version.sh

#!/usr/bin/bash

###
# SmVer version generator based on current commit.
#
# Requires to enable these Git features: unshallow fetch, fetch tags. Output difer from the Git environment:
#
#   - If the tag is added on the current commit, output follows <version core>, or <version core> "+" <build>.
#   - If the tag is added on an ancestor, this build is treaten as a pre-release, output follows <version core> "-" <pre-release>, or <version core> "-" <pre-release> "+" <build>. The pre-release is greater than the previous commit. Choice between patch, minor or major version increment is stored in the ".version" file.
#
# Parameters:
#
#   -m    Displays build metadata (<version core> "+" <build>, or <version core> "-" <pre-release> "+" <build>)
#   -c    Cache the date contained in the metadata. Data is stored in the ".version-cache-date" file. Alloys re-executing the command multiple times with a reproductible response, like in CI/CD environment.
#   -w    Compatibility for Windows MSX build, use a 0-65535 numbers for the pre-release tag.
#
# Usage:
#
#   - Without metadata: "sh cicd/version.sh"
#   - With metadata: "sh cicd/version.sh -b"
#
# See: https://semver.org/#backusnaur-form-grammar-for-valid-semver-versions
###

while getopts "g:mcw" flag; do
  case "${flag}" in
  g)
    repo_path=$OPTARG
    ;;
  m)
    metadata=true
    ;;
  c)
    cache=true
    ;;
  w)
    windows=true
    ;;
  esac
done

if [ -z "$repo_path" ]; then
  echo "Error: repo_path is undefined, use -g <path>"
  exit 1
fi

if [ -z "$(git tag --merged HEAD 'v[0-9]*.[0-9]*.[0-9]*')" ]; then
  echo "Error: no tag found, use 'git tag v0.0.0'"
  exit 1
fi

# git list ancestor tags plus merged

version_file="${repo_path}/.version.config"
if [ ! -f $version_file ]; then
  echo "patch" >"$version_file"
fi
version_config=$(cat $version_file)

cache_file="${repo_path}/.version.cache"
latest_tag_raw=$(git describe --all --abbrev=0 --match "v[0-9]*.[0-9]*.[0-9]*" --candidates=10000)
[[ $latest_tag_raw =~ ^tags/v([0-9]+).([0-9]+).([0-9]+) ]]
latest_tag_x=${BASH_REMATCH[1]}
latest_tag_y=${BASH_REMATCH[2]}
latest_tag_z=${BASH_REMATCH[3]}
count_from_tag=$(git rev-list HEAD ^$latest_tag_raw --count --ancestry-path --no-merges)

if [ "$count_from_tag" -eq 0 ]; then
  # <version core>
  base_smver="$latest_tag_x.$latest_tag_y.$latest_tag_z"

else
  # Remove all the zeros at the leading zeros, as this is not compliant with SmVer
  commit_id=$(git rev-parse --short HEAD | sed 's/^0*//')
  prerelease_smver="$count_from_tag.$commit_id"

  case "${version_config}" in
  major)
    latest_tag_x=$((latest_tag_x + 1))
    latest_tag_y=0
    latest_tag_z=0
    ;;
  minor)
    latest_tag_y=$((latest_tag_y + 1))
    latest_tag_z=0
    ;;
  patch)
    latest_tag_z=$((latest_tag_z + 1))
    ;;
  esac

  # Windows MSX binaries does not support characters in the pre-release tag, only 0-65535 numbers
  if [ "$windows" = true ]; then
    hash=$(echo -n "$prerelease_smver" | md5sum | awk '{print $1}')
    hash=$(echo "$hash" | tr '[:lower:]' '[:upper:]')
    prerelease_smver=$(echo "ibase=16; $hash % 10000" | bc)
  fi

  # <version core> "-" <pre-release>
  base_smver="$latest_tag_x.$latest_tag_y.$latest_tag_z-$prerelease_smver"
fi

if [ "$metadata" = true ]; then
  if [ "$cache" = true ] && [ -f $cache_file ]; then
    build_date=$(cat "$cache_file")

  else
    build_date=$(date -u "+%Y%m%d%H%M%S")
    echo $build_date >"$cache_file"
  fi

  metadata_smver=$build_date
  echo "$base_smver+$metadata_smver"
else
  echo "$base_smver"
fi