Stun System not unit stackable?

////! external ObjectMerger w3h BPSE STNB fnam "Custom Stun"
////! external ObjectMerger w3a AHtb STUN abuf 1 STNB alev 1 aher 1 ahdu 1 0 adur 1 0 Htb1 1 0 amat "" amcs 1 0 anam "Custom Stun"
library CustomStun initializer Init uses AutoIndex

    globals
        private constant real       INTERVAL    = 0.03125       //Interval of the timer, thus, delta value
        private constant integer    Dummy_Id    = 'h003'    //Dummy ID
        private constant integer    Bolt_Id     = 'STUN'    //Storm bolt ID
        private constant integer    Buff_Id     = 'B005'    //Stun buff ID
        private constant integer LOCUST = 'Aloc'
        private unit stunner = null
    endglobals
        
struct stun
    real Stunned = 0.
    unit target
    real duration
   static timer Timer = CreateTimer()
    static stun array D
    static integer Count = 0
        
    static method create takes unit target, real duration returns stun
        local stun d = stun.allocate()
        set d.target = target
        set d.duration = 0.
        set d.Stunned = duration
        if stun.Count == 0 then
            call TimerStart(stun.Timer,INTERVAL,true,function stun.Periodic)
        endif
        set stun.D[stun.Count] = d
        set stun.Count = stun.Count + 1
        return d
    endmethod
    
    static method Periodic takes nothing returns nothing
        local stun this
        local integer i = 0
        loop
            exitwhen i >= .Count
            set this = .D[i]
            if .duration >= .Stunned or GetWidgetLife(.target) < 0.405 then
                call .destroy()
                set .Count = .Count - 1
                if .Count > 0 then
                    set .D[i] = .D[.Count]
                    set i = i - 1
                else
                    call PauseTimer(.Timer)
                endif
            endif
            set .duration = .duration + INTERVAL
            set i = i + 1
        endloop
    endmethod
            
   private method onDestroy takes nothing returns nothing
        set .Stunned = 0
        call UnitRemoveAbility(.target, Buff_Id) 
    endmethod
    
    implement AutoData
endstruct
    
function IsStunned takes unit target returns boolean
    return stun[target] != 0
endfunction

function StopStun takes unit target returns nothing
    call UnitRemoveAbility(target,Buff_Id)
endfunction
    
function StunUnit takes unit target, real duration returns nothing
    local stun d = stun[target]
    call SetUnitX(stunner,GetUnitX(target))
    call SetUnitY(stunner,GetUnitY(target))
    call IssueTargetOrder(stunner, "thunderbolt", target )
    if d == 0 then
        set d = stun.create(target,duration)
        set stun[target] = d
    else
        set d = stun[target]
        set d.Stunned = duration
        set d.duration = 0.
    endif
endfunction

private function Init takes nothing returns nothing
    set stunner = CreateUnit(Player(12),Dummy_Id,0,0,0)
    call UnitAddAbility(stunner,Bolt_Id )
    call UnitAddAbility(stunner,LOCUST)
endfunction
endlibrary

scope TidalWave initializer Init



globals
    private constant integer SPELL = 'A008'
    private constant integer STOMP = 'A009'
    private constant string EFFECT = "MDX\\TidalErruption.mdx"
    private boolexpr b
endglobals



private function Conditions takes nothing returns boolean
    return GetSpellAbilityId() == SPELL
endfunction



private function LineFilter takes nothing returns boolean
    return IsUnitEnemy(GetFilterUnit(),GetOwningPlayer(GetTriggerUnit())) and GetWidgetLife(GetFilterUnit()) > 0.0451
endfunction

private function Actions takes nothing returns nothing
    local unit caster = GetTriggerUnit()
    local location target = GetSpellTargetLoc()
    local unit dummy
    local group g = NewGroup()
    local group hitgroup = NewGroup()
    local integer i = 1
    local integer effects = 4
    local real dist = 600
    local real divdist = dist/effects
    local real cx = GetUnitX(caster)
    local real cy = GetUnitY(caster)
    local real tx = GetLocationX(target)
    local real ty = GetLocationY(target)
    local real angle = Atan2(ty-cy,tx-cx)
    local real x
    local real y
    local unit u
    local integer c = 0
    loop
        exitwhen i > effects
        call TriggerSleepAction(0.1)
        set x = GetUnitX(caster) + (divdist * i) * Cos(angle)
        set y = GetUnitY(caster) + (divdist * i) * Sin(angle)
        set dummy = CreateUnit(GetOwningPlayer(caster),DUMMY,x,y,GetUnitFacing(caster))
        call SetUnitScale(dummy,2,2,2)
        call AddTimedEffectTarget(EFFECT,dummy,"origin",3)
        call UnitApplyTimedLife(dummy,'BTLF',3.5)
        call GroupEnumUnitsInRangeOfSegment(g,cx,cy,x,y,100,b)
        loop
            set u = FirstOfGroup(g)
            exitwhen u == null
            if not IsUnitInGroup(u,hitgroup) then
                call ThrowUnitToAir(u,28)
                call StunUnit(u,3)
                call GroupAddUnit(hitgroup,u)
            endif
            call GroupRemoveUnit(g,u)
        endloop
        set i = i + 1
        set c = c + 150
    endloop
        set u = null
    set caster = null
    set dummy = null
    call RemoveLocation(target)
    call ReleaseGroup(g)
    call ReleaseGroup(hitgroup)
    set target = null
endfunction



//===========================================================================

private function Init takes nothing returns nothing
    local trigger t = CreateTrigger()
    call TriggerRegisterAnyUnitEventBJ( t, EVENT_PLAYER_UNIT_SPELL_EFFECT)
    call TriggerAddAction( t, function Actions )
    call TriggerAddCondition(t,Condition(function Conditions))
    set b = Filter(function LineFilter)
endfunction

endscope

module AutoData 
  private static thistype array data 
     static method operator []= takes unit u, integer data returns nothing 
        set .data[GetUnitId(u)] = data 
     endmethod 
     static method operator [] takes unit u returns integer 
         return .data[GetUnitId(u)] 
     endmethod 
 endmodule