#!/usr/bin/env sh

# shellcheck disable=SC1091
[ -f /etc/profile ] && . /etc/profile

set -e

script_dir="$(CDPATH="" cd -- "$(dirname -- "$0")" && pwd -P)"

usage() {
  check_directories
  cat <<EOF
USAGE:
  ${0} [options] FILENAME

  Copy and edit the stock config file named: FILENAME
  if FILENAME is already copied, it will be edited as-is.

  Stock config files at: '${NETDATA_STOCK_CONFIG_DIR}'
  User  config files at: '${NETDATA_USER_CONFIG_DIR}'

  The editor to use can be specified either by setting the EDITOR
  environment variable, or by using the --editor option.

  The file to edit can also be specified using the --file option.

  For a list of known config files, run '${0} --list'
EOF
  exit 0
}

error() {
  echo >&2 "ERROR: ${1}"
}

abspath() {
  if [ -d "${1}/" ]; then
    echo "$(cd "${1}" && /usr/bin/env PWD= pwd -P)/"
  elif [ -f "${1}" ]; then
    echo "$(cd "$(dirname "${1}")" && /usr/bin/env PWD= pwd -P)/$(basename "${1}")"
  elif echo "${1}" | grep -q '/'; then
    if echo "${1}" | grep -q '^/'; then
      mkdir -p "$(dirname "${1}")"
      echo "$(cd "$(dirname "${1}")" && /usr/bin/env PWD= pwd -P)/$(basename "${1}")"
    else
      mkdir -p "${script_dir}/$(dirname "${1}")"
      echo "${script_dir}/${1}"
    fi
  else
    echo "${script_dir}/${1}"
  fi
}

is_prefix() {
  echo "${2}" | grep -qE "^${1}"
  return $?
}

check_directories() {
  if [ -f "${script_dir}/.container-hostname" ]; then
    NETDATA_USER_CONFIG_DIR="${script_dir}"
    NETDATA_STOCK_CONFIG_DIR="/usr/lib/netdata/conf.d"
    return
  fi

  if [ -e "${script_dir}/.environment" ]; then
    OLDPATH="${PATH}"
    # shellcheck disable=SC1091
    . "${script_dir}/.environment"
    PATH="${OLDPATH}"
  fi

  if [ -n "${NETDATA_PREFIX}" ] && [ -d "${NETDATA_PREFIX}/usr/lib/netdata/conf.d" ]; then
    stock_dir="${NETDATA_PREFIX}/usr/lib/netdata/conf.d"
  elif [ -n "${NETDATA_PREFIX}" ] && [ -d "${NETDATA_PREFIX}/lib/netdata/conf.d" ]; then
    stock_dir="${NETDATA_PREFIX}/lib/netdata/conf.d"
  elif [ -d "${script_dir}/../../usr/lib/netdata/conf.d" ]; then
    stock_dir="${script_dir}/../../usr/lib/netdata/conf.d"
  elif [ -d "${script_dir}/../../lib/netdata/conf.d" ]; then
    stock_dir="${script_dir}/../../lib/netdata/conf.d"
  elif [ -d "/usr/lib/netdata/conf.d" ]; then
    stock_dir="/usr/lib/netdata/conf.d"
  fi

  [ -z "${NETDATA_USER_CONFIG_DIR}" ] && NETDATA_USER_CONFIG_DIR="${script_dir}"
  [ -z "${NETDATA_STOCK_CONFIG_DIR}" ] && NETDATA_STOCK_CONFIG_DIR="${stock_dir}"

  if [ -z "${NETDATA_STOCK_CONFIG_DIR}" ]; then
    error "Unable to find stock config directory."
    exit 1
  fi
}

check_editor() {
  if [ -z "${editor}" ]; then
    if [ -n "${EDITOR}" ] && command -v "${EDITOR}" >/dev/null 2>&1; then
      editor="${EDITOR}"
    elif command -v editor >/dev/null 2>&1; then
      editor="editor"
    elif command -v vi >/dev/null 2>&1; then
      editor="vi"
    else
      error "Unable to find a usable editor, tried \${EDITOR} (${EDITOR}), editor, and vi."
      exit 1
    fi
  elif ! command -v "${editor}" >/dev/null 2>&1; then
    error "Unable to locate user specified editor ${editor}, is it in your PATH?"
    exit 1
  fi
}

running_in_container() {
  [ -e /.dockerenv ] && return 0
  [ -e /.dockerinit ] && return 0
  [ -e /run/.containerenv ] && return 0
  [ -r /proc/1/environ ] && tr '\000' '\n' </proc/1/environ | grep -Eiq 'container=' && return 0
  grep -qF -e /docker/ -e /libpod- /proc/self/cgroup 2>/dev/null && return 0
  return 1
}

get_docker_command() {
  if [ -x "${docker}" ]; then
    return 0
  elif command -v docker >/dev/null 2>&1; then
    docker="$(command -v docker)"
  elif command -v podman >/dev/null 2>&1; then
    docker="$(command -v podman)"
  else
    error "Unable to find a usable container tool stack. I support Docker and Podman."
    exit 1
  fi
}

run_in_container() {
  ${docker} exec "${1}" /bin/sh -c "${2}" || return 1
  return 0
}

check_for_container() {
  get_docker_command
  ${docker} container inspect "${1}" >/dev/null 2>&1 || return 1
  run_in_container "${1}" "[ -d \"${NETDATA_STOCK_CONFIG_DIR}\" ]" >/dev/null 2>&1 || return 1
  return 0
}

