#!/bin/sh

set -e

vim_dir="${HOME}/.vim"
uninstall=1
remove=1
copy=1
link=0

_usage() {
  printf "\n" >&2
  printf "Usage: setup [OPTIONS]\n" >&2
  printf "\n" >&2
  printf "Installs or Uninstalls vim configuration files.\n" >&2
  printf "\n" >&2
  printf "If called without the uninstall option then it will install the configuration files.\n" >&2
  printf "The copy and link options are ignored if called with the uninstall or remove option.\n" >&2
  printf "Options:\n" >&2
  printf "\t-c | --copy: Copy the configuration files, instead of creating symlinks.\n" >&2
  printf "\t-h | --help: Print usage information.\n" >&2
  printf "\t-l | --link: Create symlinks to the configuration files (Default).\n" >&2
  printf "\t-r | --remove: Removes the entire ~/.vim directory.\n" >&2
  printf "\t-u | --uninstall: Uninstalls configuration files.\n" >&2
  printf "" >&2
}

_parse_options() {
  arg=
  while ! test -z "$1"; do
    arg="$1"
    case $arg in
      -c | --copy)
        copy=0
        link=1
        shift;;
      -h | --help)
        _usage
        exit;;
      -l | --link)
        copy=1
        link=0
        shift;;
     -r | --remove)
        remove=0
        shift;;
      -u | --uninstall)
        uninstall=0
        shift;;
      *)
        echo "Unknown option $arg" >&2
        shift;;
    esac
  done
}

_make_dirs() {
  if ! test -d "${vim_dir}"; then
    mkdir "${vim_dir}"
  fi
}

_uninstall_vim() {
  echo "Uninstalling vim..." >&2
  test -e "${vim_dir}/vimrc" && rm "${vim_dir}/vimrc"
}

_remove_vim() {
  echo "Removing ~/.vim..." >&2
  test -d "${vim_dir}" && rm -r -i "${vim_dir}"
}

_link_vim() {
  echo "Symlinking vim configuration files..." >&2
  ln -sfv "${PWD}/vimrc" "${vim_dir}"
}

_copy_vim() {
  echo "Copying vim configuration files..." >&2
  cp "${PWD}/vimrc" "${vim_dir}"
}

_install_vim() {
  _make_dirs
  # check if in copy mode & copy configuration
  test "$copy" -eq 0 && _copy_vim && return 0
  # else check if in link mode & link configuration
  test "$link" -eq 0 && _link_vim && return 0
  # we don't know what to do w/o link or copy so error
  echo "Must supply the link or copy option, use --help for usage" >&2
  exit 1
}

#------------------------------- main -------------------------------

main() {
  _parse_options "$@"

  # check if remove is called first
  test $remove -eq 0 && _remove_vim && exit

  # then check if uninstall was called
  test $uninstall -eq 0 && _uninstall_vim && exit

  # else install the configuration files
  _install_vim
  echo "Vim will need to be started, vim plugins should download on start or call :PlugInstall."
}

main "$@"