AHK Opening last opened windows explorer window if active, else starting new - autohotkey

Question

This code figures out the current explorer windows open,
I would like to open the first in the list, and if the list is empty open a
new explorer instead.
I hope to the open/activate the either window at the current mouse position
#e::
list := ""
numberOfwindows := ""
wins := ""
WinGet, id, list, ahk_class CabinetWClass ahk_exe explorer.exe
Loop, %id%
{
numberOfwindows := A_Index
this_ID := id%A_Index%
WinGetTitle, title, ahk_id %this_ID%
wins .= A_Index A_Space title ? A_Index A_Space title "`n" : ""
}
MsgBox, number of explorer windows = %numberOfwindows%`n`n%wins%
return

Answer 1

This solves it. - however it can be optimized, anyone have any suggestions ?
#e::
list := ""
numberOfwindows := ""
wins := ""
WinGet, id, list, ahk_class CabinetWClass ahk_exe explorer.exe
Loop, %id%
{
numberOfwindows := A_Index
this_ID := id%A_Index%
WinGetTitle, title, ahk_id %this_ID%
if (A_Index = 1) { ; if it's the first index of the loop
;MsgBox %title%
win = %title% ; store the title in " win "
}
wins .= A_Index A_Space title ?½½ A_Index A_Space title "`n" : ""
}
IfWinNotExist ahk_class CabinetWClass
{
Run C:\Windows\explorer.exe
win := File Explorer
WinWait, %win% ahk_class CabinetWClass
WinMove, mxpos_new , mypos_new
WinActivate
}
;MsgBox, number of explorer windows = %numberOfwindows%`n`n%wins%
; above msgbox displays number and the names of the windows.
;~ ; we now know the win
; and its title, exe and class.
; we want it's current position.
WinGetPos, X, Y, Width, Height,%win% ahk_class CabinetWClass
;MsgBox, %X%, %Y%, %Width%, %Height%
; and we want the mouse position.
CoordMode, Mouse, Screen ; Coordinates are relative to the desktop (entire screen).
MouseGetPos, mxpos , mypos,
;MsgBox, %mxpos%, %mypos%
mxpos_new := mxpos - (Width / 2)
mypos_new := mypos - (Height / 2)
;MsgBox, %mxpos% %mypos% %Width% %Height% %mxpos_new% %mypos_new%
; activate that specific window
WinWait, %win% ahk_class CabinetWClass
WinMove, mxpos_new , mypos_new
WinActivate
return