const assert = require('node:assert/strict');
const fs = require('node:fs');
const os = require('node:os');
const path = require('node:path');
const { spawn, spawnSync } = require('node:child_process');
const { chromium } = require('playwright-core');

const BASE_URL = 'http://127.0.0.1:6970';
const RUNFILES = process.env.JS_BINARY__RUNFILES;
const WORKSPACE = process.env.JS_BINARY__WORKSPACE;
let hgCommand = 'hg';

function run(command, args, options = {}) {
  const result = spawnSync(command, args, {
    encoding: 'utf8',
    ...options,
  });
  if (result.status !== 0) {
    throw new Error(
      `${command} ${args.join(' ')} failed\n${result.stdout || ''}${result.stderr || ''}`,
    );
  }
  return result.stdout.trim();
}

function mercurialEnvironment(home) {
  return {
    ...process.env,
    HGPLAIN: '1',
    HGRCPATH: '',
    HOME: home,
  };
}

function stopProcess(child) {
  if (!child || child.exitCode !== null) return Promise.resolve();
  child.kill('SIGTERM');
  return new Promise(resolve => {
    const timer = setTimeout(() => {
      if (child.exitCode === null) child.kill('SIGKILL');
    }, 3000);
    child.once('exit', () => {
      clearTimeout(timer);
      resolve();
    });
  });
}

async function waitForHttp(url, child, logs) {
  const deadline = Date.now() + 15000;
  while (Date.now() < deadline) {
    if (child.exitCode !== null) {
      throw new Error(`Server exited early with ${child.exitCode}\n${logs.join('')}`);
    }
    try {
      const response = await fetch(url);
      if (response.ok) return;
    } catch {
      // Keep waiting for startup.
    }
    await new Promise(resolve => setTimeout(resolve, 100));
  }
  throw new Error(`Timed out waiting for ${url}\n${logs.join('')}`);
}

function createFixtureRepository(root) {
  const options = { env: mercurialEnvironment(root) };
  run(hgCommand, ['init', root], options);
  fs.mkdirSync(path.join(root, 'docs'), { recursive: true });
  fs.mkdirSync(path.join(root, 'src'), { recursive: true });
  fs.writeFileSync(
    path.join(root, 'README.md'),
    '# Fixture Repository\n\n<script>window.__hgWebXss = true</script>\n',
  );
  fs.writeFileSync(path.join(root, 'docs', 'README.md'), '# Documentation\n\nNested README.\n');
  fs.writeFileSync(path.join(root, 'src', 'main.c'), 'int main(void) { return 0; }\n');
  fs.writeFileSync(
    path.join(root, 'BUILD'),
    'cc_library(\n    name = "fixture",\n    srcs = ["src/main.c"],\n)\n',
  );
  fs.writeFileSync(
    path.join(root, 'pixel.png'),
    Buffer.from(
      'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mP8/x8AAusB9Wl2nWQAAAAASUVORK5CYII=',
      'base64',
    ),
  );
  fs.writeFileSync(path.join(root, 'movie.mp4'), Buffer.from('00000018667479706d703432', 'hex'));
  fs.writeFileSync(path.join(root, 'sound.mp3'), Buffer.from('ID3'));
  fs.writeFileSync(path.join(root, 'document.pdf'), Buffer.from('%PDF-1.4\n%%EOF\n'));
  fs.writeFileSync(path.join(root, 'archive.bin'), Buffer.from([0, 1, 2, 3]));
  run(hgCommand, ['--repository', root, 'add'], options);
  run(hgCommand, ['--repository', root, 'commit', '-u', 'Test User <[email protected]>', '-m', 'Initial fixture'], options);
  const firstNode = run(hgCommand, ['--repository', root, 'log', '-r', '.', '-T', '{node}'], options);

  fs.writeFileSync(
    path.join(root, 'README.md'),
    '# Updated Fixture Repository\n\n<script>window.__hgWebXss = true</script>\n\nSecond revision.\n',
  );
  fs.writeFileSync(path.join(root, 'new-file.txt'), 'new file\n');
  run(hgCommand, ['add', 'new-file.txt'], { ...options, cwd: root });
  run(hgCommand, ['--repository', root, 'commit', '-u', 'Test User <[email protected]>', '-m', 'Update fixture'], options);
  const tipNode = run(hgCommand, ['--repository', root, 'log', '-r', '.', '-T', '{node}'], options);
  return { firstNode, tipNode };
}

async function assertJson(pathname, status = 200) {
  const response = await fetch(`${BASE_URL}${pathname}`);
  const body = await response.text();
  assert.equal(response.status, status, `${pathname} status: ${body}`);
  return JSON.parse(body);
}

