; AttX changes selected Block Attrib matching Tag value to X
; OP:
; https://forums.autodesk.com/t5/visual-lisp-autolisp-and-general/block-attribute-reset-lisp/m-p/12959096#M470223
(defun c:AttX (/ GetTags SelectTag PickTag ss blkname tags tag newval i blkEnt ent attdata tagFound)
  ;; Function to get attribute tags from a block definition
  ; modified to return a string of tags separated by space
  (defun GetTags (blockname / blk obj taglist)
;    (setq taglist '())
    (setq taglist "")
    (if (setq blk (tblobjname "BLOCK" blockname))
      (progn
        (setq obj (entnext blk))
        (while (and obj (/= (cdr (assoc 0 (entget obj))) "ENDBLK"))
          (if (eq (cdr (assoc 0 (entget obj))) "ATTDEF")
;            (setq taglist (cons (cdr (assoc 2 (entget obj))) taglist)) 
             (setq taglist (strcat taglist " " (cdr (assoc 2 (entget obj)))))
          )
          (setq obj (entnext obj))
        )
      )
    )
    (if taglist (substr taglist 2))
  )

  ;; Function to prompt the user to select an attribute tag from a list
  (defun SelectTag (taglist / selectedtag i options)
    (if taglist
      (progn
        (setq i 0)
        (setq options "")
        (foreach tag taglist
          (setq options (strcat options (itoa i) ". " tag "\n"))
          (setq i (1+ i))
        )
        (setq selectedtag (nth (getint (strcat "\nEnter the number corresponding to the tag:\n" options)) taglist))
      )
    )
    selectedtag
  )
  ;; function to prompt for selection by picking from cursor
  ; taglist must be a string of choices separated by space
  (defun PickTag (taglist / dynmode selected options)
  ; dynamic input with selection options
  ; Also when you set dynmode to 1 or 3 during the getkword prompt 
  ; when the cursor moves from the command prompt into the drawing area 
  ; a cursor menu appears to choose from
   (if(<= (rem (getvar"dynmode") 2) 0) ; if even # chks negative value as well
     (progn
      (setq dynmode (getvar"dynmode")) ; save current setting
      (setvar "dynmode" 1) ; enable dynmode
     )
   ) ; if
   (setq options (vl-string-translate " " "/" taglist)) ; replace space with slash
   (initget 1 taglist)
   (setq selectedtag (getkword (strcat"\nSelect One [" options "]: ")))
   (if dynmode (setvar "dynmode" dynmode)) ; restore original dynmode setting
   selectedtag
  )
  ;; Prompt user to select blocks
  (setq ss (ssget '((0 . "INSERT")(66 . 1)))) ; select blocks with attribute

  ;; If blocks are selected, proceed
  (if ss
    (progn
      ;; Prompt user to select the tag to be reset
      (setq blk (ssname ss 0)) ;; Select the first block from the selection
      (setq blkname (cdr (assoc 2 (entget blk))))
      (setq tags (GetTags blkname))
;      (setq tag (SelectTag tags))
      (setq tag (PickTag tags))
      ;; Prompt user to enter the new value for the attribute tag
      (setq newval (getstring "\nEnter the new value for the attribute: "))

      ;; Iterate over the selected blocks and update the attribute
      (setq i 0)
      (while (< i (sslength ss))
        (setq blkent (ssname ss i))
        ;; Use a loop to go through all entities in the block reference
        (setq ent (entnext blkEnt)) ; Start with the first entity
        (setq tagFound nil) ; Initialize flag to check if tag is found

        (while ent
          ;; Check if the entity is an attribute and matches the selected tag
          (if (and (eq (cdr (assoc 0 (entget ent))) "ATTRIB")
                   (equal (cdr (assoc 2 (entget ent))) tag))
            (progn
              ;; Update the attribute value
              (setq attdata (entget ent))
              (entmod (subst (cons 1 newval) (assoc 1 attdata) attdata))
              (entupd ent)
              (setq tagFound t ent nil) ; Set flag if tag is updated
            )
            (setq ent (entnext ent)) ; Move to the next entity
          )
        )

        ;; Check if the tag was not found in the block
        (if (not tagFound)
          (princ (strcat "\nTag " tag " not found in block " (cdr (assoc 2 (entget blkent))))))
          
        (setq i (1+ i))
      )
    )
    (princ "\nNo blocks selected.")
  )

  (princ)
)

(prompt "\n>>>...AttX.lsp is now loaded. Type 'AttX' to start ...<<<")
(princ)