#include "ScriptController.h"

namespace gameplay
{

// Helper macros.
#define SCRIPT_EXECUTE_FUNCTION_PARAM(type, checkfunc) \
    va_list list; \
    va_start(list, args); \
    executeFunctionHelper(1, func, args, list); \
    type value = (type)checkfunc(_lua, -1); \
    lua_pop(_lua, -1); \
    va_end(list); \
    return value;

template<typename T> T ScriptController::executeFunction(const char* func, const char* args, ...)
{
    GP_ERROR("Unsupported type!");
}

template<> void ScriptController::executeFunction<void>(const char* func, const char* args, ...)
{
    va_list list;
    va_start(list, args);
    executeFunctionHelper(0, func, args, list);
    va_end(list);
}

template<> bool ScriptController::executeFunction<bool>(const char* func, const char* args, ...)
{
    SCRIPT_EXECUTE_FUNCTION_PARAM(bool, luaCheckBool);
}

template<> char ScriptController::executeFunction<char>(const char* func, const char* args, ...)
{
    SCRIPT_EXECUTE_FUNCTION_PARAM(char, luaL_checkint);
}

template<> short ScriptController::executeFunction<short>(const char* func, const char* args, ...)
{
    SCRIPT_EXECUTE_FUNCTION_PARAM(short, luaL_checkint);
}

template<> int ScriptController::executeFunction<int>(const char* func, const char* args, ...)
{
    SCRIPT_EXECUTE_FUNCTION_PARAM(int, luaL_checkint);
}

template<> long ScriptController::executeFunction<long>(const char* func, const char* args, ...)
{
    SCRIPT_EXECUTE_FUNCTION_PARAM(long, luaL_checklong);
}

template<> unsigned char ScriptController::executeFunction<unsigned char>(const char* func, const char* args, ...)
{
    SCRIPT_EXECUTE_FUNCTION_PARAM(unsigned char, luaL_checkunsigned);
}

template<> unsigned short ScriptController::executeFunction<unsigned short>(const char* func, const char* args, ...)
{
    SCRIPT_EXECUTE_FUNCTION_PARAM(unsigned short, luaL_checkunsigned);
}

template<> unsigned int ScriptController::executeFunction<unsigned int>(const char* func, const char* args, ...)
{
    SCRIPT_EXECUTE_FUNCTION_PARAM(unsigned int, luaL_checkunsigned);
}

template<> unsigned long ScriptController::executeFunction<unsigned long>(const char* func, const char* args, ...)
{
    SCRIPT_EXECUTE_FUNCTION_PARAM(unsigned long, luaL_checkunsigned);
}

template<> float ScriptController::executeFunction<float>(const char* func, const char* args, ...)
{
    SCRIPT_EXECUTE_FUNCTION_PARAM(float, luaL_checknumber);
}

template<> double ScriptController::executeFunction<double>(const char* func, const char* args, ...)
{
    SCRIPT_EXECUTE_FUNCTION_PARAM(double, luaL_checknumber);
}

template<> std::string ScriptController::executeFunction<std::string>(const char* func, const char* args, ...)
{
    SCRIPT_EXECUTE_FUNCTION_PARAM(std::string, luaL_checkstring);
}

template<typename T> T* ScriptController::executeFunction(const Type& type, const char* func, const char* args, ...)
{
    va_list list;
    va_start(list, args);
    executeFunctionHelper(1, func, args, list);

    T* value = (T*)*((T**)luaL_checkudata(_lua, -1, type.type));
    lua_pop(_lua, -1);
    va_end(list);
    return value;
}

template<typename T>T* ScriptController::getObjectPointer(int index, const char* type, bool nonNull)
{
    if (lua_type(_lua, index) == LUA_TNIL)
    {
        if (nonNull)
        {
            GP_ERROR("Attempting to pass NULL for required non-NULL parameter at index %d (likely a reference or by-value parameter).", index);
        }

        return NULL;
    }

    void* p = lua_touserdata(_lua, index);
    if (p != NULL)
    {
        if (lua_getmetatable(_lua, index))
        {
            // Check if it matches the type's metatable.
            luaL_getmetatable(_lua, type);
            if (lua_rawequal(_lua, -1, -2))
            {
                lua_pop(_lua, 2);
                T* ptr = (T*)((ScriptController::LuaObject*)p)->instance;
                if (ptr == NULL && nonNull)
                {
                    GP_ERROR("Attempting to pass NULL for required non-NULL parameter at index %d (likely a reference or by-value parameter).", index);
                }
                return ptr;
            }
            lua_pop(_lua, 1);

            // Check if it matches any of the derived types' metatables.
            const std::vector<std::string>& types = _hierarchy[type];
            for (unsigned int i = 0, count = types.size(); i < count; i++)
            {
                luaL_getmetatable(_lua, types[i].c_str());
                if (lua_rawequal(_lua, -1, -2))
                {
                    lua_pop(_lua, 2);
                    T* ptr = (T*)((ScriptController::LuaObject*)p)->instance;
                    if (ptr == NULL && nonNull)
                    {
                        GP_ERROR("Attempting to pass NULL for required non-NULL parameter at index %d (likely a reference or by-value parameter).", index);
                    }
                    return ptr;
                }
                lua_pop(_lua, 1);
            }
            
            lua_pop(_lua, 1);
        }
    }

    if (nonNull)
    {
        GP_ERROR("Failed to retrieve a valid object pointer of type '%s' for parameter %d.", type, index);
    }
    return NULL;
}

template<typename T>T* ScriptController::getObjectPointer(const char* type, const char* name)
{
    lua_getglobal(_lua, name);
    void* userdata = luaL_checkudata(_lua, -1, type);
    std::string msg = std::string("'") + std::string(type) + std::string("' expected.");
    luaL_argcheck(_lua, userdata != NULL, 1, msg.c_str());
    return (T*)((ScriptController::LuaObject*)userdata)->instance;
}

template<typename T>void ScriptController::setPointer(const char* type, const char* name, T* v)
{
    ScriptController::LuaObject* object = (ScriptController::LuaObject*)lua_newuserdata(state, sizeof(ScriptController::LuaObject));
    object->instance = (void*)v;
    object->owns = false;
    luaL_getmetatable(state, type);
    lua_setmetatable(state, -2);
    lua_setglobal(_lua, name);
}

}