name: Forward Port to Next

on:
  push:
    branches:
      - main

concurrency:
  group: forward-port
  cancel-in-progress: false

permissions:
  contents: write
  pull-requests: write

jobs:
  forward-port:
    runs-on: ubuntu-latest
    env:
      DISCORD_WEBHOOK: ${{ secrets.DISCORD_METRICS_WEBHOOK }}
    steps:
      - name: Checkout
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Check for existing PR
        id: check-pr
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          EXISTING_PR=$(gh pr list --base next --head main --state open --json number --jq '.[0].number // empty')
          if [ -n "$EXISTING_PR" ]; then
            echo "existing_pr=$EXISTING_PR" >> $GITHUB_OUTPUT
            echo "PR #$EXISTING_PR already exists for main → next"
          else
            echo "existing_pr=" >> $GITHUB_OUTPUT
            echo "No existing PR found"
          fi

      - name: Check if main has changes not in next
        id: check-diff
        if: steps.check-pr.outputs.existing_pr == ''
        run: |
          git fetch origin next
          DIFF_COUNT=$(git rev-list --count origin/next..origin/main)
          echo "diff_count=$DIFF_COUNT" >> $GITHUB_OUTPUT
          if [ "$DIFF_COUNT" -gt 0 ]; then
            echo "Found $DIFF_COUNT commit(s) in main not in next"
          else
            echo "No new commits to forward port"
          fi

      - name: Check for merge conflicts
        id: check-conflicts
        if: steps.check-pr.outputs.existing_pr == '' && steps.check-diff.outputs.diff_count != '0'
        run: |
          git config user.name "github-actions[bot]"
          git config user.email "github-actions[bot]@users.noreply.github.com"

          # Try a test merge to detect conflicts
          git checkout origin/next
          if git merge --no-commit --no-ff origin/main 2>/dev/null; then
            echo "has_conflicts=false" >> $GITHUB_OUTPUT
            echo "No merge conflicts detected"
          else
            echo "has_conflicts=true" >> $GITHUB_OUTPUT
            # Get list of conflicting files
            CONFLICTING_FILES=$(git diff --name-only --diff-filter=U | head -10)
            echo "conflicting_files<<EOF" >> $GITHUB_OUTPUT
            echo "$CONFLICTING_FILES" >> $GITHUB_OUTPUT
            echo "EOF" >> $GITHUB_OUTPUT
            echo "Merge conflicts detected in: $CONFLICTING_FILES"
          fi
          git merge --abort 2>/dev/null || true

      - name: Create forward-port PR
        id: create-pr
        if: steps.check-pr.outputs.existing_pr == '' && steps.check-diff.outputs.diff_count != '0'
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          # Get the commits being forward-ported for the PR body
          COMMITS=$(git log origin/next..origin/main --oneline --no-decorate | head -20)
          COMMIT_COUNT=$(git rev-list --count origin/next..origin/main)

          # Build conflict warning if needed
          CONFLICT_WARNING=""
          if [ "${{ steps.check-conflicts.outputs.has_conflicts }}" = "true" ]; then
            CONFLICT_WARNING="
          > [!WARNING]
          > **Merge conflicts detected.** Manual resolution required.
          >
          > Conflicting files:
          > \`\`\`
          > ${{ steps.check-conflicts.outputs.conflicting_files }}
          > \`\`\`

          ### How to resolve

          \`\`\`bash
          # Option 1: Resolve in a temporary branch (recommended)
          git fetch origin
          git checkout -b resolve-forward-port origin/next
          git merge origin/main
          # Fix conflicts in your editor, then:
          git add .
          git commit
          git push origin resolve-forward-port
          # Create PR from resolve-forward-port → next, then close this PR

          # Option 2: Resolve directly on next
          git checkout next
          git pull origin next
          git merge origin/main
          # Fix conflicts, commit, and push
          \`\`\`
          "
          fi

          # Create PR body
          BODY="## Forward Port: main → next

          This PR forward-ports changes from \`main\` to \`next\` to ensure hotfixes and releases are included in the next development branch.
          $CONFLICT_WARNING
          ### Commits ($COMMIT_COUNT total)
          \`\`\`
          $COMMITS
          \`\`\`
          $([ "$COMMIT_COUNT" -gt 20 ] && echo "... and $((COMMIT_COUNT - 20)) more")

          ---
          *Auto-generated by forward-port workflow*"

          # Create the PR
          PR_URL=$(gh pr create \
            --base next \
            --head main \
            --title "chore: forward port main to next" \
            --label "forward-port" \
            --label "automated" \
            --body "$BODY")

          PR_NUMBER=$(echo "$PR_URL" | grep -oE '[0-9]+$')
          echo "pr_number=$PR_NUMBER" >> $GITHUB_OUTPUT
          echo "pr_url=$PR_URL" >> $GITHUB_OUTPUT

          # Add conflict label if needed
          if [ "${{ steps.check-conflicts.outputs.has_conflicts }}" = "true" ]; then
            gh pr edit "$PR_NUMBER" --add-label "has-conflicts"
          fi

      - name: Send Discord notification
        if: steps.create-pr.outputs.pr_url != '' && env.DISCORD_WEBHOOK != ''
        uses: sarisia/actions-status-discord@v1
        with:
          webhook: ${{ env.DISCORD_WEBHOOK }}
          status: ${{ steps.check-conflicts.outputs.has_conflicts == 'true' && 'Warning' || 'Success' }}
          title: "🔄 Forward Port PR Created"
          description: |
            **main → next**

            ${{ steps.check-conflicts.outputs.has_conflicts == 'true' && '⚠️ **Merge conflicts detected** - manual resolution required' || '✅ No conflicts - ready for review' }}

            **Commits:** ${{ steps.check-diff.outputs.diff_count }}
            **PR:** ${{ steps.create-pr.outputs.pr_url }}
          color: ${{ steps.check-conflicts.outputs.has_conflicts == 'true' && '0xFFA500' || '0x58AFFF' }}
          username: Task Master Bot
          avatar_url: https://raw.githubusercontent.com/eyaltoledano/claude-task-master/main/images/logo.png