library UnitDamageSystem initializer Init

function UnitDamageSystem_Conditions takes nothing returns boolean
return GetEventDamage() > 0.
endfunction

function UnitDamageSystem_Actions takes nothing returns nothing
local unit Caster = GetEventDamageSource()
local unit Target = GetTriggerUnit()
local real Damage = GetEventDamage()

set Caster = null
set Target = null
endfunction

function UnitDamageSystemRemove takes unit Caster returns nothing
local integer Handle = GetHandleId(Caster)


call TriggerRemoveAction(LoadTriggerHandle(Hashtable,Handle,StringHash("Unit Damage System Trigger")),LoadTriggerActionHandle(Hashtable,Handle,StringHash("Unit Damage System Action")))
call TriggerClearActions(LoadTriggerHandle(Hashtable,Handle,StringHash("Unit Damage System Trigger")))
call TriggerClearConditions(LoadTriggerHandle(Hashtable,Handle,StringHash("Unit Damage System Trigger")))
call DestroyTrigger(LoadTriggerHandle(Hashtable,Handle,StringHash("Unit Damage System Trigger")))

call RemoveSavedHandle(Hashtable,Handle,StringHash("Unit Damage System Trigger"))
call RemoveSavedHandle(Hashtable,Handle,StringHash("Unit Damage System Action"))
endfunction

function UnitDamageSystem_Add takes unit Caster returns nothing
local integer Handle = GetHandleId(Caster)
local trigger Trigger = CreateTrigger()

call UnitDamageSystemRemove(Caster)
call TriggerRegisterUnitEvent(Trigger,Caster,EVENT_UNIT_DAMAGED)
call TriggerAddCondition(Trigger, Condition(function UnitDamageSystem_Conditions))
call SaveTriggerActionHandle(Hashtable,Handle,StringHash("Unit Damage System Action"),TriggerAddAction(Trigger, function UnitDamageSystem_Actions))
call SaveTriggerHandle(Hashtable,Handle,StringHash("Unit Damage System Trigger"),Trigger)

set Trigger = null
endfunction

private function Init takes nothing returns nothing
local group Group = CreateGroup()
local unit Picked = null

call GroupEnumUnitsInRect(Group,gg_rct_All_Map,null)

loop
set Picked = FirstOfGroup(Group)
exitwhen Picked == null
call UnitDamageSystem_Add(Picked)
endloop

call DestroyGroup(Group)
set Group = null
set Picked = null
endfunction
endlibrary