#!/bin/sh
set -e

USERNAME="fernando"
DOTFILES_URL="https://git.schauenburg.me/fernando/dotfiles.git"

if [ -t 1 ]; then
  sgr0="$(printf      '\033[0m')"
  red="$(printf       '\033[31m')"
  yellow="$(printf    '\033[33m')"
  blue="$(printf      '\033[34m')"
else
  sgr0=''
  red=''
  yellow=''
  blue=''
fi

usage() {
  echo "Usage: $(basename "$0") [-h]"
  echo ""
  echo "  -h  print this help and exit"
}

error() {
  printf "${red}ERROR:${sgr0} %s\n"  "$1" >&2
  exit 1
}

title() {
  echo "${blue}=> ${1}${sgr0}"
}

skipped() {
  echo "${yellow}SKIPPED:${sgr0} ${1}"
}

apt_install() {
  title "Install APT packages"

  apt update && apt install -y  \
    apt-file                    \
    ascii                       \
    build-essential             \
    ca-certificates             \
    cmake                       \
    cmake-doc                   \
    curl                        \
    exuberant-ctags             \
    g++                         \
    gcc                         \
    git                         \
    git-crypt                   \
    gnupg                       \
    htop                        \
    jq                          \
    make                        \
    man-db                      \
    nodejs                      \
    pkg-config                  \
    psmisc                      \
    python3                     \
    python3-virtualenv          \
    ripgrep                     \
    rsync                       \
    shellcheck                  \
    sshpass                     \
    stow                        \
    sudo                        \
    tmux                        \
    unzip                       \
    zsh
  apt-file update
}

grub_disable_timeout() {
  title "Disable GRUB timeout"

  sed -i.original -e 's/^GRUB_TIMEOUT=.*/GRUB_TIMEOUT=0/' /etc/default/grub
  update-grub
}

ensure_usr_bin_fd() {
  title "Make 'fd' available with the correct name"

  fd_executable='/usr/local/bin/fdfind'
  if [ -x "${fd_executable}" ]; then
    ln -svf "${fd_executable}" /usr/local/bin/fd
  else
    skipped "${fd_executable} does not exist"
  fi
}

ensure_usr_local_man_manN() {
  title "Make sure we have directories for all man page sections"
  mkdir -vp $(seq -f '/usr/local/man/man%.0f' 9)
}

user_setup() {
  title "Setup user: $1"

  if user_exists "$1"; then
    echo "User $1 exists. Updating..."
    user_update "$1"
  else
    echo "Creating user $1..."
    user_new "$1"
  fi

  user_allow_sudo_nopasswd "$1"
}

user_exists() {
	id -u "$1" >/dev/null 2>&1
}

user_new() {
  empty_skel="$(mktemp -d)"

  useradd \
    -m                ` # Create home directory.` \
    -k "$empty_skel"  ` # Copy files from this directory into the new home.` \
    -U                ` # Create a groups with the same name as the user.` \
    -G staff          ` # Other groups the new user will be a member of.` \
    -s /bin/zsh       ` # The new user's login shell. ` \
    "$1"              ` # The new user's name.` \
    >/dev/null 2>&1   ` # Silently.` \

  rmdir "$empty_skel"
}

# Add user $1 to the `staff` group...
# ...and change shell to `zsh` and get rid of bash files.
user_update() {
  usermod -aG staff "$1"
  chsh -s /bin/zsh "$1"
  rm -vf "$(printf "/home/$1/%s " .bash_history .bash_logout .bashrc .profile)"
}

# Allow `sudo` without password for user $1.
user_allow_sudo_nopasswd() {
  echo "$1	ALL=(ALL:ALL) NOPASSWD:ALL" >"/etc/sudoers.d/${1}_nopasswd"
}

deploy_dotfiles() {
  title "Deploy dotfiles"

  dotfiles_dir="/home/$USERNAME/.dotfiles"
  if [ -d "${dotfiles_dir}" ]; then
    skipped "${dotfiles_dir} exists"
  else
    su "$USERNAME" -c "git clone $DOTFILES_URL ${dotfiles_dir}"
    (
      cd "${dotfiles_dir}"
      su "$USERNAME" -c "./install.sh -y"
    )
  fi
}

execute() {
  apt_install
  grub_disable_timeout
  ensure_usr_bin_fd
  ensure_usr_local_man_manN
  user_setup "$USERNAME"
  deploy_dotfiles
}

main() {
  while getopts 'hn' opt; do
    case "$opt" in
    h)  # help
      usage
      exit 0
      ;;
    *)  # invalid argument
      usage
      exit 1
      ;;
    esac
  done

  [ "$(id -u)" -eq 0 ] || error "This script must be run as root!"
  execute
}

main "$@"