;;; wconfig restoration

(defun wg-restore-default-buffer ()
  "Switch to `wg-default-buffer'."
  (switch-to-buffer wg-default-buffer t))

(defun wg-restore-existing-buffer (buf)
  "Switch to and return BUF's referrent (some live buffer) if it exists."
  (wg-awhen (wg-find-buf-in-buffer-list buf (buffer-list))
    (switch-to-buffer it t)
    (wg-set-buffer-uid-or-error (wg-buf-uid buf))
    it))

(defun wg-restore-file-buffer (buf)
  "Restore BUF by finding its file.  Return the created buffer.
If BUF's file doesn't exist, call `wg-restore-default-buffer'"
  (wg-when-let ((file-name (wg-buf-file-name buf)))
    (cond ((file-exists-p file-name)
           (find-file file-name)
           (rename-buffer (wg-buf-name buf) t)
           (wg-set-buffer-uid-or-error (wg-buf-uid buf))
           (when wg-restore-mark
             (set-mark (wg-buf-mark buf))
             (deactivate-mark))
           (wg-deserialize-buffer-local-variables buf)
           (current-buffer))
          (t
           (message "Attempt to restore nonexistent file: %S" file-name)
           nil))))

(defun wg-restore-special-buffer (buf)
  "Restore a buffer with DESERIALIZER-FN."
  (wg-when-let
      ((special-data (wg-buf-special-data buf))
       (buffer (save-window-excursion
                 (condition-case err
                     (funcall (car special-data) buf)
                   (error (message "Error deserializing %S: %S"
                                   (wg-buf-name buf) err)
                          nil)))))
    (switch-to-buffer buffer t)
    (wg-set-buffer-uid-or-error (wg-buf-uid buf))
    buffer))

(defun wg-restore-buffer (buf)
  "Restore BUF and return it."
  (let (wg-buffer-auto-association-on)
    (or (wg-restore-existing-buffer buf)
        (wg-restore-special-buffer buf)
        (wg-restore-file-buffer buf)
        (progn (wg-restore-default-buffer) nil))))

(defun wg-restore-window-positions (win &optional window)
  "Restore various positions in WINDOW from their values in WIN."
  (let ((window (or window (selected-window))))
    (wg-with-slots win
        ((win-point wg-win-point)
         (win-start wg-win-start)
         (win-hscroll wg-win-hscroll))
      (set-window-start window win-start t)
      (set-window-hscroll window win-hscroll)
      (set-window-point
       window
       (cond ((not wg-restore-point) win-start)
             ((eq win-point :max) (point-max))
             (t win-point)))
      (when (>= win-start (point-max)) (recenter)))))

;; FIXME: nix these or move them to the vars section
(defvar wg-incorrectly-restored-bufs nil
  "FIXME: docstring this")

(defvar wg-record-incorrectly-restored-bufs nil
  "FIXME: docstring this")

(defun wg-restore-window (win)
  "Restore WIN in `selected-window'."
  (let ((selwin (selected-window))
        (buf (wg-find-buf-by-uid (wg-win-buf-uid win))))
    (if (not buf) (wg-restore-default-buffer)
      (when (wg-restore-buffer buf)
        (wg-restore-window-positions win selwin)
        (when wg-restore-window-dedicated-p
          (set-window-dedicated-p selwin (wg-win-dedicated win)))))))

(defun wg-reset-window-tree ()
  "Delete all but one window in `selected-frame', and reset
various parameters of that window in preparation for restoring
a wtree."
  (delete-other-windows)
  (set-window-dedicated-p nil nil))

(defun wg-restore-window-tree-helper (w)
  "Recursion helper for `wg-restore-window-tree'."
  (if (wg-wtree-p w)
      (loop with dir = (wg-wtree-dir w)
            for (win . rest) on (wg-wtree-wlist w)
            do (when rest (split-window nil (wg-w-size win dir) (not dir)))
            do (wg-restore-window-tree-helper win))
    (wg-restore-window w)
    (when (wg-win-selected w)
      (setq wg-window-tree-selected-window (selected-window)))
    (when (wg-win-minibuffer-scroll w)
      (setq minibuffer-scroll-window (selected-window)))
    (other-window 1)))

(defun wg-restore-window-tree (wtree)
  "Restore WTREE in `selected-frame'."
  (let ((window-min-width wg-window-min-width)
        (window-min-height wg-window-min-height)
        (wg-window-tree-selected-window nil))
    (wg-reset-window-tree)
    (wg-restore-window-tree-helper wtree)
    (wg-awhen wg-window-tree-selected-window (select-window it))))

(defun wg-wconfig-restore-frame-position (wconfig)
  "Restore `selected-frame's position from WCONFIG."
  (wg-when-let ((left (wg-wconfig-left wconfig))
                (top (wg-wconfig-top wconfig)))
    (set-frame-position (selected-frame) left top)))

(defun wg-wconfig-restore-scroll-bars (wconfig)
  "Restore `selected-frame's scroll-bar settings from WCONFIG."
  (set-frame-parameter
   nil 'vertical-scroll-bars (wg-wconfig-vertical-scroll-bars wconfig))
  (set-frame-parameter
   nil 'scroll-bar-width (wg-wconfig-scroll-bar-width wconfig)))

;; FIXME: throw a specific error if the restoration was unsuccessful
(defun wg-restore-wconfig (wconfig)
  "Restore WCONFIG in `selected-frame'."
  (let ((wg-record-incorrectly-restored-bufs t)
        (wg-incorrectly-restored-bufs nil))
    (wg-barf-on-active-minibuffer)
    (when wg-restore-frame-position
      (wg-wconfig-restore-frame-position wconfig))
    (let ((wtree (wg-resize-frame-scale-wtree wconfig)))
      (wg-restore-window-tree
       (if (not (wg-morph-p)) wtree (wg-morph wtree))))
    (when wg-restore-scroll-bars
      (wg-wconfig-restore-scroll-bars wconfig))
    (when wg-incorrectly-restored-bufs
      (message "Unable to restore these buffers: %S\
If you want, restore them manually and try again."
               (mapcar 'wg-buf-name wg-incorrectly-restored-bufs)))))



(provide 'workgroups-wconfig-restore)