name: mdBook

on:
  push:
    branches: [main]
    tags: ['v*']
  pull_request:
    branches: [main]
  workflow_dispatch:

permissions:
  contents: read
  pages: write
  id-token: write

concurrency:
  group: pages
  cancel-in-progress: false

env:
  # Repo path on GitHub Pages — change here if the repo is renamed.
  SITE_BASE: /meshcore-spec

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout (with tags)
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Install mise + pinned tools (mdbook, etc.)
        uses: jdx/mise-action@v2
        with:
          install: true
          cache: true

      - name: Configure Pages
        uses: actions/configure-pages@v5

      - name: Build all versions
        run: |
          set -euo pipefail

          mkdir -p _site
          WORKSPACE="$PWD"

          # ---- latest (current ref) ----
          echo "::group::build latest"
          MDBOOK_OUTPUT__HTML__SITE_URL="${SITE_BASE}/latest/" \
            mdbook build "$WORKSPACE" -d "$WORKSPACE/_site/latest"
          echo "::endgroup::"

          # ---- each v* tag ----
          # Tags are built in worktrees so the workflow's own files (this
          # file, the picker JS/CSS) don't bleed into older builds.
          mapfile -t TAGS < <(git tag --list 'v*' --sort=-v:refname)
          for tag in "${TAGS[@]:-}"; do
            [ -z "$tag" ] && continue
            echo "::group::build $tag"
            wt="$(mktemp -d -t "mdbook-${tag//\//-}-XXXXXX")"
            git worktree add --detach "$wt" "$tag"
            # If a very old tag lacks book.toml, skip it but don't fail.
            if [ -f "$wt/book.toml" ]; then
              MDBOOK_OUTPUT__HTML__SITE_URL="${SITE_BASE}/${tag}/" \
                mdbook build "$wt" -d "$WORKSPACE/_site/${tag}" || {
                  echo "::warning::mdbook build failed for ${tag}; skipping"
                  rm -rf "$WORKSPACE/_site/${tag}"
                }
            else
              echo "::warning::${tag} has no book.toml; skipping"
            fi
            git worktree remove --force "$wt"
            echo "::endgroup::"
          done

          # ---- versions.json (consumed by theme/version-picker.js) ----
          # Newest first; "latest" always at the top.
          {
            printf '['
            printf '"latest"'
            for tag in "${TAGS[@]:-}"; do
              [ -z "$tag" ] && continue
              [ -d "_site/${tag}" ] || continue
              printf ',"%s"' "$tag"
            done
            printf ']\n'
          } > _site/versions.json
          echo "versions.json:"
          cat _site/versions.json

          # ---- root redirect to /latest/ ----
          cat > _site/index.html <<'HTML'
          <!DOCTYPE html>
          <html lang="en">
          <head>
            <meta charset="utf-8">
            <meta http-equiv="refresh" content="0; url=./latest/">
            <link rel="canonical" href="./latest/">
            <title>MeshCore Protocol Specification</title>
          </head>
          <body>
            <p>Redirecting to the <a href="./latest/">latest version</a>&hellip;</p>
          </body>
          </html>
          HTML

      - name: Upload Pages artifact
        uses: actions/upload-pages-artifact@v3
        with:
          path: ./_site

  deploy:
    if: github.event_name == 'push' || github.event_name == 'workflow_dispatch'
    needs: build
    runs-on: ubuntu-latest
    environment:
      name: github-pages
      url: ${{ steps.deployment.outputs.page_url }}
    steps:
      - name: Deploy to GitHub Pages
        id: deployment
        uses: actions/deploy-pages@v4