#!/bin/bash
# Copyright 2023 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 script checks if the Maven direct dependencies of the given Bazel target
# match the ones in the POM file. In case of discrepancies, it prints the diff
# on standard output and exits with exit code 1.

set -eo pipefail

usage() {
  echo "Usage: $0 [-h] [-e <excluded group ids>] <bazel target> <pom file>"
  echo
  echo " <bazel target>: The Bazel target that generate the JAR."
  echo " <pom file>: The POM file path."
  echo " -e: Maven artifact to be ignored (of the form package:artifact, e.g. com.google.protobuf:protobuf-java"
  echo " -h: Show this help message."
  exit 1
}

BAZEL_CMD="bazel"
# Prefer using Bazelisk if available.
if command -v "bazelisk" &> /dev/null; then
  BAZEL_CMD="bazelisk"
fi
readonly BAZEL_CMD

BAZEL_TARGET=
POM_FILE=
IGNORED_MAVEN_PACKAGE=
process_params() {
  while getopts "he:" opt; do
    case "${opt}" in
      e) IGNORED_MAVEN_PACKAGE="${OPTARG}" ;;
      *) usage ;;
    esac
  done
  shift $((OPTIND - 1))
  readonly IGNORED_MAVEN_PACKAGE

  BAZEL_TARGET="$1"
  POM_FILE="$2"

  readonly BAZEL_TARGET
  readonly POM_FILE
}

process_params "$@"

echo " === Obtaining Maven dependencies"

readonly MAVEN_DIRECT_DEPS="$(mktemp)"
mvn dependency:list -DoutputFile="${MAVEN_DIRECT_DEPS}" \
  -DexcludeTransitive=true -f "${POM_FILE}" -q

# Get the sorted list of deps and get them in the form:
#    <groupId>:<artifactId>:<version>
POM_FILE_DEPS="$(cat "${MAVEN_DIRECT_DEPS}" \
  | grep compile | cut -d: -f1,2,4 | sed -E 's/^\s+//' | sort)"

echo " === Obtaining Bazel dependencies"

BAZEL_MAVEN_DEPS="$("${BAZEL_CMD}" query --output=build \
  'attr(tags, .*,filter(@maven, deps('"${BAZEL_TARGET}"', 2)))' \
    | grep maven_coordinates | cut -d'"' -f2 | cut -d'=' -f2 | sort)"

if [[ ! -z "${IGNORED_MAVEN_PACKAGE}" ]]; then
  BAZEL_MAVEN_DEPS=$(echo "${BAZEL_MAVEN_DEPS}" | grep -v -F "${IGNORED_MAVEN_PACKAGE}":)
  POM_FILE_DEPS=$(echo "${POM_FILE_DEPS}" | grep -v -F "${IGNORED_MAVEN_PACKAGE}":)
fi

readonly BAZEL_MAVEN_DEPS
readonly POM_FILE_DEPS

if ! cmp -s <(echo "${BAZEL_MAVEN_DEPS}" ) <(echo "${POM_FILE_DEPS}"); then
  echo "ERROR: There are the following mismatches between the dependencies in \
${BAZEL_TARGET} and the ones in ${POM_FILE}:" >&2
  echo
  diff -y <(echo "${BAZEL_MAVEN_DEPS}" ) <(echo "${POM_FILE_DEPS}")
  echo
  exit 1
fi