// Copyright 2024 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import * as i18n from '../../../core/i18n/i18n.js';
import * as ThirdPartyWeb from '../../../third_party/third-party-web/third-party-web.js';
import * as Extras from '../extras/extras.js';
import * as Handlers from '../handlers/handlers.js';
import type * as Types from '../types/types.js';

import {
  InsightCategory,
  InsightKeys,
  type InsightModel,
  type InsightSetContext,
  type PartialInsightModel,
} from './types.js';

export const UIStrings = {
  /** Title of an insight that provides details about the code on a web page that the user doesn't control (referred to as "third-party code"). */
  title: '3rd parties',
  /**
   * @description Description of a DevTools insight that identifies the code on the page that the user doesn't control.
   * This is displayed after a user expands the section to see more. No character length limits.
   */
  description: '3rd party code can significantly impact load performance. ' +
      '[Reduce and defer loading of 3rd party code](https://developer.chrome.com/docs/performance/insights/third-parties) to prioritize your page\'s content.',
  /** Label for a table column that displays the name of a third-party provider. */
  columnThirdParty: '3rd party',
  /** Label for a column in a data table; entries will be the download size of a web resource in kilobytes. */
  columnTransferSize: 'Transfer size',
  /** Label for a table column that displays how much time each row spent running on the main thread, entries will be the number of milliseconds spent. */
  columnMainThreadTime: 'Main thread time',
  /**
   * @description Text block indicating that no third party content was detected on the page
   */
  noThirdParties: 'No third parties found',
} as const;

const str_ = i18n.i18n.registerUIStrings('models/trace/insights/ThirdParties.ts', UIStrings);
export const i18nString = i18n.i18n.getLocalizedString.bind(undefined, str_);

export type ThirdPartiesInsightModel = InsightModel<typeof UIStrings, {
  /** The entity for this navigation's URL. Any other entity is from a third party. */
  entitySummaries: Extras.ThirdParties.EntitySummary[],
  firstPartyEntity?: Extras.ThirdParties.Entity,
}>;

function getRelatedEvents(
    summaries: Extras.ThirdParties.EntitySummary[],
    firstPartyEntity: Extras.ThirdParties.Entity|undefined): Types.Events.Event[] {
  const relatedEvents = [];
  for (const summary of summaries) {
    if (summary.entity !== firstPartyEntity) {
      relatedEvents.push(...summary.relatedEvents);
    }
  }

  return relatedEvents;
}

function finalize(partialModel: PartialInsightModel<ThirdPartiesInsightModel>): ThirdPartiesInsightModel {
  return {
    insightKey: InsightKeys.THIRD_PARTIES,
    strings: UIStrings,
    title: i18nString(UIStrings.title),
    description: i18nString(UIStrings.description),
    docs: 'https://developer.chrome.com/docs/performance/insights/third-parties',
    category: InsightCategory.ALL,
    state: partialModel.entitySummaries.find(summary => summary.entity !== partialModel.firstPartyEntity) ?
        'informative' :
        'pass',
    ...partialModel,
  };
}

export function isThirdPartyInsight(model: InsightModel): model is ThirdPartiesInsightModel {
  return model.insightKey === InsightKeys.THIRD_PARTIES;
}

export function generateInsight(
    data: Handlers.Types.HandlerData, context: InsightSetContext): ThirdPartiesInsightModel {
  const entitySummaries = Extras.ThirdParties.summarizeByThirdParty(data as Handlers.Types.HandlerData, context.bounds);

  const firstPartyUrl = context.navigation?.args.data?.documentLoaderURL ?? data.Meta.mainFrameURL;
  const firstPartyEntity = ThirdPartyWeb.ThirdPartyWeb.getEntity(firstPartyUrl) ||
      Handlers.Helpers.makeUpEntity(data.Renderer.entityMappings.createdEntityCache, firstPartyUrl);

  return finalize({
    relatedEvents: getRelatedEvents(entitySummaries, firstPartyEntity),
    firstPartyEntity,
    entitySummaries,
  });
}

export function createOverlaysForSummary(summary: Extras.ThirdParties.EntitySummary): Types.Overlays.Overlay[] {
  const overlays = [];
  for (const event of summary.relatedEvents) {
    // The events found for a third party can be vast, as they gather every
    // single main thread task along with everything else on the page. If the
    // main thread is busy with large icicles, we can easily create tens of
    // thousands of overlays. Therefore, only create overlays for events of at least 1ms.
    if (event.dur === undefined || event.dur < 1_000) {
      continue;
    }

    const overlay: Types.Overlays.Overlay = {
      type: 'ENTRY_OUTLINE',
      entry: event,
      outlineReason: 'INFO',
    };
    overlays.push(overlay);
  }
  return overlays;
}

export function createOverlays(model: ThirdPartiesInsightModel): Types.Overlays.Overlay[] {
  const overlays: Types.Overlays.Overlay[] = [];
  const summaries = model.entitySummaries ?? [];
  for (const summary of summaries) {
    if (summary.entity === model.firstPartyEntity) {
      continue;
    }

    const summaryOverlays = createOverlaysForSummary(summary);
    overlays.push(...summaryOverlays);
  }

  return overlays;
}