diff --git a/.config/doom/config.el b/.config/doom/config.el
new file mode 100644
index 0000000..4f0f438
--- /dev/null
+++ b/.config/doom/config.el
@@ -0,0 +1,111 @@
+;;; $DOOMDIR/config.el -*- lexical-binding: t; -*-
+
+;; Place your private configuration here! Remember, you do not need to run 'doom
+;; sync' after modifying this file!
+
+
+;; Some functionality uses this to identify you, e.g. GPG configuration, email
+;; clients, file templates and snippets.
+(setq user-full-name "xerus"
+      user-mail-address "27jf@pm.me")
+
+;; Doom exposes five (optional) variables for controlling fonts in Doom. Here
+;; are the three important ones:
+;;
+;; + `doom-font'
+;; + `doom-variable-pitch-font'
+;; + `doom-big-font' -- used for `doom-big-font-mode'; use this for
+;;   presentations or streaming.
+;;
+;; They all accept either a font-spec, font string ("Input Mono-12"), or xlfd
+;; font string. You generally only need these two:
+;; (setq doom-font (font-spec :family "monospace" :size 12 :weight 'semi-light)
+;;       doom-variable-pitch-font (font-spec :family "sans" :size 13))
+
+;; There are two ways to load a theme. Both assume the theme is installed and
+;; available. You can either set `doom-theme' or manually load a theme with the
+;; `load-theme' function. This is the default:
+(setq doom-theme 'doom-one)
+
+(map! :leader "u" 'evil-prev-buffer
+      :leader "i" 'evil-next-buffer
+      :leader "bq" 'doom/save-and-kill-buffer)
+
+(desktop-save-mode 1)
+
+;; Backups & auto-saves
+
+(setq auto-save-default t)
+(setq auto-save-interval 40)
+
+(setq backup-directory-alist `(("" . "~/.emacs.d/backups/")))
+(setq delete-old-versions t
+  kept-new-versions 6
+  kept-old-versions 2
+  version-control t)
+(setq vc-make-backup-files t)
+
+(setq undo-tree-auto-save-history t)
+(setq undo-tree-history-directory-alist `(("" . "~/.emacs.d/backups/undo/")))
+
+(setq amalgamating-undo-limit 5)
+
+; (advice-add 'undo-auto--last-boundary-amalgamating-number :override #'ignore)
+
+; ORG
+
+(require 'org)
+
+(setq org-image-actual-width 300)
+
+;; If you use `org' and don't want your org files in the default location below,
+;; change `org-directory'. It must be set before org loads!
+(setq org-directory "~/daten/1-projects")
+(setq org-agenda-files (apply 'append
+			      (mapcar
+			       (lambda (directory)
+				 (directory-files-recursively
+				  directory org-agenda-file-regexp))
+			       '("~/daten/Dropbox/dokumente/notes" "~/daten/1-projects" "~/daten/2-standards" "~/daten/3-resources"))))
+; (setq org-agenda-files '("~/daten/Dropbox/dokumente/notes" "~/daten/1-projects" "~/daten/2-standards" "~/daten/3-resources"))
+(setq org-roam-directory "~/daten/2-standards/org-roam")
+
+(setq default-directory org-directory)
+
+;; org toggle source blocks with C-c t
+(defvar org-blocks-hidden nil)
+(defun org-toggle-blocks ()
+  "Toggle all source code blocks."
+  (interactive)
+  (if org-blocks-hidden
+      (org-show-block-all)
+    (org-hide-block-all))
+  (setq-local org-blocks-hidden (not org-blocks-hidden)))
+(define-key org-mode-map (kbd "C-c t") 'org-toggle-blocks)
+
+(add-hook 'org-mode-hook 'org-toggle-blocks)
+(add-hook 'org-mode-hook 'org-toggle-inline-images)
+(add-hook 'org-mode-hook (apply-partially '+org/close-all-folds 2))
+
+;; This determines the style of line numbers in effect. If set to `nil', line
+;; numbers are disabled. For relative line numbers, set this to `relative'.
+(setq display-line-numbers-type 'relative)
+
+;; Here are some additional functions/macros that could help you configure Doom:
+;;
+;; - `load!' for loading external *.el files relative to this one
+;; - `use-package!' for configuring packages
+;; - `after!' for running code after a package has loaded
+;; - `add-load-path!' for adding directories to the `load-path', relative to
+;;   this file. Emacs searches the `load-path' when you load packages with
+;;   `require' or `use-package'.
+;; - `map!' for binding new keys
+;;
+;; To get information about any of these functions/macros, move the cursor over
+;; the highlighted symbol at press 'K' (non-evil users must press 'C-c c k').
+;; This will open documentation for it, including demos of how they are used.
+;;
+;; You can also try 'gd' (or 'C-c c d') to jump to their definition and see how
+;; they are implemented.
