#!/bin/bash
#
# Copyright (c) 2016-2017, Linaro Ltd.
# All rights reserved.
#
# 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.

# Presubmit tests that should be run before every patch submission.
# The check will be run against each .sh file from the git repository
# from which the script is being run.

readonly local_path=$(dirname "$0")
source "${local_path}/utils/utils.sh"

readonly shellcheck_path="${local_path}/shellcheck/shellcheck"
readonly shellcheck_url="https://git.linaro.org/people/kevin.brodsky/shellcheck-prebuilt.git/plain/shellcheck"

# Globally excluded shellcheck "checks"
# SC1090: shellcheck can't source files whose path is determined at runtime
#         (we almost always use ${local_path} when sourcing)
# SC2155: almost never an actual problem
readonly shellcheck_exclude_list="SC1090,SC2155"

declare -a shell_files

find_shell_files() {
  # In case some filenames contain spaces
  local IFS=$'\n'
  shell_files=($(safe git ls-files '*.sh'))
  readonly shell_files
}

# Fetch shellcheck from our own prebuilt shellcheck repo.
fetch_shellcheck() {
  # We use a sha1 checksum to know whether we need to download a newer version.
  local -r remote_sha1=$(safe curl -s "${shellcheck_url}.sha1")
  local -r sha1_regex='[0-9a-f]+\s+shellcheck'
  if ! [[ ${remote_sha1} =~ $sha1_regex ]]; then
    log E "Invalid remote sha1: ${remote_sha1}"
    abort
  fi

  if [[ -e "${shellcheck_path}" && -e "${shellcheck_path}.sha1" && \
        $(< "${shellcheck_path}.sha1") == "${remote_sha1}" ]]; then
    # We already have the latest shellcheck
    return
  fi

  # Download the latest shellcheck
  mkdir -p "$(dirname "${shellcheck_path}")"
  log I "Downloading shellcheck to ${shellcheck_path}"
  safe curl -s -o "${shellcheck_path}" "${shellcheck_url}"
  chmod +x "${shellcheck_path}"
  # Update the sha1
  echo "${remote_sha1}" > "${shellcheck_path}.sha1"
}

# Run shellcheck on all the .sh files.
shellcheck_tests() {
  fetch_shellcheck
  "${shellcheck_path}" --color -e "${shellcheck_exclude_list}" "${shell_files[@]}"
}

# Check for invalid constructions regarding read-only variables and the local
# scope.
readonlyvars_tests() {
  local -r str_local="local"
  local -r str_ronly="readonly"

  ! grep -Hn --color -E "\<(${str_local} ${str_ronly}|${str_ronly} ${str_local})\>" "${shell_files[@]}"
}

main() {
  find_shell_files
  shellcheck_tests
  if_error "shellcheck presubmit test FAILED."
  readonlyvars_tests
  if_error "Scope/read-only variables presubmit test FAILED."
  log S "Presubmit tests PASSED."
  exit 0
}

main "$@"