'use strict'

const crypto = require('crypto');

var calcSignature = (baseString, secretKey) => {
    const secretBuffer = new Buffer(secretKey, 'base64');
    return crypto.createHmac('sha1', secretBuffer).update(baseString).digest('base64');
};

var verifySignature = (UID, signature, timestamp, secretKey) => {
    if (Math.abs(Date.now() / 1000 - timestamp) < process.env.GIGYA_TS_DELTA) {
        let baseString = Number(timestamp) + "_" + UID;
        let expectedSig = this.calcSignature(baseString, secretKey);
        return expectedSig === signature;
    } else {
        return false;
    }
}

module.exports.calcSignature = calcSignature;
module.exports.verifySignature = verifySignature;