#!/usr/bin/env node

const fs = require('fs');
const readline = require('readline');
const nodemailer = require('nodemailer');

const mailer = nodemailer.createTransport({
    sendmail: true,
    newline: 'unix',
    path: '/usr/sbin/sendmail'
});

function mail(email, name, pick) {
    mailer.sendMail({
        from: 'ido@cassiopeia.uberspace.com',
        to: email,
        subject: `Dein Wichtel ${name} ist ...`,
        text: `Hey ${name},

Dein Wichtel ist *trommelwirbel*

${pick} !!!

Viel Spaß
Thomas

Ps.: Bitte gebt nicht mehr als 5 Euro pro Geschenk aus!
`,
    }, (err, info) => {
        console.log(info.envelope);
        console.log(info.messageId);
    });
}

function read() {
    return new Promise((resolve, reject) => {
        const people = [];
        const rl = readline.createInterface({
            input: fs.createReadStream('people.txt')
        });

        rl.on('line', line => {
            const [name, email, group] = line.split(/\s+/);
            people.push({ name, email, group });
        });

        rl.on('error', reject);

        rl.on('close', () => {
            resolve(people);
        });
    });
}

async function run() {
    const people = await read();

    people.forEach(drawer => {
        let picked;

        let pickable = people.filter(p =>
            !p.picked
            && drawer.name !== p.name
            && (!drawer.group || drawer.group !== p.group)
        );

        if (pickable.length === 0) {
            throw new Error('ohhh, noone left for ', drawer.name);
        }

        let pickIndex = Math.floor(Math.random() * pickable.length);
        drawer.pick = pickable[pickIndex].name;
        pickable[pickIndex].picked = true;
    });


    fs.writeFileSync('./picks.json', JSON.stringify(people.map(({name, pick}) => ({name, pick})), null, 4));

    people.forEach(p => mail(p.email, p.name, p.pick));
}

run();