import {Request} from "express";
import {IncomingMessage} from "http";
import {Utils} from './utils';

export type TPorts = number[];
export type TObject = { [key: string]: any };
export type TObjectArray = { [key: string]: TObject[] };

export class ServingStrategy {

    public ports: TPorts = [];
    private _activity: TObjectArray = {};
    private _portsInUse: TPorts = [];
    private _currentPort: number = 0;
    private _activeRequests: number = 0;
    private utils: Utils = new Utils();

    constructor(portList?: TPorts) {

        if (portList instanceof Array) {
            this.ports = portList;
        }

    }

    getPort() {
        return this._currentPort;
    }

    activityRequest(req: Request) {

        this._activeRequests++;

        const pathname = req.path;

        if (typeof this._activity[pathname] === 'undefined') {
            this._activity[pathname] = [];
        }

        const date = new Date();
        const freePort = Utils.getNextAfter(this.ports, this._currentPort);

        this._currentPort = freePort;

        this._activity[pathname].push({
            pathname: pathname,
            targetPort: freePort,
            path: req.url,
            queued: false,
            reqHeaders: req.headers,
            timeStart: date,
            ts: date.getTime()
        });

        this._activity[pathname][this._activity[pathname].length - 1]['index'] = this._activity[pathname].length - 1;

        return this._activity[pathname][this._activity[pathname].length - 1];

    }

    activityResponse(res: IncomingMessage, activityObject: TObject) {

        const date = new Date();

        this._activity[activityObject.pathname][activityObject.index] = {
            ...this._activity[activityObject.pathname][activityObject.index],
            timeEnd: date,
            queued: false,
            te: date.getTime(),
            resHeaders: res.headers
        };

        this._portsInUse = this._portsInUse.filter(item => item !== this._activity[activityObject.pathname][activityObject.index].targetPort);

        this._activeRequests--;

        return this._activity[activityObject.pathname][activityObject.index];

    }

    updatePorts(portList: TPorts) {
        this.ports = portList;
    }

}