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(load "package.lisp")
(load "bezier.lisp")
(in-package :so3-cnc)

(ql:quickload :alexandria)
(ql:quickload :clem)
(ql:quickload :cl-ppcre)
(ql:quickload :parse-float)
(ql:quickload :xmls)

(defparameter gcode-preamble '(((:G . 1) (:X . 0) (:Y . 0) (:F . 100))
                               ))
(defparameter gcode-postamble '(((:G . 0) (:Z . 1))
                                ((:G . 0) (:X . 0) (:Y . 0))))

(defun reshape-to-2x3 (vs)
  (clem:array->matrix
   (make-array '(3 3)
               :initial-contents (list (list (first vs) (second vs) (third vs))
                                       (list (fourth vs) (fifth vs) (sixth vs))
                                       '(0 0 1)))
   :matrix-class 'clem:double-float-matrix))

(defun vec3 (xy z)
   (clem:array->matrix
    (make-array '(3 1) :initial-contents (list (list (car xy)) (list (cdr xy)) (list z)))
    :matrix-class 'clem:double-float-matrix))

(defun point (xy) (vec3 xy 1))
(defun vec (xy) (vec3 xy 0))

(defun clem-to-list (v) (cons (clem:val v 0 0) (clem:val v 1 0)))

(defun make-matrix (a b c d e f) (reshape-to-2x3 (list a b c d e f)))
(defun make-translate (x &optional (y 0)) (reshape-to-2x3 (list 1 0 x 0 1 y)))
(defun make-identity () (reshape-to-2x3 (list 1 0 0 0 1 0)))
(defun make-scale (x &optional (y nil)) (reshape-to-2x3 (list x 0 0 0 (if (null y) x y) 0)))
(defun make-rotate (a &optional (x 0) (y 0))
  (clem:m* (make-translate x y)
           (reshape-to-2x3 (list (cos a) (- (sin a)) 0 (sin a) (cos a) 0))
           (make-translate (- x) (- y))
           ))
(defun make-skew-x (a) (reshape-to-2x3 (list 1 (tan a) 0 0 1 0)))
(defun make-skew-y (a) (reshape-to-2x3 (list 1 0 0 (tan a) 1 0)))

(defconstant point-to-mm-xform (make-scale (/ 25.4 72)))

(defun parse-transform (xform-str)
  (cl-ppcre:register-groups-bind (fun argstr) ("([a-zA-Z]+)\\(([^)]*)\\)" xform-str)
    (apply
     (alexandria:switch (fun :test #'string-equal)
       ("matrix" #'make-matrix)
       ("translate" #'make-translate)
       ("scale" #'make-scale)
       ("rotate" #'make-rotate)
       ("skewX" #'make-skew-x)
       ("skewY" #'make-skew-y)
       )
     (mapcar #'parse-float:parse-float (cl-ppcre:split "[\\s,]+" argstr))
     )))

(defstruct (svg-machine (:conc-name svgm-))
  (current '(0 . 0)) ; current position
  (rel-base '(0 . 0)) ; the position we base relative moves off of, updated at the end of each stanza
  (last-start nil) ; last path start position
  (last-ctrl-point nil) ; the last control point used in any curve operation, for S paths
  (gcode gcode-preamble) ; transformed, complete gcode
  (gcode-unxf nil) ; untransformed gcode that is being generated
  )

(defun point-add (a b)
  (point (cons (+ (clem:val a 0 0) (clem:val b 0 0)) (+ (clem:val a 1 0) (clem:val b 1 0)))))
(defun point-scale (a s)
  (point (cons (* (clem:val a 0 0) s) (* (clem:val a 1 0) s))))

