bootstrap

#!/usr/bin/env bash
#
# bootstrap installs things.
#
# Based on https://github.com/holman/dotfiles.

# Fail on errors.
set -euo pipefail

# Show executed commands.
# set -x

if [[ -t 0 ]]; then
  light_red='\e[01;31m'
  green='\e[0;32m'
  light_green='\e[01;32m'
  light_yellow='\e[01;33m'
  cyan='\e[0;36m'
  light_cyan='\e[01;36m'
  reset_color='\e[0m'
  clear_line='\e[2K'
else
  light_red=''
  green=''
  light_green=''
  light_yellow=''
  cyan=''
  light_cyan=''
  reset_color=''
  clear_line=''
fi

info() {
  printf   "\r  [%b INFO %b] %b\n" \
           "$light_cyan" "$reset_color" "$1"
}

user() {
  printf   "\r  [%b  ?   %b] %b " \
           "$light_yellow" "$reset_color" "$1"
}

success() {
  printf "\r%b  [%b  OK  %b] %b\n" \
         "$clear_line" "$light_green" "$reset_color" "$1"
}

fail() {
  printf "\r%b  [%b FAIL %b] %b\n\n" \
         "$clear_line" "$light_red" "$reset_color" "$1"
  exit 1
}

ostypes() {
  case "$OSTYPE" in
    msys)    printf 'windows';;
    cygwin)  printf "cygwin windows";;
    *)       printf '%s' "$OSTYPE";;
  esac
}

readlink-e() {
  local file="$1"

  if ! target="$(readlink --canonicalize-existing "$file" 2> /dev/null)"; then
    perl -e 'use Cwd "abs_path"; print abs_path(shift)' "$file"
    return
  fi

  printf '%s' "$target"
}

home-directory() {
  case "${1?Need OS type}" in
    windows) cygpath --unix "$USERPROFILE";;
    *)       printf '%s' "$HOME";;
  esac
}

symlink() {
  local src="${1?Need link source}"
  # If dst is not given, use src file name in $HOME, prepended with a dot.
  local dst
  if (($# >= 2)); then
    dst="$2"
  else
    dst="$HOME/.${src##*/}"
  fi

  local overwrite backup skip
  # These global variables might be changed by symlink (which is either called
  # here or by individual bootstrappers).
  # We cannot declare them here because this would overwrite their contents
  # if the variable is assigned already.
  # declare overwrite_all backup_all skip_all

  if [[ -f "$dst" ]] || \
     [[ -d "$dst" ]] || \
     [[ -L "$dst" ]]; then
    src="$(readlink-e "$src")"
    local current_target
    current_target="$(readlink-e "$dst")"

    if [[ "$current_target" == "$src" ]]; then
      success "$(printf 'Already linked %b%s%b <-> %b%s%b' \
                        "$green" "$src" "$reset_color" \
                        "$green" "$dst" "$reset_color")"
      return
    fi

    if [[ -z "${overwrite_all-}" ]] && \
       [[ -z "${backup_all-}" ]] && \
       [[ -z "${skip_all-}" ]]; then
      # shellcheck disable=SC2183
      user "$(printf "File already exists: %b%s%b (%b%s%b)
           Will be linked to: %b%s%b
           What do you want to do? (%bs%b)kip, (%bS%b)kip all, (%bo%b)verwrite, (%bO%b)verwrite all, (%bb%b)ackup, (%bB%b)ackup all?" \
           "$green" "$dst" "$reset_color" \
           "$cyan" "$(file --brief "$dst" 2>/dev/null)" "$reset_color" \
           "$green" "$src" "$reset_color" \
           "$light_yellow" "$reset_color" \
           "$light_yellow" "$reset_color" \
           "$light_yellow" "$reset_color" \
           "$light_yellow" "$reset_color" \
           "$light_yellow" "$reset_color" \
           "$light_yellow" "$reset_color")"

      while true; do
        local action
        read -rn 1 action

        case "$action" in
          o) overwrite=true;     break;;
          O) overwrite_all=true; break;;
          b) backup=true;        break;;
          B) backup_all=true;    break;;
          s) skip=true;          break;;
          S) skip_all=true;      break;;
          *) ;;
        esac
      done
    fi

    overwrite="${overwrite:-${overwrite_all-}}"
    backup="${backup:-${backup_all-}}"
    skip="${skip:-${skip_all-}}"

    if [[ -n "${skip-}" ]]; then
      success "$(printf 'Skipped %b%s%b <-> %b%s%b' \
                        "$green" "$src" "$reset_color" \
                        "$green" "$dst" "$reset_color")"
      return
    fi

