hook_functions.lua

--[[
	#Kent Hook Library.
	
	Idea of this hook library is to maximize performance by using function recursion.

	Cons:
		Be extremely cautios of what you put as arguments. It doesn't have any tests cuz of performance reasons.
		Do not try to change hook.GetTable() and hooks (except the hook that's called by now) themselves while in hook.Call.
		second arg for hook.Call literally doesn't do anything. If your addon relies of using gamemode table argument for hook.Call, then i send you my regards.
		It WILL likely (98%) break your gmod. You need to patch a lot of stuff to get it to work.
	Pros:
		Max performance as possible.
		Literraly almost 0 overhead if hook has only 1 event.
		By bytecode means, kent hook library has less bytecode per 'call' function, than DASH.

	TODO:
		Make hook priority like in srlion's lib (very easy tbh) -- done
		Test hook priority properly...

	CREDITS:
		Made by kentovka team.
			Jaff&Radon
--]]

local originalHooks = {}
local hook = {
	MONITOR_HIGH = 4,
	HIGH = 3,
	NORMAL = 2,
	LOW = 1,
	MONITOR_LOW = 0
}

local hooks = {}

local funcGM = GM or GAMEMODE or {}

local function getTable(eventTable)
	local tab = {}
	local len = 0

	for k, v in pairs(eventTable) do
		if k ~= 0 then
			len = len + 1
			if isfunction(v) then
				tab[len] = v
			else
				tab[len] = v[1]
			end
		end
	end

	table.sort( tab, function(a, b)
		local a1, b1
		if isfunction(a) then
			a1 = hook.NORMAL
		else
			a1 = a[2]
		end

		if isfunction(b) then
			b1 = hook.NORMAL
		else
			b1 = a[2]
		end

		return a1 < b1
	end)

	return tab, len
end

local function createFunc(eventTable, name)
	local tab, len = getTable(eventTable)

	local gmFunc = funcGM[name]

	if gmFunc then
		return function(...)
			local ln, i = len, 0
			::start::
			i = i + 1

			local a, b, c, d, e, f = tab[i](...)

			if a ~= nil then
				return a, b, c, d, e, f
			end

			if i ~= ln then goto start end

			return gmFunc(funcGM, ...)
		end
	else
		return function(...)
			local ln, i = len, 0
			::start::
			i = i + 1

			local a, b, c, d, e, f = tab[i](...)

			if a ~= nil then
				return a, b, c, d, e, f
			end

			if i ~= ln then goto start end
		end
	end
end

local function createSingleFunc(eventTable, name)
	local _, func = next(eventTable, 0)
	if istable(func) then
		func = func[1]
	end

	local gmFunc = (funcGM)[name]

	if gmFunc then
		return function(...)
			local a, b, c, d, e, f = func(...)

			if a == nil then
				return gmFunc(funcGM, ...)
			end
			
			return a, b, c, d, e, f
		end
	else
		return func
	end
end

local function createRecursedFunc(eventTable, name)
	local tab, len = getTable(eventTable)

	local newFunc, start
	if funcGM[name] then
		local gmFunc = funcGM[name]

		newFunc = function(...)
			return gmFunc(funcGM, ...)
		end

		start = 1
	else
		newFunc = tab[1]
		start = 2
	end

	for i = start, len do
		local oldFunc = newFunc
		local func = tab[i]

		newFunc = function(...)
			
			local a, b, c, d, e, f = func(...)

			if a ~= nil then
				return a, b, c, d, e, f
			end

			return oldFunc(...)
		end
	end

	return newFunc
end

local function createGamemodeFunc(eventTable, eventName)
	local gmFunc = funcGM[eventName]

	if gmFunc then
		return function(...)
			return gmFunc(funcGM, ...)
		end
	end
end

local function setHookFuncion(eventName, eventTable)
	hooks[eventName] = ( (eventTable == nil or eventTable[0] == 0) and createGamemodeFunc or 
		eventTable[0] == 1 and createSingleFunc or 
		eventTable[0] < 4 and createRecursedFunc or 
		createFunc)(eventTable, eventName)
end

function hook.GetTable()
	local tab = {}
	for k, v in pairs(originalHooks) do
		local subTab = {}
		tab[k] = subTab
		for k1, v1 in pairs(v) do
			if istable(v1) then
				subTab[k1] = v1[1]
			elseif isfunction(v1) then
				subTab[k1] = v1
			end
		end
	end
	return tab
end

function hook.Add(eventName, name, func, priority)
	local eventTable = originalHooks[eventName]
	if eventTable == nil then
		eventTable = {[0] = 0}
		originalHooks[eventName] = eventTable
	end

	if eventTable[name] == nil then
		eventTable[0] = eventTable[0] + 1
	end

	if not isstring(name) and IsValid(name) then
		local oldFunc = func
		
		func = function(...)
			return oldFunc(name, ...)
		end
	end

	if priority then
		eventTable[name] = {func, priority}
	else
		eventTable[name] = func
	end

	setHookFuncion(eventName, eventTable)
end

function hook.Remove(eventName, name)
	local eventTable = originalHooks[eventName]

	if eventTable and eventTable[name] then
		eventTable[name] = nil
		eventTable[0] = eventTable[0] - 1
		setHookFuncion(eventName, eventTable)
	end
end

function hook.Call(eventName, _, ...)
	local func = hooks[eventName]

	if func then
		return func(...)
	end
end

function hook.Run(eventName, ...)
	local func = hooks[eventName]

	if func then
		return func(...)
	end
end


hook.Add('PostGamemodeLoaded', 'Kent hook', function()
	funcGM = GM or GAMEMODE
	for k, v in pairs(funcGM) do
		if isfunction(v) then
			setHookFuncion(k)
		end
	end

	hook.Remove("PostGamemodeLoaded", "Kent hook")
end)

_G['hook'] = hook