(defun arc-center-xy (a xy1p)
  "Finds and returns (cx, cy), is-clockwise, theta1, theta2 - theta1, in that
   order, as specified by the SVG arc implementation notes"
  (let* ((rx (abs (first a)))
         (ry (abs (second a)))
         (rx2 (expt rx 2))
         (ry2 (expt ry 2))
         (phi (* (/ pi 180) (third a)))
         (large-arc? (not (= (fourth a) 0.0)))
         (cw? (not (= (fifth a) 0.0)))
         (xy1 (point xy1p))
         (xy2 (point (cons (sixth a) (seventh a))))
         (rphi (make-rotate (- phi)))
         (xy1-prime (clem:mat-mult rphi (point-scale (point-add xy1 (point-scale xy2 -1)) 0.5)))
         (x-prime (clem:val xy1-prime 0 0))
         (y-prime (clem:val xy1-prime 1 0))
         (Lambda (+ (/ (expt x-prime 2) rx2) (/ (expt y-prime 2) ry2))))
    (cond
      ((and (= x-prime 0) (= y-prime 0)) (error "arcs cannot start and end at same point"))
      ((> Lambda 1.0d0)
       (let ((scale (+ (sqrt Lambda) 0.0001)))
         (when (> scale 2)
           (error "poorly formed arc, maybe? ~A ~A ~A" a xy1p scale))
         (arc-center-xy (append (list (* scale rx) (* scale ry)) (subseq a 2)) xy1p)))
      (t (let* ((cxy-rc (* (if (equal large-arc? cw?) -1.0 1.0)
                           (sqrt (/ (- (* rx2 ry2) (* rx2 (expt y-prime 2)) (* ry2 (expt x-prime 2)))
                                    (+ (* rx2 (expt y-prime 2)) (* ry2 (expt x-prime 2)))))))
                (cxy-r (if (complexp cxy-rc) (break) cxy-rc))
                (cxy-prime (point (cons (/ (* cxy-r rx y-prime) ry)
                                        (/ (* -1 cxy-r ry x-prime) rx))))
                (cxy (point-add
                      (clem:mat-mult (clem:transpose rphi) cxy-prime)
                      (point-scale (clem:mat-add xy1 xy2) 0.5)))
                (cx-prime (clem:val cxy-prime 0 0))
                (cy-prime (clem:val cxy-prime 1 0))
                (theta1 (angle-between
                         '(1 . 0)
                         (cons (/ (- x-prime cx-prime) rx)
                               (/ (- y-prime cy-prime) ry))))
                (dtheta-unwhitened (angle-between
                                    (cons (/ (- x-prime cx-prime) rx)
                                          (/ (- y-prime cy-prime) ry))
                                    (cons (/ (- 0 x-prime cx-prime) rx)
                                          (/ (- 0 y-prime cy-prime) ry))))
                (dtheta (cond
                          ((and cw? (> dtheta-unwhitened 0)) (- dtheta-unwhitened tau))
                          ((and (not cw?) (< dtheta-unwhitened 0)) (+ dtheta-unwhitened tau))
                          (t dtheta-unwhitened)))
                )
           (values (cons (clem:val cxy 0 0) (clem:val cxy 1 0))
                   cw?
                   theta1
                   dtheta
                   )
           )))))

(defun splat-pairs (head pairs)
  (cond
    ((consp head) (cons (car head) (splat-pairs (cdr head) pairs)))
    ((null pairs) (list head))
    ((null head) (splat-pairs (car pairs) (cdr pairs)))
    (t (cons head (splat-pairs (car pairs) (cdr pairs))))))

(defun build-pairs (args)
  (loop for i from 0 to (1- (length args)) by 2
        collect (cons (nth i args) (nth (1+ i) args))))

(defun pair-to-abs-xy (svgm p) (vec+ p (svgm-current svgm)))
(defun pairs-to-abs-xy (svgm pairs)
  (mapcar (lambda (p) (pair-to-abs-xy svgm p)) pairs))

(defun apply-xform (xform p &key (pfunc #'point))
  (clem-to-list (clem:mat-mult xform (funcall pfunc p))))

(defun update-assoc (alist &rest update)
  (labels
      ((update-assoc-1 (alist k v)
         (cond
           ((null alist) (cons (cons k v) nil))
           ((eq (caar alist) k) (cons (cons k v) (cdr alist)))
           (t (cons (car alist) (update-assoc-1 (cdr alist) k v)))
           )))
    (reduce (lambda (al up) (update-assoc-1 al (car up) (cdr up)))
            update :initial-value alist)))

