#!/usr/bin/env bash

die() {
  echo "$1" >&2
  exit 1
}

[ -z "$CONTAINER_NAME" ] && die "\$CONTAINER_NAME not set"
[ -z "$DISPLAY" ] && die "\$DISPLAY not set (you must run the script in a desktop environment"

# From <https://liolok.com/run-desktop-app-with-systemd-nspawn-container>
if [[ -n $DBUS_SESSION_BUS_ADDRESS ]]; then # remove prefix
    host_bus=${DBUS_SESSION_BUS_ADDRESS#unix:path=}
else # default guess
    host_bus=$XDG_RUNTIME_DIR/bus
fi

if [[ -n $PULSE_SERVER ]]; then # remove prefix
  host_pulse=${PULSE_SERVER#unix:}
else # default guess
  host_pulse=$XDG_RUNTIME_DIR/pulse
fi

# Default username
run_as=user
homedir=/home/user
if [ "$CONTAINER_RUN_AS_ROOT" = true ]; then
  run_as=root
  homedir=/root
fi

sudo systemd-nspawn -M $CONTAINER_NAME \
    `# DNS (when containers do not have their own netns)` \
    --bind-ro=/run/systemd/resolve/stub-resolv.conf:/etc/resolv.conf \
    `# GPU` \
    --bind=/dev/dri/card0 \
    --bind=/dev/shm \
    --property=DeviceAllow='char-drm rw' \
    `# Input devices` \
    --bind-ro=/dev/input \
    --property=DeviceAllow='char-input r' \
    `# Xorg / Xwayland` \
    --bind-ro=/tmp/.X11-unix \
    --setenv=DISPLAY=$DISPLAY \
    `# PulseAudio` \
    --bind-ro=$host_pulse:/run/host/pulse \
    --setenv=PULSE_SERVER=unix:/run/host/pulse/native \
    `# DBus` \
    --bind-ro=$host_bus:/run/host/bus \
    --setenv=DBUS_SESSION_BUS_ADDRESS=unix:path=/run/host/bus \
    `# Scaling `\
    --setenv=GDK_SCALE="$GDK_SCALE" \
    `# Extra params` \
    $SYSTEMD_NSPAWN_EXTRA_ARGS \
    `# Launch app` \
    --user=$run_as --chdir=$homedir --as-pid2 $@