import { injectable } from 'inversify';
import { CookieJar } from 'jsdom';
import nodeFetch, { RequestInit, Response } from 'node-fetch';
import { inject } from '../../core/inject';
import { CookieSaveError } from '../error/cookie-save-error';
import { IStore } from '../store/i-store';
import { IWebCrawler } from './i-web-crawler';

@injectable()
export class WebCrawler implements IWebCrawler {
  public cookieJar: CookieJar;

  private initialized: boolean;

  private store: IStore;

  public constructor(@inject('store') store: IStore) {
    this.initialized = false;
    this.cookieJar = new CookieJar();
    this.store = store;
  }

  public fetch(url: string, requestInit: RequestInit = {}): Promise<Response> {
    return this.init().then(() => {
      const cookiedInit = {
        ...requestInit,
        ...{
          headers: {
            ...requestInit.headers,
            ...{
              Cookie: this.cookieJar.getCookieStringSync(url),
            },
          },
        },
      };
      return nodeFetch(url, cookiedInit).then((res: Response) => {
        this.setCookies(res.headers.raw()['set-cookie'], url).catch((reason: Error) => {
          throw new CookieSaveError(reason.message);
        });
        return res;
      });
    });
  }

  private init(): Promise<void> {
    if (!this.initialized) {
      return this.store.load(StoreKey.COOKIES).then((cookies: unknown) => {
        if (cookies !== undefined) {
          this.cookieJar = CookieJar.deserializeSync(cookies as string);
        }
        this.initialized = true;
      });
    } else {
      return Promise.resolve();
    }
  }

  private setCookies(header: string[], url: string): Promise<void> {
    if (header) {
      header.forEach((cookie: string) => {
        this.cookieJar.setCookieSync(cookie, url);
      });
      return this.store.save(StoreKey.COOKIES, this.cookieJar.serializeSync()).catch((reason: Error) => {
        throw new CookieSaveError(reason.message);
      });
    }
    return Promise.resolve();
  }
}