scope ChooseVampire initializer init
    globals
        private constant integer VAMPIRE1_UNIT_ID = 'U000'
        private constant integer VAMPIRE1_ITEM_ID = 'I000'
        private constant integer VAMPIRE2_UNIT_ID = 'U001'
        private constant integer VAMPIRE2_ITEM_ID = 'I001'
        private constant integer VAMPIRE3_UNIT_ID = 'U002'
        private constant integer VAMPIRE3_ITEM_ID = 'I002'
        private constant integer MAX_VAMPIRES = 3
        private integer Get_Vampires = 0
    endglobals

    private function Vampire takes item whichItem returns unit
        if (whichItem==VAMPIRE1_ITEM_ID) then
            return VAMPIRE1_UNIT_ID
        elseif (whichItem==VAMPIRE2_ITEM_ID) then
            return VAMPIRE2_UNIT_ID
        elseif (whichItem==VAMPIRE3_ITEM_ID) then
            return VAMPIRE3_UNIT_ID
        endif
        return null
    endfunction

    private function Actions takes nothing returns boolean
        local unit u = GetBuyingUnit()
        local unit t = GetSellingUnit()
        local player p = GetOwningPlayer(u)
        local item i = GetSoldItem()
        local real x = GetUnitX(u)
        local real y = GetUnitY(u)
        if (IsPlayerInForce(p,udg_vampires)) then
            call RemoveUnit(u)
            set u=CreateUnit(p,Vampire(i),x,y,GetRandomReal(0.00,360.00))
            call RemoveItem(i)
            set Get_Vampires=Get_Vampires+1
            if (GetLocalPlayer()==p) then
                call SelectUnit(u,true)
            endif
            if (Get_Vampires>=MAX_VAMPIRES) then
                call RemoveUnit(t)
            endif
        endif
        set u=null
        set t=null
        set p=null
        set i=null
        return false
    endfunction

    //===========================================================================
    private function init takes nothing returns nothing
        local trigger trig = CreateTrigger()
        local integer index = 0
        loop
            exitwhen index>=bj_MAX_PLAYER_SLOTS
            call TriggerRegisterPlayerUnitEvent(trig,Player(index),EVENT_PLAYER_UNIT_SELL_ITEM,null)
            set index=index+1
        endloop
        call TriggerAddCondition(trig,Condition(function Actions))
        set trig=null
    endfunction
endscope