import ApplicationComponent from "../ApplicationComponent";
import express, {Express, RequestHandler, Router} from "express";
import Logger from "../Logger";
import {Server} from "http";
import {IncomingForm} from "formidable";
import {FileError, ValidationBag} from "../db/Validator";

export default class ExpressAppComponent extends ApplicationComponent<void> {
    private readonly port: number;
    private server?: Server;

    constructor(port: number) {
        super();
        this.port = port;
    }

    public async start(app: Express, router: Router): Promise<void> {
        this.server = app.listen(this.port, 'localhost', () => {
            Logger.info(`Web server running on localhost:${this.port}.`);
        });

        router.use(express.json());
        router.use(express.urlencoded({
            extended: true,
        }));

        router.use((req, res, next) => {
            req.models = {};
            req.modelCollections = {};
            next();
        });
    }

    public async stop(): Promise<void> {
        if (this.server) {
            await this.close('Webserver', this.server, this.server.close);
        }
    }

    public getServer(): Server {
        if (!this.server) throw 'Server was not initialized.';
        return this.server;
    }
}

export const FILE_UPLOAD_MIDDLEWARE: (formFactory: () => IncomingForm, defaultField: string) => RequestHandler = (formFactory: () => IncomingForm, defaultField: string) => {
    return async (req, res, next) => {
        const form = formFactory();
        try {
            await new Promise<any>((resolve, reject) => {
                form.parse(req, (err, fields, files) => {
                    if (err) {
                        reject(err);
                        return;
                    }
                    req.body = fields;
                    req.files = files;
                    resolve();
                });
            });
        } catch (e) {
            const bag = new ValidationBag();
            const fileError = new FileError(e);
            fileError.thingName = defaultField;
            bag.addMessage(fileError);
            next(bag);
            return;
        }
        next();
    };
};