;;; geiser-doc.el -- accessing scheme-provided documentation

;; Copyright (C) 2009, 2010 Jose Antonio Ortega Ruiz

;; This program is free software; you can redistribute it and/or
;; modify it under the terms of the Modified BSD License. You should
;; have received a copy of the license along with this program. If
;; not, see <http://www.xfree86.org/3.3.6/COPYRIGHT2.html#5>.

;; Start date: Sat Feb 14, 2009 14:09



(require 'geiser-edit)
(require 'geiser-impl)
(require 'geiser-completion)
(require 'geiser-autodoc)
(require 'geiser-eval)
(require 'geiser-syntax)
(require 'geiser-menu)
(require 'geiser-popup)
(require 'geiser-custom)
(require 'geiser-base)

(require 'button)


;;; Customization:

(defgroup geiser-doc nil
  "Options for documentation buffers."
  :group 'geiser)

(geiser-custom--defface doc-title
  'bold geiser-doc "article titles in documentation buffers")

(geiser-custom--defface doc-link
  'link geiser-doc "links in documentation buffers")

(geiser-custom--defface doc-button
  'button geiser-doc "buttons in documentation buffers")


;;; Documentation browser history:

(defvar geiser-doc-history-size 50)

(defun geiser-doc--make-history ()
  (list nil                                   ; current
        (make-ring geiser-doc-history-size)   ; previous
        (make-ring geiser-doc-history-size))) ; next

(defsubst geiser-doc--history-current ()
  (car geiser-doc--history))

(defun geiser-doc--history-push (link)
  (unless (or (null link) (equal link (geiser-doc--history-current)))
    (when (not (null (geiser-doc--history-current)))
      (let ((next (geiser-doc--history-next)))
        (unless (equal link next)
          (when next (geiser-doc--history-previous))
          (ring-insert (nth 1 geiser-doc--history)
                       (car geiser-doc--history)))))
    (setcar geiser-doc--history link))
  link)

(defsubst geiser-doc--history-next-p ()
  (not (ring-empty-p (nth 2 geiser-doc--history))))

(defun geiser-doc--history-next (&optional forget-current)
  (when (geiser-doc--history-next-p)
    (when (and (car geiser-doc--history) (not forget-current))
      (ring-insert (nth 1 geiser-doc--history) (car geiser-doc--history)))
    (setcar geiser-doc--history (ring-remove (nth 2 geiser-doc--history) 0))))

(defsubst geiser-doc--history-previous-p ()
  (not (ring-empty-p (nth 1 geiser-doc--history))))

(defun geiser-doc--history-previous (&optional forget-current)
  (when (geiser-doc--history-previous-p)
    (when (and (car geiser-doc--history) (not forget-current))
      (ring-insert (nth 2 geiser-doc--history) (car geiser-doc--history)))
    (setcar geiser-doc--history (ring-remove (nth 1 geiser-doc--history) 0))))

(defvar geiser-doc--history nil)
(setq geiser-doc--history (geiser-doc--make-history))


;;; Links

(defsubst geiser-doc--make-link (target module impl)
  (list target module impl))

(defsubst geiser-doc--link-target (link)
  (nth 0 link))

(defsubst geiser-doc--link-module (link)
  (nth 1 link))

(defsubst geiser-doc--link-impl (link)
  (nth 2 link))

(defun geiser-doc--follow-link (link)
  (let ((target (geiser-doc--link-target link))
        (module (geiser-doc--link-module link))
        (impl (geiser-doc--link-impl link)))
    (when (and (or target module) impl)
      (with--geiser-implementation impl
        (if (null target)
            (geiser-doc-module module impl)
          (geiser-doc-symbol target module impl))))))

(make-variable-buffer-local
 (defvar geiser-doc--buffer-link nil))

(defsubst geiser-doc--implementation ()
  (geiser-doc--link-impl geiser-doc--buffer-link))

(defun geiser-doc--button-action (button)
  (let ((link (button-get button 'geiser-link)))
    (when link (geiser-doc--follow-link link))))

(define-button-type 'geiser-doc--button
  'action 'geiser-doc--button-action
  'face 'geiser-font-lock-doc-link
  'follow-link t)

(defun geiser-doc--insert-button (target module impl)
  (let ((link (geiser-doc--make-link target module impl))
        (text (format "%s" (or target module)))
        (help (format "%smodule %s"
                      (if target (format "%s in " target) "")
                      (or module "<unknown>"))))
    (insert-text-button text
                        :type 'geiser-doc--button
                        'geiser-link link
                        'help-echo help)))

