import { execFile } from "node:child_process";
import { mkdtemp, mkdir, writeFile } from "node:fs/promises";
import os from "node:os";
import path from "node:path";
import { promisify } from "node:util";
import { describe, expect, it } from "vitest";

const execFileAsync = promisify(execFile);
const verifierSourcePath = path.resolve("scripts/verify-porting-guide.mjs");

async function makeRepo(guideContent) {
  const root = await mkdtemp(path.join(os.tmpdir(), "portingDocs-porting-guide-"));
  await mkdir(path.join(root, "scripts"), { recursive: true });
  await mkdir(path.join(root, "docs"), { recursive: true });
  await writeFile(path.join(root, "scripts/verify-porting-guide.mjs"), await import("node:fs/promises").then((fs) => fs.readFile(verifierSourcePath, "utf8")));
  if (guideContent !== null) await writeFile(path.join(root, "docs/porting-guide.md"), guideContent);
  return root;
}

function validGuide(rowCount = 12) {
  const rows = Array.from({ length: rowCount }, (_, index) => `| legacy-${index} | preferred-${index} | when-${index} | note-${index} |`).join("\n");
  return `# ToolCTRL Documentation Porting Guide

## Rename/Replace Map

| Legacy | Preferred | Apply in docs when | Notes |
| --- | --- | --- | --- |
${rows}

## Do-Not-Replace Rules

- Keep runtime identifiers stable.

## Verification

- Run the verifier.
`;
}

async function runVerifier(root) {
  return execFileAsync(process.execPath, [path.join(root, "scripts/verify-porting-guide.mjs")], { cwd: root });
}

describe("verify-porting-guide", () => {
  it("passes for a complete guide with enough rename-map rows", async () => {
    const root = await makeRepo(validGuide(12));

    await expect(runVerifier(root)).resolves.toMatchObject({
      stdout: expect.stringContaining("Verified docs/porting-guide.md: 13 Rename/Replace Map table rows."),
    });
  });

  it("fails when the guide is missing", async () => {
    const root = await makeRepo(null);

    await expect(runVerifier(root)).rejects.toMatchObject({ stderr: expect.stringContaining("missing docs/porting-guide.md") });
  });

  it("fails for unresolved markers and underspecified maps", async () => {
    const root = await makeRepo(validGuide(3).replace("- Run the verifier.", "TODO: decide later."));

    await expect(runVerifier(root)).rejects.toMatchObject({ stderr: expect.stringContaining("unresolved TODO/TBD/FIXME markers") });
  });
});