// This file contains the routes for the the account linking process on the student side.

let express = require('express');
let router = express.Router();
let passport = require('passport');
let directory = require('../directory.js');
let database = require('../config/database.js');
let uuid = require('uuid');

function storePairingCode(upn, pairing_code) {
    // If a student-pairing_code pair already exists, update the pairing code
    // Else, insert a new student-pairing_code pair
    let sql = 'INSERT INTO ps_pairing_codes (upn, pairing_code) VALUES (?, ?) ON DUPLICATE KEY UPDATE pairing_code = ?';
    let values = [upn, pairing_code, pairing_code];
    database.query(sql, values, function (err, result) {
        if (err) {
            console.log('Error:', err);
        } else {
            console.log('Pairing code stored');
        }
    });
}

router.get('/student/:upn/pairing-code', function (req, res) {
    if(!req.isAuthenticated()) {
        return res.status(401).send('Unauthorized');
    }
    if (req.user.userType !== directory.USER_TYPE.STUDENT) {
        return res.status(403).send('Forbidden, not a student');
    }
    let upn = req.params.upn;
    // Is the logged in user a student with the same UPN as the one in the URL?
    // If not, return a 403 Forbidden response
    if (req.user.username !== upn) {
        console.log('UPN mismatch');
        console.log('req.user.upn:', req.user.upn);
        console.log('upn:', upn);
        return res.status(403).send('Forbidden, UPN mismatch');
    }
    // Generate a uuid (v4) as the pairing code
    let pairing_code = uuid.v4();
    // Store the pairing code in the database
    storePairingCode(upn, pairing_code);
    // Return the pairing code
    res.send(pairing_code);
});

router.get('/student/:upn', function (req, res) {
    if(!req.isAuthenticated()) {
        return res.status(401).send('Unauthorized');
    }
    if (req.user.userType !== directory.USER_TYPE.STUDENT) {
        return res.status(403).send('Forbidden, not a student');
    }
    let upn = req.params.upn;
    // Is the logged in user a student with the same UPN as the one in the URL?
    // If not, return a 403 Forbidden response
    if (req.user.username !== upn) {
        return res.status(403).send('Forbidden, UPN mismatch');
    }
    // Return the student's details in the response in JSON format
    allowedAttributes = ['username', 'first_name', 'last_name'];
    let student = {};
    allowedAttributes.forEach(function (attribute) {
        student[attribute] = req.user[attribute];
    });
    res.json(student);
});

module.exports = router;