(defun xform-gcode-xy (xform line)
  (let ((x (cdr (assoc :X line)))
        (y (cdr (assoc :Y line))))
    (cond
      ((and (null x) (null y)) line)
      ((or (null x) (null y)) (error "must specify either both x and y or neither, got " line))
      (t (let ((xformed (apply-xform xform (cons x y))))
           (update-assoc line (cons :X (car xformed)) (cons :Y (cdr xformed))))))))

(defun xform-gcode-arc (xform line)
  (let ((x (cdr (assoc :X line)))
        (y (cdr (assoc :Y line)))
        (i (cdr (assoc :I line)))
        (j (cdr (assoc :J line))))
    (let ((xfxy (apply-xform xform (cons x y)))
          (xfij (apply-xform xform (cons i j) :pfunc #'vec)))
      (update-assoc line
                    (cons :X (car xfxy))
                    (cons :Y (cdr xfxy))
                    (cons :I (car xfij))
                    (cons :J (cdr xfij))
                    ))))

(defun xform-gcode (xform lines)
  (mapcar (lambda (line)
            (let ((mode (cdr (assoc :G line))))
              (alexandria:switch (mode)
                (0 (xform-gcode-xy xform line))
                (1 (xform-gcode-xy xform line))
                (2 (xform-gcode-arc xform line))
                (3 (xform-gcode-arc xform line))
                (otherwise line)
                )))
          lines))

(defun interpolate-ellipse (arc-args svgm)
  (labels
      ((eval-ellipse (theta rx ry) (cons (* rx (cos theta)) (* ry (sin theta)))))
      (multiple-value-bind (cxy cw? theta1 dtheta) (arc-center-xy arc-args (svgm-current svgm))
        (loop for theta in (linspace theta1 (+ theta1 dtheta) (/ tau 60))
              collect
              (let ((xy (vec+ (eval-ellipse theta (first arc-args) (second arc-args)) cxy)))
                (list #\L (car xy) (cdr xy))))
        )))

(defun to-abs (s svgm)
  (labels ((from-pairs (mode ps)
             (list (splat-pairs mode (pairs-to-abs-xy svgm ps))))
           (auto-pairs () (from-pairs (char-upcase (first s)) (build-pairs (rest s))))
           )
    (alexandria:switch ((first s))
      (#\m (auto-pairs))
      (#\l (auto-pairs))
      (#\c (auto-pairs))
      (#\s (auto-pairs))
      (#\q (auto-pairs))
      (#\t (auto-pairs))
      (#\h (from-pairs #\L (list (cons (second s) 0))))
      (#\H (list (list #\L (second s) (cdr (svgm-current svgm)))))
      (#\v (from-pairs #\L (list (cons 0 (second s)))))
      (#\V (list (list #\L (car (svgm-current svgm)) (second s))))

      (#\a (let* ((args (rest s))
                  (xy (pair-to-abs-xy svgm (cons (sixth args) (seventh args)))))
             ; send the abs version through to-abs again to be transformed
             (to-abs (append '(#\A) (subseq s 1 6) (list (car xy) (cdr xy))) svgm)))
      (#\A (let* ((args (rest s))
                  (rx (first args))
                  (ry (second args))
                  (x (sixth args))
                  (y (seventh args))
                  )
             (if (> (abs (- rx ry)) 0.001)
                 ; if it's not a perfect circle, we convert it to lines. Ellipses aren't
                 ; supported by G-Code, so instead of trying to bake the xform into a special
                 ; format to pass on, we just interpolate
                 (interpolate-ellipse args svgm)
                 ; otherwise we leave it as a circle so we can use the G-Code arc commands
                 ; Since it's a circle, we can set phi to zero (because there is no major/minor axis)
                 (list (list #\A rx ry 0.0d0 (fourth args) (fifth args) x y))
                 )))

      (#\z '((#\Z))) ; z and Z are the same, but we upcase it to make conditionals simpler later
      (otherwise (list s))
      )))

(defun gcode-goto (xy &key (mode 1))
  (list (cons :G mode) (cons :X (car xy)) (cons :Y (cdr xy))))

