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@704facf57e6136b1bc63b828d79edcd491f0ee84 # v3.3.2
        with:
          path: .lycheecache
          key: cache-lychee-${{ github.sha }}
          restore-keys: cache-lychee-

      # check links with Lychee
      - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1

      - name: Lychee link checker
        uses: lycheeverse/lychee-action@c3089c702fbb949e3f7a8122be0c33c017904f9b # 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}}