+
+(load! "./togetherly.el")
diff --git a/.config/doom/init.el b/.config/doom/init.el
new file mode 100644
index 0000000..82490b3
--- /dev/null
+++ b/.config/doom/init.el
@@ -0,0 +1,183 @@
+;;; init.el -*- lexical-binding: t; -*-
+
+;; This file controls what Doom modules are enabled and what order they load
+;; in. Remember to run 'doom sync' after modifying it!
+
+;; NOTE Press 'SPC h d h' (or 'C-h d h' for non-vim users) to access Doom's
+;;      documentation. There you'll find a "Module Index" link where you'll find
+;;      a comprehensive list of Doom's modules and what flags they support.
+
+;; NOTE Move your cursor over a module's name (or its flags) and press 'K' (or
+;;      'C-c c k' for non-vim users) to view its documentation. This works on
+;;      flags as well (those symbols that start with a plus).
+;;
+;;      Alternatively, press 'gd' (or 'C-c c d') on a module to browse its
+;;      directory (for easy access to its source code).
+
+(doom! :input
+       ;;chinese
+       ;;japanese
+       ;;layout            ; auie,ctsrnm is the superior home row
+
+       :completion
+       company           ; the ultimate code completion backend
+       ;;helm              ; the *other* search engine for love and life
+       ;;ido               ; the other *other* search engine...
+       ivy               ; a search engine for love and life
+
+       :ui
+       ;;deft              ; notational velocity for Emacs
+       doom              ; what makes DOOM look the way it does
+       doom-dashboard    ; a nifty splash screen for Emacs
+       doom-quit         ; DOOM quit-message prompts when you quit Emacs
+       ;;fill-column       ; a `fill-column' indicator
+       hl-todo           ; highlight TODO/FIXME/NOTE/DEPRECATED/HACK/REVIEW
+       ;;hydra
+       ;;indent-guides     ; highlighted indent columns
+       ;;ligatures         ; ligatures and symbols to make your code pretty again
+       ;;minimap           ; show a map of the code on the side
+       modeline          ; snazzy, Atom-inspired modeline, plus API
+       ;;nav-flash         ; blink cursor line after big motions
+       ;;neotree           ; a project drawer, like NERDTree for vim
+       ophints           ; highlight the region an operation acts on
+       (popup +defaults)   ; tame sudden yet inevitable temporary windows
+       ;;tabs              ; a tab bar for Emacs
+       ;;treemacs          ; a project drawer, like neotree but cooler
+       ;;unicode           ; extended unicode support for various languages
+       vc-gutter         ; vcs diff in the fringe
+       vi-tilde-fringe   ; fringe tildes to mark beyond EOB
+       ;;window-select     ; visually switch windows
+       workspaces        ; tab emulation, persistence & separate workspaces
+       ;;zen               ; distraction-free coding or writing
+
+       :editor
+       (evil +everywhere); come to the dark side, we have cookies
+       file-templates    ; auto-snippets for empty files
+       fold              ; (nigh) universal code folding
+       ;;(format +onsave)  ; automated prettiness
+       ;;god               ; run Emacs commands without modifier keys
+       ;;lispy             ; vim for lisp, for people who don't like vim
+       ;;multiple-cursors  ; editing in many places at once
+       ;;objed             ; text object editing for the innocent
+       ;;parinfer          ; turn lisp into python, sort of
+       ;;rotate-text       ; cycle region at point between text candidates
+       snippets          ; my elves. They type so I don't have to
+       ;;word-wrap         ; soft wrapping with language-aware indent
+
+       :emacs
+       dired             ; making dired pretty [functional]
+       electric          ; smarter, keyword-based electric-indent
+       ;;ibuffer         ; interactive buffer management
+       undo              ; persistent, smarter undo for your inevitable mistakes
+       vc                ; version-control and Emacs, sitting in a tree
+
+       :term
+       ;;eshell            ; the elisp shell that works everywhere
+       ;;shell             ; simple shell REPL for Emacs
+       ;;term              ; basic terminal emulator for Emacs
+       ;;vterm             ; the best terminal emulation in Emacs
+
+       :checkers
+       syntax              ; tasing you for every semicolon you forget
+       ;;spell             ; tasing you for misspelling mispelling
+       ;;grammar           ; tasing grammar mistake every you make
+
+       :tools
+       ;;ansible
+       ;;debugger          ; FIXME stepping through code, to help you add bugs
+       ;;direnv
+       ;;docker
+       ;;editorconfig      ; let someone else argue about tabs vs spaces
+       ;;ein               ; tame Jupyter notebooks with emacs
+       (eval +overlay)     ; run code, run (also, repls)
+       ;;gist              ; interacting with github gists
+       lookup              ; navigate your code and its documentation
+       ;;lsp
+       magit             ; a git porcelain for Emacs
+       ;;make              ; run make tasks from Emacs
+       ;;pass              ; password manager for nerds
+       ;;pdf               ; pdf enhancements
+       ;;prodigy           ; FIXME managing external services & code builders
+       ;;rgb               ; creating color strings
+       ;;taskrunner        ; taskrunner for all your projects
+       ;;terraform         ; infrastructure as code
+       ;;tmux              ; an API for interacting with tmux
+       ;;upload            ; map local to remote projects via ssh/ftp
+
+       :os
+       (:if IS-MAC macos)  ; improve compatibility with macOS
+       ;;tty               ; improve the terminal Emacs experience
+
+       :lang
+       ;;agda              ; types of types of types of types...
