name: Refresh star history chart

on:
  schedule:
    # Twice daily at 06:00 and 18:00 UTC.
    - cron: "0 6,18 * * *"
  workflow_dispatch:

permissions:
  contents: write

env:
  DO_NOT_TRACK: "1"
  KTX_TELEMETRY_DISABLED: "1"
  NEXT_TELEMETRY_DISABLED: "1"

concurrency:
  group: star-history-refresh
  cancel-in-progress: true

jobs:
  refresh:
    name: Regenerate assets/star-history.svg
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repository
        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
        with:
          # RELEASE_PAT can push to the protected main branch; the default
          # GITHUB_TOKEN is rejected by the branch-protection hook (GH006).
          token: ${{ secrets.RELEASE_PAT }}

      - name: Fetch fresh star-history SVG
        run: |
          set -euo pipefail
          # cachebust forces star-history to regenerate instead of serving its
          # own server-side cache; --location follows the slug-normalizing 301.
          url="https://api.star-history.com/svg?repos=Kaelio/ktx&type=Date&cachebust=${GITHUB_RUN_ID}-${GITHUB_RUN_ATTEMPT}"
          curl --fail --location --silent --show-error \
            --retry 3 --retry-delay 5 --max-time 60 \
            -o assets/star-history.svg.new "$url"
          # Guard against error pages / truncated responses before overwriting.
          if ! grep -q "</svg>" assets/star-history.svg.new; then
            echo "Downloaded file is not a valid SVG; aborting." >&2
            exit 1
          fi
          if [ "$(wc -c < assets/star-history.svg.new)" -lt 1000 ]; then
            echo "Downloaded SVG is suspiciously small; aborting." >&2
            exit 1
          fi
          # The star-history API returns the SVG without a trailing newline,
          # which end-of-file-fixer rewrites whenever pre-commit runs
          # --all-files on a PR. Because the refresh commit below uses [skip ci],
          # the hook never runs against it here, so an un-normalized file
          # silently breaks the pre-commit check on every open PR. Normalize to
          # exactly one trailing newline before committing.
          printf '%s\n' "$(cat assets/star-history.svg.new)" > assets/star-history.svg
          rm -f assets/star-history.svg.new

      - name: Commit if changed
        run: |
          set -euo pipefail
          if git diff --quiet -- assets/star-history.svg; then
            echo "Star-history 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/star-history.svg
          # [skip ci] keeps this housekeeping commit from triggering KTX CI.
          git commit -m "chore: refresh star history chart [skip ci]"
          git push