// @ts-check

/* eslint-env node, es2020 */

import playwright from 'playwright';
import {startDevServer} from '@web/dev-server';
import getPort from 'get-port';
import * as os from 'os';
import * as path from 'path';
import {promises as fs} from 'fs';

async function main() {
  const verbose = process.argv.includes('--verbose');
  const devtools = process.argv.includes('--devtools');
  const port = await getPort();
  const server = await startDevServer({
    config: {
      rootDir: process.cwd(),
      port,
      watch: false,
    },
    readCliArgs: false,
    readFileConfig: false,
    logStartMessage: verbose,
  });

  const browserType = 'chromium';
  const userDataDir = await fs.mkdtemp(
    path.join(os.tmpdir(), 'replicache-playwright-'),
  );
  const context = await playwright[
    browserType
  ].launchPersistentContext(userDataDir, {devtools});

  const page = await context.newPage();
  await page.goto(`http://127.0.0.1:${port}/perf/index.html`);
  await page.waitForFunction('typeof nextTest ===  "function"');
  logLine('Running benchmarks please wait...');

  if (devtools) {
    console.log('Enter `await nextTest()` in the devtools console');
    return;
  }

  for (;;) {
    const testResult = await page.evaluate('nextTest()');
    if (testResult === null) {
      break;
    }
    logLine(formatAsBenchmarkJS(testResult));
  }

  logLine('Done!');

  await server.stop();

  await fs.rmdir(userDataDir, {recursive: true});

  // context.close does not terminate! Give it a second.
  Promise.race([context.close(), wait(1000)]);
}

main().catch(err => {
  console.error(err);
  process.exit(1);
});

/** @param {string} s */
function logLine(s) {
  process.stdout.write(s + '\n');
}

// TODO(arv): Use BenchmarkJS instead of our custom runner?
// eslint-disable-next-line @typescript-eslint/no-unused-vars
function formatAsBenchmarkJS({name, value, median, runs}) {
  // Example:
  //   fib(20) x 11,465 ops/sec ±1.12% (91 runs sampled)
  //   createObjectBuffer with 200 comments x 81.61 ops/sec ±1.70% (69 runs sampled)
  return `${name} x ${value} ±0.0% (${runs} runs sampled)`;
}

function wait(n) {
  return new Promise(resolve => setTimeout(resolve, n));
}