;;; core-spacemacs-buffer.el --- Spacemacs Core File
;;
;; Copyright (c) 2012-2014 Sylvain Benner
;; Copyright (c) 2014-2015 Sylvain Benner & Contributors
;;
;; Author: Sylvain Benner <sylvain.benner@gmail.com>
;; URL: https://github.com/syl20bnr/spacemacs
;;
;; This file is not part of GNU Emacs.
;;
;;; License: GPLv3
(defconst spacemacs-buffer-name "*spacemacs*"
  "The name of the spacemacs buffer.")

(defconst spacemacs--banner-length 75
  "Width of a banner.")

(defvar spacemacs--changelog-widgets ())

(defun spacemacs//insert-banner-and-buttons ()
  "Choose a banner accordingly to `dotspacemacs-startup-banner'and insert it
in spacemacs buffer along whith quick buttons underneath.

Easter egg:
Doge special text banner can be reachable via `999', `doge' or `random*'.
`random' ignore special banners whereas `random*' does not."
  (let ((banner (spacemacs//choose-banner))
        (buffer-read-only nil))
    (when banner
      (spacemacs/message (format "Banner: %s" banner))
      (if (string-match "\\.png\\'" banner)
          (spacemacs//insert-image-banner banner)
        (insert-file-contents banner))
      (spacemacs//inject-version)
      (spacemacs/insert-buttons)
      (when (eq t dotspacemacs-always-show-changelog)
        (spacemacs/toggle-changelog))
      (spacemacs//redisplay))))

(defun spacemacs//choose-banner ()
  "Return the full path of a banner based on the dotfile value."
  (cond
   ((eq 'official dotspacemacs-startup-banner)
    (if (and (display-graphic-p) (image-type-available-p 'png))
        spacemacs-banner-official-png
      (spacemacs//get-banner-path 1)))
   ((eq 'random dotspacemacs-startup-banner)
    (spacemacs//choose-random-text-banner))
   ((eq 'random* dotspacemacs-startup-banner)
    (spacemacs//choose-random-text-banner t))
   ((eq 'doge dotspacemacs-startup-banner)
    (spacemacs//get-banner-path 999))
   ((integerp dotspacemacs-startup-banner)
    (spacemacs//get-banner-path dotspacemacs-startup-banner))
   ((and dotspacemacs-startup-banner
         (string-match "\\.png\\'" dotspacemacs-startup-banner))
    (if (and (display-graphic-p) (image-type-available-p 'png))
        (if (file-exists-p dotspacemacs-startup-banner)
            dotspacemacs-startup-banner
          (spacemacs/message (format "Warning: could not find banner %s"
                                     dotspacemacs-startup-banner))
          (spacemacs//get-banner-path 1))
      (spacemacs//get-banner-path 1)))))

(defun spacemacs//choose-random-text-banner (&optional all)
  "Return the full path of a banner chosen randomly.

If ALL is non-nil then truly all banners can be selected."
  (let* ((files (directory-files spacemacs-banner-directory t))
         (count (length files))
         ;; -2 then +2 to remove `.' and `..'
         (choice (+ 2 (random (- count (if all 2 3))))))
    (nth choice files)))

(defun spacemacs//get-banner-path (index)
  "Return the full path to banner with index INDEX."
  (concat spacemacs-banner-directory (format "%03d-banner.txt" index)))

(defun spacemacs//insert-image-banner (banner)
  "Display an image banner."
  (when (file-exists-p banner)
    (let* ((spec (create-image banner))
           (size (image-size spec))
           (width (car size))
           (left-margin (floor (- spacemacs--banner-length width) 2)))
      (beginning-of-buffer)
      (insert "\n")
      (insert (make-string (- left-margin 1) ?\ ))
      (insert-image spec)
      (insert "\n\n")
      (insert "                           [S P A C E M A C S]\n\n"))))

