import assert from "node:assert/strict";
import fs from "node:fs";
import path from "node:path";
import { describe, it } from "node:test";
import { fileURLToPath } from "node:url";

const __dirname = fileURLToPath(new URL(".", import.meta.url));
const ROOT = path.resolve(__dirname, "../../");
const AGENTS_PATH = path.resolve(ROOT, "AGENTS.md");
const DOCS_DIR = path.resolve(ROOT, "docs");

// eslint-disable-next-line security/detect-non-literal-fs-filename
const readUtf8 = (filePath: string): string => fs.readFileSync(filePath, "utf8");

const getMandatoryRefsFromAgents = (content: string): string[] => {
  const marker = "## Mandatory References";
  const start = content.indexOf(marker);
  if (start < 0) {
    return [];
  }

  const tail = content.slice(start + marker.length);
  const nextHeaderIdx = tail.search(/\n##\s+/);
  const block = nextHeaderIdx >= 0 ? tail.slice(0, nextHeaderIdx) : tail;

  return block
    .split("\n")
    .map((line) => line.trim())
    .filter((line) => line.startsWith("- "))
    .map((line) => line.replace(/^- /, "").trim())
    .map((line) => {
      const backtickMatch = line.match(/`([^`]+)`/);
      return backtickMatch?.[1] ?? line;
    });
};

describe("Process docs linkage in AGENTS.md", () => {
  it("keeps required process docs listed in Mandatory References", () => {
    // eslint-disable-next-line security/detect-non-literal-fs-filename
    assert.ok(fs.existsSync(AGENTS_PATH), "AGENTS.md not found");
    const agents = readUtf8(AGENTS_PATH);
    const refs = new Set(getMandatoryRefsFromAgents(agents));

    // eslint-disable-next-line security/detect-non-literal-fs-filename
    const docsFiles = fs.readdirSync(DOCS_DIR);
    const autoRequired = docsFiles
      .filter((name) => /\.(md)$/i.test(name))
      .filter((name) => /(TEMPLATE|POLICY)\.md$/i.test(name))
      .map((name) => `docs/${name}`);

    const coreRequired = [
      "docs/ARCHITECTURE.md",
      "docs/CONTRIBUTING.md",
      "docs/TASK_INTAKE.md",
      "docs/QUALITY_GATES.md",
      "docs/TESTING.md",
      "docs/FAILURE_PLAYBOOK.md",
      "docs/HANDOFF_TEMPLATE.md",
      "docs/PUBLIC_API.md",
      "docs/CHANGE_POLICY.md",
      "docs/MIGRATION.md",
      "docs/RELEASE_HANDOFF.md",
      "CHANGELOG.md",
    ];

    const required = Array.from(new Set([ ...autoRequired, ...coreRequired ]));

    required.forEach((item) => {
      assert.ok(refs.has(item), `Missing "${item}" in AGENTS.md -> Mandatory References`);
    });
  });

  it("ensures all referenced Mandatory files exist", () => {
    const refs = getMandatoryRefsFromAgents(readUtf8(AGENTS_PATH));
    refs.forEach((relativePath) => {
      const absolutePath = path.resolve(ROOT, relativePath);
      // eslint-disable-next-line security/detect-non-literal-fs-filename
      assert.ok(fs.existsSync(absolutePath), `Mandatory reference path does not exist: "${relativePath}"`);
    });
  });
});