#!/bin/sh
#|-*- mode:lisp -*-|#
#|
exec ros -Q -- $0 "$@"
|#
(progn ;;init forms
  (ros:ensure-asdf)
  #+quicklisp(ql:quickload '(imago cl-fad) :silent t)
  )

(defpackage :ros.script.imbricate.3764151058
  (:use :cl))
(in-package :ros.script.imbricate.3764151058)

(defmacro let-when ((var test) &rest body)
  `(let ((,var ,test))
     (when ,var ,@body)))

(defun images-under-dir (dir &key (type "png"))
  (let ((images '()))
    (cl-fad:walk-directory
     dir
     (lambda (path)
       (let-when (img (and (string= type (pathname-type path))
                           (safe-open-image path)))
                 (push (nconc (list :path path) (image-stats img)) images))))
    images))

(defvar *bad-images* '())


(defun safe-open-image (path)
  (handler-case (imago:read-image (format nil "~a" path))
    (error (c)
      (push path *bad-images*)
      nil)))

(defun image-stats (img)
    (list :width (imago:image-width img)
          :height (imago:image-height img)))

(defun image-area (stat)
  (* (getf stat :width)
     (getf stat :height)))

(defun minimum-required-area (image-list)
  (loop for stats in image-list
        summing (image-area stats)))

(defun packlist-dimensions (packlist)
  (let ((w 0) (h 0))
    (dolist (img packlist)
      (setf w (max w (+ (getf img :width) (getf img :x))))
      (setf h (max h (+ (getf img :height) (getf img :y)))))
    (list w h)))

(defun fill-grid (grid x y w h)
  "fills grid with T for rectangle x y w h"
  (do-over-rect x y w h #'(lambda (xi yi) (setf (aref grid xi yi) t))))

(defun pack-images (packlist)
  "Creates an image and copies the contents of the packlist to that image"
  (destructuring-bind (cw ch) (packlist-dimensions packlist)
    (let ((tilesheet (make-instance 'imago:rgb-image :width cw :height ch)))
      (dolist (spec packlist)
        (let-when (img (safe-open-image (getf spec :path)))
                  (imago:copy tilesheet img
                              :dest-x (getf spec :x)
                              :dest-y (getf spec :y))))
      tilesheet)))

(defun packlist->tile-index (packlist)
  "renames the path1 in the packlist to a nicer name for referring toa tile location"
  (mapcar #'(lambda (pl)
              (let ((name (pathname-name (getf pl :path))))
                (remf pl :path)
                (setf (getf pl :name) name)
                pl))
          packlist))


(defun write-tile-index (tile-index file-path)
  "saves tile-index to file-path as a standard lisp object"
  (with-open-file (out file-path :direction :output)
    (print tile-index out)))


(defun build-packlist (image-list)
  (let* ((image-list (sort image-list #'> :key #'image-area))
         (side-dim (ceiling (sqrt (minimum-required-area image-list))))
         (pack-mask (make-array (list side-dim side-dim) :initial-element nil :adjustable t))
         (pack-list '()))
    (dolist (image image-list)
      (let ((width (getf image :width))
            (height (getf image :height)))
        (destructuring-bind (x y) (find-place-for pack-mask width height)
          (fill-grid pack-mask x y width height)
          (push (nconc (list :x x :y y) image) pack-list))))
    (reverse pack-list))) ;; biggest image first


(defun do-over-rect (x y w h fn)
  (loop for xi from x to (+ x w -1) do
    (loop for yi from y to (+ y h -1) do
      (funcall fn xi yi))))


(defun filled-at (grid x y)
  "returns two values. The the second is nil if x y is out of range"
  (destructuring-bind (gw gh) (array-dimensions grid)
    (if (and (< x gw) (< y gh))
        (values (aref grid x y) t)
        (values nil nil))))

(defun unfilled-over-rect (grid x y w h)
  (do-over-rect x y w h
    #'(lambda (xi yi)
        (multiple-value-bind (filled in-bounds) (filled-at grid xi yi)
          (when (or filled (not in-bounds))
            (return-from unfilled-over-rect nil)))))
  t)

(defun find-place-for (grid width height)
  "returns (x y) where a (width X height) sized rectangle will fit into grid"
  (labels ((search-loop ()
             (destructuring-bind (gw gh) (array-dimensions grid)
               (do-over-rect 0 0 gw gh
                 #'(lambda (x y)
                     (when (unfilled-over-rect grid x y width height)
                       (return-from search-loop (list x y)))))
               (progn
                 (adjust-array grid (list (* 2 gw) (* 2 gh)) :initial-element nil)
                 (search-loop)))))
    (search-loop)))



(defun main (&rest argv)
  (declare (ignorable argv))
  (destructuring-bind (path target) argv
      (let* ((tile-stats (images-under-dir path))
             (packlist (build-packlist tile-stats))
             (tilesheet (pack-images packlist))
             (tile-index (packlist->tile-index packlist)))
        (imago:write-png tilesheet (format nil "~a.png" target))
        (write-tile-index tile-index (format nil "~a-index.lisp" target))))
  (format t "ALL DONE~%"))
;;; vim: set ft=lisp lisp: