name: E2E Research Test

on:
  pull_request:
    types: [labeled]

# No concurrency group — intentionally omitted.
# Previous attempt (#3554, reverted #3599) used cancel-in-progress which
# killed in-progress PR runs before they produced useful results.
# Future iteration could safely add concurrency for scheduled/push-only
# triggers (where head_ref is empty and runs get unique groups).

permissions: {}  # Minimal top-level for OSSF Scorecard

jobs:
  build-query:
    name: Assemble query
    if: github.event.label.name == 'ldr_research' || github.event.label.name == 'ldr_research_static'
    runs-on: ubuntu-latest
    permissions:
      contents: read
    outputs:
      query: ${{ steps.assemble.outputs.query }}
      header: ${{ steps.headers.outputs.header }}
      subheader: ${{ steps.headers.outputs.subheader }}
    env:
      LABEL_NAME: ${{ github.event.label.name }}
      MAX_DIFF_SIZE: ${{ vars.MAX_DIFF_SIZE || '8000' }}
      BASE_REF: ${{ github.event.pull_request.base.ref }}
    steps:
      - name: Harden the runner (Audit all outbound calls)
        uses: step-security/harden-runner@9af89fc71515a100421586dfdb3dc9c984fbf411 # v2.19.4
        with:
          egress-policy: audit

      - name: Checkout repository
        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
        with:
          persist-credentials: false
          fetch-depth: 0

      - name: Build PR-research query
        id: assemble
        run: |
          if [ "$LABEL_NAME" = "ldr_research_static" ]; then
            cat > query.txt <<'STATIC_EOF'
          What is Local Deep Research and how does it work?
          STATIC_EOF
          else
            git fetch origin "$BASE_REF"
            git diff "origin/$BASE_REF...HEAD" --no-color > diff.txt
            DIFF_BYTES=$(wc -c < diff.txt)
            echo "Diff size: $DIFF_BYTES bytes (cap: $MAX_DIFF_SIZE)"

            head -c "$MAX_DIFF_SIZE" diff.txt > diff-trunc.txt
            if [ "$DIFF_BYTES" -gt "$MAX_DIFF_SIZE" ]; then
              printf '\n... (truncated)\n' >> diff-trunc.txt
            fi

            {
              cat <<'PROMPT_HEAD_EOF'
          Based on these code changes, research relevant documentation,
          best practices, and potential issues. Focus on any libraries, APIs, or patterns used.

          Code changes:
          PROMPT_HEAD_EOF
              cat diff-trunc.txt
              cat <<'PROMPT_TAIL_EOF'

          Research topics to cover:
          1. Documentation for any libraries or APIs being used/modified
          2. Best practices for the patterns shown
          3. Known issues or gotchas related to these changes
          4. Security considerations if applicable
          PROMPT_TAIL_EOF
            } > query.txt
          fi

          # Multi-line GH Actions output via heredoc-style delimiter.
          # Use a randomized delimiter so a query containing the literal
          # delimiter on its own line cannot prematurely terminate the
          # heredoc.
          DELIM="LDR_QUERY_EOF_$$_${RANDOM}_$(date +%N)"
          {
            echo "query<<$DELIM"
            cat query.txt
            echo "$DELIM"
          } >> "$GITHUB_OUTPUT"

      - name: Compute headers
        id: headers
        run: |
          if [ "$LABEL_NAME" = "ldr_research_static" ]; then
            echo "header=## 🧪 LDR Static Query Test Results" >> "$GITHUB_OUTPUT"
            echo "subheader=**Query:** What is Local Deep Research and how does it work?" >> "$GITHUB_OUTPUT"
          else
            echo "header=## 🔬 LDR Research Results" >> "$GITHUB_OUTPUT"
            echo "subheader=_Analysis of PR code changes_" >> "$GITHUB_OUTPUT"
          fi

  research:
    name: Run LDR research
    needs: build-query
    # Grant the perms the reusable's job needs:
    # - contents: read for actions/checkout
    # - actions: write for actions/upload-artifact@v5+
    # Without this, the reusable's `permissions: contents: read` exceeds
    # the inherited empty permissions and GitHub rejects the workflow at
    # load time (startup_failure with zero jobs).
    permissions:
      contents: read
      actions: write
    uses: ./.github/workflows/ldr-research-reusable.yml
    with:
      query: ${{ needs.build-query.outputs.query }}
      model: ${{ github.event.label.name == 'ldr_research_static' && (vars.LDR_RESEARCH_CHEAP_MODEL || 'google/gemini-2.0-flash-001') || (vars.LDR_RESEARCH_MODEL || 'google/gemini-2.0-flash-001') }}
      provider: ${{ vars.LDR_PROVIDER || 'openrouter' }}
      search-tool: ${{ vars.LDR_SEARCH_TOOL || 'serper' }}
      strategy: ${{ vars.LDR_STRATEGY || 'langgraph-agent' }}
      comment-header: ${{ needs.build-query.outputs.header }}
      comment-subheader: ${{ needs.build-query.outputs.subheader }}
    secrets:
      OPENROUTER_API_KEY: ${{ secrets.OPENROUTER_API_KEY }}
      SERPER_API_KEY: ${{ secrets.SERPER_API_KEY }}

  post-comment:
    name: Post PR comment
    needs: research
    # always() so the label-removal step runs even if research was skipped
    # (e.g. build-query failed). The download/post steps are guarded by
    # needs.research.outputs.success == 'true' so they self-skip in that
    # case.
    if: always()
    runs-on: ubuntu-latest
    permissions:
      contents: read
      pull-requests: write
      issues: write
    env:
      LABEL_NAME: ${{ github.event.label.name }}
      PR_NUMBER: ${{ github.event.pull_request.number }}
      GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
    steps:
      - name: Harden the runner (Audit all outbound calls)
        uses: step-security/harden-runner@9af89fc71515a100421586dfdb3dc9c984fbf411 # v2.19.4
        with:
          egress-policy: audit

      - name: Download research artifact
        if: needs.research.outputs.success == 'true'
        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
        with:
          name: ${{ needs.research.outputs.comment-artifact-name }}

      - name: Post or update comment
        if: needs.research.outputs.success == 'true'
        continue-on-error: true   # a GitHub API hiccup shouldn't fail the job
        uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9.0.0
        with:
          retries: 3
          script: |
            const fs = require('fs');
            const issue_number = Number(process.env.PR_NUMBER);
            // Key the marker by label so re-running the same label edits its
            // comment in place, while the other label keeps a separate comment.
            const marker = `<!-- ldr-research-results:${process.env.LABEL_NAME} -->`;
            const body = marker + '\n' + fs.readFileSync('comment.md', 'utf8');

            // Paginate — on a long-lived PR the existing comment may be past the
            // first page (listComments defaults to 30), which would otherwise
            // create a new comment every run instead of editing in place.
            const comments = await github.paginate(github.rest.issues.listComments, {
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number,
              per_page: 100,
            });
            const existing = comments.find(
              (c) => c.user.type === 'Bot' && c.body.includes(marker)
            );

            if (existing) {
              await github.rest.issues.updateComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                comment_id: existing.id,
                body,
              });
            } else {
              await github.rest.issues.createComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number,
                body,
              });
            }

      - name: Remove label for re-triggering
        if: always()
        run: |
          gh issue edit "$PR_NUMBER" --remove-label "$LABEL_NAME" 2>/dev/null || true