const crypto = require('crypto');

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

const generateWebsocketAcceptValue = (websocketKey) => {
    if (typeof websocketKey !== 'string' || typeof constants.handshakeGUID !== 'string') {
        // TODO: maybe throw error?
        return;
    }

    const concatenated = websocketKey + constants.handshakeGUID;
    const sha1HashInBase64 = crypto.createHash('sha1').update(concatenated, 'binary').digest('base64');
    
    return sha1HashInBase64;
};

const validateHeaders = ({ upgradeHeader, websocketVersion }) => {
    if (upgradeHeader !== constants.upgradeHeaderRequirement) return false;
    if (websocketVersion !== constants.websocketVersionRequirement) return false;
    return true;
};

module.exports = { generateWebsocketAcceptValue, validateHeaders };