+       ;;cc                ; C/C++/Obj-C madness
+       ;;clojure           ; java with a lisp
+       ;;common-lisp       ; if you've seen one lisp, you've seen them all
+       ;;coq               ; proofs-as-programs
+       ;;crystal           ; ruby at the speed of c
+       ;;csharp            ; unity, .NET, and mono shenanigans
+       ;;data              ; config/data formats
+       ;;(dart +flutter)   ; paint ui and not much else
+       ;;elixir            ; erlang done right
+       ;;elm               ; care for a cup of TEA?
+       emacs-lisp        ; drown in parentheses
+       ;;erlang            ; an elegant language for a more civilized age
+       ;;ess               ; emacs speaks statistics
+       ;;faust             ; dsp, but you get to keep your soul
+       ;;fsharp            ; ML stands for Microsoft's Language
+       ;;fstar             ; (dependent) types and (monadic) effects and Z3
+       ;;gdscript          ; the language you waited for
+       ;;(go +lsp)         ; the hipster dialect
+       (haskell +dante)  ; a language that's lazier than I am
+       ;;hy                ; readability of scheme w/ speed of python
+       ;;idris             ;
+       json              ; At least it ain't XML
+       (java +meghanada) ; the poster child for carpal tunnel syndrome
+       ;;javascript        ; all(hope(abandon(ye(who(enter(here))))))
+       ;;julia             ; a better, faster MATLAB
+       kotlin            ; a better, slicker Java(Script)
+       latex             ; writing papers in Emacs has never been so fun
+       ;;lean
+       ;;factor
+       ;;ledger            ; an accounting system in Emacs
+       lua               ; one-based indices? one-based indices
+       markdown          ; writing docs for people to ignore
+       ;;nim               ; python + lisp at the speed of c
+       ;;nix               ; I hereby declare "nix geht mehr!"
+       ;;ocaml             ; an objective camel
+       (org +roam +journal); organize your plain life in plain text
+       ;;php               ; perl's insecure younger brother
+       ;;plantuml          ; diagrams for confusing people more
+       ;;purescript        ; javascript, but functional
+       python            ; beautiful is better than ugly
+       qt                ; the 'cutest' gui framework ever
+       ;;racket            ; a DSL for DSLs
+       ;;raku              ; the artist formerly known as perl6
+       ;;rest              ; Emacs as a REST client
+       ;;rst               ; ReST in peace
+       ;;(ruby +rails)     ; 1.step {|i| p "Ruby is #{i.even? ? 'love' : 'life'}"}
+       ;;rust              ; Fe2O3.unwrap().unwrap().unwrap().unwrap()
+       ;;scala             ; java, but good
+       ;;scheme            ; a fully conniving family of lisps
+       sh                ; she sells {ba,z,fi}sh shells on the C xor
+       ;;sml
+       ;;solidity          ; do you need a blockchain? No.
+       ;;swift             ; who asked for emoji variables?
+       ;;terra             ; Earth and Moon in alignment for performance.
+       ;;web               ; the tubes
+       yaml              ; JSON, but readable
+
+       :email
+       ;;(mu4e +gmail)
+       ;;notmuch
+       ;;(wanderlust +gmail)
+
+       :app
+       ;;calendar
+       ;;irc               ; how neckbeards socialize
+       ;;(rss +org)        ; emacs as an RSS reader
+       ;;twitter           ; twitter client https://twitter.com/vnought
+
+       :config
+       ;;literate
+       (default +bindings +smartparens))
diff --git a/.config/doom/togetherly.el b/.config/doom/togetherly.el
new file mode 100644
index 0000000..6227abf
--- /dev/null
+++ b/.config/doom/togetherly.el
@@ -0,0 +1,561 @@
+;;; togetherly.el --- allow multiple clients to edit a single buffer online
+
+;; Copyright (C) 2015 zk_phi
+
+;; This program 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 2 of the License, or
+;; (at your option) any later version.
+;;
+;; This program 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 this program; if not, write to the Free Software
+;; Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+
+;; Author: zk_phi
+;; URL: http://hins11.yu-yake.com/
+;; Version: 0.1.1
+;; Package-Requires: ((cl-lib "0.3"))
+
+;;; Commentary:
+
+;; Server:
+;;   1. Open a buffer you want to share.