(defun spacemacs//inject-version ()
  "Inject the current version of spacemacs in the first line of the
buffer, right justified."
  (save-excursion
    (beginning-of-buffer)
    (let* ((maxcol spacemacs--banner-length)
           (injected (format "(%s)" spacemacs-version))
           (pos (- maxcol (length injected)))
           (buffer-read-only nil))
      ;; fill the first line with spaces if required
      (when (< (line-end-position) maxcol)
        (end-of-line)
        (insert-char ?\s (- maxcol (line-end-position))))
      (goto-char pos)
      (delete-char (length injected))
      (insert injected))))

(defun spacemacs//insert-changelog ()
  (save-excursion
    (beginning-of-buffer)
    (search-forward "Spacemacs\]")
    (next-line)
  (let* ((file-contents (with-temp-buffer (insert-file-contents spacemacs-changelog-file) (buffer-string)))
         (changelog-header "\nCHANGELOG"))
    (setq spacemacs--changelog-widgets (cons (widget-create 'text changelog-header) spacemacs--changelog-widgets))
    (setq spacemacs--changelog-widgets (cons (widget-create 'text (concat "\n" file-contents)) spacemacs--changelog-widgets)))))

(defun spacemacs/toggle-changelog ()
  (if (eq spacemacs--changelog-widgets nil)
      (spacemacs//insert-changelog)
    (mapc (lambda (el)
            (widget-delete el)
            (setq spacemacs--changelog-widgets (remove el spacemacs--changelog-widgets)))
          spacemacs--changelog-widgets)))

(defun spacemacs/set-mode-line (format)
  "Set mode-line format for spacemacs buffer."
  (with-current-buffer (get-buffer-create "*spacemacs*")
    (setq mode-line-format format)))

(defun spacemacs/message (msg &rest args)
  "Display MSG in message prepended with '(Spacemacs)'."
  (when dotspacemacs-verbose-loading
    (message "(Spacemacs) %s" (apply 'format msg args))))

(defun spacemacs/insert-page-break ()
  "Insert a page break line in spacemacs buffer."
  (spacemacs/append-to-buffer "\n\n\n"))

(defun spacemacs/append-to-buffer (msg &optional messagebuf)
  "Append MSG to spacemacs buffer. If MESSAGEBUF is not nil then MSG is
 also written in message buffer."
  (with-current-buffer (get-buffer-create "*spacemacs*")
    (goto-char (point-max))
    (let ((buffer-read-only nil))
      (insert msg)
      (if messagebuf (message "(Spacemacs) %s" msg)))
    (spacemacs/set-mode-line "")))

(defun spacemacs/replace-last-line-of-buffer (msg &optional messagebuf)
  "Replace the last line of the spacemacs buffer with MSG. If MESSAGEBUF is
 not nil then MSG is also written in message buffer."
  (with-current-buffer (get-buffer-create "*spacemacs*")
    (goto-char (point-max))
    (let ((buffer-read-only nil))
      (delete-region (line-beginning-position) (point-max))
      (insert msg)
      (if messagebuf (message "(Spacemacs) %s" msg)))
    (spacemacs/set-mode-line "")))

(defun spacemacs/insert-framed-text-to-buffer
    (msg &optional caption hpadding)
  "Insert MSG in spacemacs buffer within a frame of width FILL-COLUMN.

See `spacemacs//render-framed-text' for documentation of the other
parameters."
  (with-current-buffer (get-buffer-create "*spacemacs*")
    (let ((buffer-read-only nil))
      (insert (spacemacs//render-framed-text msg spacemacs--banner-length
                                             caption hpadding)))))

(defun spacemacs/insert-framed-text-from-file-to-buffer
    (filepath &optional caption hpadding)
  "Insert at point the content of FILENAME file in spacemacs buffer in a
frame.

If FILEPATH does not exists the function returns nil.