(defun push-polyline (svgm pts)
  (reduce (lambda (svgm p) (push-stanza svgm (list #\L (car p) (cdr p))))
          pts :initial-value svgm))

(defun linspace (a b step)
  (let* ((steps (abs (ceiling (/ (- b a) step))))
         (s (/ (- b a) steps)))
    (loop for i from 0 to steps collect (+ a (* s i)))))

(defun push-stanza (svgm s)
  "Creates and returns a new svg machine that includes the result of interpreting the given stanza. Stanza must be 'final', meaning that it's already in absolute coordinates."
  (let* ((mode (first s))
         (args (rest s))
         (cur-xy (svgm-current svgm))
         (ls (svgm-last-start svgm))
         (gcode (svgm-gcode svgm))
         (gunxf (svgm-gcode-unxf svgm))
         (rb (svgm-rel-base svgm))
         )
    (alexandria:switch (mode)
      ; path start/end
      (#\M (let ((p (cons (first args) (second args))))
             (make-svg-machine
              :current p :last-start p :rel-base rb
              :gcode-unxf (append gunxf (list '((:G . 0) (:Z . 1)) (gcode-goto p :mode 0) '((:G . 1) (:Z . -1))))
              :gcode gcode
              )))
      (#\Z (progn
             (when (null ls)
               (error "got Z (close path) when there's no current path"))
             (make-svg-machine
              :current ls :last-start ls :rel-base rb
              :gcode-unxf (append gunxf (list (gcode-goto ls))) :gcode gcode
              )))

      ; lines
      (#\L (let ((p (cons (first args) (second args))))
             (make-svg-machine
              :current p :last-start (if (null ls) cur-xy ls) :rel-base rb
              :gcode-unxf (append gunxf (list (gcode-goto p))) :gcode gcode
              )))

      ; cubic beziers
      (#\C (let* ((c1 (cons (first args) (second args)))
                  (c2 (cons (third args) (fourth args)))
                  (p2 (cons (fifth args) (sixth args)))
                  (svg-poly (push-polyline svgm (linterp-bezier-cubic cur-xy c1 c2 p2))))
             (make-svg-machine
              :current (svgm-current svg-poly) :last-start (svgm-last-start svg-poly)
              :gcode (svgm-gcode svg-poly) :gcode-unxf (svgm-gcode-unxf svg-poly)
              :last-ctrl-point c2 :rel-base rb
              )))
      (#\S (let* ((lcp? (svgm-last-ctrl-point svgm))
                  (lcp (if (null lcp?) cur-xy lcp?))
                  (c1 (vec+ cur-xy (vec- cur-xy lcp))))
             (push-stanza svgm (append (list #\C (car c1) (cdr c1)) args))))

      ; quadratic beziers
      (#\Q (let* ((c (cons (first args) (second args)))
                  (p2 (cons (third args) (fourth args)))
                  (svg-poly (push-polyline svgm (linterp-bezier-quadratic cur-xy c p2))))
             (make-svg-machine
              :current (svgm-current svg-poly) :last-start (svgm-last-start svg-poly)
              :gcode (svgm-gcode svg-poly) :gcode-unxf (svgm-gcode-unxf svg-poly)
              :last-ctrl-point c :rel-base rb
              )))
      (#\T (let* ((lcp? (svgm-last-ctrl-point svgm))
                  (lcp (if (null lcp?) cur-xy lcp?))
                  (c (vec+ cur-xy (vec- cur-xy lcp))))
             (push-stanza svgm (append (list #\Q (car c) (cdr c)) args))))

      ; arcs
      (#\A
       (multiple-value-bind (center-xy cw?) (arc-center-xy args cur-xy)
         (let ((xy (cons (sixth args) (seventh args)))
               (ij (vec- center-xy cur-xy)))
           (make-svg-machine
            :current xy :last-start ls :rel-base rb
            :gcode gcode
            :gcode-unxf (append gunxf (list (list (cons :G (if cw? 3 2))
                                                  (cons :I (car ij))
                                                  (cons :J (cdr ij))
                                                  (cons :X (car xy))
                                                  (cons :Y (cdr xy)))))
            ))))