+;;   2. `M-x togetherly-server-start' to start a server.
+;;   3. `M-x togetherly-server-close' when finished.
+;;
+;; Client:
+;;   1. `M-x togetherly-client-start' to request access to the server.
+;;   2. Kill `*Togetherly*' buffer when finished.
+;;
+;; See Readme.org for more information.
+
+;;; Change Log:
+
+;; 0.1.0 test release
+;; 0.1.1 add `togetherly-server-comehere' command
+
+;;; Code:
+
+(defconst togetherly-version "0.1.1")
+
+(require 'cl-lib)
+(require 'ido)
+
+;; todos
+;; -----
+;; - クライアントを複数立ち上げられるように
+;;   - ポートを切り替えてサーバーも複数立ち上がると楽しい
+;;   - *Togetherly*の代わりにプロセスバッファを作って、各変数をバッファローカルにすればおｋ？
+;; - チャットができるといい？
+;; - 画面をシェアしつつ編集を許可しないということができてもいいかも
+;;   - client ごとに read-only かどうかの属性を持てばいい？
+;; - 認証機能やっぱほしい？
+;; - 色を同期する必要はないかも
+
+;; + customs
+
+(defvar togetherly-cursor-sync-rate 0.5
+  "Interval in seconds to sync cursor positions.")
+
+(defvar togetherly-cursor-colors
+  ;; (defun color-hsl-to-hex (h s l) (apply 'color-rgb-to-hex (color-hsl-to-rgb h s l)))
+  ;; (mapcar (lambda (h) (color-hsl-to-hex h 0.6 0.3))
+  ;;         '(0.0 0.125 0.25 0.375 0.5 0.625 0.75 0.875))
+  ;; (mapcar (lambda (h) (color-hsl-to-hex h 0.6 0.8))
+  ;;         '(0.0 0.125 0.25 0.375 0.5 0.625 0.75 0.875))
+  (let ((lst (if (eq (frame-parameter nil 'background-mode) 'dark)
+                 '("#7a1e1e" "#7a631e" "#4c7a1e" "#1e7a35"
+                   "#1e7a7a" "#1e357a" "#4c1e7a" "#7a1e63")
+               '("#eaadad" "#eadbad" "#cceaad" "#adeabc"
+                 "#adeaea" "#adbcea" "#cbadea" "#eaaddb"))))
+    (setcdr (last lst) lst))
+  "(Possivly infinite) list of cursor colors.")
+
+(defvar togetherly-region-colors
+  ;; (mapcar (lambda (h) (color-hsl-to-hex h 0.6 0.2))
+  ;;         '(0.0 0.125 0.25 0.375 0.5 0.625 0.75 0.875))
+  ;; (mapcar (lambda (h) (color-hsl-to-hex h 0.6 0.9))
+  ;;         '(0.0 0.125 0.25 0.375 0.5 0.625 0.75 0.875))
+  (let ((lst (if (eq (frame-parameter nil 'background-mode) 'dark)
+                 '("#511414" "#514214" "#335114" "#145123"
+                   "#145151" "#142351" "#321451" "#511442")
+               '("#f4d6d6" "#f4edd6" "#e5f4d6" "#d6f4dd"
+                 "#d6f4f4" "#d6ddf4" "#e5d6f4" "#f4d6ed"))))
+    (setcdr (last lst) lst))
+  "(Possively infinite) list of region colors.")
+
+;; + utilities
+
+(defun togetherly--make-overlay (beg end bgcolor &optional priority omit-eol)
+  "Make cursor/region overlays."
+  (let ((ov (make-overlay 1 1)))
+    (overlay-put ov 'face `(:background ,bgcolor))
+    (overlay-put ov 'bgcolor bgcolor)
+    (overlay-put ov 'priority (or priority 0))
+    (togetherly--move-overlay ov beg end omit-eol)
+    ov))
+
+(defun togetherly--move-overlay (ov beg end &optional omit-eol)
+  "Move cursor/region overlays."
+  (let* ((eol (eql (char-before end) ?\n))
+         (end (if eol (1- end) end))
+         (after-str (when (and eol (not omit-eol))
+                      (propertize " " 'face `(:background ,(overlay-get ov 'bgcolor))))))
+    (move-overlay ov beg end (current-buffer))
+    (overlay-put ov 'after-string after-str)))
+
+(defun togetherly--buffer-string ()
+  "Like `buffer-string' but NOT aware of narrowing and
+text-properties."
+  (save-restriction
+    (widen)
+    (buffer-substring-no-properties (point-min) (point-max))))
+
+(defvar togetherly--last-display-name nil)
+(defun togetherly--read-display-name ()
+  "Read displayname with the minibuffer."
