'use strict';

const requests = require('../requests');

const PROTOCOL = "https://";

class XsuaaService {
    #url;
    #jku            // JWKS URL
    #zid;           // optional zone id

    // immutable public fields
    get url() { return this.#url; }
    get jku() { return this.#jku; }
    get zid() { return this.#zid; }

    constructor(uaaDomain, zid) {
        if (uaaDomain === undefined) {
            throw new Error("XsuaaService requires a uaaDomain to fetch JWKS from.");
        }

        this.#url = uaaDomain.startsWith(PROTOCOL) ? uaaDomain : `${PROTOCOL}${uaaDomain}`;
        this.#zid = zid;
        this.#jku = `${this.url}/token_keys`;
    }
    
    async fetchJwks() {
        return new Promise((res, rej) => {
            try {
                requests.fetchKeyFromXSUAA(this.jku, this.zid, null, function (err, json) {
                    if (err) {
                        return rej(err);
                    }

                    return res(json.keys);
                });
            } catch (e) {
                return rej(e);
            }
        });
    }

    toJSON() {
        return {
            ...this,
            url: this.url,
            zid: this.zid
        }
    }
}

module.exports = XsuaaService;