      ; rel-base update
      (:end-stanza (make-svg-machine :current cur-xy :last-start ls :rel-base cur-xy
                                     :gcode gcode :gcode-unxf gunxf))

      (otherwise (error "unsupported mode ~A" mode))
      )))

(defun run-stanzas (stanzas svgm)
  (reduce
   (lambda (isvgm s) (reduce (lambda (insvgm sabs) (push-stanza insvgm sabs))
                             (to-abs s isvgm)
                             :initial-value isvgm))
   stanzas :initial-value svgm))

(defun normalize-stanza (s)
  "Takes a stanza of the form (MODE ARG0 ARG1 ARG2 ... ARGN) and returns a list of stanzas
   in which each stanza contains only one move with a mode modifier."
  (let* ((mode (car s))
         (target-len (alexandria:switch ((char-downcase mode))
                       (#\m 2) (#\z 0) (#\l 2) (#\h 1) (#\v 1) (#\c 6)
                       (#\s 4) (#\q 4) (#\t 2) (#\a 7)))
         (args (cdr s))
         (args-len (length args))
         ; some modes switch after the first set of arguments; this captures
         ; that.
         (mode2 (cond
                  ((equal mode #\m) #\l)
                  ((equal mode #\M) #\L)
                  (t mode)
                  ))
         )
    (if (= target-len 0)
        (if (= 0 args-len)
            (list (list mode))
            (error "bad number of arguments for zero-length mode ~A: ~A" mode args-len))
        (progn
          (unless (= 0 (mod args-len target-len))
            (error "bad number of arguments in mode ~A: ~A" mode args-len))
          (labels ((split (a is-first)
                     (when (> (length a) 0)
                       (cons (cons (if is-first mode mode2) (subseq a 0 target-len))
                             (split (subseq a target-len) nil)))))
            (append (split args t) '((:end-stanza)))
            )))))

(defun load-path-args (stz)
  (let ((stz-clean (string-trim '(#\Space #\Newline #\Tab #\Linefeed #\Return #\,) stz)))
    (when (> (length stz-clean) 0)
      (multiple-value-bind (st end) (cl-ppcre:scan "[\\-]?[0-9]*(\\.[0-9]+|[0-9]*)" stz-clean)
        (cons (parse-float:parse-float (subseq stz-clean st end))
              (load-path-args (subseq stz-clean end)))))))

(defun load-path-stanzas (d)
  (when (> (length d) 0)
    (multiple-value-bind (st end) (cl-ppcre:scan "^[a-zA-Z][^a-zA-Z]*" d)
      (cons
       (cons (char d 0) (load-path-args (subseq d (1+ st) end)))
       (load-path-stanzas (subseq d end)))
      )))

(defun load-path-data (d)
  (reduce #'append (mapcar #'normalize-stanza (load-path-stanzas d))))

(defun update-struct (struct &rest bindings)
  (loop
    with copy = (copy-structure struct)
    for (slot value) on bindings by #'cddr
    do (setf (slot-value copy slot) value)
    finally (return copy)))

(defun xform-svgm (svgm xform)
  "Transforms gcode-unxf and appends it onto the gcode list"
  (update-struct svgm
                 'gcode-unxf nil
                 'gcode (append (svgm-gcode svgm)
                                (xform-gcode xform (svgm-gcode-unxf svgm)))))

(defun a (attr data)
  (let ((attr-str (cadr (assoc attr (cadr data) :test #'string-equal))))
    (if attr-str (parse-float:parse-float attr-str) 0)))

