name: Close Discussion on PR Merge

on:
  pull_request:
    types: [closed]

jobs:
  closeDiscussion:
    runs-on: ubuntu-latest
    steps:
      - name: Check if PR was merged
        if: github.event.pull_request.merged == true
        run: echo "PR was merged"

      - name: Extract Discussion Number
        if: github.event.pull_request.merged == true
        id: extract-discussion
        run: |
          echo "::set-output name=discussion::$(echo "${{ github.event.pull_request.body }}" | grep -oP '(?<=Resolves #)\d+')"
        shell: bash

      - name: Close the discussion
        if: github.event.pull_request.merged == true && steps.extract-discussion.outputs.discussion
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          DISCUSSION_ID: ${{ steps.extract-discussion.outputs.discussion }}
        run: |
          curl -X PATCH -H "Authorization: token $GITHUB_TOKEN" \
               -d '{"state": "closed"}' \
               "https://api.github.com/repos/${{ github.repository }}/discussions/${DISCUSSION_ID}"