some documentation

DOC.md

@@ -0,0 +1,53 @@
+# General Software Architecture
+
+## Events
+
+Each instance of lan-mouse can emit and receive events, where
+an event is either a mouse or keyboard event for now.
+
+The general Architecture is shown in the following flow chart:
+```mermaid
+graph TD
+    A[Wayland Backend] -->|WaylandEvent| D{Input}
+    B[X11 Backend] -->|X11Event| D{Input}
+    C[Windows Backend] -->|WindowsEvent| D{Input}
+    D -->|Abstract Event| E[Emitter]
+    E -->|Udp Event| F[Receiver]
+    F -->|Abstract Event| G{Dispatcher}
+    G -->|Wayland Event| H[Wayland Backend]
+    G -->|X11 Event| I[X11 Backend]
+    G -->|Windows Event| J[Windows Backend]
+```
+
+### Input
+The input component is responsible for translating inputs from a given backend
+to a standardized format and passing them to the event emitter.
+
+### Emitter
+The event emitter serializes events and sends them over the network
+to the correct client.
+
+### Receiver
+The receiver receives events over the network and deserializes them into
+the standardized event format.
+
+### Dispatcher
+The dispatcher component takes events from the event receiver and passes them
+to the correct backend corresponding to the type of client.
+
+
+## Requests
+
+// TODO this currently works differently
+
+Aside from events, requests can be sent via a simple protocol.
+For this, a simple tcp server is listening on the same port as the udp
+event receiver and accepts requests for connecting to a device or to
+request the keymap of a device.
+
+```mermaid
+sequenceDiagram
+    Alice->>+Bob: Request Connection (secret)
+    Bob-->>-Alice: Ack (Keyboard Layout)
+```
+