See `spacemacs//render-framed-text' for documentation of the other
parameters."
  (when (file-exists-p filepath)
    (with-current-buffer (get-buffer-create "*spacemacs*")
      (let ((buffer-read-only nil))
        (insert (spacemacs//render-framed-text filepath spacemacs--banner-length
                                               caption hpadding))))))

(defun spacemacs//render-framed-text (content &optional width caption hpadding)
  "Return a formated string framed with plained lines of width FILL-COLUMN.

CONTENT can be a text or a filepath.

WIDTH set the `fill-column' variable.

If CAPTION is non nil string then it is included in at the top of the frame.
If CAPTION length is greater than FILL-COLUMN minus 5 the function returns
nil.

HPADDING is the horizontal spacing between the text and the frame.
The vertical spacing is always one line."
  (with-temp-buffer
    (if (not (file-exists-p content))
        (insert content)
      (insert-file-contents content)
      ;; remove additional newline at eof
      (goto-char (point-max))
      (delete-char -1))
    (let* ((hpadding (or hpadding 1))
           (fill-column (if width
                            (- width hpadding)
                          fill-column))
           (sentence-end-double-space nil)
           (caption-len (length caption)))
      (fill-region (point-min) (point-max) 'justify)
      (concat
       ;; top
       "╭─"
       (if caption
           (concat caption
                   (make-string (+ (- fill-column caption-len 1)
                                   hpadding) ?─))
         (make-string fill-column ?─))
       (make-string hpadding ?─) "╮\n"
       ;; content
       (spacemacs//render-framed-line "" hpadding)
       (mapconcat (lambda (x)
                    (spacemacs//render-framed-line x hpadding))
                  (split-string (buffer-string) "\n" nil) "")
       (spacemacs//render-framed-line "" hpadding)
       ;; bottom
       "╰" (make-string hpadding ?─)
       (make-string fill-column ?─)
       (make-string hpadding ?─) "╯\n"))))

(defun spacemacs//render-framed-line (line hpadding)
  "Return a formated LINE with borders of a frame on each side and
with width FILL-COLUMN.

If length of LINE is bigger than FILL-COLUMN it returns nil.

HPADDING is the horizontal spacing betwee the content line and the frame border."
  (let* ((len (length line))
         (fill (- fill-column len)))
    (when (>= fill 0)
      (concat "│" (make-string hpadding ?\s)
              line (make-string fill ?\s)
              (make-string hpadding ?\s) "│\n"))))

(defun spacemacs/loading-animation ()
  "Display the progress bar by chunk of size `spacemacs--loading-dots-chunk-threshold'."
  (when dotspacemacs-loading-progress-bar
    (setq spacemacs-loading-counter (1+ spacemacs-loading-counter))
    (when (>= spacemacs-loading-counter spacemacs-loading-dots-chunk-threshold)
      (setq spacemacs-loading-counter 0)
      (setq spacemacs-loading-string
            (concat spacemacs-loading-string
                    (make-string spacemacs-loading-dots-chunk-size
                                 spacemacs-loading-char)))
      (spacemacs/set-mode-line spacemacs-loading-string)
      (spacemacs//redisplay))))

