diff --git a/src/workgroups-wconfig.el b/src/workgroups-wconfig.el
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+++ b/src/workgroups-wconfig.el
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+;;; workgroups-wconfig.el --- WCONFIG
+;;; Commentary:
+;; This is a window-configuration, a buffer layout, whatever you call
+;; it...  This is actually what you want to be saved and restored.
+;; (Well, technically it is (window-tree + some frame parameters))
+;;; Code:
+
+(require 'workgroups-wtree)
+
+(defun wg-frame-to-wconfig (&optional frame)
+  "Return the serialization (a wg-wconfig) of Emacs frame FRAME.
+FRAME nil defaults to `selected-frame'."
+  (let* ((frame (or frame (selected-frame)))
+         (fullscrn (frame-parameter frame 'fullscreen)))
+    (wg-make-wconfig
+     :left                  (frame-parameter frame 'left)
+     :top                   (frame-parameter frame 'top)
+     :width                 (frame-parameter frame 'width)
+     :height                (frame-parameter frame 'height)
+     :parameters            `((fullscreen . ,fullscrn))
+     :vertical-scroll-bars  (frame-parameter frame 'vertical-scroll-bars)
+     :scroll-bar-width      (frame-parameter frame 'scroll-bar-width)
+     :wtree                 (wg-window-tree-to-wtree (window-tree frame))
+     )))
+
+(defun wg-current-wconfig ()
+  "Return the current wconfig.
+If `wg-current-wconfig' is non-nil, return it.  Otherwise return
+`wg-frame-to-wconfig'."
+  (or (frame-parameter nil 'wg-current-wconfig)
+      (wg-frame-to-wconfig)))
+
+(defmacro wg-with-current-wconfig (frame wconfig &rest body)
+  "Eval BODY with WCONFIG current in FRAME.
+FRAME nil defaults to `selected-frame'."
+  (declare (indent 2))
+  (wg-with-gensyms (frame-sym old-value)
+    `(let* ((,frame-sym (or ,frame (selected-frame)))
+            (,old-value (frame-parameter ,frame-sym 'wg-current-wconfig)))
+       (unwind-protect
+           (progn
+             (set-frame-parameter ,frame-sym 'wg-current-wconfig ,wconfig)
+             ,@body)
+         (when (frame-live-p ,frame-sym)
+           (set-frame-parameter ,frame-sym 'wg-current-wconfig ,old-value))))))
+
+(defun wg-make-blank-wconfig (&optional buffer)
+  "Return a new blank wconfig.
+BUFFER or `wg-default-buffer' is visible in the only window."
+  (save-window-excursion
+    (delete-other-windows)
+    (switch-to-buffer (or buffer wg-default-buffer))
+    (wg-frame-to-wconfig)))
+
+(defun wg-wconfig-move-window (wconfig offset)
+  "Offset `selected-window' OFFSET places in WCONFIG."
+  (wg-asetf (wg-wconfig-wtree wconfig) (wg-wtree-move-window it offset))
+  wconfig)
+
+
+;;; base wconfig updating
+
+(defun wg-update-working-wconfig-on-delete-frame (frame)
+  "Update FRAME's current workgroup's working-wconfig before
+FRAME is deleted, so we don't lose its state."
+  (with-selected-frame frame
+    (wg-update-current-workgroup-working-wconfig)))
+
+
+(defun wg-wconfig-buf-uids (wconfig)
+  "Return WCONFIG's wtree's `wg-wtree-buf-uids'."
+  (if (not (wg-wconfig-wtree wconfig))
+      (error "WTREE is nil in `wg-wconfig-buf-uids'!"))
+  (wg-wtree-unique-buf-uids (wg-wconfig-wtree wconfig)))
+
+
+
+
+
+(defun wg-wconfig-restore-frame-position (wconfig &optional frame)
+  "Use WCONFIG to restore FRAME's position.
+If frame is nil then `selected-frame'."