+  (let ((name (read-string
+               (if (null togetherly--last-display-name)
+                   "Displayname : "
+                 (format "Displayname (default:%s) : " togetherly--last-display-name)))))
+    (if (and (string= name "") togetherly--last-display-name)
+        togetherly--last-display-name
+      (setq togetherly--last-display-name name))))
+
+(defvar togetherly--last-host-address "localhost")
+(defun togetherly--read-host-address ()
+  "Read host address with the minibuffer."
+  (let* ((addrs (when (and (fboundp 'network-interface-list)
+                           (fboundp 'network-interface-info))
+                  (mapcar (lambda (x)
+                            (format-network-address
+                             (car (network-interface-info (car x))) t))
+                          (network-interface-list))))
+         (addr (cl-case (length addrs)
+                 ((0) (read-string
+                       (format "Address (default:%s) : " togetherly--last-host-address)))
+                 ((1) (car addrs))
+                 (t   (ido-completing-read "Address: " addrs nil t)))))
+    (if (string= addr "")
+        togetherly--last-host-address
+      (setq togetherly--last-host-address addr))))
+
+(defvar togetherly--last-target-address "localhost")
+(defun togetherly--read-target-address ()
+  "Read target address with the minibuffer."
+  (let ((addr (read-string
+               (format "Address (default:%s) : " togetherly--last-target-address))))
+    (if (string= addr "")
+        togetherly--last-target-address
+      (setq togetherly--last-target-address addr))))
+
+(defvar togetherly--last-port 10000)
+(defun togetherly--read-port ()
+  "Read port number with the minibuffer."
+  (let ((port (read-string (format "Port (default:%s) : " togetherly--last-port))))
+    (if (string= port "")
+        togetherly--last-port
+      (setq togetherly--last-port (read port)))))
+
+;; + the protocol
+
+;; login
+;; - (login . ID) [Client->Server]
+;; - (error . MESSAGE) [Server->Client]
+
+;; share buffer-string
+;; - (refresh) [Client->Server]
+;; - (welcome BUFFER_STRING . MAJOR_MODE) [Server->Client]
+;; * `refresh' tells the server to send `welcome' message immediately.
+;; * note that `welcome' can also be sent before `refresh' request, as needed.
+
+;; share modifications
+;; - (changed NAME BEG BEFORE_STRING . AFTER_STRING) [Server<->Client]
+;; * When `changed' message sent to the server, the message is
+;;   broadcasted for ALL clients, including the client who actually
+;;   made the change. Thus clients must be aware if the message is the
+;;   one sent by himself or not.
+
+;; share members / cursor-positions
+;; - (moved MARK . POINT) [Client->Server]
+;; - (cursors (NAME1 RCOLOR1 PCOLOR1 MARK1 . POINT1) ...) [Server->Client]
+;; * `cursors' is broadcasted every `togetherly-cursor-sync-rate' seconds.
+
+;; other commands
+;; - (comehere . POINT) [Server->Client]
+
+;; + server
+;;   + vars
+
+(defvar togetherly--server nil)         ; (PROC NAME RCOLOR . PCOLOR)
+(defvar togetherly--server-buffer nil)
+(defvar togetherly--server-timer-object nil)
+(defvar togetherly--server-clients nil) ; list of (PROC NAME RCOLOR PCOLOR REGION_OV . POINT_OV)
+
+;;   + utils
+
+(defun togetherly--server-send (client obj)
+  "Send OBJ to CLIENT."
+  (process-send-string (car client) (prin1-to-string obj)))
+
+(defun togetherly--server-broadcast (obj)
+  "Send OBJ to all clients."
+  (dolist (client togetherly--server-clients)
+    (togetherly--server-send client obj)))
+
+;;   + API
+
+(defun togetherly--server-broadcast-cursor-positions ()
+  "Broadcast all clients' cursor positions."
+  (togetherly--server-broadcast
+   (cons 'cursors
+         (nconc
+          (mapcar
+           (lambda (c) (cl-destructuring-bind (_ name rcolor pcolor region-ov . ___) c
+                         `(,name ,rcolor ,pcolor
+                                 ,(overlay-start region-ov)
+                                 . ,(1- (overlay-end region-ov)))))
+           togetherly--server-clients)
+          (with-current-buffer togetherly--server-buffer
+            (cl-destructuring-bind (_ name rcolor . pcolor) togetherly--server
+              `((,name ,rcolor ,pcolor ,(when mark-active (mark)) . ,(point)))))))))
+
+;; Sync modifications on change.
+(defvar togetherly--server-last-change nil)
+(defun togetherly--server-before-change (beg end)
+  (setq togetherly--server-last-change
+        ;; store 2 extra characters to make it easier to detect confliction
+        ;;                                            vvvvvvvvvvvvvvvvvvvvvvvvvvv
+        (cons beg (buffer-substring-no-properties beg (min (+ end 2) (point-max))))))
+(defun togetherly--server-after-change (beg end _)
+  (togetherly--server-broadcast
+   `(changed ,(cadr togetherly--server)
+             ,(car togetherly--server-last-change)
+             ,(cdr togetherly--server-last-change)
+             . ,(buffer-substring-no-properties beg (min (+ end 2) (point-max))))))
+
+(defun togetherly-server-comehere ()
+  (interactive)
+  (togetherly--server-broadcast `(comehere . ,(point))))
+
+(defun togetherly--server-process-message (proc message)
+  "Process MESSAGE from client process PROC."
