Detecting when a unit is about to attack?

//=============================================
// Trigger:       unit - a unit owned by player x aquires a target
// Script Author: Mar_Sara[LoC]
// Info:          Workaround for the missing event...
// Required Variables:
//     - TrigDeath - Trigger Array
//     - TrigAquireTarg - Trigger Array
//     - TrigIndex - Integer
//=============================================
function Trig_AquireTarget_Conditions takes nothing returns boolean
    // Perform any test on target here

    // You can make the Attacking Unit only do something
    // if  the target is of a certain type, has a
    // certain health value, is a hero, etc...
    return true
endfunction

function Trig_AquireTarget_Actions takes nothing returns nothing
    // Add Actions for when unit aquires target here

    // This function executes BEFORE the attacking unit
    // actually attacks.  It runs once you either click
    // on the target, a unit comes within its aqusition
    // range, or you order it to attack.  This will also
    // run if the unit is ordered to attack by triggers.

    // Order the unit to use a spell on the target,
    // tell him to stop, or you could even heal him
endfunction

function Trig_Death_Actions takes nothing returns nothing

    // This function removes any unneeded triggers created
    // via the main trigger, then left-shifts the entire
    // array, allowing more triggers to be created.
    // DO NOT edit this function

    local integer i
    local integer j
    local trigger ThisTrigger

    set ThisTrigger = GetTriggeringTrigger()

    // Find Current Trigger
    set i = 0
    loop
        exitwhen udg_TrigDeath[i] = ThisTrigger
        set i = i + 1
    endloop

    // Delete unneeded Triggers
    call DestroyTrigger( udg_TrigDeath[i] )
    call DestroyTrigger( udg_TrigAquireTarg[i] )

    // Shift Triggers Right of [i] Left 1
    set j = i
    loop
        exitwhen j > udg_TrigIndex
        set udg_TrigDeath[j] = udg_TrigDeath[j+1]
        set udg_TrigAquireTarg[j] = udg_TrigAquireTarg[j+1]
        set j = j + 1
    endloop

    set udg_TrigIndex = udg_TrigIndex - 1

endfunction

function Trig_DisallowAttack_Conditions takes nothing returns boolean
    // Perform any tests on the triggering unit here

    // You can limit the effects for specific types
    // of units, or even units trained from specific 
    // structures/races.

    // if you need to limit it to specific players,
    // change the EVENTS at the bottom to only include
    // the players wanted.

    return true
endfunction

function Trig_DisallowAttack_Actions takes nothing returns nothing

    // This is the main function, it creates all the 
    // triggers used. (DO NOT change any thing here)

    // Depending of the EVENT change to:
    // Structure - GetConstructedStructure()
    // Unit - GetTrainedUnit()
    // Summon - GetSummonedUnit()
    // Rescued Unit - GetRescuer()
    local unit theUnit = GetTrainedUnit()

    // Create Aquire Target Trigger
    set udg_TrigAquireTarg[udg_TrigIndex] = CreateTrigger( )
    call TriggerRegisterUnitEvent( udg_TrigAquireTarg[udg_TrigIndex], theUnit, EVENT_UNIT_ACQUIRED_TARGET )
    call TriggerAddCondition( udg_TrigAquireTarg[udg_TrigIndex], Condition( function Trig_AquireTarget_Conditions ) )
    call TriggerAddAction( udg_TrigAquireTarg[udg_TrigIndex], function Trig_AquireTarget_Actions )

    // Create trigger to remove excess triggers
    set udg_TrigDeath[udg_TrigIndex] = CreateTrigger( )
    call TriggerRegisterUnitEvent( udg_TrigDeath[udg_TrigIndex], theUnit, EVENT_UNIT_DEATH )
    call TriggerAddAction( udg_TrigDeath[udg_TrigIndex], function Trig_Death_Actions )

    set udg_TrigIndex = udg_TrigIndex + 1
endfunction

//===========================================================================
function InitTrig_DisallowAttack takes nothing returns nothing
    set gg_trg_DisallowAttack = CreateTrigger(  )
    //======EVENTS========//
    // Copy this line for all required players. (Also edit the EVENT_PLAYER_UNIT_TRAIN_FINISH for the approate type)
    call TriggerRegisterPlayerUnitEventSimple( gg_trg_DisallowAttack, Player(0), EVENT_PLAYER_UNIT_TRAIN_FINISH)
    //======CONDITIONS====// (DO NOT edit this line)
    call TriggerAddCondition( gg_trg_DisallowAttack, Condition( function Trig_DisallowAttack_Conditions ) )
    //======ACTIONS=======// (DO NOT edit this line)
    call TriggerAddAction( gg_trg_DisallowAttack, function Trig_DisallowAttack_Actions )
endfunction