.github/workflows/diff-coverage.yml
name: Diff Coverage (Kover + diff-cover)

on:
  pull_request:
    branches: [ main ]

permissions:
  contents: read
  pull-requests: write

jobs:
  diff-coverage:
    runs-on: ubuntu-latest
    env:
      THRESHOLD: "80"
      COVER_XML: build/reports/kover/report.xml

    steps:
      - name: Checkout
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      # JDK + Gradle 캐시
      - name: Set up JDK
        uses: actions/setup-java@v4
        with:
          distribution: temurin
          java-version: "21"
          cache: gradle

      # 프로젝트 .gradle 캐시(증분 빌드 가속)
      - name: Cache project .gradle
        uses: actions/cache@v3
        with:
          path: .gradle
          key: gradle-project-${{ runner.os }}-${{ hashFiles('**/*.gradle*', '**/gradle-wrapper.properties') }}
          restore-keys: gradle-project-${{ runner.os }}-

      - name: Build & Test (Kover XML)
        run: ./gradlew --no-daemon test koverXmlReport

      - name: Verify coverage XML exists
        run: |
          test -f "${{ env.COVER_XML }}" || {
            echo "Coverage XML not found at ${{ env.COVER_XML }}"; exit 1;
          }

      - name: Set up Python
        uses: actions/setup-python@v5
        with:
          python-version: "3.x"

      - name: Install diff-cover
        run: pip install diff-cover

      # 로그에 요약 + 임계치 체크(미달 시 실패)
      - name: Diff coverage (fail-under + log)
        run: |
          diff-cover "${{ env.COVER_XML }}" \
            --compare-branch origin/${{ github.base_ref || 'main' }} \
            --src-roots src/main/kotlin src/test/kotlin \
            --fail-under "${{ env.THRESHOLD }}" \
            --format ansi:-

      # HTML/Markdown 리포트 생성
      - name: Diff coverage (reports)
        run: |
          diff-cover "${{ env.COVER_XML }}" \
            --compare-branch origin/${{ github.base_ref || 'main' }} \
            --src-roots src/main/kotlin src/test/kotlin \
            --format html:diff-cover.html,markdown:diff-cover.md

      # 전체/변경 파일 커버리지 수치를 추출(코멘트는 만들지 않음)
      - name: JaCoCo coverage summary (no comment)
        id: jacoco
        uses: madrapps/jacoco-report@v1.7.2
        with:
          paths: ${{ github.workspace }}/${{ env.COVER_XML }}
          token: ${{ secrets.GITHUB_TOKEN }}
          min-coverage-overall: 0
          min-coverage-changed-files: 0
          comment-type: "none"

      # diff-cover.md -> 테이블 변환 + summary 덧붙여 최종 코멘트 생성
      - name: Merge coverage reports (build pr-comment.md)
        run: |
          echo "# 📊 Coverage Report" > pr-comment.md
          echo "" >> pr-comment.md
          echo "- Overall coverage: **${{ steps.jacoco.outputs['coverage-overall'] }}**" >> pr-comment.md
          echo "- Changed files coverage: **${{ steps.jacoco.outputs['coverage-changed-files'] }}**" >> pr-comment.md
          echo "" >> pr-comment.md
          echo "### 🔍 Diff Coverage" >> pr-comment.md
          echo "" >> pr-comment.md
          echo "|Files|Diff Coverage (%)|Missing lines|" >> pr-comment.md
          echo "|-----|-----------------|--------------|" >> pr-comment.md

          # 3번째 줄부터 읽고, 빈 줄은 무시, '## Summary' 만나면 종료
          tail -n +3 diff-cover.md | while read -r line; do
            [[ -z "$line" ]] && continue
            [[ "$line" == "## Summary"* ]] && break

            file=$(echo "$line"    | sed -E 's/^- ([^(]+) .*/\1/')
            percent=$(echo "$line" | sed -E 's/.*\(([0-9.]+%)\).*/\1/')
            missing=$(echo "$line" | grep -o 'Missing lines.*' | sed -E 's/Missing lines //')
            [[ -z "$missing" ]] && missing=" "

            # 경로 앞 6개 컴포넌트 제거 (src/main/kotlin/... 기준)
            short_file=$(echo "$file" | cut -d'/' -f7-)

            echo "|$short_file|$percent|$missing|" >> pr-comment.md
          done

          echo "" >> pr-comment.md
          # 원본의 Summary 블록 추가
          awk '/^## Summary/{flag=1} flag' diff-cover.md >> pr-comment.md

      # 스티키 코멘트로 PR에 1개만 유지
      - name: Post PR comment (sticky)
        uses: marocchino/sticky-pull-request-comment@v2
        with:
          path: pr-comment.md

      # HTML 리포트는 아티팩트로 업로드(다운로드해서 열어보기)
      - name: Upload HTML report
        uses: actions/upload-artifact@v4
        with:
          name: diff-cover-report
          path: diff-cover.html
          if-no-files-found: error
          retention-days: 14