#!/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"

# Source configuration files if any
config="$HOME/.config/app_containers/$CONTAINER_NAME.sh"
if [ -f "$config" ]; then
  source "$config"
fi

# Create a XDG_RUNTIME_DIR for guest on host
container_xdg_runtime="$(mktemp -d)"
trap 'rm -rf -- "$container_xdg_runtime"' EXIT

# Link the current wayland session to the container's xdg runtime
# Note that the session itself must be bind-mounted first
ln -s /run/host/$WAYLAND_DISPLAY $container_xdg_runtime/$WAYLAND_DISPLAY

# 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 (assume `user` always has the same uid as the host user)
run_as=user
homedir=/home/user
if [ "$CONTAINER_RUN_AS_ROOT" = true ]; then
  run_as=root
  homedir=/root
fi

SUDO_ASKPASS=$HOME/.local/bin/askpass-bemenu sudo -A systemd-nspawn -M $CONTAINER_NAME \
    `# DNS (when containers do not have their own netns)` \
    --bind-ro=/run/systemd/resolve/stub-resolv.conf:/etc/resolv.conf \
    `# GPU` \
    --bind=/dev/dri \
    --property=DeviceAllow='char-drm rw' \
    `# Input devices` \
    --bind-ro=/dev/input \
    --property=DeviceAllow='char-input r' \
    `# Xdg runtime` \
    --bind=$container_xdg_runtime:/run/xdg \
    --setenv=XDG_RUNTIME_DIR=/run/xdg \
    `# Xorg / Xwayland` \
    --bind=/tmp/.X11-unix \
    --setenv=DISPLAY=$DISPLAY \
    `# Wayland (note the symlink created before in xdg runtime)` \
    --bind-ro=$XDG_RUNTIME_DIR/$WAYLAND_DISPLAY:/run/host/$WAYLAND_DISPLAY \
    --setenv=WAYLAND_DISPLAY=$WAYLAND_DISPLAY \
    `# PulseAudio` \
    --bind-ro=$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" \
    `# Have QT apps run under Wayland for proper scaling` \
    --setenv=QT_QPA_PLATFORM=wayland \
    `# Hacks for Proton (enable logging, disable futex-based synchronization)` \
    --setenv=PROTON_LOG=1 \
    --setenv=PROTON_NO_FSYNC=1 \
    `# Extra params` \
    $SYSTEMD_NSPAWN_EXTRA_ARGS \
    `# Launch app` \
    --user=$run_as --chdir=$homedir --as-pid2 $@