# Extended robustness: corpus render-stability sweep + libFuzzer run.
#
# DELIBERATELY ISOLATED from the main CI gate:
#   - never triggers on push or pull_request, so it can NEVER block a merge,
#     push, or pull;
#   - the whole job is continue-on-error, so a crash finding or a build/runner
#     problem reports red here but does not fail any required check;
#   - runs on a weekly schedule and on manual dispatch only.
#
# A full 24h fuzz run needs a self-hosted runner (GitHub-hosted runners cap a job
# at 6h). Use the workflow_dispatch `duration_seconds` input for that; the weekly
# schedule does a short smoke instead.

name: Fuzz & corpus sweep

on:
  schedule:
    - cron: "0 3 * * 0" # Sundays 03:00 UTC — short smoke
  workflow_dispatch:
    inputs:
      duration_seconds:
        description: "libFuzzer -max_total_time (e.g. 1800 smoke, 86400 for 24h on a self-hosted runner)"
        default: "1800"
      sanitizers:
        description: "Sanitizer set (fuzzer,address,undefined needs an ASan/UBSan-built PDFium; fuzzer = coverage-only)"
        default: "fuzzer,address,undefined"

permissions:
  contents: read

concurrency:
  group: fuzz-${{ github.ref }}
  cancel-in-progress: true

jobs:
  fuzz:
    # Non-blocking by construction: nothing depends on this job and it is allowed to fail.
    continue-on-error: true
    runs-on: ubuntu-latest
    timeout-minutes: 1500 # permits a 24h dispatch on a self-hosted runner; hosted runners stop at 6h
    env:
      VCPKG_DEFAULT_BINARY_CACHE: ${{ github.workspace }}/.vcpkg-cache
      FUZZ_SANITIZERS: ${{ github.event.inputs.sanitizers || 'fuzzer' }}
      FUZZ_DURATION: ${{ github.event.inputs.duration_seconds || '600' }}
    steps:
      - uses: actions/checkout@v4

      - name: Install Ninja + Clang
        shell: bash
        run: |
          sudo apt-get update
          sudo apt-get install -y ninja-build clang

      - name: Locate vcpkg
        shell: bash
        run: |
          echo "VCPKG_ROOT=$VCPKG_INSTALLATION_ROOT" >> "$GITHUB_ENV"
          mkdir -p "$VCPKG_DEFAULT_BINARY_CACHE"

      - name: Cache vcpkg artifacts
        uses: actions/cache@v4
        with:
          path: ${{ env.VCPKG_DEFAULT_BINARY_CACHE }}
          key: vcpkg-fuzz-${{ hashFiles('vcpkg.json') }}
          restore-keys: vcpkg-fuzz-

      - name: Pin vcpkg dependency baseline
        shell: bash
        run: |
          if ! grep -q '"builtin-baseline"' vcpkg.json; then
            "$VCPKG_ROOT/vcpkg" x-update-baseline --add-initial-baseline
          fi

      - name: Configure (fuzz-linux)
        run: cmake --preset fuzz-linux -DPDFENGINE_FUZZ_SANITIZERS="$FUZZ_SANITIZERS"

      - name: Build fuzzer
        run: cmake --build --preset fuzz-linux --target pdfengine_fuzz

      - name: Fetch corpus (pinned + hash-verified)
        shell: bash
        run: python3 scripts/fetch_corpus.py --manifest tests/regression/corpus-manifest.json || echo "corpus fetch failed (network) — continuing with committed corpus"

      - name: Render-stability sweep (replay every corpus PDF once)
        shell: bash
        run: |
          BIN=out/build/fuzz-linux/bin/pdfengine_fuzz
          mkdir -p engine/fuzz/artifacts
          "$BIN" -runs=0 -artifact_prefix=engine/fuzz/artifacts/ corpus/ corpus/fuzz/ || true

      - name: Fuzz run
        shell: bash
        run: |
          BIN=out/build/fuzz-linux/bin/pdfengine_fuzz
          "$BIN" -max_total_time="$FUZZ_DURATION" -print_final_stats=1 \
                 -artifact_prefix=engine/fuzz/artifacts/ corpus/fuzz/ corpus/ || true

      - name: Upload crash artifacts
        if: always()
        uses: actions/upload-artifact@v4
        with:
          name: fuzz-artifacts
          path: engine/fuzz/artifacts/
          if-no-files-found: ignore