name: Skill PR Validation

on:
  pull_request:
    branches: [main]
    paths:
      - '.claude/skills/**'
      - 'skills-engine/**'

jobs:
  # ── Job 1: Policy gate ────────────────────────────────────────────────
  # Block PRs that add NEW skill files while also modifying source code.
  # Skill PRs should contain instructions for Claude, not raw source edits.
  policy-check:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Check for mixed skill + source changes
        run: |
          ADDED_SKILLS=$(git diff --name-only --diff-filter=A origin/main...HEAD \
            | grep '^\\.claude/skills/' || true)
          CHANGED=$(git diff --name-only origin/main...HEAD)
          SOURCE=$(echo "$CHANGED" \
            | grep -E '^src/|^container/|^package\.json|^package-lock\.json' || true)

          if [ -n "$ADDED_SKILLS" ] && [ -n "$SOURCE" ]; then
            echo "::error::PRs that add new skills should not modify source files."
            echo ""
            echo "New skill files:"
            echo "$ADDED_SKILLS"
            echo ""
            echo "Source files:"
            echo "$SOURCE"
            echo ""
            echo "Please split into separate PRs. See CONTRIBUTING.md."
            exit 1
          fi

      - name: Comment on failure
        if: failure()
        uses: actions/github-script@v7
        with:
          script: |
            github.rest.issues.createComment({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: context.issue.number,
              body: `This PR adds a skill while also modifying source code. A skill PR should not change source files—the skill should contain **instructions** for Claude to follow.

            If you're fixing a bug or simplifying code, please submit that as a separate PR.

            See [CONTRIBUTING.md](https://github.com/${context.repo.owner}/${context.repo.repo}/blob/main/CONTRIBUTING.md) for details.`
            })

  # ── Job 2: Detect which skills changed ────────────────────────────────
  detect-changed:
    runs-on: ubuntu-latest
    outputs:
      skills: ${{ steps.detect.outputs.skills }}
      has_skills: ${{ steps.detect.outputs.has_skills }}
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Detect changed skills
        id: detect
        run: |
          CHANGED_SKILLS=$(git diff --name-only origin/main...HEAD \
            | grep '^\\.claude/skills/' \
            | sed 's|^\.claude/skills/||' \
            | cut -d/ -f1 \
            | sort -u \
            | jq -R . | jq -s .)
          echo "skills=$CHANGED_SKILLS" >> "$GITHUB_OUTPUT"
          if [ "$CHANGED_SKILLS" = "[]" ]; then
            echo "has_skills=false" >> "$GITHUB_OUTPUT"
          else
            echo "has_skills=true" >> "$GITHUB_OUTPUT"
          fi
          echo "Changed skills: $CHANGED_SKILLS"

  # ── Job 3: Validate each changed skill in isolation ───────────────────
  validate-skills:
    needs: detect-changed
    if: needs.detect-changed.outputs.has_skills == 'true'
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
        skill: ${{ fromJson(needs.detect-changed.outputs.skills) }}
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: 20
          cache: npm
      - run: npm ci

      - name: Initialize skills system
        run: >-
          npx tsx -e
          "import { initNanoclawDir } from './skills-engine/index'; initNanoclawDir();"

      - name: Apply skill
        run: npx tsx scripts/apply-skill.ts ".claude/skills/${{ matrix.skill }}"

      - name: Typecheck after apply
        run: npx tsc --noEmit

      - name: Run skill tests
        run: |
          TEST_CMD=$(npx tsx -e "
            import { parse } from 'yaml';
            import fs from 'fs';
            const m = parse(fs.readFileSync('.claude/skills/${{ matrix.skill }}/manifest.yaml', 'utf-8'));
            if (m.test) console.log(m.test);
          ")
          if [ -n "$TEST_CMD" ]; then
            echo "Running: $TEST_CMD"
            eval "$TEST_CMD"
          else
            echo "No test command defined, skipping"
          fi

  # ── Summary gate for branch protection ────────────────────────────────
  skill-validation-summary:
    needs:
      - policy-check
      - detect-changed
      - validate-skills
    if: always()
    runs-on: ubuntu-latest
    steps:
      - name: Check results
        run: |
          echo "policy-check: ${{ needs.policy-check.result }}"
          echo "validate-skills: ${{ needs.validate-skills.result }}"

          if [ "${{ needs.policy-check.result }}" = "failure" ]; then
            echo "::error::Policy check failed"
            exit 1
          fi
          if [ "${{ needs.validate-skills.result }}" = "failure" ]; then
            echo "::error::Skill validation failed"
            exit 1
          fi
          echo "All skill checks passed"