import coreModule from 'app/core/core_module';
import appEvents from 'app/core/app_events';
import angular from 'angular';

const template = `
<input type="file" id="dashupload" name="dashupload" class="hide" onchange="angular.element(this).scope().file_selected"/>
<label class="btn btn-success" for="dashupload">
  <i class="fa fa-upload"></i>
  {{btnText}}
</label>
`;

/** @ngInject */
function uploadDashboardDirective(timer, alertSrv, $location) {
  return {
    restrict: 'E',
    template: template,
    scope: {
      onUpload: '&',
      btnText: '@?',
    },
    link: (scope, elem) => {
      scope.btnText = angular.isDefined(scope.btnText) ? scope.btnText : 'Upload .json File';

      function file_selected(evt) {
        const files = evt.target.files; // FileList object
        const readerOnload = () => {
          return e => {
            let dash;
            try {
              dash = JSON.parse(e.target.result);
            } catch (err) {
              console.log(err);
              appEvents.emit('alert-error', ['Import failed', 'JSON -> JS Serialization failed: ' + err.message]);
              return;
            }

            scope.$apply(() => {
              scope.onUpload({ dash: dash });
            });
          };
        };

        let i = 0;
        let file = files[i];

        while (file) {
          const reader = new FileReader();
          reader.onload = readerOnload();
          reader.readAsText(file);
          i += 1;
          file = files[i];
        }
      }

      const wnd: any = window;
      // Check for the various File API support.
      if (wnd.File && wnd.FileReader && wnd.FileList && wnd.Blob) {
        // Something
        elem[0].addEventListener('change', file_selected, false);
      } else {
        alertSrv.set('Oops', 'Sorry, the HTML5 File APIs are not fully supported in this browser.', 'error');
      }
    },
  };
}

coreModule.directive('dashUpload', uploadDashboardDirective);
