name: PR Template Check

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

permissions:
  pull-requests: read

jobs:
  validate_pr_body:
    runs-on: ubuntu-latest
    steps:
      - name: Validate required PR sections
        uses: actions/github-script@v7
        with:
          script: |
            const pr = context.payload.pull_request;
            const body = (pr.body || "").trim();

            function sectionContent(title) {
              const escaped = title.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
              const re = new RegExp(`^##\\s+${escaped}\\s*$`, "m");
              const match = body.match(re);
              if (!match) return null;
              const start = match.index + match[0].length;
              const rest = body.slice(start);
              const next = rest.search(/^##\s+/m);
              return (next === -1 ? rest : rest.slice(0, next)).trim();
            }

            const required = ["Summary", "Why", "Testing", "Breaking changes", "Linked issues"];
            const missing = [];
            const empty = [];

            for (const name of required) {
              const content = sectionContent(name);
              if (content === null) {
                missing.push(name);
                continue;
              }

              const cleaned = content
                .replace(/<!--[\s\S]*?-->/g, "")
                .replace(/`/g, "")
                .replace(/\s+/g, " ")
                .trim()
                .toLowerCase();

              if (
                cleaned.length < 4 ||
                cleaned === "none" ||
                cleaned.includes("what changed in this pr") ||
                cleaned.includes("why this change is needed") ||
                cleaned.includes("what you tested") ||
                cleaned.includes("example: fixes #123")
              ) {
                empty.push(name);
              }
            }

            if (missing.length || empty.length) {
              const lines = [
                "PR description is missing required detail.",
                "",
              ];
              if (missing.length) lines.push(`Missing sections: ${missing.join(", ")}`);
              if (empty.length) lines.push(`Incomplete sections: ${empty.join(", ")}`);
              lines.push("");
              lines.push("Please fill the PR template before merging.");
              core.setFailed(lines.join("\n"));
            } else {
              core.info("PR template check passed.");
            }