Spell on strike triggering help

I want a spell that deals extra chaos damage with every strike.

The trigger:

Event

-A unit is attacked

Conditions

-Level of (spell name) for attacking unit is greater than 0 and attacked unit is magic immune equal to false

Events

-Cause attacking unit to damage attacked unit, dealing (damage) damage of attack type chaos and damage type unknown

(Pretty simple ^^)

The problem is the chaos damage is dealt before the attacked unit receives basic damage.

Is there a way to make the trigger work when a unit receives damage?|||Add some on hit ability to the hero and use 'a unit starts the effect of an ability'.

EDIT: Unless the damage is constant in which case that's actually exactly what you're asking and I haven't helped in the least. The Orb of Slow item ability is great for implementing on-hit abilities.

If you don't want to do that, you can use the following trigger:


Code:

function Trig_On_Hit_Conditions takes nothing returns boolean
    if ( not ( GetUnitAbilityLevel(GetAttacker(), 'ANab') > 0 ) ) then
        return false
    endif
    if ( IsUnitType(GetTriggerUnit(), UNIT_TYPE_MAGIC_IMMUNE) ) then
        return false
    endif
    return true
endfunction

function Trig_TOnHit_Conditions takes nothing returns boolean
    return ( GetEventDamageSource() == LoadUnitHandle( udg_htGlobal, GetHandleId(GetTriggeringTrigger()), 0 ) )
endfunction

function Trig_TOnHit_Actions takes nothing returns nothing
    call UnitDamageTarget( GetEventDamageSource(), GetTriggerUnit(), AMOUNT_GOES_HERE, true, false, ATTACK_TYPE_CHAOS, WEAPON_TYPE_WHOKNOWS )
    call RemoveSavedHandle( udg_htGlobal, GetHandleId(GetTriggeringTrigger()), 0 )
    call DestroyTrigger( GetTriggeringTrigger() )
endfunction

function Trig_On_Hit_Actions takes nothing returns nothing
    local trigger t = CreateTrigger()
    call SaveUnitHandle( udg_htGlobal, GetHandleId(t), 0, GetAttacker() )
    call TriggerRegisterUnitEvent( t, GetTriggerUnit(), EVENT_UNIT_DAMAGED )
    call TriggerAddCondition( t, Condition(function Trig_TOnHit_Conditions) )
    call TriggerAddAction( t, function Trig_TOnHit_Actions )
    set u = null
    call TriggerSleepAction( 2.00 )
    call DestroyTrigger(t)
    set t = null
endfunction

//===========================================================================
function InitTrig_On_Hit takes nothing returns nothing
    set gg_trg_On_Hit = CreateTrigger(  )
    call TriggerRegisterAnyUnitEventBJ( gg_trg_On_Hit, EVENT_PLAYER_UNIT_ATTACKED )
    call TriggerAddCondition( gg_trg_On_Hit, Condition( function Trig_On_Hit_Conditions ) )
    call TriggerAddAction( gg_trg_On_Hit, function Trig_On_Hit_Actions )
endfunction

I don't use EVENT_UNIT_DAMAGED much but that SHOULD work. Be sure to replace AMOUNT_GOES_HERE with the amount you want.

EDIT2: Forgot to mention, if you want to use that trigger, create a global hashtable variable called htGlobal.