import fs from "node:fs";
import os from "node:os";
import path from "node:path";
import assert from "node:assert/strict";
import { execFileSync } from "node:child_process";
import { afterEach, describe, it } from "vitest";

import { checkDocsLinks, formatDocsLinkCheckResult } from "./docs-link-check";

const fixtures: string[] = [];

function createFixture(files: Record<string, string>): string {
  const rootDir = fs.mkdtempSync(path.join(os.tmpdir(), "docs-link-check-"));
  fixtures.push(rootDir);

  for (const [relativePath, content] of Object.entries(files)) {
    const absolutePath = path.join(rootDir, relativePath);
    fs.mkdirSync(path.dirname(absolutePath), { recursive: true });
    fs.writeFileSync(absolutePath, content);
  }

  return rootDir;
}

afterEach(() => {
  while (fixtures.length > 0) {
    fs.rmSync(fixtures.pop() as string, { recursive: true, force: true });
  }
});

describe("docs-link-check", () => {
  it("passes for valid local Markdown links and anchors", () => {
    const rootDir = createFixture({
      "README.md": "# Root\nSee [plugins](docs/plugins.md#plugin-boundaries).",
      "docs/plugins.md": "# Plugin Boundaries\nSee [feature inventory](feature-inventory.md).",
      "docs/feature-inventory.md": "# Feature Inventory\n",
    });

    const result = checkDocsLinks(rootDir, ["README.md", "docs"]);
    const output = formatDocsLinkCheckResult(result);

    assert.deepEqual(result.failures, []);
    assert.match(output, /^PASS docs link check/);
  });

  it("fails with file context for missing local paths", () => {
    const rootDir = createFixture({
      "README.md": "# Root\nSee [missing](docs/missing.md).",
    });

    const result = checkDocsLinks(rootDir, ["README.md", "docs"]);

    assert.match(result.failures.join("\n"), /README\.md:\d+:\d+: broken local link "docs\/missing\.md"/);
  });

  it("fails with file context for missing local anchors", () => {
    const rootDir = createFixture({
      "README.md": "# Root\nSee [plugins](docs/plugins.md#missing-anchor).",
      "docs/plugins.md": "# Plugin Boundaries\n",
    });

    const result = checkDocsLinks(rootDir, ["README.md", "docs"]);

    assert.match(result.failures.join("\n"), /README\.md:\d+:\d+: broken local anchor "#missing-anchor"/);
  });

  it("ignores external URLs and special link schemes", () => {
    const rootDir = createFixture({
      "README.md": [
        "# Root",
        "See [external](https://example.com/missing#anchor).",
        "Send [mail](mailto:help@example.com) or [call](tel:+15555550100).",
        "Jump to [local](#root).",
      ].join("\n"),
    });

    const result = checkDocsLinks(rootDir, ["README.md"]);

    assert.deepEqual(result.failures, []);
  });

  it("fails closed when a configured docs root is missing", () => {
    const rootDir = createFixture({
      "README.md": "# Root\n",
    });

    const result = checkDocsLinks(rootDir, ["README.md", "docs"]);

    assert.match(result.failures.join("\n"), /docs-roots: missing configured docs root docs/);
  });

  it("fails closed when no Markdown files are checked", () => {
    const rootDir = createFixture({
      "src/index.ts": "export {};",
    });

    const result = checkDocsLinks(rootDir, ["docs"]);

    assert.match(result.failures.join("\n"), /docs-roots: checked 0 Markdown files/);
  });

  it("exits non-zero from the CLI when local links are broken", () => {
    const rootDir = createFixture({
      "README.md": "# Root\nSee [missing](docs/missing.md).",
      "AGENTS.md": "# Agents\n",
      "SECURITY.md": "# Security\n",
      "CHANGELOG.md": "# Changelog\n",
      "docs/index.md": "# Docs\n",
      "guides/index.md": "# Guides\n",
      "llm-docs/index.md": "# LLM Docs\n",
    });

    let output = "";
    assert.throws(() => {
      try {
        execFileSync("pnpm", ["exec", "tsx", path.resolve("scripts/docs-link-check.ts"), rootDir], { encoding: "utf8", stdio: "pipe" });
      } catch (error) {
        if (error && typeof error === "object") {
          const failure = error as { stderr?: Buffer | string; stdout?: Buffer | string };
          output = `${String(failure.stderr ?? "")}\n${String(failure.stdout ?? "")}`;
        }
        throw error;
      }
    });
    assert.match(output, /broken local link "docs\/missing\.md"/);
  });
});