contract-check.yml

name: API Contract Check

on:
  pull_request:
    branches: [ main ]
    paths:
      - '**.go'
      - 'go.mod'
      - 'go.sum'
      - 'modules/**/go.mod'
      - 'modules/**/go.sum'

permissions:
  contents: read
  pull-requests: write
  actions: read

env:
  GO_VERSION: '^1.26'

jobs:
  contract-check:
    name: API Contract Check
    runs-on: ubuntu-latest
    steps:
      - name: Checkout PR code
        uses: actions/checkout@v7
        with:
          fetch-depth: 0

      - name: Set up Go
        uses: actions/setup-go@v7
        with:
          go-version: ${{ env.GO_VERSION }}
          check-latest: true
          cache: true

      - name: Build modcli
        run: |
          cd cmd/modcli
          go build -o modcli

      - name: Extract contracts from main branch
        run: |
          git checkout origin/main
          mkdir -p artifacts/contracts/main
          
          # Extract core framework contract
          ./cmd/modcli/modcli contract extract . -o artifacts/contracts/main/core.json
          
          # Extract contracts for all modules
          for module_dir in modules/*/; do
            module_name=$(basename "$module_dir")
            if [ -f "$module_dir/go.mod" ]; then
              echo "Extracting contract for module: $module_name"
              ./cmd/modcli/modcli contract extract "./$module_dir" -o "artifacts/contracts/main/${module_name}.json" || echo "Failed to extract $module_name"
            fi
          done

      - name: Checkout PR branch
        run: |
          git checkout ${{ github.event.pull_request.head.sha }}

      - name: Extract contracts from PR branch
        run: |
          mkdir -p artifacts/contracts/pr
          
          # Extract core framework contract
          ./cmd/modcli/modcli contract extract . -o artifacts/contracts/pr/core.json
          
          # Extract contracts for all modules
          for module_dir in modules/*/; do
            module_name=$(basename "$module_dir")
            if [ -f "$module_dir/go.mod" ]; then
              echo "Extracting contract for module: $module_name"
              ./cmd/modcli/modcli contract extract "./$module_dir" -o "artifacts/contracts/pr/${module_name}.json" || echo "Failed to extract $module_name"
            fi
          done

      - name: Compare contracts and generate diffs
        id: contract-diff
        run: |
          mkdir -p artifacts/diffs

          breaking_changes=false
          has_changes=false

          # Compare core framework
          if [ -f "artifacts/contracts/main/core.json" ] && [ -f "artifacts/contracts/pr/core.json" ]; then
            echo "Comparing core framework contract..."
            if ./cmd/modcli/modcli contract compare artifacts/contracts/main/core.json artifacts/contracts/pr/core.json -o artifacts/diffs/core.json --format=markdown > artifacts/diffs/core.md 2>&1; then
              if [ -s "artifacts/diffs/core.md" ]; then
                echo "Core framework: Changes detected (no breaking changes)"
                has_changes=true
              else
                echo "Core framework: No changes"
              fi
            else
              echo "Core framework: Breaking changes detected!"
              breaking_changes=true
              has_changes=true
            fi
          fi

          # Compare all modules
          for module_dir in modules/*/; do
            module_name=$(basename "$module_dir")
            if [ -f "artifacts/contracts/main/${module_name}.json" ] && [ -f "artifacts/contracts/pr/${module_name}.json" ]; then
              echo "Comparing module: $module_name"
              if ./cmd/modcli/modcli contract compare "artifacts/contracts/main/${module_name}.json" "artifacts/contracts/pr/${module_name}.json" -o "artifacts/diffs/${module_name}.json" --format=markdown > "artifacts/diffs/${module_name}.md" 2>&1; then
                if [ -s "artifacts/diffs/${module_name}.md" ]; then
                  echo "Module $module_name: Changes detected (no breaking changes)"
                  has_changes=true
                else
                  echo "Module $module_name: No changes"
                fi
              else
                echo "Module $module_name: Breaking changes detected!"
                breaking_changes=true
                has_changes=true
              fi
            fi
          done

          echo "breaking_changes=$breaking_changes" >> $GITHUB_OUTPUT
          echo "has_changes=$has_changes" >> $GITHUB_OUTPUT

