const clsHooked = require('cls-hooked');
var NAMESPACE = '';
const {v4: uuid} = require('uuid');

module.exports = {
    init(ns) {
        return clsHooked.createNamespace(NAMESPACE = ns);
    },
    getRequestId() {
        if(!NAMESPACE) throw new Error('Namespace has not been inited');
        return clsHooked.getNamespace(NAMESPACE)?.get('requestId');
    },
    getMetadata() {
        if(!NAMESPACE) throw new Error('Namespace has not been inited');

        return clsHooked.getNamespace(NAMESPACE)?.get('metadata');
    },
    assignRequestId(namespace, func, extraMetadata, incomingRequestId = uuid()) {
        namespace.bind(async () => {
            namespace.set('requestId', incomingRequestId);
            if(extraMetadata) {
                namespace.set('metadata', extraMetadata)
            }
            await func();
        })();
    },
    attachContext(contextNamespace) {
        return (req, res, next) => {
            const ns = this.init(contextNamespace);
            this.assignRequestId(ns, next, null, req.headers['x-requestid']);
        }
    },
}