; Potion Mode

(defconst potion-indent-offset 2 "Offset for indentation.")

; Stolen from Ioke Mode
(defconst potion-operator-symbols
  '("?" "..." "=>" "++"	"--" "*" "/" "%" "+" "-" "<<" ">>" ">" "<" "<=" ">=" "<=>" "==" "!=" "=~" "!~" "&" "^" "|" "&&" "||" ".." "=" "+=" "-=" "*=" "/=" "%=" "&=" "^=" "|=" "<<=" ">>=" "<-" "<->" "->")
  "Potion mode operator symbols")

(defgroup potion-font-lock-faces nil
  "Specific Potion faces for highlighting Potion sources."
  :prefix "potion-font-lock-"
  :group (if (featurep 'xemacs)
             'font-lock-faces
           'font-lock-highlighting-faces))

(defface potion-font-lock-integer-face
  '((((class grayscale)) (:foreground "LightGray"))
    (((class color)) (:foreground "LightSalmon"))
    (t (:bold t)))
  "Font Lock Mode face used to highlight ."
  :group 'potion-font-lock-faces)

(defconst potion-font-lock-integer-face 'potion-font-lock-integer-face)

(defface potion-font-lock-operator-face
  '((((class grayscale)) (:foreground "DimGray"))
    (((class color)) (:foreground "SteelBlue1"))
    (t (:bold t)))
  "Font Lock Mode face used to highlight ."
  :group 'potion-font-lock-faces)

(defconst potion-font-lock-operator-face 'potion-font-lock-operator-face)

(defface potion-font-lock-variable-name-face
  '((((class grayscale)) (:foreground "DimGray"))
    (((class color)) (:foreground "LightSkyBlue2"))
    (t (:bold t)))
  "Font Lock Mode face used to highlight ."
  :group 'potion-font-lock-faces)

(defconst potion-font-lock-variable-name-face 'font-lock-reference-face)

(defface potion-font-lock-function-name-face
  '((((class grayscale)) (:foreground "LightGray"))
    (((class color)) (:foreground "light goldenrod"))
    (t (:bold t)))
  "Font Lock Mode face used to highlight ."
  :group 'potion-font-lock-faces)

(defconst potion-font-lock-function-name-face 'potion-font-lock-function-name-face)

(defface potion-font-lock-punctuation-face
  '((((class grayscale)) (:foreground "DimGray"))
    (((class color)) (:foreground "RosyBrown2"))
    (t (:bold t)))
  "Font Lock Mode face used to highlight ."
  :group 'potion-font-lock-faces)

(defconst potion-font-lock-punctuation-face 'potion-font-lock-punctuation-face)

(defconst potion-font-lock-builtin-face font-lock-keyword-face)

(defface potion-font-lock-boolean-face
  '((((class grayscale)) (:foreground "Gray50"))
    (((class color)) (:foreground "Aquamarine"))
    (t (:bold t)))
  "Font Lock Mode face used to highlight ."
  :group 'potion-font-lock-faces)

(defconst potion-font-lock-boolean-face 'potion-font-lock-boolean-face)

(defconst potion-font-lock-class-name-face font-lock-type-face)

(defface potion-font-lock-path-face
  '((((class grayscale)) (:foreground "Gray50"))
    (((class color)) (:foreground "plum3"))
    (t (:bold t)))
  "Font Lock Mode face used to highlight ."
  :group 'potion-font-lock-faces)

(defconst potion-font-lock-path-face 'potion-font-lock-path-face)

(defface potion-font-lock-closure-face
  '((((class grayscale)) (:foreground "Gray50"))
    (((class color)) (:foreground "SlateGray3"))
    (t (:bold t)))
  "Font Lock Mode face used to highlight ."
  :group 'potion-font-lock-faces)

(defconst potion-font-lock-closure-face 'potion-font-lock-closure-face)


(defvar potion-font-lock-keywords
  (list
   '("\\([0-9]+\\)" 1 potion-font-lock-integer-face)
   '("\\([A-Z]+\\S-+\\)" 1 potion-font-lock-class-name-face)
   '("\\(/\\S-+\\)" 1 potion-font-lock-path-face)
   '("\\([()]\\)" 1 potion-font-lock-closure-face)
   `(,(format "\\(%s\\)" (regexp-opt potion-operator-symbols)) 1 potion-font-lock-operator-face)
   '("\\(\\S-+\\)\\s-+=\\s-+(" 1 potion-font-lock-function-name-face)
   '("\\(\\S-+\\)\\s-+=" 1 potion-font-lock-variable-name-face)
   '("\\([:,\\.]\\)" 1 potion-font-lock-punctuation-face)
   '("\\(loop\\|elsif\\|if\\|class\\|while\\|to\\|return\\|else\\)" 1 potion-font-lock-builtin-face)
   '("\\(true\\|false\\|nil\\)" 1 potion-font-boolean-face)
   )
  "Highlighting for Potion mode")


(defvar potion-mode-hook nil)


(defvar potion-mode-syntax-table
  (let ((st (make-syntax-table)))
    (modify-syntax-entry ?# "<" st)
    (modify-syntax-entry ?\' "\"" st)
    st))

(defun potion-indent-line ()
  "Indentation for Potion"
  (interactive)
  (beginning-of-line)
  (if (bobp)
      (indent-line-to 0)
    (let ((not-indented t) cur-indent)
      (if (looking-at "^[ \t]*\\.")
	  (progn
	    (save-excursion
	      (forward-line -1)
	      (setq cur-indent (- (current-indentation) potion-indent-offset))))
	(save-excursion
	  (while not-indented
	    (forward-line -1)
	    (end-of-line)
	    (if (looking-back ":[ \t]*")
		(progn
		  (setq cur-indent (+ (current-indentation) potion-indent-offset))
		  (setq not-indented nil))
	      (if (looking-back "\\.[ \t]*")
		  (progn
		    (setq cur-indent (- (current-indentation) potion-indent-offset))
		    (setq not-indented nil))
		(if (progn
		      (beginning-of-line)
		      (bobp))
		    (setq not-indented nil)))))))
      (if cur-indent
	  (indent-line-to (max 0 cur-indent))
	(indent-line-to 0)))))
		  
		

(define-derived-mode potion-mode fundamental-mode "Potion"
  "A major mode for editing Potion files."
  :syntax-table potion-mode-syntax-table
  (set (make-local-variable 'comment-start) "# ")
  (set (make-local-variable 'font-lock-defaults) '(potion-font-lock-keywords))
  (set (make-local-variable 'indent-line-function) 'potion-indent-line))

(run-hooks 'potion-mode-hook)

(provide 'potion-mode)