      - name: Upload contract artifacts
        uses: actions/upload-artifact@v7
        if: always()
        with:
          name: api-contracts-${{ github.run_number }}
          path: artifacts/
          retention-days: 30

      - name: Generate contract summary
        id: summary
        if: steps.contract-diff.outputs.has_changes == 'true'
        run: |
          echo "## 📋 API Contract Changes Summary" > contract-summary.md
          echo "" >> contract-summary.md
          
          if [ "${{ steps.contract-diff.outputs.breaking_changes }}" == "true" ]; then
            echo "⚠️ **WARNING: This PR contains breaking API changes!**" >> contract-summary.md
            echo "" >> contract-summary.md
          else
            echo "✅ **No breaking changes detected - only additions and non-breaking modifications**" >> contract-summary.md
            echo "" >> contract-summary.md
          fi
          
          echo "### Changed Components:" >> contract-summary.md
          echo "" >> contract-summary.md
          
          # Add core framework diff if it exists
          if [ -f "artifacts/diffs/core.md" ] && [ -s "artifacts/diffs/core.md" ]; then
            echo "#### Core Framework" >> contract-summary.md
            echo "" >> contract-summary.md
            cat artifacts/diffs/core.md >> contract-summary.md
            echo "" >> contract-summary.md
          fi
          
          # Add module diffs
          for diff_file in artifacts/diffs/*.md; do
            if [ -f "$diff_file" ] && [ -s "$diff_file" ]; then
              module_name=$(basename "$diff_file" .md)
              if [ "$module_name" != "core" ]; then
                echo "#### Module: $module_name" >> contract-summary.md
                echo "" >> contract-summary.md
                cat "$diff_file" >> contract-summary.md
                echo "" >> contract-summary.md
              fi
            fi
          done
          
          echo "### Artifacts" >> contract-summary.md
          echo "" >> contract-summary.md
          echo "📁 Full contract diffs and JSON artifacts are available in the [workflow artifacts](${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }})." >> contract-summary.md

      - name: Comment PR with contract changes
        if: steps.contract-diff.outputs.has_changes == 'true'
        uses: actions/github-script@v9
        with:
          script: |
            const fs = require('fs');
            const path = 'contract-summary.md';
            
            if (fs.existsSync(path)) {
              const summary = fs.readFileSync(path, 'utf8');
              
              // Find existing contract comment
              const { data: comments } = await github.rest.issues.listComments({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: context.payload.pull_request.number,
              });
              
              const botComment = comments.find(comment => 
                comment.user.type === 'Bot' && 
                comment.body.includes('📋 API Contract Changes Summary')
              );
              
              if (botComment) {
                // Update existing comment
                await github.rest.issues.updateComment({
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  comment_id: botComment.id,
                  body: summary
                });
              } else {
                // Create new comment
                await github.rest.issues.createComment({
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  issue_number: context.payload.pull_request.number,
                  body: summary
                });
              }
            }

      - name: Fail if breaking changes
        if: steps.contract-diff.outputs.breaking_changes == 'true'
        run: |
          echo "::error::Breaking API changes detected! Please review the contract diff and ensure this is intentional."
          echo "If this is a major version change, consider:"
          echo "1. Updating version numbers appropriately"
          echo "2. Adding migration guides"
          echo "3. Updating documentation"
          echo "4. Communicating breaking changes to users"
          exit 1

  # Success job that only runs if contract check passes or no changes
  contract-passed:
    name: API Contract Passed
    runs-on: ubuntu-latest
    needs: contract-check
    if: always() && (needs.contract-check.result == 'success' || needs.contract-check.outputs.has_changes != 'true')
    steps:
      - name: Contract check passed
        run: |
          echo "✅ API contract check passed - no breaking changes detected"