# systemd unit for Fire Gimbal Control - a TEMPLATE. scripts/install-tower fills
# in the @...@ fields and installs it; to do it by hand, replace them and copy it
# to /etc/systemd/system/, then:
#   sudo loginctl enable-linger <user>        # see below - not optional
#   sudo systemctl daemon-reload && sudo systemctl enable fire-gimbal-control
#
# The unit runs the program through scripts/fgc, inside tmux, so a tower started
# at boot still has the dashboard: `scripts/fgc attach` from any ssh session.
# fgc returns once the program is up, hence oneshot + RemainAfterExit; stopping
# the unit runs `fgc stop`, which shuts the camera and motors down cleanly.
#
# Lingering: without it /run/user/<uid> does not exist until someone logs in, so
# a program started at boot takes its single-instance lock in /tmp, and a later
# ssh session looks in /run/user, finds nothing, and `fgc status` says it is not
# running - while a second copy could start beside it.
#
# @ARGS@ is normally `--init --start`: the firmware keeps no position across a
# power cycle, so without --init the gimbal sits un-homed and captures nothing.
# --init also means the gimbal HOMES UNATTENDED at every boot.
#
# MQTT credentials: /etc/fire_gimbal_control/credentials.env (FGC_MQTT_USER,
# FGC_MQTT_PW), read by fgc inside the tmux pane rather than passed through this
# unit - a tmux server that already exists would not hand a new session the
# unit's environment.

[Unit]
Description=Fire Gimbal Control
After=network-online.target
Wants=network-online.target

[Service]
Type=oneshot
RemainAfterExit=yes
User=@USER@
WorkingDirectory=@REPO@
ExecStart=@REPO@/scripts/fgc start @ARGS@
ExecStop=@REPO@/scripts/fgc stop
TimeoutStartSec=120
TimeoutStopSec=60

[Install]
WantedBy=multi-user.target