'use strict';

const JwksReplica = require('./JwksReplica.js');
const XsuaaService = require('../service/XsuaaService.js');
const IdentityService = require('../service/IdentityService.js');

class JwksManager {
    #replicas;

    constructor() {
        this.#replicas = new Map();
    }

    /**
     * Sets the expirationTime of any future JwksReplica objects created by this manager. Does not affect already created (and therefore cached) objects.
     * @param expirationTime in ms
     * @returns this
     */
    withExpirationTime(expirationTime) {
        if (expirationTime > 0) {
            this.expirationTime = expirationTime;
        }

        return this;
    }

    /**
     * Sets the refreshPeriod of any future JwksReplica objects created by this manager. Does not affect already created (and therefore cached) objects.
     * @param refreshPeriod in ms
     * @returns this
     */
    withRefreshPeriod(refreshPeriod) {
        if (refreshPeriod > 0) {
            this.refreshPeriod = refreshPeriod;
        }

        return this;
    }

    getXsuaaJwks(uaaDomain, zid, attributes = {}) {
        if (!uaaDomain) {
            throw new Error("Cannot get JWKS from empty uaaDomain.");
        }

        const jwksParams = { zid };

        let jwksReplica, replicaKey;
        if (!attributes.disableCache) {
            const keyParts = {domain: uaaDomain, ...jwksParams};
            replicaKey = this.createCacheKey(keyParts);

            jwksReplica = this.#replicas.get(replicaKey);
        }

        if (!jwksReplica) {
            const xsuaaService = new XsuaaService(uaaDomain, zid);
            jwksReplica = new JwksReplica(xsuaaService, this.expirationTime, this.refreshPeriod).withParams(jwksParams);

            !attributes.disableCache && this.#replicas.set(replicaKey, jwksReplica);
        }

        return jwksReplica;
    }

    getIdentityJwks(issuerDomain, serviceCredentials, token, attributes = {}) {
        if (!issuerDomain) {
            throw new Error("Cannot get JWKS from empty domain.");
        }

        const jwksParams = {
            client_id: serviceCredentials.clientid,
            app_tid: token.getAppTID(),
            azp: token.getAzp()
        }

        let jwksReplica, replicaKey;
        if (!attributes.disableCache) {
            const keyParts = {domain: issuerDomain, ...jwksParams};
            replicaKey = this.createCacheKey(keyParts);

            jwksReplica = this.#replicas.get(replicaKey);
        }

        if (!jwksReplica) {
            const service = new IdentityService(serviceCredentials).withCustomDomain(issuerDomain);
            jwksReplica = new JwksReplica(service, this.expirationTime, this.refreshPeriod).withParams(jwksParams);

            !attributes.disableCache && this.#replicas.set(replicaKey, jwksReplica);
        }

        return jwksReplica;
    }

    /**
     * Creates a string cache key from the given key-value pairs, ignoring keys with null or undefined values.
     * @param {object} parts
     * @returns a cache key in string format, e.g. app_tid:foo:client_id:bar:azp:baz
     */
    createCacheKey(parts) {        
        if (!parts || Object.entries(parts).length < 1) {
            throw new Error("Could not create JwksManager key. Key parts must contain at least one element.");
        }

        return Object.entries(parts)
        .filter(([value]) => value != null)
        .map(([key, value]) => `${key}:${value}`)
        .join(":");
    }
}

module.exports = JwksManager;