'use strict';

const CONFIG = require('./xssec.config');

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

function TokenExchanger(serviceCredentials, forceNoExchange) {

    this.prepareToken = function(accessToken, cb) {
        var token = new TokenInfo(accessToken);

        if (token.isValid() && !token.isTokenIssuedByXSUAA() && !(forceNoExchange === true)) {
            return exchangeIASToken(token, accessToken, cb);
        } else {
            cb(null, token);
        }
    }
    
    function exchangeIASToken(ias_token, accessToken, cb) {
        if(CONFIG.IAS_XSUAA_XCHANGE_ENABLED !== true) {
            return cb(new Error("Unexpected TokenType"));
        }

        //try to convert (IAS) token to an XSUAA token using the ZoneId from the token
        requests.requestUserToken(accessToken, serviceCredentials, null, null, null, ias_token.getAppTID(), function(err, xsuaaToken, json) {
            if(err) {
                cb(err);
            } else {
                var xtoken = new TokenInfo(xsuaaToken);
                cb(null, xtoken);
            }
        })
    }
}

module.exports = TokenExchanger;