import { Injectable, CanActivate, ExecutionContext } from '@nestjs/common';
import { Observable } from 'rxjs';
import { OAuth2Service } from 'src/modules/oauth2/oauth2.service';
import { UserService } from 'src/modules/objects/user/user.service';

/**
 * Injects and validates OAuth2 bearer tokens.
 */
@Injectable()
export class OAuth2Guard implements CanActivate {
  constructor(private _oauth2: OAuth2Service, private _user: UserService) {}

  canActivate(
    context: ExecutionContext,
  ): boolean | Promise<boolean> | Observable<boolean> {
    const http = context.switchToHttp();
    const request = http.getRequest();
    const response = http.getResponse();

    return new Promise((resolve, reject) => {
      try {
        this._oauth2.oauth.bearer(request, response, (content) => {
          if (content instanceof Error) {
            return reject(content);
          }

          this._user
            .getById(response.locals.accessToken.user_id, [
              'picture',
              'privileges',
            ])
            .then((user) => {
              request.user = user;
              resolve(true);
            })
            .catch(reject);
        });
      } catch (e: any) {
        reject(e);
      }
    });
  }
}