'use strict';

// Node.js Lambda functions receive the event, context and callback parameters
exports.handler = (event, context, callback) => {

    // Extract the headers from the incoming request
    const request = event.Records[0].cf.request;
    const headers = request.headers;

    // Define the auth credentials
    const authUser = 'user';
    const authPass = 'pass';

    // Construct the expected Basic Auth string for the credentials
    const authString = 'Basic ' + new Buffer(authUser + ':' + authPass).toString('base64');

    // If there is no auth header or its value doesn't match our expected string
    if (typeof headers.authorization == 'undefined' || headers.authorization[0].value != authString) {
        // Construct a 401 (unauthorized) response requiring Basic Auth
        const response = {
            status: '401',
            statusDescription: 'Unauthorized',
            body: 'Unauthorized',
            headers: { 'www-authenticate': [{ key: 'WWW-Authenticate', value: 'Basic' }] },
        };

        // Return the response to the client - callback(Error error, Object result);
        callback(null, response);
    }

    // Otherwise, continue processing the request
    callback(null, request);
};