+  (cl-case (car message)
+
+    ((login)
+     (let ((name (cdr message)))
+       (cond
+        ((or (string= name (cadr togetherly--server))
+             (member name (mapcar 'cadr togetherly--server-clients)))
+         (process-send-string proc "(error . \"Duplicate Displayname\")")
+         (delete-process proc))
+        (t
+         (set-process-query-on-exit-flag proc nil)
+         (with-current-buffer togetherly--server-buffer
+           (let* ((pcolor (car togetherly-cursor-colors))
+                  (rcolor (car togetherly-region-colors))
+                  (client `(,proc ,name ,rcolor ,pcolor
+                                  ,(togetherly--make-overlay 1 2 rcolor 0)
+                                  . ,(togetherly--make-overlay 1 2 pcolor 1))))
+             (setq togetherly-region-colors (cdr togetherly-region-colors)
+                   togetherly-cursor-colors (cdr togetherly-cursor-colors))
+             (push client togetherly--server-clients)
+             (setq header-line-format
+                   (concat " " (propertize name 'face `(:background ,pcolor))
+                           " " header-line-format))))
+         (togetherly--server-send
+          (car togetherly--server-clients)
+          (with-current-buffer togetherly--server-buffer
+            `(welcome ,(togetherly--buffer-string) . ,major-mode)))
+         (message "Togetherly: %s logged in." name)))))
+
+    ((changed)
+     (let ((client (assoc proc togetherly--server-clients))
+           (inhibit-modification-hooks t))
+       (when client
+         (cl-destructuring-bind (_ beg before-string . after-string) (cdr message)
+           (condition-case nil
+               (with-current-buffer togetherly--server-buffer
+                 (save-excursion
+                   (goto-char beg)
+                   (unless (looking-at (regexp-quote before-string)) (error ""))
+                   (replace-match after-string t t))
+                 (togetherly--server-broadcast message))
+             ;; confliction detected
+             (error
+              (with-current-buffer togetherly--server-buffer
+                (togetherly--server-send
+                 client `(welcome ,(togetherly--buffer-string) . ,major-mode)))))))))
+
+    ((moved)
+     (let ((client (assoc proc togetherly--server-clients)))
+       (when client
+         (cl-destructuring-bind (mark . point) (cdr message)
+           (condition-case nil
+               (cl-destructuring-bind (_ __ ___ ____ region-ov . point-ov) client
+                 (with-current-buffer togetherly--server-buffer
+                   (togetherly--move-overlay point-ov point (1+ point))
+                   (if mark
+                       (togetherly--move-overlay region-ov mark (1+ point) t)
+                     (togetherly--move-overlay region-ov 0 0 t))))
+             ;; confliction detected
+             (error
+              (with-current-buffer togetherly--server-buffer
+                (togetherly--server-send
+                 client `(welcome ,(togetherly--buffer-string) . ,major-mode)))))))))
+
+    ((refresh)
+     (let ((client (assoc proc togetherly--server-clients)))
+       (with-current-buffer togetherly--server-buffer
+         (togetherly--server-send
+          client `(welcome ,(togetherly--buffer-string) . ,major-mode)))))))
+
+;;   + server process
+
+(defun togetherly-server-start ()
+  "Start a Togetherly server with this buffer."
+  (interactive)
+  (cond ((null togetherly--server)
+         (let* ((addr (togetherly--read-host-address))
+                (server-port (togetherly--read-port))
+                (server-name (togetherly--read-display-name))
+                (server-proc (make-network-process
+                              :name "togetherly-server" :server t
+                              :service server-port :noquery t :host addr
+                              :sentinel 'togetherly--server-sentinel-function
+                              :filter 'togetherly--server-filter-function))
+                (rcolor (car togetherly-region-colors))
+                (pcolor (car togetherly-cursor-colors)))
+           (setq togetherly-region-colors   (cdr togetherly-region-colors)
+                 togetherly-cursor-colors   (cdr togetherly-cursor-colors)
+                 togetherly--server         `(,server-proc ,server-name ,rcolor . ,pcolor)
+                 togetherly--server-buffer  (current-buffer)
+                 togetherly--server-clients nil
+                 togetherly--server-timer-object
+                 (run-with-timer nil togetherly-cursor-sync-rate
+                                 'togetherly--server-broadcast-cursor-positions))
+           (set (make-local-variable 'header-line-format)
+                (concat " " (propertize server-name 'face `(:background ,pcolor)))))
+         (add-hook 'before-change-functions 'togetherly--server-before-change nil t)
+         (add-hook 'after-change-functions 'togetherly--server-after-change nil t)
+         (add-hook 'kill-buffer-query-functions 'togetherly--server-kill-buffer-query))
+        ((y-or-n-p "Togetherly server already started. Migrate to this buffer ? ")
+         (set (make-local-variable 'header-line-format)
+              (buffer-local-value 'header-line-format togetherly--server-buffer))
+         (add-hook 'before-change-functions 'togetherly--server-before-change nil t)
+         (add-hook 'after-change-functions 'togetherly--server-after-change nil t)
+         (with-current-buffer togetherly--server-buffer
+           (remove-hook 'before-change-functions 'togetherly--server-before-change t)
+           (remove-hook 'after-change-functions 'togetherly--server-after-change t)
+           (kill-local-variable 'header-line-format))
+         (setq togetherly--server-buffer (current-buffer))
+         (togetherly--server-broadcast `(welcome ,(togetherly--buffer-string) . ,major-mode)))
+        (t
+         (message "Togetherly: Canceled."))))
