#!/usr/bin/env bash
# Copyright 2020 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# This bash library (even though it doesn't have the .sh extension) will be
# found when callers type `source module <file>` because init.sh added this
# directory to the caller's PATH. The <file> argument specified on the `source`
# line will be passed to this library as '$1'. We'll look for the caller's
# library by searching the MODULE_SEARCH_PATH array.
#
# This library does not use an include guard because it can, and should, be
# sourced many times. Therefore, this library must not define any global
# variables or functions.

if [[ -z "${MODULE_SEARCH_PATH[0]:-}" ]]; then
  echo >&2 \
    "No MODULE_SEARCH_PATH set. " \
    "Did you forget to source init.sh, maybe from $0?"
  exit 1
fi

for dir in "${MODULE_SEARCH_PATH[@]}"; do
  if [[ -r "${dir}/$1" ]]; then
    source "${dir}/$1"
    return 0
  fi
done

echo >&2 "Unable to find module '$1' in search path: ${MODULE_SEARCH_PATH[@]}"
exit 1