local EVENTS = {};
local GLOBAL_EVENTS = {};

local _addEventHandler = addEventHandler;
local _removeEventHandler = removeEventHandler;
local _getEventHandlers = getEventHandlers;
local _addEvent = addEvent;

function addEvent(sEventName, bGlobal)
    if type(sEventName) ~= 'string' then
        return false
    end

    if type(bGlobal) ~= 'boolean' then
        bGlobal = false
    end

    if not EVENTS[sEventName] then
        EVENTS[sEventName] = {}
    end

    if bGlobal then
        GLOBAL_EVENTS[sEventName] = true
    end

    return _addEvent(sEventName, bGlobal)
end

local function getEventHandlers(sEventName, pElementAttachedTo)
    if type(sEventName) ~= 'string' then
        return false
    end

    if type (pElementAttachedTo) ~= 'userdata' then
        return false;
    end

    if not isElement(pElementAttachedTo) then
        return false;
    end
    
    return _getEventHandlers(sEventName, pElementAttachedTo) or {}
end

local function isEventHandlerAdded(sEventName, pElementAttachedTo, func)
    if type (sEventName) ~= 'string' then
        return false
    end

    if type (func) ~= 'function' then
        return false
    end

    if type (pElementAttachedTo) ~= 'userdata' or not isElement(pElementAttachedTo) then
        return true
    end

    if EVENTS[sEventName] and EVENTS[sEventName][pElementAttachedTo] and EVENTS[sEventName][pElementAttachedTo][func] then
        return true
    end

    local aAttachedFunctions = getEventHandlers(sEventName, pElementAttachedTo)
    
    if type(aAttachedFunctions) ~= 'table' then
        return false
    end

    if next(aAttachedFunctions) == nil then
        return false;
    end

    for i, v in next, aAttachedFunctions, nil do
        if (v == func) then
            return true
        end
    end

    return false
end

local function addEventHandler(sEventName, pElementAttachedTo, func, ...)
    if isEventHandlerAdded(sEventName, pElementAttachedTo, func) then
        return false
    end

    if _addEventHandler(sEventName, pElementAttachedTo, func, ...) then
        if not EVENTS[sEventName] then
            EVENTS[sEventName] = {}
        end

        if not EVENTS[sEventName][pElementAttachedTo] then
            EVENTS[sEventName][pElementAttachedTo] = {}
        end

        EVENTS[sEventName][pElementAttachedTo][func] = true
        return true
    end
end

local function removeEventHandler(sEventName, pElementAttachedTo, func)
    if isEventHandlerAdded(sEventName, pElementAttachedTo, func) then
        if EVENTS[sEventName] and EVENTS[sEventName][pElementAttachedTo] then
            if EVENTS[sEventName][pElementAttachedTo][func] then
                EVENTS[sEventName][pElementAttachedTo][func] = nil
            end

            if next(EVENTS[sEventName][pElementAttachedTo]) == nil then
                EVENTS[sEventName][pElementAttachedTo] = nil
            end

            if next(EVENTS[sEventName]) == nil then
                EVENTS[sEventName] = nil
            end
        end
        return _removeEventHandler(sEventName, pElementAttachedTo, func)
    end

    return false
end

local function RegisterNetEvent(event, attach, func, propagate, priority)
    assert(type(event) == 'string', 'eventName not is a string')

    addEvent(event, true)
    if isElement(attach) and func then
        addEventHandler(event, attach, func, propagate, priority)
    end
end

local function RegisterCommand(commandName, func, restrict, sensivite)
    return addCommandHandler(commandName, func, restrict, sensivite);
end

_G.addEventHandler = _addEventHandler;
_G.removeEventHandler = _removeEventHandler;
_G.getEventHandlers = _getEventHandlers;

_G.addEventHandler = addEventHandler;
_G.removeEventHandler = removeEventHandler;
_G.getEventHandlers = getEventHandlers;
_G.RegisterNetEvent = RegisterNetEvent;
_G.RegisterCommand = RegisterCommand;
_G.isEventHandlerAdded = isEventHandlerAdded;