event.lua

local name, ns = ...
local oGlow = ns.oGlow

local argcheck = oGlow.argcheck

local eventFrame = CreateFrame'Frame'
eventFrame:SetScript('OnEvent', function(self, event, ...)
	return oGlow[event](oGlow, event, ...)
end)

local eventMetatable = {
	__call = function(funcs, self, ...)
		for _, func in next, funcs do
			func(self, ...)
		end
	end,
}

function oGlow:RegisterEvent(event, func)
	argcheck(event, 2, 'string')

	if(type(func) == 'string' and type(self[func]) == 'function') then
		func = self[func]
	end

	local curev = self[event]
	local kind = type(curev)
	if(curev and func) then
		if(kind == 'function' and curev ~= func) then
			self[event] = setmetatable({curev, func}, eventMetatable)
		elseif(kind == 'table') then
			for _, infunc in next, curev do
				if(infunc == func) then return end
			end

			table.insert(curev, func)
		end
	elseif(eventFrame:IsEventRegistered(event)) then
		return
	else
		if(type(func) == 'function') then
			self[event] = func
		elseif(not self[event]) then
			return error("Handler for event [%s] does not exist.", event)
		end

		eventFrame:RegisterEvent(event)
	end
end

function oGlow:IsEventRegistered(event)
	return eventFrame:IsEventRegistered(event)
end

function oGlow:UnregisterEvent(event, func)
	argcheck(event, 2, 'string')

	local curev = self[event]
	if(type(curev) == 'table' and func) then
		for k, infunc in next, curev do
			if(infunc == func) then
				table.remove(curev, k)

				local n = #curev
				if(n == 1) then
					local _, handler = next(curev)
					self[event] = handler
				elseif(n == 0) then
					eventFrame:UnregisterEvent(event)
				end

				break
			end
		end
	elseif(curev == func) then
		self[event] = nil
		eventFrame:UnregisterEvent(event)
	end
end