name: Enforce release label and template on release branches

on:
  pull_request:
    types: [opened, edited, synchronize, reopened, labeled, unlabeled]

jobs:
  enforce-label-and-template:
    runs-on: ubuntu-latest
    steps:
      - name: Require "release" label and release template for release/* base
        uses: actions/github-script@v7
        with:
          script: |
            const pr = context.payload.pull_request;
            const base = pr.base.ref;          // target branch, e.g. "release/1.2.3"
            const labels = pr.labels.map(l => l.name);
            const body = (pr.body || "").trim();

            // Only enforce on release branches
            if (!base.startsWith("release/")) {
              core.info(`Base branch "${base}" is not release/*, skipping checks.`);
              return;
            }

            const errors = [];

            // 1) Enforce "release" label
            const hasReleaseLabel = labels.includes("release");
            if (!hasReleaseLabel) {
              errors.push('PRs into release/* must have the "release" label before they can be merged.');
            }

            // 2) Enforce that the PR used the release template (checks for "# Release Notes")
            const releaseNotesHeader = "# Release Notes";
            const hasReleaseNotesSection = body.includes(releaseNotesHeader);
            if (!hasReleaseNotesSection) {
              errors.push(
                'PRs into release/* must use the release PR template and include a "# Release Notes" section.'
              );
            } else {
              // 3) Enforce that the Release Notes section has some real content
              const startIndex = body.indexOf(releaseNotesHeader);
              let afterHeader = body.slice(startIndex + releaseNotesHeader.length);

              // Split into lines after the header
              const lines = afterHeader.split(/\r?\n/);

              const releaseNotesLines = [];
              let started = false;

              for (const line of lines) {
                const trimmed = line.trim();

                // Skip the first blank line(s) right after the heading
                if (!started && trimmed === "") {
                  continue;
                }

                started = true;

                // Stop when we hit a new Markdown heading or a horizontal rule (---)
                if (/^#{1,6}\s+/.test(trimmed)) {
                  break;
                }
                if (/^---\s*$/.test(trimmed)) {
                  break;
                }

                releaseNotesLines.push(trimmed);
              }

              // Filter out placeholder-only lines (empty or just "-")
              const meaningfulLines = releaseNotesLines.filter(l => l !== "" && l !== "-");

              if (meaningfulLines.length === 0) {
                errors.push(
                  'The "# Release Notes" section appears empty. Please replace the placeholder "-" with actual release notes.'
                );
              }
            }

            if (errors.length > 0) {
              core.setFailed(errors.join("\n"));
            } else {
              core.info("Release label and template checks passed.");
            }