(defun spacemacs/insert-buttons ()
  (goto-char (point-max))
  (insert "      ")
  (widget-create 'url-link
                 :tag "Homepage"
                 :help-echo "Open the Spacemacs Github page in your browser."
                 :mouse-face 'highlight
                 :follow-link "\C-m"
                 "https://github.com/syl20bnr/spacemacs")
  (insert " ")
  (widget-create 'url-link
                 :tag "Documentation"
                 :help-echo "Open the Spacemacs documentation in your browser."
                 :mouse-face 'highlight
                 :follow-link "\C-m"
                 "https://github.com/syl20bnr/spacemacs/blob/master/doc/DOCUMENTATION.md")
  (insert " ")
  (widget-create 'url-link
                 :tag "Gitter Chat"
                 :help-echo "Ask questions and chat with fellow users in our chat room."
                 :mouse-face 'highlight
                 :follow-link "\C-m"
                 "https://gitter.im/syl20bnr/spacemacs")
  (insert " ")
  (widget-create 'push-button
                 :help-echo "Update all ELPA packages to the latest versions."
                 :action (lambda (&rest ignore) (configuration-layer/update-packages))
                 :mouse-face 'highlight
                 :follow-link "\C-m"
                 "Update")
  (insert " ")
  (widget-create 'push-button
                 :help-echo "Rollback ELPA package upgrades if something got borked."
                 :action (lambda (&rest ignore) (call-interactively 'configuration-layer/rollback))
                 :mouse-face 'highlight
                 :follow-link "\C-m"
                 "Rollback")
  (insert "\n")
  (let ((button-title "[Toggle Changelog] [Search in Spacemacs]"))
    ; Compute the correct number of spaces to center the button.
    (dotimes (i (/ (- spacemacs--banner-length (string-width button-title) 1) 2)) (insert " "))
    (widget-create 'push-button
                   :help-echo "Hide or show the Changelog"
                   :action (lambda (&rest ignore) (spacemacs/toggle-changelog))
                   :mouse-face 'highlight
                   :follow-link "\C-m"
                   "Toggle Changelog"))
    (widget-insert " ")
    (widget-create 'url-link
                   :help-echo "Find Spacemacs package and layer configs using helm-spacemacs."
                   :action (lambda (&rest ignore) (call-interactively 'helm-spacemacs))
                   :mouse-face 'highlight
                   :follow-link "\C-m"
                   "Search in Spacemacs")
  (insert "\n\n"))

(defun spacemacs//insert-file-list (list-display-name list shortcut-char)
  (when (car list)
    (define-key spacemacs-mode-map shortcut-char `(lambda ()
                                                    (interactive)
                                                    (goto-char ,(point))
                                                    (next-line)
                                                    (back-to-indentation)))
    (insert (concat "  " (format "[%s] " shortcut-char) list-display-name))
    (mapc (lambda (el)
            (insert "\n    ")
            (widget-create 'push-button
                           :action `(lambda (&rest ignore) (find-file-existing ,el))
                           :mouse-face 'highlight
                           :follow-link "\C-m"
                           :button-prefix ""
                           :button-suffix ""
                           :format "%[%t%]"
                           (abbreviate-file-name el)))
          list)))

(defun spacemacs/insert-startupify-lists ()
  (interactive)
  (with-current-buffer (get-buffer-create "*spacemacs*")
    (let ((buffer-read-only nil)
          (list-separator "\n\n"))
      (goto-char (point-max))
      (page-break-lines-mode)
      (spacemacs/insert-page-break)
      (mapc (lambda (el)
              (cond
               ((eq el 'recents)
                (recentf-mode)
                (when (spacemacs//insert-file-list "Recent Files:" (recentf-elements 5) "r")
                  (insert list-separator)))
               ((eq el 'bookmarks)
                (helm-mode)
                (when (spacemacs//insert-file-list "Bookmarks:" (bookmark-all-names) "b")
                  (insert list-separator)))
               ((eq el 'projects)
                (projectile-mode)
                (when (spacemacs//insert-file-list "Projects:" (projectile-relevant-known-projects) "p")
                  (insert list-separator))))) dotspacemacs-startup-lists))))

(defun spacemacs/goto-link-line ()
  "Move the point to the beginning of the link line."
  (interactive)
  (when (and dotspacemacs-startup-banner
             (not configuration-layer-error-count))
    (with-current-buffer spacemacs-buffer-name
      (goto-char (point-min))
      (re-search-forward "Homepage")
      (beginning-of-line))))

;;this feels like the wrong place to put these
(add-hook 'spacemacs-mode-hook (lambda ()
                                 (local-set-key [tab] 'widget-forward)
                                 (local-set-key [S-tab] 'widget-backward)
                                 ;; S-tab is backtab in terminal
                                 (local-set-key [backtab] 'widget-backward)))

(provide 'core-spacemacs-buffer)