// Added manually for preventing project from caching on client browser

function launchFlutter() {
  // Download main.dart.js
  _flutter.loader.load({
          serviceWorker: {
            serviceWorkerVersion: serviceWorkerVersion,
          },
          onEntrypointLoaded: function(engineInitializer) {
            engineInitializer.initializeEngine({
                useColorEmoji: true,
              }).then(function(appRunner) {
              appRunner.runApp();
            });
          }
  });
}

window.addEventListener('load', function(ev) {
  if ('serviceWorker' in navigator) {

      // getting rid of undesired to fetch remote version.json file updated
      var seconds = new Date().getTime();
      var xmlhttp = new XMLHttpRequest();
      xmlhttp.open("GET", '/version.json?v=' + seconds, true);
      xmlhttp.addEventListener('load', function() {
          if (xmlhttp.status == 200) {
              var buildNumber = xmlhttp.responseText;
              console.log('remote version is ' + buildNumber);
              var currentBuildNumber = window.localStorage.getItem('buildNumber');

              console.log('local version is ' + currentBuildNumber);
              // clear worker cache if remote and local version are different
              if (currentBuildNumber != buildNumber) {
                  console.log('App update is necessary. Clearing service workers cache');
                  caches.delete('flutter-app-manifest');
                  caches.delete('flutter-temp-cache');
                  caches.delete('flutter-app-cache');

                  // store new version number
                  window.localStorage.setItem('buildNumber', buildNumber);
              } else {
                  console.log('App is up to date');
              }
          }
          launchFlutter();
      });

      xmlhttp.addEventListener('error', function() {
          launchFlutter();
      });

      xmlhttp.addEventListener('abort', function() {
          launchFlutter();
      });

      xmlhttp.addEventListener('timeout', function() {
          launchFlutter();
      });

      xmlhttp.send();
  } else {
      console.log('Service worker not found. Continue app loading.');
      launchFlutter();
  }
});