import { Injectable } from '@angular/core';
import { hobaParseChallengeHeader } from '@src/assets/js/hoba.js';
import { signChallenge } from '@src/assets/js/hoba-pgp.js';
import {environment} from '@src/environments/environment';
import {LoggingService} from '@app/_services/logging.service';
import {MutableKeyStore, MutablePgpKeyStore} from '@app/_pgp';
import {ErrorDialogService} from '@app/_services/error-dialog.service';
import {tap} from 'rxjs/operators';
import { HttpClient } from '@angular/common/http';
import {Observable } from 'rxjs';

@Injectable({
  providedIn: 'root'
})
export class AuthService {
  sessionToken: any;
  sessionLoginCount = 0;
  privateKey: any;
  mutableKeyStore: MutableKeyStore = new MutablePgpKeyStore();

  constructor(
    private httpClient: HttpClient,
    private loggingService: LoggingService,
    private errorDialogService: ErrorDialogService
  ) {
    // TODO setting these together shoulds be atomic
    if (sessionStorage.getItem(btoa('CICADA_SESSION_TOKEN'))) {
      this.sessionToken = sessionStorage.getItem(btoa('CICADA_SESSION_TOKEN'));
    }
    if (localStorage.getItem(btoa('CICADA_PRIVATE_KEY'))) {
      this.privateKey = localStorage.getItem(btoa('CICADA_PRIVATE_KEY'));
    }
  }

  setState(s): void {
    document.getElementById('state').innerHTML = s;
  }

  getWithToken(): void {
    const xhr = new XMLHttpRequest();
    xhr.responseType = 'text';
    xhr.open('GET', environment.cicMetaUrl + window.location.search.substring(1));
    xhr.setRequestHeader('Authorization', 'Bearer ' + this.sessionToken);
    xhr.setRequestHeader('Content-Type', 'application/json');
    xhr.setRequestHeader('x-cic-automerge', 'none');
    xhr.addEventListener('load', (e) => {
      if (xhr.status === 401) {
        throw new Error('login rejected');
      }
      this.sessionLoginCount++;
      this.setState('Click button to perform login ' + this.sessionLoginCount + ' with token ' + this.sessionToken);
      return;
    });
    xhr.send();
  }

  sendResponse(hobaResponseEncoded): void {
    const xhr = new XMLHttpRequest();
    xhr.responseType = 'text';
    xhr.open('GET', environment.cicMetaUrl + window.location.search.substring(1));
    xhr.setRequestHeader('Authorization', 'HOBA ' + hobaResponseEncoded);
    xhr.setRequestHeader('Content-Type', 'application/json');
    xhr.setRequestHeader('x-cic-automerge', 'none');
    xhr.addEventListener('load', (e) => {
      if (xhr.status === 401) {
        throw new Error('login rejected');
      }
      this.sessionToken = xhr.getResponseHeader('Token');
      sessionStorage.setItem(btoa('CICADA_SESSION_TOKEN'), this.sessionToken);
      this.sessionLoginCount++;
      this.setState('Click button to perform login ' + this.sessionLoginCount + ' with token ' + this.sessionToken);
      return;
    });
    xhr.send();
  }

  getChallenge(): void {
    const xhr = new XMLHttpRequest();
    xhr.responseType = 'arraybuffer';
    xhr.open('GET', environment.cicMetaUrl + window.location.search.substring(1));
    xhr.onload = async (e) => {
      if (xhr.status === 401) {
        const authHeader = xhr.getResponseHeader('WWW-Authenticate');
        const o = hobaParseChallengeHeader(authHeader);
        await this.loginResponse(o);
      }
    };
    xhr.send();
  }


  login(): boolean {
    if (this.sessionToken !== undefined) {
      try {
        this.getWithToken();
        return true;
      } catch (e) {
        this.loggingService.sendErrorLevelMessage('Login token failed', this, {error: e});
      }
    } else {
      try {
        this.getChallenge();
      } catch (e) {
        this.loggingService.sendErrorLevelMessage('Login challenge failed', this, {error: e});
      }
    }
    return false;
  }


  async loginResponse(o): Promise<any> {
    const r = await signChallenge(o.challenge, o.realm, environment.cicMetaUrl, this.mutableKeyStore);
    this.sendResponse(r);
  }

  loginView(): void {
    document.getElementById('one').style.display = 'none';
    document.getElementById('two').style.display = 'block';
    this.setState('Click button to log in with PGP key ' + this.mutableKeyStore.getPrivateKeyId());
  }

  async setKey(privateKeyArmored): Promise<boolean> {
    try {
      const isValidKeyCheck = await this.mutableKeyStore.isValidKey(privateKeyArmored)
      if (!isValidKeyCheck) {
        throw Error('The private key is invalid');
      }
      const key = await this.mutableKeyStore.importPrivateKey(privateKeyArmored);
      localStorage.setItem(btoa('CICADA_PRIVATE_KEY'), privateKeyArmored);
    } catch (err) {
      this.loggingService.sendErrorLevelMessage('Failed setting key', this, {error: err});
      // TODO use a global error handler here
      this.errorDialogService.openDialog({
        message: `Failed to set key: ${err.message || err.statusText}`,
      });
      return false;
    }
    this.loginView();
    return true;
  }

  logout(): void {
    sessionStorage.removeItem(btoa('CICADA_SESSION_TOKEN'));
    window.location.reload(true);
  }

  getTrustedUsers(): any {
    let trustedUsers = [];
    this.mutableKeyStore.getPublicKeys().forEach(key => trustedUsers.push(key.users[0].userId));
    return trustedUsers;
  }

  getPublicKeys(): Observable<any> {
    return this.httpClient.get(`${environment.publicKeysUrl}`, {responseType: 'text'})
        .pipe(tap(
          data => { },
          error => { this.loggingService.sendErrorLevelMessage('Unable to load trusted public keys.', this, {error}); }
        ));
  }

  async getPrivateKeys(): Promise<void> {
    if (this.privateKey !== undefined) {
      await this.mutableKeyStore.importPrivateKey(this.privateKey);
    }
  }
}