#! /bin/bash

#
# This is a hook script for the yupdate tool, it is automatically executed
# before running "rake install" command.
#
# This script prepares the live system for compiling and installing new code.
#
# The script does several tasks:
# - it checks if there is enough RAM, if there is not enough RAM the system
#   might freeze completely
# - installs some packages required for compilations (mainly make, npm and nodejs),
# - if there is no package repository configured it adds the main OSS repository
#   automatically
# - optionally caches the installed NPM packages, this is useful if you want to
#   run the yupdate script several times
#

set -e

if [ "$DEBUG" == "1" ]; then
  set -x
fi

if [ "$YUPDATE_SKIP_FRONTEND" == "1" ]; then
  exit 0
fi

# the needed packages for compiling the cockpit module
PACKAGES=(appstream-glib-devel make npm)
# name of the service
SERVICE_NAME="agama"

# add repositories
function add_repos() {
  # only if no repository is defined
  if zypper lr | grep -q "No repositories defined"; then
    SYSTEM=$(. /etc/os-release && echo "$ID")

    # check the installed system, add the proper repo for TW or Leap
    if [ "$SYSTEM" = "opensuse-tumbleweed" ]; then
      URL="http://download.opensuse.org/tumbleweed/repo/oss"
    elif [ "$SYSTEM" = "opensuse-leap" ]; then
      URL="http://download.opensuse.org/distribution/leap/\${releasever}/repo/oss/"
    else
      echo "Unsupported system: $SYSTEM"
      exit 1
    fi

    zypper addrepo "$URL" main-repo
    zypper --gpg-auto-import-keys refresh
  fi
}

function install_packages() {
  # stop the service, it might hold the libzypp lock preventing from installing the packages
  systemctl stop "$SERVICE_NAME"

  add_repos
  zypper --non-interactive install --no-recommends "${PACKAGES[@]}"

  systemctl start "$SERVICE_NAME"
}

# restore the NPM cache if it is present
function load_npm_cache() {
  CACHEDIR="$HOME/.cache/$SERVICE_NAME-devel/"

  if [ -d "$CACHEDIR/node_modules" ]; then
    echo "Restoring NPM cache..."
    MYDIR=$(realpath "$(dirname "$0")")
    cp -aR "$CACHEDIR/node_modules" "$MYDIR/web/"
  fi
}

# memory check, with not enough memory the system freezes
RAM=$(grep "MemTotal:" /proc/meminfo | sed -e "s/MemTotal:[[:space:]]*\([0-9]\+\) kB/\\1/")
# less than ~2GB RAM
if [ "$RAM" -lt 2000000 ] && [ "$SKIP_MEM_CHECK" != "1" ]; then
  echo >&2
  echo "ERROR: The system has too low memory ($RAM kB) for applying the update." >&2
  echo "The system could completely freeze and become unresponsive." >&2
  echo "You can skip this check with SKIP_MEM_CHECK=1 environment variable." >&2
  echo >&2

  exit 1
fi

# check if all needed packages are installed, if not then install them
rpm -q --whatprovides "${PACKAGES[@]}" > /dev/null || install_packages

# optionally restore the cached NPM packages
if [ "$NPM_CACHE" = "1" ] ; then
  load_npm_cache
fi