name: Version Gate

on:
  pull_request:
    paths:
      - 'VERSION'
      - 'CHANGELOG.md'
      - 'package.json'

concurrency:
  group: version-gate-${{ github.event.pull_request.number }}
  cancel-in-progress: true

jobs:
  check:
    name: Check VERSION is not stale vs queue
    runs-on: ubuntu-latest
    permissions:
      contents: read
      pull-requests: read
    steps:
      - name: Checkout PR head
        uses: actions/checkout@v4
        with:
          fetch-depth: 0
          ref: ${{ github.event.pull_request.head.sha }}

      - name: Setup Bun
        uses: oven-sh/setup-bun@v2

      - name: Read versions
        id: versions
        run: |
          set -euo pipefail
          PR_VERSION=$(cat VERSION | tr -d '[:space:]')
          BASE_REF="${{ github.event.pull_request.base.ref }}"
          git fetch origin "$BASE_REF" --depth=1 --quiet || true
          BASE_VERSION=$(git show "origin/$BASE_REF:VERSION" 2>/dev/null | tr -d '[:space:]' || echo "0.0.0.0")
          {
            echo "pr_version=$PR_VERSION"
            echo "base_version=$BASE_VERSION"
            echo "base_ref=$BASE_REF"
          } >> "$GITHUB_OUTPUT"

      - name: Detect bump level
        id: bump
        run: |
          LEVEL=$(bun run scripts/detect-bump.ts "${{ steps.versions.outputs.base_version }}" "${{ steps.versions.outputs.pr_version }}")
          echo "level=$LEVEL" >> "$GITHUB_OUTPUT"

      - name: Query queue (util) — fail-open on error
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          set +e
          bun run bin/gstack-next-version \
            --base "${{ steps.versions.outputs.base_ref }}" \
            --bump "${{ steps.bump.outputs.level }}" \
            --current-version "${{ steps.versions.outputs.base_version }}" \
            --workspace-root null \
            --exclude-pr "${{ github.event.pull_request.number }}" \
            > next.json 2> next.err
          RC=$?
          if [ "$RC" != "0" ] || [ ! -s next.json ]; then
            echo '{"offline":true}' > next.json
            echo "::warning::util exit=$RC — failing open. stderr:"
            cat next.err || true
          fi

      - name: Compare PR VERSION to next free slot
        env:
          PR_VERSION: ${{ steps.versions.outputs.pr_version }}
        run: |
          bun run scripts/compare-pr-version.ts next.json "${{ github.event.pull_request.number }}"