Release Candidate Preview

name: Deploy RC preview to GitHub Pages

on:
  push:
    tags: ["v*"]
  workflow_dispatch:

permissions:
  contents: write

jobs:
  deploy-rc-pages:
    runs-on: ubuntu-latest

    steps:
      - name: Guard - only run for RC tags; deploy only on GitHub
        run: |
          set -euo pipefail
          TAG="${GITHUB_REF_NAME:-}"
          CI_PROVIDER="${CI_PROVIDER:-github}"
          ENABLE_DEPLOY="${ENABLE_DEPLOY:-false}"

          if [[ -z "$TAG" ]] || [[ "$TAG" != v* ]] || [[ "$TAG" != *"-rc"* ]]; then
            echo "Not an RC tag ($TAG); skipping."
            exit 0
          fi
          if [[ "${ENABLE_DEPLOY}" != "true" ]]; then
            echo "Skipping deploy: ENABLE_DEPLOY=${ENABLE_DEPLOY}"
            exit 0
          fi
          if [[ "${ACT:-false}" == "true" ]]; then
            echo "Skipping deploy: act"
            exit 0
          fi
          if [[ "${CI_PROVIDER}" != "github" ]]; then
            echo "Skipping deploy: CI_PROVIDER=${CI_PROVIDER}"
            exit 0
          fi

      - name: Checkout (tag)
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Setup Python
        uses: actions/setup-python@v5
        with:
          python-version: "3.11"

      - name: Install dependencies
        run: |
          set -euo pipefail
          pip install -r mkdocs/requirements.txt

      - name: Build site (strict default)
        run: |
          set -euo pipefail
          export MKDOCS_STRICT="${MKDOCS_STRICT:-true}"
          export TMPDIR="${RUNNER_TEMP:-$TMPDIR}"
          export OUTPUT_DIR="${OUTPUT_DIR:-${TMPDIR}/dist/}"
          tools/build.sh --config mkdocs/mkdocs.yml

      - name: Checkout gh-pages branch
        run: |
          set -euo pipefail
          git fetch origin gh-pages:gh-pages || true
          if git show-ref --verify --quiet refs/heads/gh-pages; then
            git switch gh-pages
          else
            git switch --orphan gh-pages
            rm -rf ./*
            git config user.name "github-actions[bot]"
            git config user.email "github-actions[bot]@users.noreply.github.com"
            git commit --allow-empty -m "Initialize gh-pages"
          fi

      - name: Publish RC preview under /rc/<tag>/
        run: |
          export MKDOCS_STRICT="${MKDOCS_STRICT:-true}"
          export TMPDIR="${RUNNER_TEMP:-$TMPDIR}"
          export OUTPUT_DIR="${OUTPUT_DIR:-${TMPDIR}/dist/}"

          set -euo pipefail
          REF="${GITHUB_REF_NAME}"
          mkdir -p "rc/${REF}"
          rm -rf "rc/${REF:?}/"* || true
          cp -a "$OUTPUT_DIR" "rc/${REF}/"

          mkdir -p rc
          if [ ! -f rc/index.html ]; then
            cat > rc/index.html << 'EOF'
          <!doctype html><meta charset="utf-8"><title>RC Previews</title>
          <h1>Release Candidate Preview</h1>
          <p><a href="rc/${REF:?}/">${REF:?}</p>
          EOF
          fi

          git add -A
          git config user.name "github-actions[bot]"
          git config user.email "github-actions[bot]@users.noreply.github.com"
          git commit -m "Deploy RC preview ${REF}" || echo "No changes to commit"
          git push origin gh-pages