Shared Semver

name: Shared - Semantic Versioning

on:
  workflow_call:
    inputs:
      runner:
        description: 'Runner type'
        required: false
        type: string
        default: 'ubuntu-latest'
      update_changelog:
        description: 'Generate and commit CHANGELOG.md'
        required: false
        type: boolean
        default: false
      tag_prefix:
        description: 'Prefix for version tags'
        required: false
        type: string
        default: 'v'
      major_pattern:
        description: 'Regex pattern for major version bump'
        required: false
        type: string
        default: '(MAJOR|BREAKING CHANGE)'
      minor_pattern:
        description: 'Regex pattern for minor version bump'
        required: false
        type: string
        default: '(feat)'

    outputs:
      version:
        description: 'Semantic version (e.g. 1.2.3)'
        value: ${{ jobs.semver.outputs.version }}
      version_tag:
        description: 'Semantic version tag (e.g. v1.2.3)'
        value: ${{ jobs.semver.outputs.version_tag }}

# Least privilege for what this workflow actually does. Without it the
# job inherits whatever the calling repository's default happens to be,
# which on older repositories is write-all.
permissions:
  contents: write

jobs:
  semver:
    name: Semantic Version
    runs-on: ${{ inputs.runner }}
    timeout-minutes: 10

    outputs:
      version: ${{ steps.semver.outputs.version }}
      version_tag: ${{ steps.semver.outputs.version_tag }}

    steps:
      - name: Checkout
        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
        with:
          fetch-depth: 0

      - name: Fetch all tags
        run: git fetch --tags --force

      - name: Calculate semantic version
        id: semver
        env:
          TAG_PREFIX: ${{ inputs.tag_prefix }}
          MAJOR_PATTERN: ${{ inputs.major_pattern }}
          MINOR_PATTERN: ${{ inputs.minor_pattern }}
        run: |
          LAST_TAG=$(git tag -l "${TAG_PREFIX}*" --sort=-v:refname | head -n1)
          if [ -z "$LAST_TAG" ]; then
            LAST_TAG="${TAG_PREFIX}0.0.0"
            echo "No previous tag found, starting from $LAST_TAG"
          else
            echo "Last tag: $LAST_TAG"
          fi

          LAST_VERSION="${LAST_TAG#"${TAG_PREFIX}"}"
          IFS='.' read -r MAJOR MINOR PATCH <<< "$LAST_VERSION"

          if git rev-parse "$LAST_TAG" >/dev/null 2>&1; then
            COMMITS=$(git log "${LAST_TAG}..HEAD" --pretty=format:'%s%n%b')
          else
            COMMITS=$(git log --pretty=format:'%s%n%b')
          fi

          if [ -z "$COMMITS" ]; then
            echo "No new commits since $LAST_TAG"
            VERSION="${MAJOR}.${MINOR}.${PATCH}"
          elif echo "$COMMITS" | grep -qE "$MAJOR_PATTERN"; then
            MAJOR=$((MAJOR + 1)); MINOR=0; PATCH=0
            VERSION="${MAJOR}.${MINOR}.${PATCH}"
          elif echo "$COMMITS" | grep -qE "$MINOR_PATTERN"; then
            MINOR=$((MINOR + 1)); PATCH=0
            VERSION="${MAJOR}.${MINOR}.${PATCH}"
          else
            PATCH=$((PATCH + 1))
            VERSION="${MAJOR}.${MINOR}.${PATCH}"
          fi

          echo "Calculated version: $VERSION"
          echo "version=$VERSION" >> "$GITHUB_OUTPUT"
          echo "version_tag=${TAG_PREFIX}${VERSION}" >> "$GITHUB_OUTPUT"

      - name: Export version
        run: |
          echo "VERSION=${{ steps.semver.outputs.version_tag }}" >> $GITHUB_ENV
          echo "### Version: ${{ steps.semver.outputs.version_tag }}" >> $GITHUB_STEP_SUMMARY

      - name: Update CHANGELOG.md
        if: inputs.update_changelog
        env:
          TAG_PREFIX: ${{ inputs.tag_prefix }}
        run: |
          set -e
          TODAY="$(date +%Y-%m-%d)"
          VERSION_LINE="## ${VERSION} - ${TODAY}"

          PREV_TAG=$(git tag -l "${TAG_PREFIX}*" --sort=-v:refname | head -n1)
          if [ -n "$PREV_TAG" ] && git rev-parse "$PREV_TAG" >/dev/null 2>&1; then
            RANGE="${PREV_TAG}..HEAD"
          else
            RANGE="$(git rev-list --max-parents=0 HEAD)^..HEAD"
          fi

          COMMITS="$(git log --pretty=format:'- %s (%h)' ${RANGE})"
          echo "Preparing CHANGELOG for ${VERSION}"

          if [ -f CHANGELOG.md ]; then
            tail -n +1 CHANGELOG.md > /tmp/CHANGELOG_OLD.md
          else
            touch /tmp/CHANGELOG_OLD.md
          fi

          {
            echo "${VERSION_LINE}"
            echo ""
            if [ -n "${COMMITS}" ]; then
              echo "${COMMITS}"
            else
              echo "- No changes recorded."
            fi
            echo ""
            cat /tmp/CHANGELOG_OLD.md
          } > CHANGELOG.md

      - name: Commit and push CHANGELOG
        if: inputs.update_changelog
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          git config user.name "github-actions[bot]"
          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
          git add CHANGELOG.md
          if ! git diff --cached --quiet; then
            git commit -m "chore(release): ${VERSION} - update CHANGELOG [skip ci]"
            git push
          else
            echo "No CHANGELOG changes to commit."
          fi