{ pkgs, ... }:

let
  shutdownWaitMinutes = 15;
  shutdownScript = pkgs.writeScript "shutdown" ''
STATUS_FILES="/media/internal/backups-pub-solar/status"

running=""

for f in $STATUS_FILES; do
  declare started
  declare finished

  started=$(source $f ; echo ''${BACKUP_STARTED})
  finished=$(source $f ; echo ''${BACKUP_FINISHED})

  if [ -z "''${finished}" ]; then
    echo "backup $(dirname $f) still running"
    running="yes"
    break
  fi
done

if [ -n "''${running}" ] && [ "''${running}" = "yes" ]; then
  echo "backups are still running"
  exit 1
fi

echo "WARNING: System will be shut down within the next 15 minutes" | wall

sleep 10

shutdown -P +${builtins.toString shutdownWaitMinutes}
  '';
in
{
  systemd.services."shutdown-after-backup" = {
    enable = true;
    serviceConfig = {
      ExecStart = shutdownScript;
    };
  };

  systemd.timers."shutdown-after-backup" = {
    enable = true;
    serviceConfig = {
      OnCalendar = "3..9:*";
    };
  };
}