library Neartest
//*************************************************
//* _   _                          _   
//*| \ | | ___  __ _ _ __ ___  ___| |_ 
//*|  \| |/ _ \/ _` | '__/ _ \/ __| __|
//*| |\  |  __/ (_| | | |  __/\__ \ |_ 
//*|_| \_|\___|\__,_|_|  \___||___/\__|
//* by dhguardianes
//*  this idea by Tom_Kazansky
//* -------------
//* Easiest and with more flexible way to retrieve the nearest unit from a point
//*
//* function GetNearestUnit( X,Y,Radius,Boolexpr)
//*
//*      The extra integer argument skips that many units in the
//*      list of near units.
//*      Example: If takes "3" then it would return the second nearest
//*      unit.
//*      The extra real argument is the range to pick unit
//*      return null if no unit is picked.
//* Example:
//*
//* set TempUnit = GetNearestUnit(GetLocationX(TempLoc),GetLocationY(TempLoc),800,Condition(function IsBuilding))
//*
//************************************************

//=========================================================================================
    globals
        private unit GetUnit
        private real Distance
        private real x
        private real y
        private real value
        private constant group g = CreateGroup()
    endglobals
//=========================================================================================
    function IsHero takes nothing returns boolean
        return ( IsUnitType(GetFilterUnit(), UNIT_TYPE_HERO) and (GetUnitState(GetFilterUnit(), UNIT_STATE_LIFE) > 0) == true )
    endfunction
    function IsBuilding takes nothing returns boolean
        return ( IsUnitType(GetFilterUnit(), UNIT_TYPE_STRUCTURE) and (GetUnitState(GetFilterUnit(), UNIT_STATE_LIFE) > 0) == true )
    endfunction
    function IsBuildingPlayer0 takes nothing returns boolean
        return ( IsUnitType(GetFilterUnit(), UNIT_TYPE_STRUCTURE) and (GetUnitState(GetFilterUnit(), UNIT_STATE_LIFE) > 0) and ( GetOwningPlayer(GetFilterUnit()) == Player(0) ) == true )
    endfunction
    function IsBuildingPlayer6 takes nothing returns boolean
        return ( IsUnitType(GetFilterUnit(), UNIT_TYPE_STRUCTURE) and (GetUnitState(GetFilterUnit(), UNIT_STATE_LIFE) > 0) and ( GetOwningPlayer(GetFilterUnit()) == Player(6) ) == true )
    endfunction

    private function callback takes nothing returns nothing
        set value = SquareRoot((GetUnitX(GetEnumUnit()) - x) * (GetUnitX(GetEnumUnit()) - x) + (GetUnitY(GetEnumUnit()) - y) * (GetUnitY(GetEnumUnit()) - y))
        if ( value < Distance ) then
            set Distance = value
            set GetUnit = GetEnumUnit()
        endif
    endfunction
    function GetNearestUnit takes real newX, real newY, real newR, boolexpr newB returns unit
        set Distance = newR
        set x = newX
        set y = newY
        set GetUnit = null
        call GroupEnumUnitsInRangeOfLoc(g, Location(newX, newY), newR, newB)
        call ForGroup(g, function callback)
        call GroupClear(g)
        return GetUnit
    endfunction
endlibrary