/**
 * @license
 * Copyright Google LLC All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.dev/license
 */

import {Injectable, inject} from '@angular/core';
import {Events, MessageBus} from 'protocol';

import {Frame, TOP_LEVEL_FRAME_ID} from './application-environment';

@Injectable()
export class FrameManager {
  private _selectedFrameId: number | null = null;
  private _frames = new Map<number, Frame>();
  private _inspectedWindowTabId: number | null = null;
  private _frameUrlToFrameIds = new Map<string, Set<number>>();
  private _messageBus = inject<MessageBus<Events>>(MessageBus);

  get frames(): Frame[] {
    return Array.from(this._frames.values());
  }

  get selectedFrame(): Frame | null {
    if (this._selectedFrameId === null) {
      return null;
    }

    return this._frames.get(this._selectedFrameId) ?? null;
  }

  static initialize(inspectedWindowTabIdTestOnly?: number | null) {
    const manager = new FrameManager();
    manager.initialize(inspectedWindowTabIdTestOnly);
    return manager;
  }

  private initialize(inspectedWindowTabIdTestOnly?: number | null): void {
    if (inspectedWindowTabIdTestOnly === undefined) {
      this._inspectedWindowTabId = globalThis.chrome.devtools.inspectedWindow.tabId;
    } else {
      this._inspectedWindowTabId = inspectedWindowTabIdTestOnly;
    }

    this._messageBus.on('frameConnected', (frameId: number) => {
      if (this._frames.has(frameId)) {
        this._selectedFrameId = frameId;
      }
    });

    this._messageBus.on('contentScriptConnected', (frameId: number, name: string, url: string) => {
      // fragments are not considered when doing URL matching on a page
      // https://bugs.chromium.org/p/chromium/issues/detail?id=841429
      const urlWithoutHash = new URL(url);
      urlWithoutHash.hash = '';

      this.addFrame({name, id: frameId, url: urlWithoutHash});

      if (this.frames.length === 1) {
        this.inspectFrame(this._frames.get(frameId)!);
      }
    });

    this._messageBus.on('contentScriptDisconnected', (frameId: number) => {
      if (!this._frames.has(frameId)) {
        return;
      }

      this.removeFrame(this._frames.get(frameId)!);

      // Defensive check. This case should never happen, since we're always connected to at least
      // the top level frame.
      if (this.frames.length === 0) {
        this._selectedFrameId = null;
        console.error('Angular DevTools is not connected to any frames.');
        return;
      }

      if (frameId === this._selectedFrameId) {
        this._selectedFrameId = TOP_LEVEL_FRAME_ID;
        this.inspectFrame(this._frames.get(this._selectedFrameId!)!);
        return;
      }
    });
  }

  isSelectedFrame(frame: Frame): boolean {
    return this._selectedFrameId === frame.id;
  }

  inspectFrame(frame: Frame): void {
    if (this._inspectedWindowTabId === null) {
      return;
    }

    if (!this._frames.has(frame.id)) {
      throw new Error('Attempted to inspect a frame that is not connected to Angular DevTools.');
    }

    this._selectedFrameId = null;
    this._messageBus.emit('enableFrameConnection', [frame.id, this._inspectedWindowTabId]);
  }

  frameHasUniqueUrl(frame: Frame | null): boolean {
    if (frame === null) {
      return false;
    }
    const frameUrl = frame.url.toString();
    const frameIds = this._frameUrlToFrameIds.get(frameUrl) ?? new Set<number>();
    return frameIds.size === 1;
  }

  private addFrame(frame: Frame): void {
    this._frames.set(frame.id, frame);
    const frameUrl = frame.url.toString();
    const frameIdSet = this._frameUrlToFrameIds.get(frameUrl) ?? new Set<number>();
    frameIdSet.add(frame.id);
    this._frameUrlToFrameIds.set(frameUrl, frameIdSet);
  }

  private removeFrame(frame: Frame): void {
    const frameId = frame.id;
    const frameUrl = frame.url.toString();
    const urlFrameIds = this._frameUrlToFrameIds.get(frameUrl) ?? new Set<number>();
    urlFrameIds.delete(frameId);
    if (urlFrameIds.size === 0) {
      this._frameUrlToFrameIds.delete(frameUrl);
    }
    this._frames.delete(frameId);
  }
}