name: Mutation testing

# Mutation testing (gremlins) is the objective check for "fake" tests: it mutates the
# source and a surviving (LIVED) mutant means no test caught the change. It is SLOW, so it
# runs nightly / on demand and scoped per package — never per-commit. It is informational:
# no thresholds are set, so it reports survivors as artifacts without failing the build.
on:
  schedule:
    - cron: "0 3 * * *" # 03:00 UTC daily
  workflow_dispatch:

permissions:
  contents: read

jobs:
  gremlins:
    runs-on: ubuntu-latest
    timeout-minutes: 120
    strategy:
      fail-fast: false
      matrix:
        include:
          - name: sub
            path: ./internal/sub/
            exclude: ""
          - name: runtime
            path: ./internal/web/runtime/
            exclude: ""
          - name: link
            path: ./internal/util/link/
            exclude: ""
          - name: database
            path: ./internal/database/
            exclude: 'dump_sqlite\.go'
          - name: service
            path: ./internal/web/service/
            exclude: 'server\.go|xray\.go|inbound\.go|client_bulk\.go|inbound_traffic\.go|.*_postgres_test\.go'
    steps:
      - uses: actions/checkout@v7
      - uses: actions/setup-go@v6
        with:
          go-version-file: go.mod
          cache: true
      - name: Stub internal/web/dist for go:embed
        run: mkdir -p internal/web/dist && touch internal/web/dist/.gitkeep
      - name: Install gremlins
        run: go install github.com/go-gremlins/gremlins/cmd/gremlins@v0.6.0
      - name: Run gremlins on ${{ matrix.name }}
        run: |
          OUT="mutation-${{ matrix.name }}.json"
          if [ -n "${{ matrix.exclude }}" ]; then
            gremlins unleash -E '${{ matrix.exclude }}' -o "$OUT" ${{ matrix.path }}
          else
            gremlins unleash -o "$OUT" ${{ matrix.path }}
          fi
      - name: Upload mutation report
        if: always()
        uses: actions/upload-artifact@v7
        with:
          name: mutation-${{ matrix.name }}
          path: mutation-${{ matrix.name }}.json
          if-no-files-found: ignore