+  (wg-when-let ((left (wg-wconfig-left wconfig))
+                (top (wg-wconfig-top wconfig)))
+    ;; Check that arguments are integers
+    ;; Problem: https://github.com/pashinin/workgroups2/issues/15
+    (if (and (integerp left)
+             (integerp top))
+        (set-frame-position 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)))
+
+;;(defun wg-wconfig-restore-fullscreen (wconfig)
+;;  "Restore `selected-frame's fullscreen settings from WCONFIG."
+;;  (set-frame-parameter
+;;   nil 'fullscreen (wg-wconfig-parameters wconfig))
+;;  )
+
+(defun wg-scale-wconfigs-wtree (wconfig new-width new-height)
+  "Scale WCONFIG's wtree with NEW-WIDTH and NEW-HEIGHT.
+Return a copy WCONFIG's wtree scaled with `wg-scale-wtree' by the
+ratio or NEW-WIDTH to WCONFIG's width, and NEW-HEIGHT to
+WCONFIG's height."
+  (wg-normalize-wtree
+   (wg-scale-wtree
+    (wg-wconfig-wtree wconfig)
+    (/ (float new-width)  (wg-wconfig-width wconfig))
+    (/ (float new-height) (wg-wconfig-height wconfig)))))
+;; (wg-wconfig-width (wg-current-wconfig))
+;; (wg-wconfig-wtree (wg-current-wconfig))
+
+
+(defun wg-scale-wconfig-to-frame (wconfig)
+  "Scale WCONFIG buffers to fit current frame size.
+Return a scaled copy of WCONFIG."
+  (interactive)
+  (wg-scale-wconfigs-wtree wconfig
+                           (frame-parameter nil 'width)
+                           (frame-parameter nil 'height)))
+;; (wg-scale-wconfig-to-frame (wg-current-wconfig))
+
+(defun wg-frame-resize-and-position (wconfig &optional frame)
+  "Apply WCONFIG's size and position to a FRAME."
+  (interactive)
+  (unless frame
+    (setq frame (selected-frame)))
+  (let* ((params (wg-wconfig-parameters wconfig))
+         fullscreen)
+    (set-frame-parameter frame 'fullscreen (if (assoc 'fullscreen params)
+                                               (cdr (assoc 'fullscreen params))
+                                             nil))
+    (when (and wg-restore-frame-position
+               (not (frame-parameter frame 'fullscreen)))
+      (wg-wconfig-restore-frame-position wconfig frame))
+    ))
+
+(defun wg-restore-frame-size-position (wconfig &optional fs)
+  "Smart-restore of frame size and position.
+
+Depending on `wg-remember-frame-for-each-wg' frame parameters may
+be restored for each workgroup.
+
+If `wg-remember-frame-for-each-wg' is nil (by default) then
+current frame parameters are saved/restored to/from first
+workgroup. And frame parameters for all other workgroups are just
+ignored.
+"
+  (interactive)
+  (let* ((params (wg-wconfig-parameters wconfig))
+         fullscreen)
+    ;; Frame maximized / fullscreen / none
+    (unless wg-remember-frame-for-each-wg
+      (setq params (wg-wconfig-parameters (wg-workgroup-working-wconfig (wg-first-workgroup)))))
+    (setq fullscreen (if (assoc 'fullscreen params)
+                         (cdr (assoc 'fullscreen params))
+                       nil))
+    (when (and fs
+               fullscreen
+               (or wg-remember-frame-for-each-wg
+                   (null (wg-current-workgroup t))))
+      (set-frame-parameter nil 'fullscreen fullscreen)
+      ;; I had bugs restoring maximized frame:
+      ;; Frame could be maximized but buffers are not scaled to fit it.
+      ;;
+      ;; Maybe because of `set-frame-parameter' takes some time to finish and is async.