async function assertPageHasNoBrowserErrors(browser, pathname, assertion) {
  const page = await browser.newPage();
  const errors = [];
  page.on('pageerror', error => errors.push(`pageerror: ${error.stack || error.message}`));
  page.on('console', message => {
    if (message.type() === 'error') errors.push(`console: ${message.text()}`);
  });
  page.on('requestfailed', request => {
    errors.push(`requestfailed: ${request.url()} ${request.failure()?.errorText || ''}`);
  });
  page.on('response', response => {
    if (response.status() >= 400) {
      errors.push(`response: ${response.status()} ${response.url()}`);
    }
  });

  const response = await page.goto(`${BASE_URL}${pathname}`, { waitUntil: 'networkidle' });
  assert.equal(response.status(), 200, `${pathname} document status`);
  await assertion(page);
  if (errors.length > 0) {
    throw new Error(`${pathname} browser errors\n${errors.join('\n')}`);
  }
  await page.close();
}

async function main() {
  assert.ok(RUNFILES, 'rules_js runfiles path is required');
  assert.ok(WORKSPACE, 'rules_js workspace name is required');

  const fixtureRoot = fs.mkdtempSync(path.join(os.tmpdir(), 'hg-web-e2e-'));
  const appLogs = [];
  const hgLogs = [];
  let hgServer;
  let appServer;
  let browser;

  try {
    const runfilesWorkspace = path.join(RUNFILES, WORKSPACE);
    const serverBinary = path.join(runfilesWorkspace, 'hg-web', 'hg_web_server');
    hgCommand = path.join(
      runfilesWorkspace,
      'third_party',
      'mercurial',
      'runtime',
      'bin',
      'hg',
    );
    const chromiumPath = path.resolve(process.env.CHROMIUM_PATH);

    assert.ok(fs.existsSync(serverBinary), `missing server binary: ${serverBinary}`);
    assert.ok(fs.existsSync(hgCommand), `missing bundled Mercurial: ${hgCommand}`);
    assert.ok(fs.existsSync(chromiumPath), `missing Chromium binary: ${chromiumPath}`);
    const { firstNode, tipNode } = createFixtureRepository(fixtureRoot);

    hgServer = spawn(
      hgCommand,
      [
        '--repository', fixtureRoot,
        'serve',
        '--address', '127.0.0.1',
        '--port', '4444',
        '--accesslog', '-',
        '--errorlog', '-',
      ],
      {
        env: mercurialEnvironment(fixtureRoot),
        stdio: ['ignore', 'pipe', 'pipe'],
      },
    );
    hgServer.stdout.on('data', chunk => hgLogs.push(chunk.toString()));
    hgServer.stderr.on('data', chunk => hgLogs.push(chunk.toString()));

    appServer = spawn(serverBinary, [], {
      cwd: runfilesWorkspace,
      stdio: ['ignore', 'pipe', 'pipe'],
    });
    appServer.stdout.on('data', chunk => appLogs.push(chunk.toString()));
    appServer.stderr.on('data', chunk => appLogs.push(chunk.toString()));

    await waitForHttp(`${BASE_URL}/`, appServer, appLogs);
    if (hgServer.exitCode !== null) {
      throw new Error(`Mercurial server exited early with ${hgServer.exitCode}\n${hgLogs.join('')}`);
    }
    await waitForHttp(`${BASE_URL}/api/repo/list`, hgServer, hgLogs);

    for (const pathname of ['/', '/directory', '/directory?path=docs', '/graph', `/changeset/${tipNode}`]) {
      const response = await fetch(`${BASE_URL}${pathname}`);
      assert.equal(response.status, 200, `${pathname} shell route`);
      assert.match(await response.text(), /<title>Zenbu Repository<\/title>/);
    }
    for (const pathname of ['/page.js', '/index.css', '/base.css', '/pencil_lines.png', '/panda.png']) {
      const response = await fetch(`${BASE_URL}${pathname}`);
      assert.equal(response.status, 200, `${pathname} static asset`);
      assert.ok((await response.arrayBuffer()).byteLength > 0, `${pathname} is non-empty`);
    }
    for (const pathname of ['/hg-web-background.jpg', '/pencil_texture.png']) {
      assert.equal((await fetch(`${BASE_URL}${pathname}`)).status, 404);
    }

    const rootList = await assertJson('/api/repo/list');
    assert.ok(rootList.directories.some(entry => entry.basename === 'docs'));
    assert.ok(rootList.files.some(entry => entry.basename === 'README.md'));

    const nestedList = await assertJson('/api/repo/list?path=docs');
    assert.ok(nestedList.files.some(entry => entry.basename === 'README.md'));

