#!/usr/bin/env sh
#  SPDX-License-Identifier: GPL-3.0
#  Denis Kanuf <https://denkn.at>

die() {
	>&2 printf '\e[1;31mdied: %s\e[0m\n' "$*"
	exit 1
}

l() {
	>&2 printf '\e[1m%s\e[0m\n' "$*"
}

d() {
	>&2 printf '\e[1;34m# %s\e[0m\n' "$*"
	"$@" || die "$*"
}

MNAME=octoprint
MDIR=/var/lib/machines/$MNAME
TDIR=/var/lib/machines/$MNAME-template
DEVPTN='/dev/ttyUSB*'
LICENSE="$(cat <<EOF
#  SPDX-License-Identifier: GPL-3.0
#  Denis Knauf <https://denkn.at>
EOF
)"

alias OP='d systemd-nspawn --machine=$MNAME --hostname=$MNAME --directory="$MDIR" --tmpfs=/run --tmpfs=/run/lock'

t_mkdir() {
	for d
	do
		d install -d "$TDIR/$d"
	done
}

###############################################################################

ho_install() {
d apt install -y systemd-container debootstrap cron-apt dnsmasq

d dd of=/etc/cron-apt/action.d/6-upgrade <<EOF
safe-upgrade -y
EOF

if [ -d "$MDIR" ]
then
	l skipping debootstrap
else
	d rm -rf "$MDIR".tmp
	d debootstrap --include=systemd-container stable "$MDIR".tmp
	d mv "$MDIR".tmp "$MDIR"
fi

OP apt update
OP apt dist-upgrade -y
OP apt install -y nullmailer python3-pip cron-apt ffmpeg
OP pip3 install octoprint
OP sh -c 'getent passwd octoprint || useradd -mrUd /var/lib/octoprint -G dialout octoprint'

d install -o root -g root -m 0755 "$0" /usr/local/sbin/hexapi
d install -o root -g root -m 0755 "$0" "$MDIR"/usr/local/sbin/hexapi

d dd of="$MDIR"/etc/cron-apt/action.d/6-upgrade <<EOF
safe-upgrade -y
EOF

d dd of=/etc/systemd/system/octoprint-container@.service <<EOF
${LICENSE}
#  Based on systemd-nspawn@.service

[Unit]
Description=OctoPrint Container for %i
Documentation=man:systemd-nspawn(1)
PartOf=machines.target
Before=machines.target
After=network.target systemd-resolved.service
RequiresMountsFor=/var/lib/machines
BindTo=dev-%i.device

[Service]
ExecStart=/usr/bin/systemd-nspawn --quiet --keep-unit --boot --link-journal=try-guest \
	--settings=override \
	--directory=/var/lib/machines/octoprint@ttyUSB0 --template=/var/lib/machines/octoprint-template \
	--overlay=/var/lib/machines/octoprint/etc:/var/lib/machines/octoprint@%i/etc:/etc \
	--bind-ro=/var/lib/machines/octoprint/usr:/usr --bind=/dev/%i --machine=%i --hostname=%i
KillMode=mixed
Type=notify
RestartForceExitStatus=133
SuccessExitStatus=133
WatchdogSec=3min
Slice=machine.slice
Delegate=yes
TasksMax=16384

# Enforce a strict device policy, similar to the one nspawn configures when it
# allocates its own scope unit. Make sure to keep these policies in sync if you
# change them!
DevicePolicy=closed
DeviceAllow=/dev/net/tun rwm
DeviceAllow=char-pts rw

# nspawn itself needs access to /dev/loop-control and /dev/loop, to implement
# the --image= option. Add these here, too.
DeviceAllow=/dev/loop-control rw
DeviceAllow=block-loop rw
DeviceAllow=block-blkext rw

# nspawn can set up LUKS encrypted loopback files, in which case it needs
# access to /dev/mapper/control and the block devices /dev/mapper/*.
DeviceAllow=/dev/mapper/control rw
DeviceAllow=block-device-mapper rw

# octoprint needs access to serial-interfaces.
DeviceAllow=/dev/%i rw
DeviceAllow=char-ttyUSB rw

[Install]
WantedBy=machines.target
EOF

d dd of="/etc/udev/rules.d/50-octoprint-container.rules" <<EOF
SUBSYSTEMS=="usb", KERNEL=="ttyUSB*", ACTION=="add", TAG+="systemd", ENV{SYSTEMD_WANTS}+="octoprint-container@%k.service" ENV{SYSTEMD_ALIAS}+="/dev/%k"
EOF

d dd of="$MDIR"/etc/systemd/system/octoprint-init.service <<EOF
${LICENSE}
[Unit]
Description=Initialize Octoprint 3d-printer web interface
Before=octoprint.service
[Service]
Type=oneshot
ExecStart=/usr/local/sbin/hexapi install_env
[Install]
WantedBy=multi-user.target
EOF

d ln -fs ../octoprint-init.service "$MDIR"/etc/systemd/system/multi-user.target.wants/octoprint-init.service

d dd of="$MDIR"/etc/systemd/system/octoprint.service <<EOF
${LICENSE}
[Unit]
Description=OctoPrint 3D-printer web interface
After=octoprint-init.service
[Service]
EnvironmentFile=/local/env
EnvironmentFile=-/env
ExecStart=/usr/local/bin/octoprint serve --host=\${OCTOPRINT_HOST} --port=\${OCTOPRINT_PORT}
User=octoprint
Group=octoprint
[Install]
WantedBy=multi-user.target
EOF

t_mkdir /dev /media /opt /etc /mnt /usr /usr/lib /local /home /srv /run /boot /tmp /root /var \
	/var/backups /var/opt /var/lib /var/local /var/spool /var/spool/cron /var/spool/rsyslog \
	/var/spool/mail /var/log /var/cache /var/tmp /var/mail /proc /sys

d systemctl daemon-reload
}

###############################################################################

ho_list() {
for f in $DEVPTN
do
	echo "found: $f"
done
}

###############################################################################

ho_environment() {
device=$(hostname)
if [ "$device" = "${device#ttyUSB}" ]
then
	>&2  echo "not a container for running octoprint - no device"
	exit 0
elif [ -e "/dev/$device" ]
then
	> /local/env  echo OCTOPRINT_HOST=0.0.0.0
	>>/local/env  echo OCTOPRINT_PORT=$((2000+${device#*USB}))
	install -o octoprint -g octoprint -m 700 -d /var/lib/octoprint
	/usr/bin/systemctl enable --no-block --now octoprint.service
	/usr/bin/systemctl disable octoprint-init.service
else
	>&2  echo "Device not found: $device"
	exit 1
fi
}

###############################################################################

case "$1" in
install) ho_install ;;
list) ho_list ;;
install_env) ho_environment ;;
*)
	>&2 echo "Usage: $0 install"
	exit 1
	;;
esac