#!/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
TAG_VERSION="" # version file that might have a leading v to work around go mod funkyness

SEMVER_STRICT=${SEMVER_STRICT:-0} # require semver versions

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"

    # If this is a golang project, use funky v-prefixed versions
    if [ -f "Gopkg.toml" ] || [ -f "go.mod" ]
    then
      echo "go-based project found, using v-prefixed version for git tags: v${NEW_VERSION}"
      TAG_VERSION=v${NEW_VERSION}
    else
      TAG_VERSION=${NEW_VERSION}
    fi

  elif [ -f "package.json" ]
  then
    NEW_VERSION=$(python -c 'import json,sys;obj=json.load(sys.stdin); print obj["version"]' < package.json)
    TAG_VERSION=$NEW_VERSION
    VERSIONFILE="package.json"
  elif [ -f "pom.xml" ]
  then
    NEW_VERSION=$(xmllint --xpath '/*[local-name()="project"]/*[local-name()="version"]/text()' pom.xml)
    TAG_VERSION=$NEW_VERSION
    VERSIONFILE="pom.xml"
  else
    echo "ERROR: No versioning file found!"
    fail_validation=1
  fi
}

# 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
    if [ "$SEMVER_STRICT" -eq "1" ]
    then
      echo "Version string '$NEW_VERSION' in '$VERSIONFILE' is not a SemVer released version, SEMVER_STRICT enabled, failing!"
      fail_validation=1
    else
      echo "Version string '$NEW_VERSION' in '$VERSIONFILE' is not a SemVer released version, skipping."
    fi
  fi
}

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

# from https://github.com/cloudflare/semver_bash/blob/master/semver.sh
function semverParseInto() {
    local RE='[^0-9]*\([0-9]*\)[.]\([0-9]*\)[.]\([0-9]*\)\([0-9A-Za-z-]*\)'
    #MAJOR
    eval $2=`echo $1 | sed -e "s#$RE#\1#"`
    #MINOR
    eval $3=`echo $1 | sed -e "s#$RE#\2#"`
    #MINOR
    eval $4=`echo $1 | sed -e "s#$RE#\3#"`
    #SPECIAL
    eval $5=`echo $1 | sed -e "s#$RE#\4#"`
}

# if it's a -dev version check if a previous tag has been created (to avoid going from 2.7.0-dev to 2.7.1-dev)
function is_valid_version {
  local MAJOR=0 MINOR=0 PATCH=0 SPECIAL=""
  local C_MAJOR=0 C_MINOR=0 C_PATCH=0 C_SPECIAL="" # these are used in the inner loops to compare

  semverParseInto $NEW_VERSION MAJOR MINOR PATCH SPECIAL

  found_parent=false

  # if minor == 0, check that there was a release with MAJOR-1.X.X
  if [[ "$MINOR" == 0 ]]; then
    new_major=$(( $MAJOR - 1 ))
    parent_version="$new_major.x.x"
    for existing_tag in $existing_tags
    do
      semverParseInto $existing_tag C_MAJOR C_MINOR C_PATCH C_SPECIAL
      if [[ "$new_major" == "$C_MAJOR" ]]; then
        found_parent=true
      fi
    done

  # if patch == 0, check that there was a release with MAJOR.MINOR-1.X
  elif [[ "$PATCH" == 0 ]]; then
    new_minor=$(( $MINOR - 1 ))
    parent_version="$MAJOR.$new_minor.x"
    for existing_tag in $existing_tags
    do
      semverParseInto $existing_tag C_MAJOR C_MINOR C_PATCH C_SPECIAL
      if [[ "$new_minor" == "$C_MINOR" ]]; then
        found_parent=true
      fi
    done

  # if patch != 0 check that there was a release with MAJOR.MINOR.PATCH-1
  elif [[ "$PATCH" != 0 ]]; then
    new_patch=$(( $PATCH - 1 ))
    parent_version="$MAJOR.$MINOR.$new_patch"
    for existing_tag in $existing_tags
    do
      semverParseInto $existing_tag C_MAJOR C_MINOR C_PATCH C_SPECIAL
      if [[ "$MAJOR" == "$C_MAJOR" && "$MINOR" == "$C_MINOR" && "$new_patch" == "$C_PATCH" ]]
      then
        found_parent=true
      fi
    done
  fi

  # if we are the beginning the is no parent, but that's fine
  if [[ "$MAJOR" == 0 ]]; then
    found_parent=true
  fi

  if [[ $found_parent == false ]]; then
    echo "Invalid $NEW_VERSION version. Expected parent version $parent_version does not exist."
    fail_validation=1
  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="[FfRrOoMm] +(--platform=[^ ]+ +)?([^@: ]+)(:([^: ]+)|@sha[^ ]+)?"
      if [[ "$df_parent" =~ $df_pattern ]]
      then

        p_image="${BASH_REMATCH[2]}"
        p_sha=${BASH_REMATCH[3]}
        p_version="${BASH_REMATCH[4]}"

        echo "IMAGE: '${p_image}'"
        echo "VERSION: '$p_version'"
        echo "SHA: '$p_sha'"

        if [[ "${p_image}" == "scratch" ]]
        then
          echo "  OK: Using the versionless 'scratch' parent: '$df_parent'"
        elif [[ "${p_image}:${p_version}" == "gcr.io/distroless/static:nonroot" ]]
        then
          echo "  OK: Using static distroless image with nonroot: '${p_image}:${p_version}'"
        elif [[ "${p_version}" =~ ^([0-9]+)\.([0-9]+)\.([0-9]+)$ ]]
        then
          echo "  OK: Parent '$p_image:$p_version' is a released SemVer version"
        elif [[ "${p_sha}" =~ ^@sha256:[0-9a-f]{64}.*$ ]]
        then
          # allow sha256 hashes to be used as version specifiers
          echo "  OK: Parent '$p_image$p_sha' is using a specific sha256 hash as a version"
        elif [[ "${p_version}" =~ ^.*([0-9]+)\.([0-9]+).*$ ]]
        then
          # handle non-SemVer versions that have a Major.Minor version specifier in the name
          #  'ubuntu:16.04'
          #  'postgres:10.3-alpine'
          #  'openjdk:8-jre-alpine3.8'
          echo "  OK: Parent '$p_image:$p_version' is using a non-SemVer, but sufficient, version"
        elif [[ -z "${p_version}" ]]
        then
          echo "  ERROR: Parent '$p_image' is NOT using a specific version"
          fail_validation=1
        else
          echo "  ERROR: Parent '$p_image:$p_version' is NOT using a specific version"
          fail_validation=1
        fi

      else
        echo "  ERROR: Couldn't find a parent image in $df_parent"
      fi

    done

  done  < <( find "${WORKSPACE}" -name 'Dockerfile*' ! -path "*/vendor/*" ! -name "*dockerignore" -print0 )
}

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

echo "Branches:"
branches=$(git branch -v)
echo $branches

echo "Existing git tags:"
existing_tags=$(git tag -l)
echo $existing_tags

read_version
is_valid_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