(defun geiser-doc--xbutton-action (button)
  (when geiser-doc--buffer-link
    (let ((kind (or (button-get button 'x-kind) 'source))
          (target (geiser-doc--link-target geiser-doc--buffer-link))
          (module (geiser-doc--link-module geiser-doc--buffer-link))
          (impl (geiser-doc--link-impl geiser-doc--buffer-link)))
      (with--geiser-implementation impl
        (if (eq kind 'source)
            (if target (geiser-edit-symbol target nil (point-marker))
              (geiser-edit-module module)))))))

(define-button-type 'geiser-doc--xbutton
  'action 'geiser-doc--xbutton-action
  'face 'geiser-font-lock-doc-button
  'follow-link t)

(defun geiser-doc--insert-xbutton (&optional manual)
  (insert-text-button (if manual "[manual]" "[source]")
                      :type 'geiser-doc--xbutton
                      'x-kind (if manual 'manual 'source)))

(defun geiser-doc--insert-xbuttons ()
  (geiser-doc--insert-xbutton))

(defun geiser-doc--insert-footer ()
  (newline 3)
  (when (geiser-doc--history-previous-p)
    (insert-text-button "[back]"
                        'action '(lambda (b) (geiser-doc-previous))
                        'face 'geiser-font-lock-doc-button
                        'follow-link t)
    (insert "  "))
  (when (geiser-doc--history-next-p)
    (insert-text-button "[forward]"
                        'action '(lambda (b) (geiser-doc-next))
                        'face 'geiser-font-lock-doc-button
                        'follow-link t)))


;;; Auxiliary functions:

(defun geiser-doc--insert-title (title &optional top)
  (let ((p (point)))
    (if (not (listp title))
        (insert (format "%s" title))
      (insert "(" (format "%s" (car title)))
      (dolist (a (cdr title))
        (insert " " (if (eq a '\#:rest) "." (format "%s" a))))
      (insert ")"))
    (put-text-property p (point) 'face 'geiser-font-lock-doc-title)
    (when top
      (let ((len (max 1 (- (window-width)
                           (- (point) (line-beginning-position))
                           10))))
        (insert (make-string len ?\ ))
        (geiser-doc--insert-xbuttons)))
    (newline)))

(defun geiser-doc--insert-list (title lst module impl)
  (when lst
    (geiser-doc--insert-title title)
    (newline)
    (dolist (w lst)
      (insert (format "\t- "))
      (if module
          (geiser-doc--insert-button w module impl)
        (geiser-doc--insert-button nil w impl))
      (newline))
    (newline)))


;;; Commands:

(geiser-impl--define-caller geiser-doc--external-help display-help
  (symbol module)
  "By default, Geiser will display help about an identifier in a
help buffer, after collecting the associated signature and
docstring. You can provide an alternative function for displaying
help (e.g. browse an HTML page) implementing this method.")

(defun geiser-doc--get-docstring (symbol module)
  (geiser-eval--send/result
   `(:eval ((:ge symbol-documentation) ',symbol) ,module)))

(defun geiser-doc--get-module-exports (module)
  (geiser-eval--send/result
   `(:eval ((:ge module-exports) (:module ,module)))))

(defun geiser-doc-symbol (symbol &optional module impl)
  (let ((module (or module (geiser-eval--get-module)))
        (impl (or impl geiser-impl--implementation)))
    (unless (geiser-doc--external-help impl symbol module)
      (let ((ds (geiser-doc--get-docstring symbol module)))
        (if (or (not ds) (not (listp ds)))
            (message "No documentation available for '%s'" symbol)
          (geiser-doc--with-buffer
            (erase-buffer)
            (geiser-doc--insert-title
             (geiser-autodoc--str (list (symbol-name symbol) 0)
                                  (cdr (assoc 'signature ds)))
             t)
            (newline)
            (insert (or (cdr (assoc 'docstring ds)) ""))
            (setq geiser-doc--buffer-link
                  (geiser-doc--history-push
                   (geiser-doc--make-link symbol module impl)))
            (geiser-doc--insert-footer)
            (goto-char (point-min)))
          (geiser-doc--pop-to-buffer))))))

(defun geiser-doc-symbol-at-point (&optional arg)
  "Get docstring for symbol at point.
With prefix argument, ask for symbol (with completion)."
  (interactive "P")
  (let ((symbol (or (and (not arg) (symbol-at-point))
                    (geiser-completion--read-symbol "Symbol: "
                                                    (symbol-at-point)))))
    (when symbol (geiser-doc-symbol symbol))))


