import assert = require("assert");
import * as _ from "lodash";
import { APIs } from "../helpers";
import {IChassisMiddleware, IOperation } from "../interfaces";

/**
 * Emit a local Event
 * ------------------
 *
 */

export default class Emit implements IChassisMiddleware {
    name = "api.emit";
    title = "Emit a local event";

    /**
     * feature to send an event on local event bus
     *
     * @param context
     * @param options
     * @returns {TargetEndpoint}
     */

    fn(op: IOperation, _options: any): Function {
        let options = _.extend( {}, _options );
        assert(options.event, "missing emit.event");

        return (req, _res, next) => {
            let body = _.isObject(req.body)?req.body:options.body;
            let meta = APIs.getOperationContext(op, req, options.meta);
            op.context.bus.emit(options.event, { 
                data: body, 
                meta: meta 
            } );
            op.context.log( { code: "emit:event", message: options.event, meta: meta, body: body });
            next();
        }
    };


}