Chat Event Pet Feeder Script help

[Inokis]

This script works fine if you type in the pet name manually, as it appears in the Chat Frame (substituting UnitName('Pet') for the actual name):

function PetActionEXPBar_FeedPet()
	local petname = UnitName("Pet");
	if ( event == "CHAT_MSG_SPELL_PERIODIC_SELF_BUFFS") then
		if arg1 == ( "UnitName('Pet') gains 1 Happiness from Feed Pet Effect." ) then
		PetEXPBarFeedText:Show();
		PetEXPBarFeedText:SetText("1 Loyalty Gain");
		end
	end
end

Is there any way to insert the local 'petname' variable into the Arg 1 conditional and have it match the chat frame text?

[Inokis]

If anyone has any ideas or workarounds for making this work, feel free to chime in.