// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// This script runs in HTML files and loads and instantiates unit tests
// for the flutter web engine that are compiled to dart2js. It is based
// off of the `test/dart.js` script from the `test` dart package.

export const runTest = (configuration) => {
  // Sends an error message to the server indicating that the script failed to
  // load.
  //
  // This mimics a MultiChannel-formatted message.
  var sendLoadException = function (message) {
    window.parent.postMessage({
      "href": window.location.href,
      "data": [0, { "type": "loadException", "message": message }],
      "exception": true,
    }, window.location.origin);
  }

  // Listen for dartLoadException events and forward to the server.
  window.addEventListener('dartLoadException', function (e) {
    sendLoadException(e.detail);
  });

  // The basename of the current page.
  var name = window.location.href.replace(/.*\//, '').replace(/#.*/, '');

  // Find <link rel="x-dart-test">.
  var links = document.getElementsByTagName("link");
  var testLinks = [];
  var length = links.length;
  for (var i = 0; i < length; ++i) {
    if (links[i].rel == "x-dart-test") testLinks.push(links[i]);
  }

  if (testLinks.length != 1) {
    sendLoadException(
      'Expected exactly 1 <link rel="x-dart-test"> in ' + name + ', found ' +
      testLinks.length + '.');
    return;
  }

  var link = testLinks[0];

  if (link.href == '') {
    sendLoadException(
      'Expected <link rel="x-dart-test"> in ' + name + ' to have an "href" ' +
      'attribute.');
    return;
  }

  try {
    window._flutter.loader.loadEntrypoint({
      entrypointUrl: link.href + '.browser_test.dart.js',
      onEntrypointLoaded: function(engineInitializer) {
        engineInitializer.initializeEngine(configuration).then(function(appRunner) {
          appRunner.runApp();
        });
      }
    });
  } catch (exception) {
    const message = `Failed to bootstrap unit test: ${exception}`;
    sendLoadException(message);
  }
};