;;; ein-utils.el --- Utility module

;; Copyright (C) 2012- Takafumi Arakaki

;; Author: Takafumi Arakaki <aka.tkf at gmail.com>

;; This file is NOT part of GNU Emacs.

;; ein-utils.el is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; ein-utils.el is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with ein-utils.el.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;;

;;; Code:

(eval-when-compile (require 'cl))
(require 'json)


;;; Macros and core functions/variables

(defmacro ein:aif (test-form then-form &rest else-forms)
  "Anaphoric IF.  Adapted from `e2wm:aif'."
  (declare (debug (form form &rest form)))
  `(let ((it ,test-form))
     (if it ,then-form ,@else-forms)))
(put 'ein:aif 'lisp-indent-function 2)

(defmacro ein:aand (test &rest rest)
  "Anaphoric AND.  Adapted from `e2wm:aand'."
  (declare (debug (form &rest form)))
  `(let ((it ,test))
     (if it ,(if rest (macroexpand-all `(ein:aand ,@rest)) 'it))))

(defmacro ein:and-let* (bindings &rest form)
  "Gauche's `and-let*'."
  (declare (debug (((symbolp form)) &rest form))
           (indent 1))
  (if (null bindings)
      `(progn ,@form)
    (let* ((head (car bindings))
           (tail (cdr bindings))
           (rest (macroexpand-all `(ein:and-let* ,tail ,@form))))
      (cond
       ((symbolp head) `(if ,head ,rest))
       ((= (length head) 1) `(if ,(car head) ,rest))
       (t `(let (,head) (if ,(car head) ,rest)))))))

(defmacro ein:deflocal (name &optional initvalue docstring)
  "Define permanent buffer local variable named NAME.
INITVALUE and DOCSTRING are passed to `defvar'."
  (declare (indent defun)
           (doc-string 3))
  `(progn
     (defvar ,name ,initvalue ,docstring)
     (make-variable-buffer-local ',name)
     (put ',name 'permanent-local t)))

(defmacro ein:with-read-only-buffer (buffer &rest body)
  (declare (indent 1))
  `(with-current-buffer ,buffer
     (setq buffer-read-only t)
     (save-excursion
       (let ((inhibit-read-only t))
         ,@body))))

(defmacro ein:with-live-buffer (buffer &rest body)
  "Execute BODY in BUFFER if BUFFER is alive."
  (declare (indent 1) (debug t))
  `(when (buffer-live-p ,buffer)
     (with-current-buffer ,buffer
       ,@body)))

(defmacro ein:with-possibly-killed-buffer (buffer &rest body)
  "Execute BODY in BUFFER if BUFFER is live.
Execute BODY if BUFFER is not live anyway."
  (declare (indent 1) (debug t))
  `(if (buffer-live-p ,buffer)
       (with-current-buffer ,buffer
         ,@body)
     ,@body))

(defvar ein:dotty-syntax-table
  (let ((table (make-syntax-table c-mode-syntax-table)))
    (modify-syntax-entry ?. "w" table)
    (modify-syntax-entry ?_ "w" table)
    table)
  "Adapted from `python-dotty-syntax-table'.")

(defun ein:object-at-point ()
  "Return dotty.words.at.point.
When region is active, text in region is returned after trimmed
white spaces, newlines and dots.
When object is not found at the point, return the object just
before previous opening parenthesis."
  ;; For auto popup tooltip (or something like eldoc), probably it is
  ;; better to return function (any word before "(").  I should write
  ;; another function or add option to this function when the auto
  ;; popup tooltip is implemented.
  (if (region-active-p)
      (ein:trim (buffer-substring (region-beginning) (region-end))
                "\\s-\\|\n\\|\\.")
    (save-excursion
      (with-syntax-table ein:dotty-syntax-table
        (ein:aif (thing-at-point 'word)
            it
          (unless (looking-at "(")
            (search-backward "(" (point-at-bol) t))
          (thing-at-point 'word))))))

(defun ein:object-at-point-or-error ()
  (or (ein:object-at-point) (error "No object found at the point")))


;;; URL utils

(defvar ein:url-localhost-template "http://127.0.0.1:%s")

(defun ein:url (url-or-port &rest paths)
  (loop with url = (if (integerp url-or-port)
                       (format ein:url-localhost-template url-or-port)
                     url-or-port)
        for p in paths
        do (setq url (concat (ein:trim-right url "/")
                             "/"
                             (ein:trim-left p "/")))
        finally return url))

(defun ein:url-no-cache (url)
  "Imitate `cache=false' of `jQuery.ajax'.
See: http://api.jquery.com/jQuery.ajax/"
  (concat url (format-time-string "?_=%s")))


;;; JSON utils

(defmacro ein:with-json-setting (&rest body)
  `(let ((json-object-type 'plist)
         (json-array-type 'list))
     ,@body))

(defun ein:json-read ()
  "Read json from `url-retrieve'-ed buffer.

