name: PR Body Check
on:
  pull_request:
    types:
      - opened
      - edited
      - reopened
      - synchronize
    branches:
      - develop

permissions:
  contents: read
  issues: read
  pull-requests: read

jobs:
  pr-body-check:
    if: github.repository_owner == 'GameServerManagers' && github.event.pull_request.user.type != 'Bot' && !startsWith(github.event.pull_request.head.ref, 'repo-sync/')
    runs-on: ubuntu-latest
    steps:
      - name: Check pull request body follows the template
        uses: actions/github-script@v9
        with:
          script: |
            const body = (context.payload.pull_request.body || '').replace(/<!--[\s\S]*?-->/g, '');
            const requiredHeadings = ['# Description', '## Type of change', '## Testing', '## Checklist'];
            const missing = requiredHeadings.filter((h) => !body.split(/\r?\n/).some((line) => line.trim() === h));
            const errors = [];

            if (missing.length > 0) {
              errors.push(`Missing template sections: ${missing.join(', ')}. Use .github/pull_request_template.md as the pull request body.`);
            }
            if (/^\s*fixes #\[issue\]\s*$/im.test(body)) {
              errors.push('Replace the "Fixes #[issue]" placeholder with the issue number, for example "Fixes #123".');
            }

            const closingKeyword = /\b(close[sd]?|fix(e[sd])?|resolve[sd]?):?\s+([\w.-]+\/[\w.-]+)?#\d+/i;
            const relatedIssue = /\brelated to:?\s+([\w.-]+\/[\w.-]+)?#\d+/i;
            if (!closingKeyword.test(body) && !relatedIssue.test(body)) {
              core.warning('No closing keyword found. Add "Fixes #123" to link the issue, or "Related to #123" if this pull request does not fully resolve it.');
            }

            const repoName = `${context.repo.owner}/${context.repo.repo}`.toLowerCase();
            const closingRefs = [...body.matchAll(/\b(?:close[sd]?|fix(?:e[sd])?|resolve[sd]?):?\s+([\w.-]+\/[\w.-]+)?#(\d+)/gi)]
              .filter((m) => !m[1] || m[1].toLowerCase() === repoName)
              .map((m) => Number(m[2]));
            const wanted = [...new Set(closingRefs)];
            if (wanted.length > 0) {
              const vars = { owner: context.repo.owner, repo: context.repo.repo };
              const { repository } = await github.graphql(
                `query($owner: String!, $repo: String!, $number: Int!) {
                  repository(owner: $owner, name: $repo) {
                    pullRequest(number: $number) { closingIssuesReferences(first: 50) { nodes { number } } }
                  }
                }`,
                { ...vars, number: context.payload.pull_request.number }
              );
              const linked = new Set(repository.pullRequest.closingIssuesReferences.nodes.map((n) => n.number));
              const unlinked = [];
              for (const number of wanted.filter((n) => !linked.has(n))) {
                try {
                  const { repository: ref } = await github.graphql(
                    `query($owner: String!, $repo: String!, $number: Int!) {
                      repository(owner: $owner, name: $repo) { issueOrPullRequest(number: $number) { __typename } }
                    }`,
                    { ...vars, number }
                  );
                  if (ref.issueOrPullRequest?.__typename === 'Issue') {
                    unlinked.push(`#${number}`);
                  }
                } catch (error) {
                  core.warning(`Could not look up #${number}: ${error.message}`);
                }
              }
              if (unlinked.length > 0) {
                errors.push(`Not linked in Development: ${unlinked.join(', ')}. Closing keywords in pull requests to develop do not link issues. A maintainer with write access must link these issues in the Development section, then re-run this check. No PR content change is needed to resolve the missing links.`);
              }
            }

            if (errors.length > 0) {
              core.setFailed(errors.join('\n'));
            }