name: "[PR Management] Request Backport via Mergify"

on:
  pull_request_target:
    types: [closed]
    branches: [main]

permissions:
  pull-requests: write

jobs:
  comment-backport:
    if: github.event.pull_request.merged == true
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repository
        uses: actions/checkout@v4
        with:
          ref: ${{ github.base_ref }}

      - name: Post Mergify backport command
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          set -euo pipefail

          pr_number=${{ github.event.pull_request.number }}
          repo="${{ github.repository }}"

          labels_json='${{ toJson(github.event.pull_request.labels.*.name) }}'
          labels=$(echo "$labels_json" | jq -r '.[] // empty')

          echo "Labels on PR: $labels"

          matches=$(echo "$labels" | grep -oE '^require backport/v[0-9]+\.[0-9]+$' || true)

          if [[ -z "$matches" ]]; then
            echo "No back‑port labels found — skipping."
            exit 0
          fi

          branches=$(echo "$matches" \
            | sed -E 's/^require backport\/v/release-harvester-v/' \
            | sort -u | tr '\n' ' ')
          branches=${branches%% }

          cmd="@Mergifyio backport $branches"
          echo "Posting Mergify command: $cmd"
          gh pr comment "$pr_number" --repo "$repo" --body "$cmd"