+
+(defun togetherly--server-filter-function (proc str)
+  (with-current-buffer (get-buffer-create " *togetherly-server-tmp*")
+    (save-excursion
+      (goto-char (point-max))
+      (insert str))
+    (let (message)
+      (while (setq message (ignore-errors (read (current-buffer))))
+        (togetherly--server-process-message proc message)
+        (delete-region (point) (point-min)))
+      (goto-char (point-min)))))
+
+(defun togetherly--server-sentinel-function (proc message)
+  (unless (string-match "^open" message)
+    (let ((client (assoc proc togetherly--server-clients)))
+      (cond (client                     ; client process is killed
+             (cl-destructuring-bind (proc name _ __ region-ov . point-ov) client
+               (with-current-buffer togetherly--server-buffer
+                 (let* ((old-header header-line-format)
+                        (new-header (with-temp-buffer
+                                      (insert old-header)
+                                      (search-backward (regexp-quote (concat " " name " ")))
+                                      (replace-match "")
+                                      (buffer-string))))
+                   (setq header-line-format new-header)
+                   (delete-overlay region-ov)
+                   (delete-overlay point-ov)))
+               (setq togetherly--server-clients (delq client togetherly--server-clients))
+               (unless (string-match "^delete" message)
+                 (message "Togetherly: %s logged out." name))))
+            ((eq proc (car togetherly--server)) ; server process is killed
+             (mapc (lambda (c) (delete-process (car c))) togetherly--server-clients)
+             (setq togetherly--server nil)
+             (cancel-timer togetherly--server-timer-object)
+             (with-current-buffer togetherly--server-buffer
+               (kill-local-variable 'header-line-format))
+             (remove-hook 'kill-buffer-query-functions 'togetherly--server-kill-buffer-query)
+             (remove-hook 'before-change-functions 'togetherly--server-before-change t)
+             (remove-hook 'after-change-functions 'togetherly--server-after-change t))))))
+
+(defun togetherly--server-kill-buffer-query ()
+  (or (not (eq (current-buffer) togetherly--server-buffer))
+      (when (y-or-n-p "This buffer is running the Togetherly server. Really continue ? ")
+        (delete-process (car togetherly--server))
+        t)))
+
+(defun togetherly-server-close ()
+  "Close the Togetherly server."
+  (interactive)
+  (delete-process (car togetherly--server)))
+
+;; + client
+;;   + vars
+
+(defvar togetherly--client-name nil)
+(defvar togetherly--client-process nil)
+(defvar togetherly--client-overlays nil)
+(defvar togetherly--client-timer-object nil)
+
+;;   + utils
+
+(defun togetherly--client-send (obj)
+  "Send OBJ to the server."
+  (process-send-string togetherly--client-process (prin1-to-string obj)))
+
+;;   + API
+
+(defun togetherly--client-report-cursor-position ()
+  "Report the cursor position to the server."
+  (with-current-buffer "*Togetherly*"
+    (togetherly--client-send `(moved ,(when (use-region-p) (mark)) . ,(point)))))
+
+(defvar togetherly--client-last-change nil)
+(defun togetherly--client-before-change (beg end)
+  (setq togetherly--client-last-change
+        (cons beg (buffer-substring-no-properties beg (min (+ end 2) (point-max))))))
+(defun togetherly--client-after-change (beg end _)
+  (togetherly--client-send
+   `(changed ,togetherly--client-name
+             ,(car togetherly--client-last-change)
+             ,(cdr togetherly--client-last-change)
+             . ,(buffer-substring-no-properties beg (min (+ end 2) (point-max))))))
+
+(defun togetherly--client-process-message (proc message)
+  "Process MESSAGE from server process PROC."
