#! @shell@
set -e
set -o pipefail
export PATH=@path@:$PATH


showSyntax() {
  echo "darwin-rebuild [--help] {build | switch | check | changelog}" >&2
  echo "               [--list-generations] [{--profile-name | -p} name] [--rollback]" >&2
  echo "               [{--switch-generation | -G} generation] [--verbose...] [-v...]" >&2
  echo "               [-Q] [{--max-jobs | -j} number] [--cores number] [--dry-run]" >&1
  echo "               [--keep-going] [-k] [--keep-failed] [-K] [--fallback] [--show-trace]" >&2
  echo "               [-I path] [--option name value] [--arg name value] [--argstr name value]" >&2
  exec man darwin-rebuild
  exit 1
}

# Parse the command line.
origArgs=("$@")
extraBuildFlags=()
extraProfileFlags=()
profile=@profile@
action=

while [ "$#" -gt 0 ]; do
  i="$1"; shift 1
  case "$i" in
    --help)
      showSyntax
      ;;
    switch|build|changelog|check)
      action="$i"
      ;;
    --show-trace|--no-build-hook|--dry-run|--keep-going|-k|--keep-failed|-K|--verbose|-v|-vv|-vvv|-vvvv|-vvvvv|--fallback|-Q)
      extraBuildFlags+=("$i")
      ;;
    -j[0-9]*)
      extraBuildFlags+=("$i")
      ;;
    --max-jobs|-j|--cores|-I)
      if [ -z "$1" ]; then
        echo "$0: ‘$i’ requires an argument"
        exit 1
      fi
      j="$1"; shift 1
      extraBuildFlags+=("$i" "$j")
      ;;
    --arg|--argstr|--option)
      if [ -z "$1" -o -z "$2" ]; then
        echo "$0: ‘$i’ requires two arguments"
        exit 1
      fi
      j="$1"; shift 1
      k="$1"; shift 1
      extraBuildFlags+=("$i" "$j" "$k")
      ;;
    --list-generations)
      action="list"
      extraProfileFlags=("$i")
      ;;
    --rollback)
      action="rollback"
      extraProfileFlags=("$i")
      ;;
    --switch-generation|-G)
      action="rollback"
      if [ -z "$1" ]; then
        echo "$0: ‘$i’ requires an argument"
        exit 1
      fi
      j="$1"; shift 1
      extraProfileFlags=("$i" "$j")
      ;;
    --profile-name|-p)
      if [ -z "$1" ]; then
        echo "$0: ‘--profile-name’ requires an argument"
        exit 1
      fi
      if [ "$1" != system ]; then
        profile="/nix/var/nix/profiles/system-profiles/$1"
        mkdir -p -m 0755 "$(dirname "$profile")"
      fi
      shift 1
      ;;
    *)
      echo "$0: unknown option \`$i'"
      exit 1
      ;;
  esac
done

if [ -z "$action" ]; then showSyntax; fi

if ! [ "$action" = build ]; then
  extraBuildFlags+=("--no-out-link")
fi

if ! [ "$action" = list -o "$action" = rollback ]; then
  echo "building the system configuration..." >&2
  systemConfig="$(nix-build '<darwin>' ${extraBuildFlags[@]} -A system)"
fi

if [ "$action" = list -o "$action" = rollback ]; then
  if [ "$USER" != root -a ! -w $(dirname "$profile") ]; then
    sudo nix-env -p $profile ${extraProfileFlags[@]}
  else
    nix-env -p $profile ${extraProfileFlags[@]}
  fi

  systemConfig="$(cat $profile/systemConfig)"
fi

if [ -z "$systemConfig" ]; then exit 0; fi

if [ -n "$rollbackFlags" ]; then
  echo $systemConfig
fi

if [ "$action" = switch ]; then
  if [ "$USER" != root -a ! -w $(dirname "$profile") ]; then
    sudo nix-env -p $profile --set $systemConfig
  else
    nix-env -p $profile --set $systemConfig
  fi
fi

if [ "$action" = switch -o "$action" = rollback ]; then
  $systemConfig/activate-user

  if [ "$USER" != root ]; then
    sudo $systemConfig/activate
  else
    $systemConfig/activate
  fi
fi

if [ "$action" = changelog ]; then
  echo >&2
  echo "CHANGELOG" >&2
  echo >&2
  head -n 32 $systemConfig/darwin-changes
  echo >&2
fi

if [ "$action" = check ]; then
  export checkActivation=1
  $systemConfig/activate-user
fi