import { IMessenger, Symbol } from '@crealogix-map/core';
import { CloseBrowserMessage } from './CloseBrowserMessage';
import { BrowserModule } from './BrowserModule';
import { IBrowserService } from './IBrowserService';
import { ScreenRotation } from './ScreenRotation';
import { ConfigureRotationMessage } from './ConfigureRotationMessage';
import { OpenPageMessage } from './OpenPageMessage';
import { OpenExternalPageMessage } from './OpenExternalPageMessage';
import { OpenLocalPageMessage } from './OpenLocalPageMessage';
import { ShowPdfMessage } from './ShowPdfMessage';

/**
 * The standard implementation of the IBrowserService.
 */
export class BrowserService implements IBrowserService {
  constructor(private messenger: IMessenger) {
  }

  /**
   * Close the open page in the browser.
   */
  readonly openPage = (url: string): void => {
    this.messenger.send(new OpenPageMessage(url));
  }

  /**
   * Close the open page in the browser.
   */
  readonly openExternalPage = (url: string): void => {
    this.messenger.send(new OpenExternalPageMessage(url));
  }

  /**
   * Close the open page in the browser.
   */
  readonly openLocalPage = (path: string): void => {
    this.messenger.send(new OpenLocalPageMessage(path));
  }

  /**
   * Close the open page in the browser.
   */
  readonly closePage = (): void => {
    this.messenger.send(new CloseBrowserMessage());
  }

  /**
   * Set the allowed orientations of the screen to the given rotation.
   */
  readonly configureRotation = (rotation: ScreenRotation): void => {
    this.messenger.send(new ConfigureRotationMessage(rotation));
  }

  /**
   * Download the pdf at the given url.
   * @param {string} url
   */
  readonly downloadPdf = (url: string): void => {
    const request = new XMLHttpRequest();
    request.open('GET', url);
    request.responseType = 'arraybuffer';
    request.onload = () => {
      const arrayBuffer = request.response;
      if (request.status === 200 && arrayBuffer) {
        const byteArray = new Uint8Array(arrayBuffer);
        const payload = btoa(this.uint8ToString(byteArray));
        this.messenger.send(new ShowPdfMessage(url, payload));
      } else {
        throw new Error('Legacy download '.concat(url, ' failed.'));
      }
    };
    request.send(null);
  }

  readonly uint8ToString = (u8a: Uint8Array) => {
    const CHUNK_SZ = 0x8000;
    const c = [];
    for (let i = 0; i < u8a.length; i += CHUNK_SZ) {
      c.push(String.fromCharCode.apply(null, u8a.slice(i, i + CHUNK_SZ)));
    }

    return c.join('');
  }

  readonly symbol: Symbol = BrowserModule.serviceSymbol;
}