name: Docs link check

on:
  push:
    branches:
    - main
  pull_request:

permissions:
  contents: read

jobs:
  lychee:
    runs-on: ubuntu-latest
    steps:
      - name: Check out repository
        uses: actions/checkout@v4
        with:
          # For pull_request events, use the PR head (commit from the contributor's branch/repo)
          repository: ${{ github.event.pull_request.head.repo.full_name || github.repository }}
          ref: ${{ github.event.pull_request.head.sha || github.sha }}
          fetch-depth: 0

      # Cache lychee results (e.g. to avoid hitting rate limits)
      # https://lychee.cli.rs/github_action_recipes/caching/
      - name: Restore lychee cache
        uses: actions/cache@v4
        with:
          path: .lycheecache
          key: cache-lychee-${{ github.sha }}
          restore-keys: cache-lychee-

      # https://github.com/lycheeverse/lychee/issues/1487
      - name: Install CA Certificates for lychee
        run: |
          sudo apt-get install ca-certificates

      - name: Install lychee
        run: |
          set -euo pipefail
          mkdir -p "$HOME/.local/bin"
          cd "$RUNNER_TEMP"
          # TODO: Lychee v0.19.1 doesn't support regex in --exclude-path, so use nightly
          # release until there is a released version containing regex support.
          curl -sSL -o lychee.tar.gz \
            https://github.com/lycheeverse/lychee/releases/download/nightly/lychee-x86_64-unknown-linux-gnu.tar.gz
          tar -xzf lychee.tar.gz
          BIN_PATH=$(find . -maxdepth 2 -type f -name lychee | head -n1)
          install -m 0755 "$BIN_PATH" "$HOME/.local/bin/lychee"
          echo "$HOME/.local/bin" >> "$GITHUB_PATH"
          lychee --version

      - name: Check documentation links with lychee
        env:
          # Set GITHUB_TOKEN to avoid github rate limits on URL checks
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          set -euo pipefail

          # Set offline mode for pull requests, full check for pushes to main
          if [[ "${{ github.event_name }}" == "pull_request" ]]; then
            echo "Running lychee in offline mode (internal links only) for PR check"
            OFFLINE_FLAG="--offline"
          else
            echo "Running lychee in full mode (all links) for main branch"
            OFFLINE_FLAG=""
          fi

          # Run lychee against all files in repo
          lychee \
            --cache \
            --no-progress \
            --root-dir "${{ github.workspace }}" \
            --exclude-path ".*ATTRIBUTIONS.*" \
            --accept "200..=299, 403, 429" \
            --exclude-all-private --exclude 0.0.0.0 \
            $OFFLINE_FLAG \
            .