#!/usr/bin/env bash
set -e

DOTFILES="$(cd $(dirname "${BASH_SOURCE:-${(%):-%x}}") && pwd -P)"
PREFIX="${PREFIX:-/mnt}"
NIXOSPREFIX="${PREFIX}/etc/nixos"
NIXOSFLAGS="-I 'config=$DOTFILES/config' -I 'packages=$DOTFILES/packages'"
HOST=${1:-${HOST:-kuro}}

if [ $EUID -nq 0 ]; then
  sudo nix-channel --update
  sudo nixos-rebuild $NIXOSFLAGS switch
else
  if [ ! -f "$DOTFILES/configuration.$HOST.nix" ]; then
    >&2 echo "No configuration exists for host '$HOST'"
    exit 1
  elif [ ! -f "$NIXOSPREFIX/hardware-configuration.nix" ]; then
    >&2 echo "No hardware-configuration.nix file exists in $NIXOSPREFIX"
    >&2 echo "Did you forget to set up your partitions?"
    exit 2
  fi

  mkdir -p "$NIXOSPREFIX"
  cat << EOF > "$NIXOSPREFIX/configuration.nix"
{ config, ... }:
{
  imports = [
    ../dotfiles/configuration.$HOST.nix
    ./hardware-configuration.nix
  ];
}
EOF

  nix-channel --add https://nixos.org/channels/nixos-19.09 nixos
  nix-channel --add https://github.com/rycee/home-manager/archive/master.tar.gz home-manager
  nix-channel --add https://nixos.org/channels/nixpkgs-unstable nixpkgs-unstable
  nix-channel --update

  nixos-generate-config --root "$PREFIX"
  nixos-install --root "$PREFIX" $NIXOSFLAGS
fi