#!/usr/bin/env bash

# Copyright 2018-present Open Networking Foundation
#
# 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.

# tagcollisionreject.sh
# checks that there isn't an existing tag in the repo that has this tag

set -eu -o pipefail

VERSIONFILE="" # file path to file containing version number
NEW_VERSION="" # version number found in $VERSIONFILE

releaseversion=0
fail_validation=0

# when not running under Jenkins, use current dir as workspace
WORKSPACE=${WORKSPACE:-.}

# find the version string in the repo, read into NEW_VERSION
# Add additional places NEW_VERSION could be found to this function
function read_version {
  if [ -f "VERSION" ]
  then
    NEW_VERSION=$(head -n1 "VERSION")
    VERSIONFILE="VERSION"
  else
    echo "ERROR: No versioning file found!"
    exit 1
  fi
}

# check if the version is already a tag in git
function is_git_tag_duplicated {
  for existing_tag in $(git tag)
  do
    if [ "$NEW_VERSION" = "$existing_tag" ]
    then
      echo "ERROR: Duplicate tag: $existing_tag"
      exit 2
    fi
  done
}

# check if the version is a released version
function check_if_releaseversion {
  if [[ "$NEW_VERSION" =~ ^([0-9]+)\.([0-9]+)\.([0-9]+)$ ]]
  then
    echo "Version string '$NEW_VERSION' found in '$VERSIONFILE' is a SemVer released version!"
    releaseversion=1
  else
    echo "Version string '$NEW_VERSION' found in '$VERSIONFILE' is not a SemVer released version, skipping."
  fi
}

# check if Dockerfiles have a released version as their parent
function dockerfile_parentcheck {
  while IFS= read -r -d '' dockerfile
  do
    echo "Checking dockerfile: '$dockerfile'"

    # split on newlines
    IFS=$'\n'
    df_parents=($(grep "^FROM" "$dockerfile"))

    # check all parents in the Dockerfile
    for df_parent in "${df_parents[@]}"
    do

      df_pattern="FROM (.*):(.*)"
      if [[ "$df_parent" =~ $df_pattern ]]
      then

        p_image="${BASH_REMATCH[1]}"
        p_version="${BASH_REMATCH[2]}"

        if [[ "${p_version}" =~ ^([0-9]+)\.([0-9]+)\.([0-9]+)$ ]]
        then
          echo "  OK: Parent '$p_image:$p_version' is a released SemVer version"
        elif [[ "${p_version}" =~ ^([0-9]+)\.([0-9]+).*$ ]]
        then
          # handle the non-SemVer 'ubuntu:16.04' and 'postgres:10.3-alpine' cases
          echo "  OK: Parent '$p_image:$p_version' is using a non-SemVer, but sufficient, version"
        else
          echo "  ERROR: Parent '$p_image:$p_version' is NOT using an specific version"
          fail_validation=1
        fi

      elif [[ "$df_parent" =~ ^FROM\ scratch$ ]]
      then
        # Handle the parent-less `FROM scratch` case:
        #  https://docs.docker.com/develop/develop-images/baseimages/
        echo "  OK: Using the versionless 'scratch' parent: '$df_parent'"
      else
        echo "  ERROR: Couldn't find a parent image in $df_parent"
      fi

    done

  done  < <( find "${WORKSPACE}" -name 'Dockerfile*' -print0 )
}

echo "Checking git repo with remotes:"
git remote -v

echo "Branches:"
git branch -v

echo "Existing git tags:"
git tag -n

read_version
check_if_releaseversion

# perform checks if a released version
if [ "$releaseversion" -eq "1" ]
then
  is_git_tag_duplicated
  dockerfile_parentcheck
fi

exit $fail_validation