const express = require('express');
const path = require('path');
const app = express();
const { spawnSync } = require('child_process');
const moment = require('moment');
const { WebUntis } = require('webuntis');
var cron = require('node-cron');

// Befehl für die Skriptausführung
const command = process.platform === 'win32' ? 'python' : 'python3';
// Pfad zum Kalender-Skript
const scriptPath = path.resolve(__dirname, 'getCalendar.py');
// Pfad zum Ordner mit den Webseiten-Dateien
const static = path.join(__dirname, 'static');

// Verwende EJS als Vorlagen-Engine
app.set('view engine', 'ejs');

function getlast50weeks() {
    let currentWeek = moment().startOf('isoWeek');
    let last50WeeksCache = [];

    for (let i = 0; i < 50; i++) {
        const startOfWeek = currentWeek.clone().format('DD.MM.YYYY');
        const endOfWeek = currentWeek.clone().add(6, 'days').format('DD.MM.YYYY');
        last50WeeksCache.push(startOfWeek + " - " + endOfWeek);
        currentWeek.subtract(7, 'days');
    }
    
    return last50WeeksCache;
}

let last50Weeks = getlast50weeks();

cron.schedule('0 6 * * *', () => {
    last50Weeks = getlast50weeks();
});

function getCalendarEntries(weekDate) {
    const [startDateStr, endDateStr] = weekDate.split(" - ");
    
    // Argumente für das Kalender-Skript
    const args = [
        process.env.CALDAV_URL,
        process.env.CALDAV_USER,
        process.env.CALDAV_PASSWORD,
        process.env.CALDAV_CALENDAR,
        startDateStr,
        endDateStr
    ];
    
    // Skript ausführen und Output in einer Variable speichern
    const result = spawnSync(command, [scriptPath, ...args], { encoding: 'utf-8' }).stdout;
    
    if (result === "") {
        return "Keine Termine gefunden";
    }
    
    return result;
}

async function getUntis(weekDate) {
    let untisSchools = [];
    let untisUsernames = [];
    let untisPasswords = [];
    let untisServers = [];
    
    let optionsSuccess = true;
    try {
        untisSchools = process.env.UNTIS_SCHOOLS.split(",");
        untisUsernames = process.env.UNTIS_USERNAMES.split(",");
        untisPasswords = process.env.UNTIS_PASSWORDS.split(",");
        untisServers = process.env.UNTIS_SERVERS.split(",");
    } catch (error) {
        optionsSuccess = false;
    }
    
    if (!optionsSuccess) {
        return "Keine Untis-Optionen gefunden";
    }
    
    let teachingContent = "";
    
    await Promise.all(untisSchools.map(async (school, index) => {
        if(untisUsernames[index].length > 0 && untisPasswords[index].length > 0 && untisServers[index].length > 0) {
            const client = new WebUntis(school, untisUsernames[index], untisPasswords[index], untisServers[index]);
            
            // Anmelden
            await client.login();
            
            const cookie = await client._buildCookies();
            const jwtToken = await client._getJWT();
            const authorization = `Bearer ${jwtToken}`;
            
            const [startDateDay, startDateMonth, startDateYear] = weekDate.split(" - ")[0].split(".")
            let startDate = new Date(`${startDateYear}-${startDateMonth}-${startDateDay}T00:00:00.000Z`);
            
            for (let i = 0; i < 7; i++) {
                const timetable = await client.getOwnClassTimetableFor(startDate).catch(error => {
                    console.error(error);
                });
                
                try {
                    const lessonid = timetable[0].kl[0].id;
                    
                    startDateStr = startDate.toISOString().split("T")[0];
                    
                    await fetch(`https://${untisServers[index]}/WebUntis/api/rest/view/v1/calendar-entry/detail?elementId=${lessonid}&elementType=1&endDateTime=${startDateStr}T23%3A59%3A59&startDateTime=${startDateStr}T00%3A00%3A00`, {
                        "headers": {
                          "authorization": authorization,
                          "cookie": cookie,
                        },
                        "method": "GET"
                    }).then(res => res.json()).then(json => {
                        for (entry of json.calendarEntries) {
                            if (!teachingContent.includes(entry.teachingContent)) {
                                if (teachingContent != "") teachingContent += '\n';
                                teachingContent += "- "+entry.teachingContent;
                            }
                        }
                    });
                } catch (error) {}
                
                startDate.setDate(startDate.getDate() + i);
            }
            
            // Abmelden
            await client.logout();
        }
    }));
    
    if(teachingContent == "") teachingContent = "Keine Unterrichtsinhalte gefunden";
    return teachingContent;
}

app.use("/", express.static(static));

// Definiere eine Route für die Startseite
app.get('/', (req, res) => {
    res.render(path.join(static, 'index'), {options:last50Weeks });
});

app.get('/getlast50weeks', (req, res) => {
    res.send(last50Weeks);
});

// Definiere eine Route für die Ausgabe der Daten
app.get('/getreport', async (req, res) => {
    const weekDate = last50Weeks[req.query.week];
    res.send({
        calendar: getCalendarEntries(weekDate),
        untis: await getUntis(weekDate)
    });
});

// Starte den Webserver
app.listen(3000, () => {
    console.log('Webserver läuft auf Port 3000');
});