CREATE_MILESTONE.yml

name: CREATE_NEW_MILESTONE

on:
  milestone:
    types: ['closed']

jobs:
  create_milestone:
    runs-on: ubuntu-latest
    name: Create new Milestone
    if: startsWith(github.event.milestone.title, 'M')
    steps:
      - name: Get new Milestone Title
        id: get_title
        env:
          TITLE: ${{github.event.milestone.title}}
        run: |
          MILESTONE_NUMBER=${TITLE:1}
          INCREMENTED_NUMBER=$((MILESTONE_NUMBER + 1))
          echo "MILESTONE_NAME=M$INCREMENTED_NUMBER" >> $GITHUB_OUTPUT
      - name: Check if Milestone already exists
        id: check_if_milestone_exists
        env:
          TITLE: ${{steps.get_title.outputs.MILESTONE_NAME}}
        run: |
          existing_milestones=$(
            gh api -H "Accept: application/vnd.github.v3+json" \
              /repos/${{ github.repository }}/milestones \
              --jq '[.[] | select(.title | startswith("'$TITLE'")) | .number ][0]'
          )
          if [ -z "$existing_milestones" ]; then
            echo "MILESTONE_EXISTS=false" >> $GITHUB_OUTPUT
          else
            echo "MILESTONE_EXISTS=true" >> $GITHUB_OUTPUT
          fi
      - name: Create new Milestone
        if: steps.check_if_milestone_exists.outputs.MILESTONE_EXISTS == 'false'
        env:
          TITLE: ${{steps.get_title.outputs.MILESTONE_NAME}}
          GH_TOKEN: ${{ github.token }}
        shell: bash
        run: |
          gh api \
            --method POST \
            /repos/${{ github.repository }}/milestones \
            -f "title=$TITLE" -f "state=open"