    const fileResponse = await fetch(`${BASE_URL}/api/repo/file?path=src%2Fmain.c`);
    assert.equal(fileResponse.status, 200);
    assert.match(await fileResponse.text(), /int main/);

    for (const [filename, contentType, disposition] of [
      ['pixel.png', 'image/png', 'inline'],
      ['movie.mp4', 'video/mp4', 'inline'],
      ['sound.mp3', 'audio/mpeg', 'inline'],
      ['document.pdf', 'application/pdf', 'inline'],
      ['archive.bin', 'application/octet-stream', 'attachment'],
    ]) {
      const response = await fetch(
        `${BASE_URL}/api/repo/file?path=${encodeURIComponent(filename)}`,
      );
      assert.equal(response.status, 200, `${filename} response`);
      assert.match(response.headers.get('content-type') || '', new RegExp(`^${contentType}`));
      assert.equal(response.headers.get('content-disposition'), disposition);
      assert.equal(response.headers.get('x-content-type-options'), 'nosniff');
      assert.ok((await response.arrayBuffer()).byteLength > 0);
    }
    const binaryResponse = await fetch(`${BASE_URL}/api/repo/file?path=archive.bin`);
    assert.deepEqual(
      Buffer.from(await binaryResponse.arrayBuffer()),
      Buffer.from([0, 1, 2, 3]),
    );

    const readmeResponse = await fetch(`${BASE_URL}/api/repo/readme?path=docs`);
    assert.equal(readmeResponse.status, 200);
    assert.match(await readmeResponse.text(), /Nested README/);
    assert.equal((await fetch(`${BASE_URL}/api/repo/readme?path=src`)).status, 204);

    const graph = await assertJson('/api/graph/tip?style=json');
    assert.equal(graph.node, tipNode);
    assert.ok(graph.changesets.length >= 2);

    const changeset = await assertJson(`/api/changeset/${tipNode}`);
    assert.equal(changeset.node, tipNode);
    assert.equal(changeset.desc, 'Update fixture');
    assert.ok(changeset.files.some(entry => entry.file === 'new-file.txt' && entry.status === 'added'));
    assert.ok(changeset.diff.length > 0);

    for (const pathname of [
      '/api/repo/list?path=..%2Fetc',
      '/api/repo/file?path=..%2FREADME.md',
      '/api/graph/not-a-node?style=json',
      '/api/changeset/not-a-node',
    ]) {
      const response = await fetch(`${BASE_URL}${pathname}`);
      assert.equal(response.status, 400, `${pathname} rejects invalid input`);
    }
    assert.equal((await fetch(`${BASE_URL}/missing-route`)).status, 404);

    const identify = run(
      hgCommand,
      ['identify', `${BASE_URL}/repo`],
      { env: mercurialEnvironment(fixtureRoot) },
    );
    assert.match(identify, new RegExp(`^${tipNode.slice(0, 12)}`));

    browser = await chromium.launch({
      executablePath: chromiumPath,
      headless: true,
      args: ['--no-sandbox'],
    });

    await assertPageHasNoBrowserErrors(browser, '/', async page => {
      await page.getByRole('heading', { name: 'Zenbu Repository' }).waitFor();
      await page.getByText('Recent Commits').waitFor();
      await page.getByText('Repository Files').waitFor();
      assert.equal(await page.evaluate(() => window.__hgWebXss), undefined);
      assert.equal(
        await page.locator('.graph-container').evaluate(
          element => getComputedStyle(element).backgroundImage,
        ),
        'none',
      );
      await page.locator('.theme-toggle').click();
    });

    await assertPageHasNoBrowserErrors(browser, '/directory', async page => {
      await page.getByText('Repository Files').waitFor();
      await page.getByRole('link', { name: 'README.md' }).first().click();
      await page.getByText('Updated Fixture Repository').waitFor();
      assert.equal(await page.evaluate(() => window.__hgWebXss), undefined);
      await page.keyboard.press('Escape');

      let delayedReadmeRequested = false;
      let markReadmeRequested;
      const readmeRequested = new Promise(resolve => {
        markReadmeRequested = resolve;
      });
      await page.route(/\/api\/repo\/readme\?path=/, async route => {
        delayedReadmeRequested = true;
        markReadmeRequested();
        await new Promise(resolve => setTimeout(resolve, 500));
        await route.continue();
      });
      await page.getByRole('link', { name: 'docs' }).click();
      await Promise.race([
        readmeRequested,
        new Promise((_, reject) => {
          setTimeout(() => reject(new Error('Timed out waiting for delayed README request')), 5000);
        }),
      ]);
      await page.getByRole('link', { name: 'root' }).click();
      await page.getByText('Updated Fixture Repository').waitFor();
      await page.waitForTimeout(600);
      assert.equal(await page.getByText('Documentation').count(), 0);
      assert.equal(delayedReadmeRequested, true);

