#!/usr/bin/mscgen -Tpng

msc {
       hscale="1.5";

       u [label = "touch/pointer event" ],
       l [label = "launcher app" ],
       s [label = "runtime/shell-client"],
       a [label = "applaunchd" ],
       g [label = "gRPC-proxy" ],
       c [label = "compositor" ],
       d [label = "libsystemd"];

       |||;

       --- [label = "initial phase - subscribe for signal/status events, assume app_id already started" ];

       s >> a [label = "subscribe for applaunchd GetStatusEvents"];

       --- [label = "handling of application switching" ];

       u => l [label = "tapShortCut(appid)" ];
       l => a [label = "StartApplication(appid)"];
       a => d [label = "start application's systemd unit"];
       d => a [label = "return status from starting systemd unit"];
       a => s [label = "StartResponse(status = TRUE)"];
       a => s [label = "StatusResponse(app_id, 'started')"];
       s => c [label = "activate_app(app_id)"];
}