+  (cl-case (car message)
+
+    ((welcome)
+     (with-current-buffer "*Togetherly*"
+       (let ((inhibit-modification-hooks t)
+             (original-pos (point))
+             (mode (cddr message)))
+         (erase-buffer)
+         (insert (cadr message))
+         (unless (eq major-mode mode)
+           (funcall (or (and (fboundp mode) mode) 'fundamental-mode)))
+         (goto-char (max (min original-pos (point-max)) (point-min)))
+         ;; local hooks must be set after changing major-mode
+         (add-hook 'before-change-functions 'togetherly--client-before-change nil t)
+         (add-hook 'after-change-functions 'togetherly--client-after-change nil t)))
+     (message "Togetherly: Buffer refreshed."))
+
+    ((error)
+     (delete-process proc)
+     (message "Togetherly Error: %s." (cdr message)))
+
+    ((changed)
+     (cl-destructuring-bind (name beg before-string . after-string) (cdr message)
+       (unless (string= name togetherly--client-name)
+         (condition-case nil
+             (with-current-buffer "*Togetherly*"
+               (save-excursion
+                 (goto-char beg)
+                 (unless (looking-at (regexp-quote before-string)) (error ""))
+                 (let ((inhibit-modification-hooks t))
+                   (replace-match after-string t t))))
+           ;; confliction detected
+           (error (togetherly--client-send '(refresh)))))))
+
+    ((cursors)
+     (mapc 'delete-overlay togetherly--client-overlays)
+     (with-current-buffer "*Togetherly*"
+       (setq header-line-format
+             (mapconcat (lambda (c)
+                          (cl-destructuring-bind (n _ p  . __) c
+                            (concat " " (propertize n 'face `(:background ,p)))))
+                        (cdr message) " "))
+       (dolist (cursor (cdr message))
+         (cl-destructuring-bind (name rcolor pcolor mark . point) cursor
+           (unless (string= name togetherly--client-name)
+             (when mark
+               (push (togetherly--make-overlay mark (1+ point) rcolor 0 t)
+                     togetherly--client-overlays))
+             (push (togetherly--make-overlay point (1+ point) pcolor 1)
+                   togetherly--client-overlays))))))
+
+    ((comehere)
+     (let* ((buf (get-buffer "*Togetherly*"))
+            (windows (mapcar (lambda (w) (cons (window-buffer w) w)) (window-list)))
+            (windows (cl-remove-if-not (lambda (p) (eq buf (car p))) windows)))
+       (condition-case nil
+           (if windows
+               (dolist (window (mapcar 'cdr windows))
+                 (with-selected-window window
+                   (goto-char (cdr message))
+                   (recenter)))
+             (with-current-buffer "*Togetherly*"
+               (goto-char (cdr message))
+               (recenter)))
+         (error (togetherly--client-send '(refresh))))))))
+
+;;   + client process
+
+(defun togetherly--client-filter-function (proc str)
+  (with-current-buffer (get-buffer-create " *togetherly-client-tmp*")
+    (save-excursion
+      (goto-char (point-max))
+      (insert str))
+    (let (message)
+      (while (setq message (ignore-errors (read (current-buffer))))
+        (togetherly--client-process-message proc message)
+        (delete-region (point) (point-min)))
+      (goto-char (point-min)))))
+
+(defun togetherly-client-start ()
+  (interactive)
+  (when (or (null togetherly--client-process)
+            (when (y-or-n-p "Already running Togetherly client. Kill the client first ? ")
+              (delete-process togetherly--client-process)
+              t))
+    (let* ((host (togetherly--read-target-address))
+           (port (togetherly--read-port))
+           (name (setq togetherly--client-name (togetherly--read-display-name))))
+      (setq togetherly--client-process
+            (make-network-process
+             :name "togetherly" :host host :service port :noquery t
+             :buffer (get-buffer-create "*Togetherly*")
+             :sentinel 'togetherly--client-sentinel-function
+             :filter 'togetherly--client-filter-function))
+      (switch-to-buffer "*Togetherly*")
+      (setq togetherly--client-timer-object
+            (run-with-timer nil togetherly-cursor-sync-rate
+                            'togetherly--client-report-cursor-position))
+      (add-hook 'kill-buffer-query-functions 'togetherly--client-kill-buffer-query)
+      (togetherly--client-send `(login . ,name)))))
+
+(defun togetherly--client-sentinel-function (proc message)
+  (setq togetherly--client-process nil)
+  (cancel-timer togetherly--client-timer-object)
+  (remove-hook 'kill-buffer-query-functions 'togetherly--client-kill-buffer-query)
+  (when (get-buffer "*Togetherly*")
+    (kill-buffer "*Togetherly*")))
+
+(defun togetherly--client-kill-buffer-query ()
+  (or (not (string= (buffer-name) "*Togetherly*"))
+      (y-or-n-p "Really logout from Togetherly server ? ")))
+
+;; + provide
+
+(provide 'togetherly)
+
+;;; togetherly.el ends here