name: Milestone

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

jobs:
  milestone:
    runs-on: ubuntu-latest

    permissions:
      actions: none
      checks: none
      contents: read
      deployments: none
      issues: write
      packages: none
      pull-requests: write
      repository-projects: none
      security-events: none
      statuses: none

    steps:
      - uses: actions/github-script@v4
        with:
          script: |
            if (!context.payload.pull_request.merged) {
              console.log('PR was not merged, skipping.');
              return;
            }
            if (!!context.payload.pull_request.milestone) {
              console.log('PR has existing milestone, skipping.');
              return;
            }
            milestones = await github.issues.listMilestones({
              owner: context.repo.owner,
              repo: context.repo.repo,
              state: 'open',
              sort: 'due_on',
              direction: 'asc'
            })
            if (milestones.data.length === 0) {
              console.log('There are no milestones, skipping.');
              return;
            }
            await github.issues.update({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: context.payload.pull_request.number,
              milestone: milestones.data[0].number
            });