(defun geiser-doc-module (&optional module impl)
  "Display information about a given module."
  (interactive)
  (let* ((module (or module (geiser-completion--read-module)))
         (exports (geiser-doc--get-module-exports module))
         (impl (or impl geiser-impl--implementation)))
    (if (not exports)
        (message "No information available for %s" module)
      (geiser-doc--with-buffer
        (erase-buffer)
        (geiser-doc--insert-title (format "%s" module) t)
        (newline)
        (dolist (g '(("Procedures:" . procs)
                     ("Variables:" . vars)
                     ("Syntax:" . syntax)))
          (geiser-doc--insert-list (car g)
                                   (cdr (assoc (cdr g) exports))
                                   module
                                   impl))
        (geiser-doc--insert-list "Submodules:"
                                 (cdr (assoc 'modules exports))
                                 nil
                                 impl)
        (setq geiser-doc--buffer-link
              (geiser-doc--history-push
               (geiser-doc--make-link nil module impl)))
        (geiser-doc--insert-footer)
        (goto-char (point-min)))
      (geiser-doc--pop-to-buffer))))

(defun geiser-doc-next (&optional forget-current)
  "Go to next page in documentation browser.
With prefix, the current page is deleted from history."
  (interactive "P")
  (let ((link (geiser-doc--history-next forget-current)))
    (unless link (error "No next page"))
    (geiser-doc--follow-link link)))

(defun geiser-doc-previous (&optional forget-current)
  "Go to previous page in documentation browser.
With prefix, the current page is deleted from history."
  (interactive "P")
  (let ((link (geiser-doc--history-previous forget-current)))
    (unless link (error "No previous page"))
    (geiser-doc--follow-link link)))

(defun geiser-doc-kill-page ()
  "Kill current page if a previous or next one exists."
  (interactive)
  (condition-case nil
      (geiser-doc-previous t)
    (error (geiser-doc-next t))))

(defun geiser-doc-refresh ()
  "Refresh the contents of current page."
  (interactive)
  (when geiser-doc--buffer-link
    (geiser-doc--follow-link geiser-doc--buffer-link)))

(defun geiser-doc-clean-history ()
  "Clean up the document browser history."
  (interactive)
  (when (y-or-n-p "Clean browsing history? ")
    (setq geiser-doc--history (geiser-doc--make-history))
    (geiser-doc-refresh))
  (message ""))


;;; Documentation browser and mode:

(defsubst geiser-doc--module ()
  (geiser-impl--call-method
   'find-module
   (geiser-doc--implementation)
   (geiser-doc--link-module geiser-doc--buffer-link)))

(defun geiser-doc-edit-symbol-at-point ()
  "Open definition of symbol at point."
  (interactive)
  (let* ((impl (geiser-doc--implementation))
         (module (geiser-doc--module)))
    (unless (and impl module)
      (error "I don't know what module this buffer refers to."))
    (with--geiser-implementation impl
      (let ((geiser-eval--get-module-function (lambda (&rest x) module)))
        (geiser-edit-symbol-at-point)))))

(defvar geiser-doc-mode-map nil)
(setq geiser-doc-mode-map
      (let ((map (make-sparse-keymap)))
        (suppress-keymap map)
        (set-keymap-parent map button-buffer-map)
        map))

(defun geiser-doc--visible-p () )

(geiser-menu--defmenu doc geiser-doc-mode-map
  ("Next" "\C-c\C-f" geiser-doc-next "Next item"
   :enable (geiser-doc--history-next-p))
  ("Previous" "\C-c\C-b" geiser-doc-previous "Previous item"
   :enable (geiser-doc--history-previous-p))
  ("Refresh" "\C-c\C-r" geiser-doc-refresh "Refresh current page")
  --
  ("Kill item" "\C-c\C-k" geiser-doc-kill-page "Kill this page")
  ("Clean history" "\C-c\C-c" geiser-doc-clean-history)
  --
  (custom "Browser options" geiser-doc))

(defun geiser-doc-mode ()
  "Major mode for browsing scheme documentation.
\\{geiser-doc-mode-map}"
  (interactive)
  (kill-all-local-variables)
  (buffer-disable-undo)
  (use-local-map geiser-doc-mode-map)
  (set-syntax-table scheme-mode-syntax-table)
  (setq mode-name "Geiser Doc")
  (setq major-mode 'geiser-doc-mode)
  (setq buffer-read-only t))

(geiser-popup--define doc "*Geiser documentation*" geiser-doc-mode)


(provide 'geiser-doc)
;;; geiser-doc.el ends here