import { test } from "node:test";
import assert from "node:assert";
import { mkdtempSync, writeFileSync } from "node:fs";
import { tmpdir } from "node:os";
import { join } from "node:path";
import { detectKeyboardLayout, detectLang } from "../src/locale.js";

function withFakeLocalectl(output: string, fn: () => void) {
  const dir = mkdtempSync(join(tmpdir(), "fake-localectl-"));
  writeFileSync(join(dir, "localectl"), `#!/bin/sh\ncat <<'EOF'\n${output}\nEOF\n`, { mode: 0o755 });
  const originalPath = process.env.PATH;
  process.env.PATH = `${dir}:${originalPath}`;
  try {
    fn();
  } finally {
    process.env.PATH = originalPath;
  }
}

test("detectKeyboardLayout reads the X11 Layout line", () => {
  withFakeLocalectl(
    `   System Locale: LANG=de_DE.UTF-8
       VC Keymap: de-latin1
      X11 Layout: de
       X11 Model: pc105`,
    () => {
      assert.strictEqual(detectKeyboardLayout(), "de");
    },
  );
});

test("detectKeyboardLayout falls back to 'us' when localectl has no X11 Layout line", () => {
  withFakeLocalectl(`   System Locale: LANG=en_US.UTF-8\n       VC Keymap: us`, () => {
    assert.strictEqual(detectKeyboardLayout(), "us");
  });
});

test("detectKeyboardLayout falls back to 'us' when localectl is missing entirely", () => {
  const originalPath = process.env.PATH;
  process.env.PATH = "/nonexistent";
  try {
    assert.strictEqual(detectKeyboardLayout(), "us");
  } finally {
    process.env.PATH = originalPath;
  }
});

test("detectLang reads $LANG", () => {
  const original = process.env.LANG;
  process.env.LANG = "de_DE.UTF-8";
  try {
    assert.strictEqual(detectLang(), "de_DE.UTF-8");
  } finally {
    if (original === undefined) delete process.env.LANG;
    else process.env.LANG = original;
  }
});

test("detectLang returns null when $LANG is unset", () => {
  const original = process.env.LANG;
  delete process.env.LANG;
  try {
    assert.strictEqual(detectLang(), null);
  } finally {
    if (original !== undefined) process.env.LANG = original;
  }
});