name: Update star history chart

on:
  push:
    branches:
      - main
    # The job commits the regenerated SVGs back to main. Ignoring them here
    # means the bot's own commit — which touches nothing else — cannot retrigger
    # this workflow. (GitHub also declines to raise `push` events for commits
    # made with GITHUB_TOKEN, so this is the second of two guards.)
    paths-ignore:
      - "assets/img/star-history-*.svg"
  # Stars keep accruing even when nobody pushes, so refresh weekly regardless.
  schedule:
    - cron: "17 4 * * 1"
  workflow_dispatch:

permissions:
  contents: write

# Never let two runs race to commit the same files.
concurrency:
  group: star-history
  cancel-in-progress: false

jobs:
  update:
    runs-on: ubuntu-latest
    # This repo is a template; without this guard every site generated from it
    # would burn Actions minutes charting someone else's repository.
    if: github.repository == 'alshedivat/al-folio'
    steps:
      - name: Checkout 🛎️
        uses: actions/checkout@v6

      - name: Regenerate chart 📈
        env:
          # Lifts the API limit from 60 to 5000 requests/hour. The stargazer
          # data itself is public — no personal or scoped token is needed.
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: python3 bin/generate_star_history.py --repo "${{ github.repository }}" --out-dir assets/img

      - name: Commit if changed 💾
        run: |
          set -euo pipefail
          if git diff --quiet -- assets/img/star-history-light.svg assets/img/star-history-dark.svg; then
            echo "Chart unchanged; nothing to commit."
            exit 0
          fi
          git config user.name "github-actions[bot]"
          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
          git add assets/img/star-history-light.svg assets/img/star-history-dark.svg
          git commit -m "chore: refresh star history chart [skip ci]"
          # Regenerating the chart takes about a minute, and update-tocs.yml
          # triggers on the same push and commits to main in ~15s, so main can
          # move underneath this job. That is a plain non-fast-forward, not a
          # permissions problem, so rebase onto the new tip and retry instead of
          # failing the run. Only the two generated SVGs are in flight here, and
          # nothing else writes them, so the rebase cannot conflict in practice.
          for attempt in 1 2 3; do
            if git push; then
              echo "Pushed on attempt ${attempt}."
              exit 0
            fi
            echo "Push rejected (main moved); rebasing onto origin/main and retrying."
            git pull --rebase origin main
          done
          echo "::error::Could not push the refreshed chart after 3 attempts."
          exit 1