name: issue-lint

on:
  issues:
    types: [opened]

jobs:
  issue-lint:
    runs-on: ubuntu-latest

    steps:
    - uses: actions/checkout@v3

    - uses: actions/github-script@v6
      with:
        github-token: ${{ secrets.GITHUB_TOKEN }}
        script: |
          const fs = require('fs').promises;

          const getTitles = (str) => (
            [...str.matchAll(/^## (.*)/gm)].map((m) => m[0])
          );

          const titles = getTitles(context.payload.issue.body);

          for (let file of await fs.readdir('.github/ISSUE_TEMPLATE')) {
            if (!file.endsWith('.md')) {
              continue;
            }

            const template = await fs.readFile(`.github/ISSUE_TEMPLATE/${file}`, 'utf-8');
            const templateTitles = getTitles(template);

            if (templateTitles.every((title) => titles.includes(title))) {
              process.exit(0);
            }
          }

          await github.rest.issues.createComment({
            owner: context.issue.owner,
            repo: context.issue.repo,
            issue_number: context.issue.number,
            body: 'This issue is being automatically closed because it does not follow the issue template.\n'
              + 'Please reopen the issue and make sure to include all sections of the template.',
          });

          await github.rest.issues.update({
            owner: context.issue.owner,
            repo: context.issue.repo,
            issue_number: context.issue.number,
            state: 'closed',
          });