name: R test
on: [push, pull_request]

jobs:
  r-tests:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      # Detect an R package (DESCRIPTION with Package:) or a tests tree
      - name: Detect R tests
        id: detect
        shell: bash
        run: |
          set -euo pipefail
          # Look for an R package
          PKG_DIR=$(git ls-files '**/DESCRIPTION' | while read -r f; do
            if grep -q '^Package:' "$f"; then dirname "$f"; break; fi
          done || true)

          if [ -n "${PKG_DIR:-}" ]; then
            echo "found=true"       >> "$GITHUB_OUTPUT"
            echo "kind=package"     >> "$GITHUB_OUTPUT"
            echo "dir=$PKG_DIR"     >> "$GITHUB_OUTPUT"
            echo "Detected R package at $PKG_DIR"
            exit 0
          fi

          # Otherwise, look for a tests/testthat directory
          CANDIDATE=$(find . -type d -path '*/tests/testthat' | head -n1 || true)
          if [ -n "${CANDIDATE:-}" ]; then
            # project dir = parent of 'tests'
            PROJ_DIR="$(dirname "$(dirname "$CANDIDATE")")"
            echo "found=true"       >> "$GITHUB_OUTPUT"
            echo "kind=tests"       >> "$GITHUB_OUTPUT"
            echo "dir=$PROJ_DIR"    >> "$GITHUB_OUTPUT"
            echo "Detected testthat directory at $CANDIDATE (project: $PROJ_DIR)"
            exit 0
          fi

          echo "found=false"        >> "$GITHUB_OUTPUT"
          echo "No R package or tests/testthat found; skipping."

      - name: Set up R
        if: steps.detect.outputs.found == 'true'
        uses: r-lib/actions/setup-r@v2
        with:
          use-public-rspm: true  # fast Linux binaries

      - name: Install dependencies
        if: steps.detect.outputs.found == 'true'
        uses: r-lib/actions/setup-r-dependencies@v2
        with:
          extra-packages: any::testthat
          cache-version: 1

      - name: Run tests (R package)
        if: steps.detect.outputs.found == 'true' && steps.detect.outputs.kind == 'package'
        working-directory: ${{ steps.detect.outputs.dir }}
        shell: Rscript {0}
        run: |
          testthat::test_local()

      - name: Run tests (non-package testthat dir)
        if: steps.detect.outputs.found == 'true' && steps.detect.outputs.kind == 'tests'
        working-directory: ${{ steps.detect.outputs.dir }}
        shell: Rscript {0}
        run: |
          # Optionally source code from an R/ folder if you have one:
          if (dir.exists("R")) {
            testthat::source_dir("R", recurse = TRUE)
          }
          testthat::test_dir("tests/testthat")

      - name: Skip (no R tests found)
        if: steps.detect.outputs.found != 'true'
        run: echo "No R package or tests/testthat directory found; skipping R tests."