(defun load-unxf-path (svgm data)
  (run-stanzas (load-path-data (cadr (assoc "d" (cadr data) :test #'string-equal))) svgm))
(defun load-unxf-line (svgm d)
  (run-stanzas (list (list #\M (a "x1" d) (a "y1" d)) (list #\L (a "x2" d) (a "y2" d))) svgm))
(defun load-unxf-circle (svgm d)
  (let* ((cx (a "cx" d)) (cy (a "cy" d)) (r (a "r" d))
         (xx (+ cx r)) (yy cy))
    (update-struct
     svgm
     'gcode-unxf (list
                  (list '(:G . 0) '(:Z . 1))
                  (list '(:G . 0) (cons :X xx) (cons :Y yy))
                  (list '(:G . 1) '(:Z . -1))
                  (list '(:G . 2) (cons :X xx) (cons :Y yy) (cons :I (- r)) '(:J . 0))
                  (list '(:G . 0) '(:Z . 1))
                  ))))
(defun load-unxf-polygon (svgm d)
  (let ((points (load-path-args (cadr (assoc "points" (cadr d) :test #'string-equal)))))
    (run-stanzas (append (list (list #\M (first points) (second points)))
                         (normalize-stanza (cons #\L (cddr points))))
                 svgm)
    ))
(defun load-unxf-rect (svgm d)
  (let ((x (a "x" d))
        (y (a "y" d))
        (w (a "width" d))
        (h (a "height" d)))
    (run-stanzas (list (list #\M x y)
                       (list #\l w 0)
                       (list #\l 0 h)
                       (list #\l (- w) 0)
                       '(#\Z))
                 svgm)))
(defun load-unxf-ellipse (svgm d)
  (let* ((rx (a "rx" d))
         (ry (a "ry" d))
         (sx (+ (a "cx" d) rx))
         (mx (- (a "cx" d) rx))
         (sy (a "cy" d)))
    (run-stanzas (list (list #\M sx sy)
                       (list #\A rx ry 0 0 0 mx sy)
                       (list #\A rx ry 0 0 0 sx sy)
                       )
                 svgm)
    ))

(defun load-unxf-gcode (svgm data)
  (funcall (alexandria:switch ((caar data) :test #'string-equal)
             ("path" #'load-unxf-path)
             ("line" #'load-unxf-line)
             ("circle" #'load-unxf-circle)
             ("ellipse" #'load-unxf-ellipse)
             ("polygon" #'load-unxf-polygon)
             ("rect" #'load-unxf-rect)
             (otherwise (lambda (svgm &rest _) svgm))
             )
           svgm data))

(defun print-xform-stack (xforms)
  (format t "[~%")
  (mapcar (lambda (x) (clem:print-matrix x) (format t "~%")) xforms)
  (format t "]~%")
  xforms)

(defun load-svg-from-xml (data svgm xform-stack)
  (if (listp data)
      (let* ((tag (car data))
             (attributes (cadr data))
             (xform-attr (assoc "transform" attributes :test #'string-equal))
             (new-xform-stack (if (null xform-attr)
                                  xform-stack
                                  (cons (parse-transform (cadr xform-attr)) xform-stack)))
             (xform (reduce #'clem:mat-mult (reverse new-xform-stack)
                            :initial-value (clem:identity-matrix 3)))
             (children (cddr data))
             (svgm-unxf (load-unxf-gcode svgm data))
             (svgm-new (xform-svgm svgm-unxf xform))
             )
        (reduce (lambda (asvgm child)
                  (load-svg-from-xml child asvgm new-xform-stack))
                children
                :initial-value svgm-new)
        )
      svgm))

(defun svg-load (svgdata)
  (load-svg-from-xml svgdata (make-svg-machine) (list point-to-mm-xform)))

(defun svg-to-gcode (fname gcode-out)
  (with-open-file (outf gcode-out :direction :output :if-exists :supersede)
    (let* ((svgtxt (alexandria:read-file-into-string fname))
           (svgdata (xmls:parse svgtxt)))
      (svgm-emit-gcode outf (svg-load svgdata)))))

(defun svgm-emit-gcode (outstream svgm)
  (labels ((gcode-number (n) (if (< (abs (- (round n) n)) 0.001)
                                 (format nil "~D" (round n))
                                 (format nil "~,2F" n)))
           (emit-assignment (reg) (format nil "~A~A" (car reg) (gcode-number (cdr reg))))
           (emit-line (line) (format nil "~{~A~^ ~}" (mapcar #'emit-assignment line))))
    (format outstream "~{~A~^~%~}" (mapcar #'emit-line (append (svgm-gcode svgm) gcode-postamble)))))