import {HttpService, Injectable, Logger} from '@nestjs/common';
import {Client, Issuer, TokenSet} from "openid-client";
import {ConfigService} from "@nestjs/config";

@Injectable()
export class AuthService {
  private Client!: Client;
  private _tokenSet!: TokenSet;
  private logger: Logger = new Logger('AuthService');

  constructor(
    private readonly http: HttpService,
    private readonly config: ConfigService
  ) {
  }

  async client() {
    if (!this.Client) {
      const issuer = await Issuer.discover(this.config.get('KC_ISSUER'));
      const {Client} = issuer;

      this.Client = new Client({
        client_id: this.config.get('KC_CLIENT'),
        client_secret: this.config.get('KC_SECRET'),
      });
      this.Client.authorizationUrl({scope: 'offline_access'})
    }
    return this.Client;
  }

  get accessToken() {
    return this._tokenSet.access_token;
  }

  get refreshToken() {
    return this._tokenSet.refresh_token;
  }

  async login() {
    const Client = await this.client();
    return Client.grant({
      grant_type: 'client_credentials',
    }).then((c) => {
      this.logger.debug('Get access token');
      this._tokenSet = c;
      return c;
    }).catch(error => {
      this.logger.error(`Error login ${error}`);
    });
  }

  async refresh() {
    const Client = await this.client();
    return Client.refresh(this._tokenSet.refresh_token).then((c) => {
      this.logger.debug('Refresh token');
      this._tokenSet = c;
      return c;
    }).catch(error => {
      this.logger.error(`Error refreshing token ${error}`);
      return this.login();
    });
  }

  get isTokenExpired(): boolean {
    return this._tokenSet.expired();
  }

  async isActive() {
    const Client = await this.client();
    return Client.introspect(this.accessToken).then(({active}) => active);
  }

  async tokenLife() {
    const expiresIn = this._tokenSet.expires_in / 60;
    const lifeTime = Number(this.config.get('TOKEN_LIFETIME'));
    return Number((100 - (lifeTime - expiresIn) * 100 / lifeTime).toFixed(1));
  }

  async logout() {
    const Client = await this.client();
    return await Client.revoke(this._tokenSet.access_token);
  }
}