install

#! /usr/bin/env bash

readonly url=https://raw.githubusercontent.com/KineticCafe/docker-ansible/main/kineticcafe-ansible
declare script
script="$(basename "${url}")"
readonly script

declare -a symlinked_commands
symlinked_commands=(
  ansible ansible-community ansible-config
  ansible-connection ansible-console ansible-doc
  ansible-galaxy ansible-inventory ansible-playbook
  ansible-pull ansible-test ansible-vault
)
readonly symlinked_commands

# cross-platform equivalent to GNU readlink -f.
canonicalize() {
  local t
  t="$1"

  cd "$(dirname "${t}")" || return 1
  t="$(basename "${t}")"

  while [[ -L "${t}" ]]; do
    t="$(readlink "${t}")"
    cd "$(dirname "${t}")" || return 1
    t="$(basename "${t}")"
  done

  echo "$(pwd -P)/${t}"
}

usage() {
  cat <<USAGE
usage: $(basename "$0") [--no-symlinks|-S] [--force|-f] [--verbose|-v] TARGET
       $(basename "$0") --help | -h | -?

Installs the ${script} script to TARGET. Installation will be skipped
if the TARGET/${script} already exists and --force is not supplied.

Unless --no-symlinks is provided, it will also attempt to install symlinks for
Ansible commands:

  ansible              ansible-community   ansible-config
  ansible-connection   ansible-console     ansible-doc
  ansible-galaxy       ansible-inventory   ansible-playbook
  ansible-pull         ansible-test        ansible-vault

Symlink installation will be skipped if the file already exists and is not
already a symlink to TARGET/${script} and --force is not supplied.
USAGE
}

declare force install_symlinks no_download target target_script verbose
force=false
install_symlinks=true
no_download=false
verbose=false

while (($#)); do
  case "$1" in
  --force | -f) force=true ;;
  --verbose | -v) verbose=true ;;
  --no-download) no_download=true ;;
  --no-symlinks | -S) install_symlinks=false ;;
  --help | -h | -?)
    usage
    exit 0
    ;;
  *)
    if [[ ! -d "$1" ]]; then
      printf >&2 "error: '%s' is not a directory\n\n" "$1"
      usage >&2
      exit 1
    fi

    if [[ -n "${target}" ]]; then
      printf >&2 "warning: target '%s' is being replaced with '%s'" \
        "$target" "$1"
    fi

    target="$1"
    ;;
  esac

  shift
done

if [[ -z "${target}" ]]; then
  printf >&2 "error: no TARGET provided\n\n"
  usage >&2
  exit 1
fi

target_script="${target}/${script}"

download-script() {
  local -a cmd
  cmd=(curl -sSL --fail "${url}" -o "${target_script}")

  [[ "${verbose}" ]] && echo "${cmd[*]}"

  if ! "${cmd[@]}"; then
    echo >&2 "error: could not download ${url} into ${target_script}."
    exit 1
  fi
}

if "${no_download}" && ! [[ -x "${target_script}" ]]; then
  echo >&2 "error: ${target_script} does not exist and no download is set."
  exit 1
elif [[ -x "${target_script}" ]] && ! "${force}"; then
  echo >&2 "error: ${target_script} already exists."
  exit 1
fi

if ! [[ -x "${target_script}" ]] && ! "${no_download}"; then
  download-script

  if ! [[ -x "${target_script}" ]]; then
    if "${verbose}"; then
      chmod -v +x "${target_script}"
    else
      chmod +x "${target_script}"
    fi
  fi
fi

"${install_symlinks}" || exit 0

declare symlinked_command target_command canonical_target

for symlinked_command in "${symlinked_commands[@]}"; do
  target_command="${target}/${symlinked_command}"

  if [[ -f "${target_command}" ]]; then
    canonical_target="$(canonicalize "${target_command}")"

    if [[ "${canonical_target}" != "${target_script}" ]]; then
      "${force}" || continue
    fi
  fi

  if "${verbose}"; then
    ln -sfv "${target_script}" "${target_command}"
  else
    ln -sf "${target_script}" "${target_command}"
  fi
done