    if [[ -n "${overwrite-}" ]]; then
      rm -rf -- "$dst"
      success "$(printf 'Removed %b%s%b' \
                        "$green" "$dst" "$reset_color")"
    fi

    if [[ -n "${backup-}" ]]; then
      mv -- "$dst" "${dst}.backup"
      success "$(printf 'Moved %b%s%b to %b%s%b' \
                        "$green" "$dst" "$reset_color" \
                        "$green" "${dst}.backup" "$reset_color")"
    fi
  fi

  mkdir -p "$(dirname -- "$dst")"
  # Create native symlinks on Windows.
  CYGWIN=winsymlinks:nativestrict ln -s "$src" "$dst"

  success "$(printf 'Linked %b%s%b to %b%s%b' \
                    "$green" "$src" "$reset_color" \
                    "$green" "$dst" "$reset_color")"
}

symlink-dotfiles-to-home() {
  local root="${1?Need dotfiles root directory}"
  local home="${2?Need home directory}"
  local ostype="${3?Need OS type}"

  # shellcheck disable=SC2016
  info "$(printf 'Installing dotfiles to %b$HOME%b=%b%s%b for %b$OSTYPE%b=%b%s%b' \
                  "$light_red" "$reset_color" \
                  "$green" "$home" "$reset_color" \
                  "$light_red" "$reset_color" \
                  "$light_yellow" "$ostype" "$reset_color")"

  # Add a symlink for this dotfiles directory.
  symlink "$root" "$home/.dotfiles"
}

run-topic-bootstrapper() {
  local bootstrapper="${1?Need bootstrapper}"
  shift
  local home="${1?Need home directory}"
  shift
  local ostype="${1?Need OS type}"
  shift
  local script

  local topic
  topic="${bootstrapper%/bootstrap}"
  topic_name="${topic##*/}"

  # If we got extra args this is the list of topics we can only install.
  while (($#)); do
    if [[ "$topic_name" == "$1" ]]; then
      break
    fi

    shift

    if ! (($#)); then
      return
    fi
  done

  info "$(printf 'Running %b%s%b' \
                  "$green" "$bootstrapper" "$reset_color")"

  # Build script wrapper around bootstrapper.
  script="\
    set -euo pipefail

    source '$0' # This script.
    source '$root/macos/homebrew'
    source '$bootstrapper'

    # Write out the perhaps changed values for the *_all variables.
    >&3 printf '# magic unicorns!\n'
    >&3 printf 'overwrite_all=%s\n' \"\$overwrite_all\"
    >&3 printf 'backup_all=%s\n' \"\$backup_all\"
    >&3 printf 'skip_all=%s\n' \"\$skip_all\"
    >&3 printf '# magic unicorns end!\n'
  "

  variables="$(mktemp)"

  # Run wrapper with bash (like we do here).
  # We pass some variables that we manage on our side and that may be used by
  # the individual bootstrappers.
  # The *_all variables may also be changed by user input.
  /usr/bin/env topic="$topic" \
               \
               overwrite_all="${overwrite_all-}" \
               backup_all="${backup_all-}" \
               skip_all="${skip_all-}" \
               \
               bash -c "$script" \
               3>"$variables"

  eval "$(cat "$variables")"
  rm -f "$variables"
}

install-dotfiles() {
  local root home ostype bootstrappers bootstrapper

  root="$(dirname "$(readlink-e "$0")")"

  info "$(printf "Installing dotfiles from %b%s%b" \
                 "$green" "$root" "$reset_color")"

  for ostype in $(ostypes); do
    home="$(home-directory "$ostype")"
    symlink-dotfiles-to-home "$root" "$home" "$ostype"

    # Find topics with bootstrappers. Bash > 3 cannot be assumed (on macOS).
    # https://stackoverflow.com/a/32931403/149264
    IFS=$'\n' read -r -d '' -a bootstrappers < <(find -H \
                                                     "$home/.dotfiles" \
                                                     -mindepth 2 \
                                                     -maxdepth 2 \
                                                     -type f \
                                                     -name bootstrap \
                                                   | sort && printf '\0')

    for bootstrapper in "${bootstrappers[@]}"; do
      run-topic-bootstrapper "$bootstrapper" "$home" "$ostype" "$@"
    done
  done

  info "$(printf 'All installed from %b%s%b' \
                 "$green" "$root" "$reset_color")"
}

if [[ "${1-}" == --force ]]; then
  overwrite_all=true
  shift
fi

# If we are sourced from a topic bootstrapper script this will be set and we
# will only provide our functions.
if [[ -z "${topic-}" ]]; then
  install-dotfiles "$@"
fi