#!/usr/bin/env bash
set -euo pipefail

top=$(dirname "$(realpath "$0")")
hostDir="$top/hosts/$HOSTNAME"

if [ ! -d "$hostDir" ]; then
  echo "aborting: host directory $hostDir doesn't exist"
  exit 1
fi

# Make the configuration repository's commit available to the NixOS module.
export NIXOS_CONFIG_REVISION
NIXOS_CONFIG_REVISION=$(git -C "$top" rev-parse --verify HEAD)
if [[ -n $(git -C "$top" status --porcelain) ]]; then
  NIXOS_CONFIG_REVISION+="-dirty"
fi

(
  # The result symlink created in the current directory is registered as a root of the Nix
  # garbage collector, so it's important that we call nixos-rebuild from the host directory.
  # (nix-build has an --out-link option but that option cannot be set via nixos-rebuild).
  cd "$hostDir" &&

  exec nixos-rebuild "$@" --file "$top/default.nix" --attr "configurations.$HOSTNAME"
)