+      ;; So I tried this and it helped
+      (sleep-for 0 100))
+
+    ;; Position
+    (when (and wg-restore-frame-position
+               wg-remember-frame-for-each-wg
+               (not (frame-parameter nil 'fullscreen)))
+      (wg-wconfig-restore-frame-position wconfig))
+    ))
+
+
+(defun wg-restore-frames ()
+  "Try to recreate opened frames, take info from session's 'frame-list parameter."
+  (interactive)
+  (delete-other-frames)
+  (when (wg-current-session t)
+    (let ((fl (wg-session-parameter (wg-current-session t) 'frame-list nil))
+          (frame (selected-frame)))
+      (mapc (lambda (wconfig)
+              (with-selected-frame (make-frame)
+                ;;(wg-frame-resize-and-position wconfig)
+                ;;(wg-restore-frame-size-position wconfig)
+                ;;(wg-wconfig-restore-frame-position wconfig)
+                (wg-restore-wconfig wconfig)
+                )) fl)
+      (select-frame-set-input-focus frame))))
+
+;; FIXME: throw a specific error if the restoration was unsuccessful
+(defun wg-restore-wconfig (wconfig &optional frame)
+  "Restore a workgroup configuration WCONFIG in a FRAME.
+Runs each time you're switching workgroups."
+  (unless frame (setq frame (selected-frame)))
+  (let ((wg-record-incorrectly-restored-bufs t)
+        (wg-incorrectly-restored-bufs nil)
+        (params (wg-wconfig-parameters wconfig))
+        fullscreen wtree)
+    (wg-barf-on-active-minibuffer)
+    (when wg-restore-scroll-bars
+      (wg-wconfig-restore-scroll-bars wconfig))
+
+    ;; Restore buffers
+    (wg-restore-window-tree
+     (wg-scale-wconfig-to-frame wconfig))
+
+    ;; Restore frame position
+    (when (and wg-restore-frame-position
+               (not (frame-parameter nil 'fullscreen))
+               (null (wg-current-workgroup t)))
+      (wg-wconfig-restore-frame-position wconfig frame))
+
+    (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)))))
+
+
+;;; saved wconfig commands
+
+(defun wg-save-wconfig ()
+  "Save the current wconfig to the current workgroup's saved wconfigs."
+  (interactive)
+  (let* ((workgroup (wg-current-workgroup))
+         (name (wg-read-saved-wconfig-name workgroup))
+         (wconfig (wg-current-wconfig)))
+    (setf (wg-wconfig-name wconfig) name)
+    (wg-workgroup-save-wconfig workgroup wconfig)
+    (wg-fontified-message
+      (:cmd "Saved: ")
+      (:cur name))))
+
+(defun wg-restore-saved-wconfig ()
+  "Restore one of the current workgroup's saved wconfigs in `selected-frame'."
+  (interactive)
+  (let ((workgroup (wg-current-workgroup)))
+    (wg-restore-wconfig-undoably
+     (wg-workgroup-get-saved-wconfig
+      workgroup
+      (wg-completing-read
+       "Saved wconfig: "
+       (mapcar 'wg-wconfig-name (wg-workgroup-saved-wconfigs workgroup))
+       nil t)))))
+
+(defun wg-kill-saved-wconfig ()
+  "Kill one of the current workgroup's saved wconfigs.
+Also add it to the wconfig kill-ring."
+  (interactive)
+  (let* ((workgroup (wg-current-workgroup))
+         (wconfig (wg-read-saved-wconfig workgroup)))
+    (wg-workgroup-kill-saved-wconfig workgroup wconfig)
+    (wg-add-to-wconfig-kill-ring wconfig)
+    (wg-fontified-message
+      (:cmd "Deleted: ")
+      (:cur (wg-wconfig-name wconfig)))))
+
+
+(defun wg-reverse-wconfig (wconfig &optional dir)
+  "Reverse WCONFIG's wtree's wlist in direction DIR."
+  (wg-asetf (wg-wconfig-wtree wconfig) (wg-reverse-wlist it dir))
+  wconfig)
+
+
+(provide 'workgroups-wconfig)
+;;; workgroups-wconfig.el ends here