#!/usr/bin/env bash

# Install the Nix package manager as a secondary package manager.
# This can sometimes be useful for getting more recent packages.

set -e
set -x

# Abort installation if Nix is already installed
if [ -d /nix ]; then
  exit 0
fi

# Workaround to make a single user install work as root
if [ "${USER:-}" == "root" ] || [ "${UID:-}" == "0" ]; then
  mkdir -p /etc/nix
  echo "build-users-group =" > /etc/nix/nix.conf
fi

# Download the Nix installer and it's signature from NixOS.org
curl -so install-nix https://releases.nixos.org/nix/nix-2.24.12/install

# Run the installer
sh ./install-nix

# Source the nix profile 
cat << EOF > ~/.bashrc
# Source nix if it's installed
if [ -r ~/.nix-profile/etc/profile.d/nix.sh ]; then
  . ~/.nix-profile/etc/profile.d/nix.sh
elif [ -r "${XDG_STATE_HOME:-$HOME/.local/state}/nix/profile/etc/profile.d/nix.sh" ]; then
	. "${XDG_STATE_HOME:-$HOME/.local/state}/nix/profile/etc/profile.d/nix.sh"
fi
EOF

# Remove the installer and signature
rm -f ./install-nix

# Enable flakes and the nix command
NIX_CONF_DIR=~/.config/nix
NIX_CONF_FILE=${NIX_CONF_DIR}/nix.conf
mkdir -p ${NIX_CONF_DIR}
cat <<EOF > ${NIX_CONF_FILE}
experimental-features = flakes nix-command
use-xdg-base-directories = true
EOF
# Conditionally add a link to system certificates for nix
if [ -f /etc/ssl/certs/ca-certificates.crt ]; then
  echo 'ssl-cert-file = /etc/ssl/certs/ca-certificates.crt' >> ${NIX_CONF_FILE}
fi