Custom bosses leaving combat?

[Arugos]

Hi i made a lua scripted boss but even after my char die or after i .npc return him ,hes still considered in combat and is not regenering hp and is still casting spells every certain amount of seconds like specified in the script.How do i make him go out of combat when he has nothing to kill in his combat range?


function Onyxia_Firenova(Unit)
Unit:CastSpell(37371)
end
function Onyxia_Coneoffire(Unit)
Unit:CastSpell(36876)
end
function Onyxia_Fieryblast(Unit)
Unit:CastSpell(38382)
end
function Onyxia_Thickskin(Unit)
Unit:CastSpell(43823)
end
function Onyxia_Burningwish(Unit)
Unit:CastSpell(18789)
end
function Onyxia_Burningrage(Unit)
Unit:CastSpell(38771)
end
function Onyxia_OnCombat(Unit, Event)
Unit:SendChatMessage (11, 0, "You killed me once,now i am back and i wont let it happen again!")
Unit:RegisterEvent("Onyxia_Firenova",50000, 0)
Unit:RegisterEvent("Onyxia_Coneoffire",30000, 0)
Unit:RegisterEvent("Onyxia_Fieryblast",25000, 0)
Unit:RegisterEvent("Onyxia_Thickskin",500, 0)
Unit:RegisterEvent("Onyxia_Burningwish",40000, 0)
Unit:RegisterEvent("Onyxia_Burningrage",25000, 0)
end
function Onyxia_OnKill(Unit, event)
Unit:SendChatMessage(12,0,"You gonna fail!")
end
function Onyxia_OnDied(Unit)
Unit:SendChatMessage(12,0,"No....not again!!!")
Unit:RemoveEvents()
end
function Onyxia_OnLeaveCombat(Unit)
Unit:SendChatMessage(12,0,"I will be waiting...!")
Unit:RemoveEvents()
end
RegisterUnitEvent(111112, 1,"Onyxia_OnCombat")
RegisterUnitEvent(111112, 3,"Onyxia_OnKill")
RegisterUnitEvent(111112, 4,"Onyxia_OnDied")
RegisterUnitEvent(111112, 2,"Onyxia_OnLeaveCombat")

[Arugos]

any idea ???