      await page.getByRole('link', { name: 'pixel.png' }).click();
      const image = page.locator('.static-file-image');
      await image.waitFor();
      await image.evaluate(element => {
        const imageElement = element;
        if (imageElement.complete) return;
        return new Promise((resolve, reject) => {
          imageElement.addEventListener('load', resolve, { once: true });
          imageElement.addEventListener('error', reject, { once: true });
        });
      });
      assert.equal(await image.evaluate(element => element.naturalWidth), 1);
      await page.getByRole('dialog', { name: 'Preview pixel.png' }).waitFor();
      await page.keyboard.press('Escape');

      await page.getByRole('link', { name: 'BUILD' }).click();
      const buildCode = page.locator('code.language-python');
      await buildCode.waitFor();
      await page.getByText('cc_library').waitFor();
      assert.match(await buildCode.textContent(), /name = "fixture"/);
      await page.keyboard.press('Escape');

      await page.getByRole('link', { name: 'src' }).click();
      await page.getByRole('link', { name: 'main.c' }).click();
      await page.getByText('int main(void)').waitFor();
      await page.keyboard.press('Escape');
    });

    await assertPageHasNoBrowserErrors(browser, '/directory?path=docs', async page => {
      await page.getByText('Documentation').waitFor();
      await page.getByRole('link', { name: 'README.md' }).click();
      await page.getByText('Nested README.').waitFor();
    });

    await assertPageHasNoBrowserErrors(browser, '/graph', async page => {
      await page.getByText('Commit Graph').waitFor();
      await page.waitForFunction(() => new URL(window.location.href).searchParams.has('tip'));
      const graphUrl = page.url();
      const rows = page.locator('.graph-row');
      await rows.first().click();
      await page.waitForURL(/\/changeset\/[0-9a-f]+$/);
      await page.getByRole('heading', { name: 'Update fixture' }).waitFor();
      await page.getByRole('button', { name: 'Back', exact: true }).click();
      await page.waitForFunction(expected => window.location.href === expected, graphUrl);
      await page.getByText('Commit Graph').waitFor();
    });

    await assertPageHasNoBrowserErrors(browser, `/changeset/${tipNode}`, async page => {
      await page.getByRole('heading', { name: 'Update fixture' }).waitFor();
      await page.locator('.changeset-files code').filter({ hasText: 'new-file.txt' }).waitFor();
      await page.getByText('added', { exact: true }).waitFor();
      await page.getByRole('region', { name: 'Changeset diff' }).waitFor();
      await page.locator('.diff-column-headings').getByText('Before').first().waitFor();
      await page.locator('.diff-column-headings').getByText('After').first().waitFor();
      await page.locator('.diff-left.diff-remove').filter({ hasText: '# Fixture Repository' }).waitFor();
      await page.locator('.diff-right.diff-add').filter({ hasText: '# Updated Fixture Repository' }).waitFor();
      assert.equal(
        await page.locator('.diff-left.diff-context').filter({ hasText: '<script>' }).first().textContent(),
        '<script>window.__hgWebXss = true</script>',
      );
      assert.equal(
        await page.locator('.changeset-paper').evaluate(
          element => getComputedStyle(element).backgroundImage,
        ),
        'none',
      );
      await page.getByRole('button', { name: firstNode.slice(0, 12) }).click();
      await page.waitForFunction(
        expectedPath => window.location.pathname === expectedPath,
        `/changeset/${firstNode}`,
      );
      await page.getByRole('heading', { name: 'Initial fixture' }).waitFor();
      await page.getByRole('button', { name: 'Back', exact: true }).click();
      await page.getByRole('heading', { name: 'Update fixture' }).waitFor();
      await page.getByRole('button', { name: 'Back', exact: true }).click();
      await page.getByText('Commit Graph').waitFor();
    });

    await assertPageHasNoBrowserErrors(browser, '/changeset/not-a-node', async page => {
      await page.getByText('Recent Commits').waitFor();
    });

    await stopProcess(hgServer);
    const unavailable = await fetch(`${BASE_URL}/api/repo/list`);
    assert.equal(unavailable.status, 502);
    assert.equal((await fetch(`${BASE_URL}/`)).status, 200);
  } finally {
    if (browser) await browser.close();
    await stopProcess(appServer);
    await stopProcess(hgServer);
    fs.rmSync(fixtureRoot, { recursive: true, force: true });
  }
}

main().catch(error => {
  console.error(error.stack || error);
  process.exitCode = 1;
});