# GitHub Actions Workflow — Automated PR Review with Claude Code
# Squad: claude-code-mastery
# Template: Drop into .github/workflows/ and configure secrets
#
# Prerequisites:
#   1. Store ANTHROPIC_API_KEY in GitHub repository secrets
#   2. Enable "Allow GitHub Actions to create and approve pull requests" in repo settings
#
# Usage:
#   Automatically triggered on PR open/update. Posts a review comment with findings.

name: Claude Code PR Review

on:
  pull_request:
    types: [opened, synchronize, ready_for_review]
    # Optionally limit to specific paths:
    # paths:
    #   - 'src/**'
    #   - 'packages/**'

# Required permissions for posting PR comments
permissions:
  contents: read
  pull-requests: write

# Prevent concurrent reviews on the same PR
concurrency:
  group: claude-review-${{ github.event.pull_request.number }}
  cancel-in-progress: true

jobs:
  review:
    name: Claude Code Review
    # Skip draft PRs and bot-authored PRs
    if: |
      !github.event.pull_request.draft &&
      github.event.pull_request.user.login != 'dependabot[bot]' &&
      github.event.pull_request.user.login != 'claude-code[bot]'
    runs-on: ubuntu-latest
    timeout-minutes: 15

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

      - name: Setup Node.js
        uses: actions/setup-node@v4
        with:
          node-version: '20'

      - name: Install Claude Code
        run: npm install -g @anthropic-ai/claude-code

      - name: Get PR Context
        id: pr-context
        run: |
          # Get the diff between base and head
          git diff origin/${{ github.base_ref }}...HEAD > /tmp/pr-diff.txt
          DIFF_SIZE=$(wc -c < /tmp/pr-diff.txt)
          FILES_CHANGED=$(git diff --name-only origin/${{ github.base_ref }}...HEAD | wc -l)
          echo "diff_size=$DIFF_SIZE" >> $GITHUB_OUTPUT
          echo "files_changed=$FILES_CHANGED" >> $GITHUB_OUTPUT

          # Get the file list for context
          git diff --name-only origin/${{ github.base_ref }}...HEAD > /tmp/files-changed.txt

      - name: Skip Large PRs
        if: steps.pr-context.outputs.diff_size > 200000
        run: |
          echo "PR diff is too large (${{ steps.pr-context.outputs.diff_size }} bytes). Skipping automated review."
          echo "Consider breaking this PR into smaller changes."
          exit 0

      - name: Run Claude Review
        id: review
        env:
          ANTHROPIC_API_KEY: ${{ secrets.ANTHROPIC_API_KEY }}
        run: |
          # Truncate diff to avoid token limits (50KB)
          head -c 50000 /tmp/pr-diff.txt > /tmp/pr-diff-truncated.txt

          PROMPT="You are a senior code reviewer. Review this pull request diff and provide actionable feedback.

          PR Title: ${{ github.event.pull_request.title }}
          PR Description: ${{ github.event.pull_request.body }}
          Files Changed: ${{ steps.pr-context.outputs.files_changed }}
          Changed Files: $(cat /tmp/files-changed.txt)

          Focus on:
          1. Bugs and logic errors
          2. Security vulnerabilities
          3. Performance issues
          4. Code quality and maintainability
          5. Missing error handling
          6. Test coverage gaps

          Format your response as:
          ## Summary
          [1-2 sentence summary]

          ## Findings
          For each finding:
          - **[SEVERITY]** File: description
            Suggestion: how to fix

          Severity levels: CRITICAL, HIGH, MEDIUM, LOW, INFO

          ## Verdict
          APPROVE / REQUEST_CHANGES / COMMENT

          Diff:
          $(cat /tmp/pr-diff-truncated.txt)"

          claude -p \
            --output-format text \
            --max-turns 3 \
            "$PROMPT" > /tmp/review-output.txt 2>/tmp/review-error.txt || true

          # Check if review was generated
          if [ -s /tmp/review-output.txt ]; then
            echo "review_success=true" >> $GITHUB_OUTPUT
          else
            echo "review_success=false" >> $GITHUB_OUTPUT
            echo "Review generation failed. Error output:"
            cat /tmp/review-error.txt
          fi

      - name: Post Review Comment
        if: steps.review.outputs.review_success == 'true'
        uses: actions/github-script@v7
        with:
          script: |
            const fs = require('fs');
            const review = fs.readFileSync('/tmp/review-output.txt', 'utf8');

            // Check for existing Claude review comment and update it
            const { data: comments } = await github.rest.issues.listComments({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: context.issue.number,
            });

            const existingComment = comments.find(c =>
              c.body.includes('<!-- claude-code-review -->')
            );

            const body = `<!-- claude-code-review -->
            ## Claude Code Review

            ${review}

            ---
            *Automated review by [Claude Code](https://claude.ai/code) | Commit: \`${context.sha.substring(0, 7)}\` | Files: ${process.env.FILES_CHANGED}*`;

            if (existingComment) {
              await github.rest.issues.updateComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                comment_id: existingComment.id,
                body: body,
              });
            } else {
              await github.rest.issues.createComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: context.issue.number,
                body: body,
              });
            }
        env:
          FILES_CHANGED: ${{ steps.pr-context.outputs.files_changed }}

      - name: Review Failed
        if: steps.review.outputs.review_success == 'false'
        run: |
          echo "::warning::Claude Code review could not be generated. This is non-blocking."