(define (agw-vec-list vl) (vector->list (cadr vl)))

(define (agw-p67-font)
  (for-each
   (lambda (im)
     (let ((dr    (car (gimp-image-get-active-drawable im)))
           (fname (car (gimp-image-get-filename        im))))
       (unless (eq? (gimp-image-base-type im) RGB)
         (gimp-image-convert-rgb im))
       (gimp-drawable-desaturate dr DESATURATE-LUMINANCE)
       (gimp-image-convert-indexed
        im
        CONVERT-DITHER-NONE
        CONVERT-PALETTE-CUSTOM
        0     ; num-cols (ign.)
        FALSE ; alpha-dither
        FALSE ; remove-unused
        "p67 palette")
       (gimp-file-save RUN-NONINTERACTIVE im dr fname fname)))
   (agw-vec-list (gimp-image-list))))

(define (agw-destructure im)
  (for-each
   (lambda (dr)
     (when (gimp-item-is-drawable dr)
       (plug-in-colortoalpha RUN-NONINTERACTIVE im dr (car (gimp-context-get-foreground)))))
   (agw-vec-list (gimp-image-get-layers im))))

(define (agw-export-font start dir pfx sfx im)
  (letrec ((num (string->number start 16))
           (pre (string-append dir "/" pfx))
           (fnc (lambda (ls n)
                  (let* ((dr  (car ls))
                         (nx  (cdr ls))
                         (dr? (gimp-item-is-drawable dr))
                         (fnm (string-append pre (number->string n 16) sfx)))
                    (when dr?
                      (gimp-file-save RUN-NONINTERACTIVE im dr fnm fnm))
                    (unless (null? nx)
                      (fnc nx (if dr? (succ n) n)))))))
    (fnc (agw-vec-list (gimp-image-get-layers im)) num)))

(define author  "Alison Gray Watson")
(define license "Public domain")
(define path    "<Image>/:>")

(script-fu-register
 "agw-p67-font"
 "P67 Font" "Converts open images to a project67 font"
 author license "2021" "")
(script-fu-register
 "agw-destructure"
 "Destructure" "Deletes foreground color from all layers"
 author license "2021" ""
 SF-IMAGE "Image" 0)
(script-fu-register
 "agw-export-font"
 "Export Layers" "Exports all layers with hex names"
 author license "2021" ""
 SF-STRING "Start Number (Hex)" "21"
 SF-DIRNAME "Output Directory" "/tmp"
 SF-STRING "Prefix (Optional)" ""
 SF-STRING "Suffix (Required)" ".png"
 SF-IMAGE "Image" 0)

(script-fu-menu-register "agw-p67-font"    path)
(script-fu-menu-register "agw-destructure" path)
(script-fu-menu-register "agw-export-font" path)