name: Publish GitHub Action

on:
  push:
    branches:
      - main
    paths:
      - github-action/package.json

permissions:
  contents: write

jobs:
  verify_action:
    name: Verify action
    runs-on: linux
    steps:
      - name: Checkout repository
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Set up Node.js
        uses: actions/setup-node@v4
        with:
          node-version: 22
          cache: npm
          cache-dependency-path: github-action/package-lock.json

      - name: Install action dependencies
        working-directory: github-action
        run: npm ci

      - name: Create verification fixture
        shell: bash
        run: |
          mkdir -p test-action-input
          cat <<'EOF' > test-action-input/main.lua
          local message = {}

          message.hello = function()
            return "hello"
          end

          return message
          EOF

      - name: Run action locally
        uses: ./github-action
        with:
          source-root: test-action-input
          output-file: test-action-output/compiled.lua

      - name: Assert compiled output exists
        shell: bash
        run: test -f test-action-output/compiled.lua

  derive_release:
    name: Derive release metadata
    runs-on: linux
    needs: verify_action
    outputs:
      version: ${{ steps.derive.outputs.version }}
      release_tag: ${{ steps.derive.outputs.release_tag }}
      rolling_minor_tag: ${{ steps.derive.outputs.rolling_minor_tag }}
      rolling_major_tag: ${{ steps.derive.outputs.rolling_major_tag }}
      bump_kind: ${{ steps.derive.outputs.bump_kind }}
      should_publish: ${{ steps.derive.outputs.should_publish }}
      latest_release_tag: ${{ steps.derive.outputs.latest_release_tag }}
    steps:
      - name: Checkout repository
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Derive version and tags
        id: derive
        shell: bash
        run: |
          set -euo pipefail

          version=$(node -p "require('./github-action/package.json').version")
          if [[ ! "$version" =~ ^[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
            echo "github-action/package.json version must be semver X.Y.Z, got: $version" >&2
            exit 1
          fi

          IFS='.' read -r major minor patch <<< "$version"
          release_tag="action/v${version}"
          rolling_minor_tag="action/v${major}.${minor}"
          rolling_major_tag="action/v${major}"

          latest_release_tag=$(git tag --list 'action/v*.*.*' --sort=-version:refname | head -n 1)

          bump_kind="initial"
          should_publish="true"

          if [[ -n "$latest_release_tag" ]]; then
            latest_version=${latest_release_tag#action/v}

            if [[ "$version" == "$latest_version" ]]; then
              should_publish="false"
              bump_kind="duplicate"
            else
              IFS='.' read -r latest_major latest_minor latest_patch <<< "$latest_version"

              if (( major < latest_major )) || \
                 (( major == latest_major && minor < latest_minor )) || \
                 (( major == latest_major && minor == latest_minor && patch < latest_patch )); then
                echo "github-action/package.json version $version must be greater than latest published $latest_version" >&2
                exit 1
              fi

              if (( major > latest_major )); then
                bump_kind="major"
              elif (( minor > latest_minor )); then
                bump_kind="minor"
              elif (( patch > latest_patch )); then
                bump_kind="patch"
              else
                echo "Unable to derive release kind from $latest_version -> $version" >&2
                exit 1
              fi
            fi
          fi

          echo "version=$version" >> "$GITHUB_OUTPUT"
          echo "release_tag=$release_tag" >> "$GITHUB_OUTPUT"
          echo "rolling_minor_tag=$rolling_minor_tag" >> "$GITHUB_OUTPUT"
          echo "rolling_major_tag=$rolling_major_tag" >> "$GITHUB_OUTPUT"
          echo "bump_kind=$bump_kind" >> "$GITHUB_OUTPUT"
          echo "should_publish=$should_publish" >> "$GITHUB_OUTPUT"
          echo "latest_release_tag=$latest_release_tag" >> "$GITHUB_OUTPUT"

      - name: Summarize release plan
        shell: bash
        run: |
          {
            echo "## Action release plan"
            echo ""
            echo "- Version: ${{ steps.derive.outputs.version }}"
            echo "- Release tag: ${{ steps.derive.outputs.release_tag }}"
            echo "- Rolling minor tag: ${{ steps.derive.outputs.rolling_minor_tag }}"
            echo "- Rolling major tag: ${{ steps.derive.outputs.rolling_major_tag }}"
            echo "- Bump kind: ${{ steps.derive.outputs.bump_kind }}"
            echo "- Latest published tag: ${{ steps.derive.outputs.latest_release_tag || 'none' }}"
            echo "- Will publish: ${{ steps.derive.outputs.should_publish }}"
          } >> "$GITHUB_STEP_SUMMARY"

  publish_tags:
    name: Publish tags
    runs-on: linux
    needs: derive_release
    if: ${{ needs.derive_release.outputs.should_publish == 'true' }}
    steps:
      - name: Checkout repository
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Create immutable release tag
        shell: bash
        run: |
          set -euo pipefail
          release_tag='${{ needs.derive_release.outputs.release_tag }}'

          if git rev-parse "$release_tag" >/dev/null 2>&1; then
            echo "Release tag $release_tag already exists" >&2
            exit 1
          fi

          git tag "$release_tag" "$GITHUB_SHA"

      - name: Update rolling tags
        shell: bash
        run: |
          set -euo pipefail
          git tag -f '${{ needs.derive_release.outputs.rolling_minor_tag }}' "$GITHUB_SHA"
          git tag -f '${{ needs.derive_release.outputs.rolling_major_tag }}' "$GITHUB_SHA"

      - name: Push release tags
        shell: bash
        run: |
          set -euo pipefail
          git push origin '${{ needs.derive_release.outputs.release_tag }}'
          git push origin '${{ needs.derive_release.outputs.rolling_minor_tag }}' --force
          git push origin '${{ needs.derive_release.outputs.rolling_major_tag }}' --force

      - name: Summarize published tags
        shell: bash
        run: |
          {
            echo "## Published action tags"
            echo ""
            echo "- Immutable: ${{ needs.derive_release.outputs.release_tag }}"
            echo "- Rolling minor: ${{ needs.derive_release.outputs.rolling_minor_tag }}"
            echo "- Rolling major: ${{ needs.derive_release.outputs.rolling_major_tag }}"
            echo "- Bump kind: ${{ needs.derive_release.outputs.bump_kind }}"
          } >> "$GITHUB_STEP_SUMMARY"