name: PR Hygiene

on:
  pull_request:
    types:
      - opened
      - edited
      - reopened
      - synchronize

permissions:
  contents: read
  pull-requests: read

jobs:
  validate:
    runs-on: ubuntu-latest
    steps:
      - name: Validate pull request body
        uses: actions/github-script@v7
        with:
          script: |
            const body = context.payload.pull_request.body || "";

            function getSection(title) {
              const escaped = title.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
              const regex = new RegExp(`##\\s+${escaped}\\s*\\n([\\s\\S]*?)(?=\\n##\\s+|$)`, "i");
              const match = body.match(regex);
              return match ? match[1].trim() : "";
            }

            const linkedIssue = getSection("Linked issue");
            const howToTest = getSection("How to test");

            const hasIssueReference =
              /#\d+/.test(linkedIssue) ||
              /https:\/\/github\.com\/[^/\s]+\/[^/\s]+\/issues\/\d+/i.test(linkedIssue);

            const sanitizedHowToTest = howToTest
              .replace(/Describe the verification steps\. If no runtime test applies, explain why\./i, "")
              .trim();

            const failures = [];

            if (!hasIssueReference) {
              failures.push("Add an issue reference under `## Linked issue` (for example `Closes #123`).");
            }

            if (!sanitizedHowToTest) {
              failures.push("Fill in `## How to test` with verification steps or explain why no runtime test applies.");
            }

            if (failures.length > 0) {
              core.setFailed(failures.join("\n"));
            } else {
              core.info("Pull request body passed hygiene checks.");
            }