/**
 * Required External Modules and Interfaces
 */
import express, {Request, Response} from 'express';
import logger from '../../middleware/logger';
import {Guid} from 'guid-typescript';
import * as icalgenerator from './icalgenerator/icalgenerator.service';

/**
 * Router Definition
 */
export const raPlaMiddlewareRouter = express.Router();

/**
 * @swagger
 * /rapla-middleware:
 *      get:
 *          summary: Retrieve the adjusted RaPla .ics file
 *          description: Downloads the current .ics file from DHBW servers, removes unwanted events and returns the file.
 *              Required urls can be generated on https://rapla-middleware.p4ddy.com
 *          tags:
 *              - rapla-middleware
 *          responses:
 *              200:
 *                  description: The .ics file
 *              400:
 *                  description: Wrong parameters, see response body for detailed information
 *              500:
 *                  description: A server error occurred. Please try again. If this issue persists, contact the admin.
 *          parameters:
 *              -   in: query
 *                  name: user
 *                  required: true
 *                  description: The user from RaPla, can be taken directly from the RaPla link
 *                  schema:
 *                      type: string
 *                  example: mueller
 *              -   in: query
 *                  name: file
 *                  required: true
 *                  description: The file from RaPla, can be taken directly from the RaPla link
 *                  schema:
 *                      type: string
 *                  example: TINF19B4
 *              -   in: query
 *                  name: blockers
 *                  required: false
 *                  description: Whether to remove blockers from the .ics file
 *                  schema:
 *                      type: boolean
 *                  example: 1
 *              -   in: query
 *                  name: wahl
 *                  required: false
 *                  description: The chosen elective module which is not to be filtered out
 *                  schema:
 *                      type: integer
 *                  example: 0
 *              -   in: query
 *                  name: pflicht
 *                  required: false
 *                  description: The chosen profile module which is not to be filtered out
 *                  schema:
 *                      type: integer
 *                  example: 2
 */
raPlaMiddlewareRouter.get('/', async (req: Request, res: Response) => {
	try {
		let user = (req.query.user ?? '').toString();
		let file = (req.query.file ?? '').toString();
		let blockers = (req.query.blockers ?? '').toString() === '1';
		let wahl = (req.query.wahl ?? '').toString();
		let pflicht = (req.query.pflicht ?? '').toString();

		const allowedCharsRegex: RegExp = /^[a-zA-Z0-9]+$/;

		if (user === '' || file === '') {
			res.status(400).send('Please at least provide user and file for RaPla!');
			return;
		} else if (!allowedCharsRegex.test(user) || !allowedCharsRegex.test(file)) {
			res.status(400).send('Please provide a valid user and file!');
			return;
		}

		let resultingFile = await icalgenerator.getiCalFile(user, file, blockers, wahl, pflicht);

		res.set({'Content-Disposition': 'attachment; filename=' + file + '.ics'});
		res.status(200).send(resultingFile);
	} catch (e: any) {
		let errorGuid = Guid.create().toString();
		logger.error('Error handling a request: ' + e.message, {reference: errorGuid});
		res.status(500).send({
			'status': 'PROCESSING_ERROR',
			'message': 'Internal Server Error. Try again later.',
			'reference': errorGuid
		});
	}
});