handle_container() {
  if running_in_container; then
    return 0
  elif [ -z "${container}" ] && [ -f "${script_dir}/.container-hostname" ]; then
    echo >&2 "Autodetected containerized Netdata instance. Attempting to autodetect container ID."
    possible_container="$(cat "${script_dir}/.container-hostname")"
    if check_for_container "${possible_container}"; then
      container="${possible_container}"
    elif check_for_container netdata; then
      container="netdata"
    else
      error "Could not autodetect container ID. It must be supplied on the command line with the --container option."
      exit 1
    fi

    echo >&2 "Found Netdata container with ID or name ${container}"
  elif [ -n "${container}" ]; then
    if ! check_for_container "${container}"; then
      error "No container with ID or name ${container} exists."
      exit 1
    fi
  fi
}

list_files() {
  check_directories
  handle_container

  if test -t && command -v tput > /dev/null 2>&1; then
    width="$(tput cols)"
  fi

  if [ -z "${container}" ]; then
    if [ "$(uname -s)" = "Linux" ]; then
      # shellcheck disable=SC2046,SC2086
      files="$(cd "${NETDATA_STOCK_CONFIG_DIR}" && ls ${width:+-C} ${width:+-w ${width}} $(find . -type f | cut -d '/' -f 2-))"
    elif [ "$(uname -s)" = "FreeBSD" ]; then
      if [ -n "${width}" ]; then
        export COLUMNS="${width}"
      fi

      # shellcheck disable=SC2046
      files="$(cd "${NETDATA_STOCK_CONFIG_DIR}" && ls ${width:+-C} $(find . -type f | cut -d '/' -f 2-))"
    else
      # shellcheck disable=SC2046
      files="$(cd "${NETDATA_STOCK_CONFIG_DIR}" && ls $(find . -type f | cut -d '/' -f 2-))"
    fi
  else
    files="$(run_in_container "${container}" "cd /usr/lib/netdata/conf.d && ls ${width:+-C} ${width:+-w ${width}} \$(find . -type f | cut -d '/' -f 2-)")"
  fi

  if [ -z "${files}" ]; then
    error "Failed to find any configuration files."
    exit 1
  fi

  cat <<EOF
The following configuration files are known to this script:

${files}
EOF
  exit 0
}

parse_args() {
  while [ -n "${1}" ]; do
    case "${1}" in
      "--help") usage ;;
      "--list") list_files ;;
      "--file")
        if [ -n "${2}" ]; then
          file="${2}"
          shift 1
        else
          error "No file specified to edit."
          exit 1
        fi
        ;;
      "--container")
        if [ -n "${2}" ]; then
          container="${2}"
          shift 1
        else
          error "No container ID or name specified with the --container option."
          exit 1
        fi
        ;;
      "--editor")
        if [ -n "${2}" ]; then
          editor="${2}"
          shift 1
        else
          error "No editor specified with the --editor option."
          exit 1
        fi
        ;;
      *)
        if [ -z "${2}" ]; then
          file="${1}"
        else
          error "Unrecognized option ${1}."
          exit 1
        fi
        ;;
    esac
    shift 1
  done

  [ -z "${file}" ] && usage

  absfile="$(abspath "${file}")"
  if ! is_prefix "${script_dir}" "${absfile}"; then
    error "${file} is not located under ${script_dir}"
    exit 1
  fi

  file="${absfile##"${script_dir}"}"
}

copy_native() {
  if [ ! -w "${NETDATA_USER_CONFIG_DIR}" ]; then
    error "Cannot write to ${NETDATA_USER_CONFIG_DIR}!"
    exit 1
  fi

  if [ -f "${NETDATA_STOCK_CONFIG_DIR}/${1}" ]; then
    echo >&2 "Copying '${NETDATA_STOCK_CONFIG_DIR}/${1}' to '${NETDATA_USER_CONFIG_DIR}/${1}' ... "
    cp -p "${NETDATA_STOCK_CONFIG_DIR}/${1}" "${NETDATA_USER_CONFIG_DIR}/${1}" || exit 1
  else
    echo >&2 "Creating empty '${NETDATA_USER_CONFIG_DIR}/${1}' ... "
    touch "${NETDATA_USER_CONFIG_DIR}/${1}" || exit 1
  fi
}

copy_container() {
  if [ ! -w "${NETDATA_USER_CONFIG_DIR}" ]; then
    error "Cannot write to ${NETDATA_USER_CONFIG_DIR}!"
    exit 1
  fi

  if run_in_container "${container}" "[ -f \"${NETDATA_STOCK_CONFIG_DIR}/${1}\" ]"; then
    echo >&2 "Copying '${NETDATA_STOCK_CONFIG_DIR}/${1}' to '${NETDATA_USER_CONFIG_DIR}/${1}' ... "
    ${docker} cp -a "${container}:${NETDATA_STOCK_CONFIG_DIR}/${1}" "${NETDATA_USER_CONFIG_DIR}/${1}" || exit 1
  else
    echo >&2 "Creating empty '${NETDATA_USER_CONFIG_DIR}/${1}' ... "
    touch "${NETDATA_USER_CONFIG_DIR}/${1}" || exit 1
  fi
}

copy() {
  if [ -f "${NETDATA_USER_CONFIG_DIR}/${1}" ]; then
    return 0
  elif [ -n "${container}" ]; then
    copy_container "${1}"
  else
    copy_native "${1}"
  fi
}

edit() {
  echo >&2 "Editing '${1}' ..."

  # check we can edit
  if [ ! -w "${1}" ]; then
    error "Cannot write to ${1}!"
    exit 1
  fi

  "${editor}" "${1}"
  exit $?
}

main() {
  parse_args "${@}"
  check_directories
  check_editor
  handle_container
  copy "${file}"
  edit "${absfile}"
}

main "${@}"
