mashafrancis/butternut-user

import { Injectable } from '@nestjs/common';
import { RequestContext } from '../../_helpers';
import {
    AccessDecisionManager,
    AccessDecisionStrategyEnum,
} from '../access-decision';
import { VoterRegistry } from '../voter';
import { AuthorizationCheckerInterface } from './authorization-checker.interface';

@Injectable()
export class AuthorizationChecker implements AuthorizationCheckerInterface {
    private readonly adm: AccessDecisionManager;
    private readonly tokenStorage;

    constructor(voterRegistry: VoterRegistry) {
        this.adm = new AccessDecisionManager(
            voterRegistry.getVoters(),
            AccessDecisionStrategyEnum.STRATEGY_AFFIRMATIVE,
            true,
        );
        this.tokenStorage = function () {
            return {
                getUser: () => RequestContext.currentUser(),
            };
        };
    }

    public async isGranted(attributes, subject = null) {
        const token = this.tokenStorage();

        if (!Array.isArray(attributes)) {
            // tslint:disable-next-line:no-parameter-reassignment
            attributes = [attributes];
        }

        return this.adm.decide(token, attributes, subject);
    }
}