaVM::getBoolean( const string &key )
{
	int n = findValue( key );	

	bool res = lua_toboolean( m_lua, -1 );
	lua_pop( m_lua, n );	

	//dumpStack( );
	
	return res;
}

vector<string> LuaVM::getStringArray( const string &key )
{
	vector<string> res;
	
	int n = findValue( key );
	
	if( !lua_istable( m_lua, -1 ) ) {
		lua_pop( m_lua, n );
		ostringstream ss;
		ss << "key '" << key << "' refers not to a table";
		throw runtime_error( ss.str( ) );
	}
	
	//dumpStack( );
	
	lua_pushvalue( m_lua, -1 );
	lua_pushnil( m_lua );
	while( lua_next( m_lua, -2 ) ) {
		res.push_back( lua_tostring( m_lua, -1 ) );
		lua_pop( m_lua, 1 );
	}
	lua_pop( m_lua, 1 );
		
	lua_pop( m_lua, n );
	
	return res;
}