// Copyright (C) 2020 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import {globals} from '../frontend/globals';

type TraceCategories = 'Trace Actions'|'Record Trace'|'User Actions';
const ANALYTICS_ID = 'UA-137828855-1';

export function initAnalytics() {
  // Only initialize logging on prod or staging
  if (window.location.origin.endsWith('.perfetto.dev') ||
      window.location.origin.endsWith('staging-dot-perfetto-ui.appspot.com')) {
    return new Analytics();
  }
  return new NullAnalytics();
}

export class NullAnalytics {
  updatePath(_: string) {}
  logEvent(_x: TraceCategories|null, _y: string) {}
  logError(_x: string) {}
}

export class Analytics {
  constructor() {
    // The code below is taken from the official Google Analytics docs [1] and
    // adapted to TypeScript. We have it here rather than as an inline script
    // in index.html (as suggested by GA's docs) because inline scripts don't
    // play nicely with the CSP policy, at least in Firefox (Firefox doesn't
    // support all CSP 3 features we use).
    // [1] https://developers.google.com/analytics/devguides/collection/gtagjs .
    const gtagGlobals = window as {} as {
      dataLayer: IArguments[],
      gtag: () => void,
    };
    gtagGlobals.dataLayer = gtagGlobals.dataLayer || [];
    if (gtagGlobals.gtag === undefined) {
      gtagGlobals.gtag = () => gtagGlobals.dataLayer.push(arguments);
    }
    gtag('js', new Date());
  }

  updatePath(path: string) {
    gtag('config', ANALYTICS_ID, {
      'anonymize_ip': true,
      'page_path': path,
      'referrer': document.referrer.split('?')[0],
      'dimension1': globals.isInternalUser,
    });
  }

  logEvent(category: TraceCategories|null, event: string) {
    gtag('event', event, {'event_category': category});
  }

  logError(description: string, fatal = true) {
    gtag('event', 'exception', {description, fatal});
  }
}