#!/usr/bin/env bash

dryrun=''
if [[ "$1" == '-d' ]]; then
  dryrun=echo
fi

function cd_git_root {
  >&2 echo "looking for .git"
  if [ -d ".git" ]; then
    >&2 echo "found .git"
    return
  else
    >&2 echo "going up a directory"
    cd ..
    if [ "$(pwd)" != '/' ]; then
      cd_git_root
    else
      clone_repo
    fi
  fi
}

function clone_repo {
  >&2 echo "Cloning nix-config"

  git_dir=~/"git/dudeofawesome"
  $dryrun mkdir -p "$git_dir"
  $dryrun cd "$git_dir"
  $dryrun git clone "https://github.com/dudeofawesome/nix-config"
  $dryrun cd "nix-config"
}

function install_nix {
  if [ ! "$(diskutil list "Nix Store")" ]; then
    >&2 echo "====/ INSTALL NIX /===="
    # https://nix.dev/install-nix
    $dryrun curl -L https://nixos.org/nix/install \
      | $dryrun sh -s -- --daemon
  fi
}

function install_nix_darwin {
  if [ ! -x "$(command -v darwin-rebuild)" ]; then
    >&2 echo "====/ SETUP BASE NIX-DARWIN /===="

    base_config=~/".config/nix-darwin"

    # Create temporary configuration.nix flake
    # https://github.com/LnL7/nix-darwin#step-1-creating-flakenix
    $dryrun mkdir -p "$base_config"
    $dryrun pushd "$base_config"
    $dryrun nix \
      --experimental-features 'nix-command flakes' \
      flake init -t nix-darwin
    $dryrun sed -i '' "s/simple/$(scutil --get LocalHostName)/" flake.nix
    if [[ "$(uname -p)" == "arm" ]]; then
      # switch to arm
      $dryrun sed -i '' "s/x86_64-darwin/aarch64-darwin/" flake.nix
    fi
    $dryrun popd

    # Install nix-darwin
    # https://github.com/LnL7/nix-darwin#step-2-installing-nix-darwin
    $dryrun nix \
      --experimental-features 'nix-command flakes' \
      run nix-darwin -- switch --flake "$base_config"

    # clean up
    $dryrun rm -rf "$base_config"
  fi
}

function install_brew {
  if [ ! -d "/opt/homebrew" ]; then
    >&2 echo "====/ INSTALL HOMEBREW /===="
    $dryrun sudo --validate
    $dryrun /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
  fi
}

function main {
  cd_git_root

  install_nix

  # load nix env vars
  source /etc/bashrc

  install_nix_darwin

  # load nix-darwin env vars
  source /etc/bashrc

  install_brew

  >&2 echo "====/ APPLY FLAKE /===="
  flake=$(hostname)
  if [ ! -d "hosts/darwin/$flake" ]; then
    read -p 'What host would you like to apply? ' flake
  fi
  # Apply flake
  $dryrun darwin-rebuild switch --flake ".#$flake"
}

main