name: Check links with Lychee

on:
  pull_request:
    paths:
      - "docs/**"
      - "*.md"
    branches:
      - main

# Remove default permissions of GITHUB_TOKEN for security
# https://docs.github.com/en/actions/using-jobs/assigning-permissions-to-jobs
permissions: {}

jobs:
  link-checker:
    runs-on: ubuntu-latest
    steps:
      # Cache lychee results (e.g. to avoid hitting rate limits)
      - name: Restore lychee cache
        uses: actions/cache@0c45773b623bea8c8e75f6c82b208c3cf94ea4f9 # v4.0.2
        with:
          path: .lycheecache
          key: cache-lychee-${{ github.sha }}
          restore-keys: cache-lychee-

      # check links with Lychee
      - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29 # v4.1.6

      - name: Lychee link checker
        uses: lycheeverse/lychee-action@054a8e8c7a88ada133165c6633a49825a32174e2 # for v1.8.0
        with:
          # arguments with file types to check
          args: >-
            --cache
            --verbose
            --no-progress
            --max-cache-age=1d
            './**/*.md'
            './**/*.html'
          # fail the action on broken links
          fail: true
        env:
          # to be used in case rate limits are surpassed
          GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}