* `json-object-type' is `plist'. This is mainly for readability.
* `json-array-type' is `list'.  Notebook data is edited locally thus
  data type must be edit-friendly.  `vector' type is not."
  (goto-char (point-max))
  (backward-sexp)
  (ein:with-json-setting
   (json-read)))

(defun ein:json-read-from-string (string)
  (ein:with-json-setting
   (json-read-from-string string)))

(defun ein:json-any-to-bool (obj)
  (if (and obj (not (eq obj json-false))) t json-false))

(defun ein:json-encode-char (char)
  "Fixed `json-encode-char'."
  (setq char (json-encode-char0 char 'ucs))
  (let ((control-char (car (rassoc char json-special-chars))))
    (cond
     ;; Special JSON character (\n, \r, etc.)
     (control-char
      (format "\\%c" control-char))
     ;; ASCIIish printable character
     ((and (> char 31) (< char 160))    ; s/161/160/
      (format "%c" char))
     ;; Fallback: UCS code point in \uNNNN form
     (t
      (format "\\u%04x" char)))))

(defadvice json-encode-char (around ein:json-encode-char (char) activate)
  "Replace `json-encode-char' with `ein:json-encode-char'."
  (setq ad-return-value (ein:json-encode-char char)))


;;; EWOC

(defun ein:ewoc-create (pretty-printer &optional header footer nosep)
  "Do nothing wrapper of `ewoc-create' to provide better error message."
  (condition-case nil
      (ewoc-create pretty-printer header footer nosep)
    ((debug wrong-number-of-arguments)
     (ein:display-warning "Incompatible EOWC version.
  The version of ewoc.el you are using is too old for EIN.
  Please install the newer version.
  See also: https://github.com/tkf/emacs-ipython-notebook/issues/49")
     (error "Incompatible EOWC version."))))


;;; Text property

(defun ein:propertize-read-only (string &rest properties)
  (apply #'propertize string 'read-only t 'front-sticky t properties))

(defun ein:insert-read-only (string &rest properties)
  (insert (apply #'ein:propertize-read-only string properties)))


;;; String manipulation

(defun ein:trim (string &optional regexp)
  (ein:trim-left (ein:trim-right string regexp) regexp))

(defun ein:trim-left (string &optional regexp)
  (unless regexp (setq regexp "\\s-\\|\n"))
  (ein:trim-regexp string (format "^\\(%s\\)+" regexp)))

(defun ein:trim-right (string &optional regexp)
  (unless regexp (setq regexp "\\s-\\|\n"))
  (ein:trim-regexp string (format "\\(%s\\)+$" regexp)))

(defun ein:trim-regexp (string regexp)
  (if (string-match regexp string)
      (replace-match "" t t string)
    string))

(defun ein:trim-indent (string)
  "Strip uniform amount of indentation from lines in STRING."
  (let* ((lines (split-string string "\n"))
         (indent
          (let ((lens
                 (loop for line in lines
                       for stripped = (ein:trim-left line)
                       unless (equal stripped "")
                       collect (- (length line) (length stripped)))))
            (if lens (apply #'ein:min lens) 0)))
         (trimmed
          (loop for line in lines
                if (> (length line) indent)
                collect (ein:trim-right (substring line indent))
                else
                collect line)))
    (ein:join-str "\n" trimmed)))

(defun ein:join-str (sep strings)
  (mapconcat 'identity strings sep))

(defun ein:join-path (paths)
  (mapconcat 'file-name-as-directory paths ""))

(defun ein:string-fill-paragraph (string &optional justify)
  (with-temp-buffer
    (erase-buffer)
    (insert string)
    (goto-char (point-min))
    (fill-paragraph justify)
    (buffer-string)))

(defmacro ein:case-equal (str &rest clauses)
  "Similar to `case' but comparison is done by `equal'.
Adapted from twittering-mode.el's `case-string'."
  (declare (indent 1))
  `(cond
    ,@(mapcar
       (lambda (clause)
	 (let ((keylist (car clause))
	       (body (cdr clause)))
	   `(,(if (listp keylist)
		  `(or ,@(mapcar (lambda (key) `(equal ,str ,key))
				 keylist))
		't)
	     ,@body)))
       clauses)))


;;; Misc

(defun ein:plist-iter (plist)
  "Return list of (key . value) in PLIST."
  (loop for p in plist
        for i from 0
        for key-p = (= (% i 2) 0)
        with key = nil
        if key-p do (setq key p)
        else collect `(,key . ,p)))

(defun ein:hash-keys (table)
  (let (keys)
    (maphash (lambda (k v) (push k keys)) table)
    keys))

(defun ein:hash-vals (table)
  (let (vals)
    (maphash (lambda (k v) (push v vals)) table)
    vals))

(defun ein:filter (predicate sequence)
  (loop for item in sequence
        when (funcall predicate item)
        collect item))

(defun ein:clip-list (list first last)
  "Return elements in region of the LIST specified by FIRST and LAST element.

