{ pkgs ? import <nixpkgs> {} }:
pkgs.mkShell {
  name = "node-environment";
  buildInputs = with pkgs; [
    nodejs
  ];
  shellHook = ''
    function log_header {
      echo -ne "==> \e[32m\e[1m$1\e[0m\n\n"
    }
    function log_subheader {
      echo -ne "--> \e[33m\e[1m$1\e[0m\n\n"
    }
    function log {
      echo -ne "    $1\n"
    }
    
    echo ""
    log_header "node_environment"
    mkdir -p .npm/bin
    export PATH=$PWD/.npm/bin:$PATH
    log_subheader "upgrading npm"
    npm install -g npm --prefix $PWD/.npm
    echo ""
    if [ -s global_packages.txt ]; then
      log_subheader "found global_packages.txt, installing packages"
      cat global_packages.txt | xargs npm install -g --prefix $PWD/.npm
      echo ""
    fi
    if [ -s package.json ]; then
      log_subheader "found package.json, running 'npm install'"
      npm install
      echo ""
    fi
    log_header "package versions"
    log "node $(node --version)"
    log "npm $(npm --version)"
  '';
}