Example::

    (ein:clip-list '(1 2 3 4 5 6) 2 4)  ;=> (2 3 4)"
  (loop for elem in list
        with clipped
        with in-region-p = nil
        when (eq elem first)
        do (setq in-region-p t)
        when in-region-p
        do (push elem clipped)
        when (eq elem last)
        return (reverse clipped)))

(defun ein:get-value (obj)
  "Get value from obj if it is a variable or function."
  (cond
   ((not (symbolp obj)) obj)
   ((boundp obj) (eval obj))
   ((fboundp obj) (funcall obj))))

(defun ein:choose-setting (symbol value)
  "Choose setting in stored in SYMBOL based on VALUE.
The value of SYMBOL can be string, alist or function."
  (let ((setting (eval symbol)))
    (cond
     ((stringp setting) setting)
     ((functionp setting) (funcall setting value))
     ((listp setting)
      (ein:get-value (or (assoc-default value setting)
                         (assoc-default 'default setting))))
     (t (error "Unsupported type of `%s': %s" symbol (type-of setting))))))

(defmacro ein:setf-default (place val)
  "Set VAL to PLACE using `setf' if the value of PLACE is `nil'."
  `(unless ,place
     (setf ,place ,val)))

(defun ein:funcall-packed (func-arg &rest args)
  "Call \"packed\" function.
FUNC-ARG is a `cons' of the form: (FUNC ARG).
FUNC is called as (apply FUNC ARG ARGS)."
  (apply (car func-arg) (cdr func-arg) args))

(defun ein:eval-if-bound (symbol)
  (if (boundp symbol) (eval symbol)))

(defun ein:remove-by-index (list indices)
  "Remove elements from LIST if its index is in INDICES.
NOTE: This function creates new list."
  (loop for l in list
        for i from 0
        when (not (memq i indices))
        collect l))

(defun ein:min (x &rest xs)
  (loop for y in xs if (< y x) do (setq x y))
  x)

(defun ein:do-nothing (&rest -ignore-)
  "A function which can take any number of variables and do nothing.")

(defun ein:ask-choice-char (prompt choices)
  "Show PROMPT and read one of acceptable key specified as CHOICES."
  (let ((char-list (loop for i from 0 below (length choices)
                         collect (elt choices i)))
        (answer 'recenter))
    (while
        (let ((key
               (let ((cursor-in-echo-area t))
                 (read-key (propertize (if (eq answer 'recenter)
                                           prompt
                                         (concat "Please choose answer from"
                                                 (format " %s.  " choices)
                                                 prompt))
                                       'face 'minibuffer-prompt)))))
          (setq answer (lookup-key query-replace-map (vector key) t))
          (cond
           ((memq key char-list) (setq answer key) nil)
           ((eq answer 'recenter) (recenter) t)
           ((memq answer '(exit-prefix quit)) (signal 'quit nil) t)
           (t t)))
      (ding)
      (discard-input))
    answer))


(defun ein:truncate-lines-on ()
  "Set `truncate-lines' on (set it to `t')."
  (setq truncate-lines t))


;;; Emacs utilities

(defun ein:display-warning (message &optional level)
  "Simple wrapper around `display-warning'.
LEVEL must be one of :emergency, :error or :warning (default).
This must be used only for notifying user.
Use `ein:log' for debugging and logging."
  ;; FIXME: Probably set BUFFER-NAME per notebook?
  ;; FIXME: Call `ein:log' here (but do not display in minibuffer).
  (display-warning 'ein message level))

(defun ein:get-docstring (function)
  "Return docstring of FUNCTION."
  ;; Borrowed from `ac-symbol-documentation'.
  (with-temp-buffer
    ;; import help-xref-following
    (require 'help-mode)
    (erase-buffer)
    (let ((standard-output (current-buffer))
          (help-xref-following t)
          (major-mode 'help-mode)) ; avoid error in Emacs 24
      (describe-function-1 function))
    (buffer-string)))

(defun ein:generate-menu (list-name-callback)
  (mapcar (lambda (name-callback)
            (destructuring-bind (name callback &rest args) name-callback
              `[,name ,callback :help ,(ein:get-docstring callback) ,@args]))
          list-name-callback))


;;; utils.js compatible

(defun ein:utils-uuid ()
  "Return string with random (version 4) UUID.
Adapted from org-mode's `org-id-uuid'."
  (let ((rnd (md5 (format "%s%s%s%s%s%s%s"
			  (random t)
			  (current-time)
			  (user-uid)
			  (emacs-pid)
			  (user-full-name)
			  user-mail-address
			  (recent-keys)))))
    (format "%s-%s-4%s-%s%s-%s"
	    (substring rnd 0 8)
	    (substring rnd 8 12)
	    (substring rnd 13 16)
	    (format "%x"
		    (logior
		     #b10000000
		     (logand
		      #b10111111
		      (string-to-number
		       (substring rnd 16 18) 16))))
	    (substring rnd 18 20)
	    (substring rnd 20 32))))


(provide 'ein-utils)

;;; ein-utils.el ends here