// Usage: Replace the 4 constants below, then run `await generateMarkdownTable()` to create markdown
// Requires the event to be an `event series`; `39c3ht` is not so this will fail: https://docs.pretix.eu/guides/event-series/?h=dates#how-to-create-an-event-series
const token = "";                                        // generate using https://docs.pretix.eu/dev/api/tokenauth.html#obtaining-an-api-token
const baseUrl = 'https://tickets.hamburg.ccc.de/api/v2'; 
const organizer = "hackertours";                         // example extracted from https://tickets.hamburg.ccc.de/hackertours/39c3ht
const eventName = "39c3ht";                              // example extracted from https://tickets.hamburg.ccc.de/hackertours/39c3ht

async function generateMarkdownTable() {
    async function fetchAllSubevents() {
        const results = [];
        let url = `${baseUrl}/organizers/${organizer}/events/${eventName}/subevents/`;
        while (url) {
            const resp = await fetch(url, {
                headers: {
                    'Authorization': `Token ${token}`,
                    'Accept': 'application/json'
                }
            });
            if (!resp.ok) {
                throw new Error(`Failed to fetch subevents: ${resp.status} ${await resp.text()}`);
            }
            const json = await resp.json();
            results.push(...json.results);
            url = json.next;
        }
        return results;
    }

    function slugify(name) {
        return name
            .toLowerCase()
            .replace(/[“”"']/g, '')
            .replace(/\(.*?\)/g, '')
            .replace(/&/g, 'and')
            .replace(/[^a-z0-9]+/g, '-')
            .replace(/^-+|-+$/g, '');
    }

    function langTags(title) {
        const tags = [];
        const hasGerman = /\(german\)|\bgerman\b|[äöüß]|stadtrundgang|rote flora|gängeviertel/.test(title);
        const hasEnglish = /\(english\)|\benglish\b/.test(title);
        const bilingual = /\b(bilingual)\b/.test(title);
        if (bilingual) {
            tags.push('{{< lang de >}}', '{{< lang en >}}');
        } else {
            if (hasGerman) tags.push('{{< lang de >}}');
            if (hasEnglish) tags.push('{{< lang en >}}');
        }
        return tags.join(' ');
    }

    function formatDay(date) {
        return date.toLocaleDateString('de-DE', { day: '2-digit', month: '2-digit' });
    }

    const subevents = await fetchAllSubevents();
    if (!subevents.length) return '| Zeit | | |\n|------|---|---|';

    const dayMap = new Map();
    for (const s of subevents) {
        if (!s.date_from) continue;
        const d = new Date(s.date_from);
        const dayKey = d.toISOString().slice(0, 10);
        if (!dayMap.has(dayKey)) {
            dayMap.set(dayKey, { dateObj: d, events: [] });
        }
        const hour = d.getUTCHours();
        const minute = d.getUTCMinutes();
        let title = ((s.name && (s.name.en || Object.values(s.name)[0])) || 'Untitled').replace(/^.*?-\s*/, '');
        const slug = slugify(title);
        const tags = langTags(title);
        title = title.replace("(German)", "").replace("(English)", "").replace("(Bilingual)", "");
        const md = `${hour.toString().padStart(2, '0')}:${minute.toString().padStart(2, '0')} [${title}](./${slug}/)${tags ? ' ' + tags : ''}`;
        dayMap.get(dayKey).events.push({ hour, minute, md });
    }

    const days = Array.from(dayMap.entries()).sort((a, b) => a[1].dateObj - b[1].dateObj);

    const hourSet = new Set();
    for (const [, { events }] of days) {
        for (const e of events) hourSet.add(e.hour);
    }
    const hoursSorted = Array.from(hourSet).sort((a, b) => a - b);

    const baseDate = new Date('2025-12-26T00:00:00Z');
    const headerCells = days.map(([key, val]) => {
        const dayNumber = Math.floor((val.dateObj - baseDate) / (1000 * 60 * 60 * 24));
        return `Tag ${dayNumber} (${formatDay(val.dateObj)})`;
    });

    let md = '| Zeit | ' + headerCells.join(' | ') + ' |\n';
    md += '|------|' + headerCells.map(() => '---').join('|') + '|\n';

    for (const hour of hoursSorted) {
        const hourLabel = `${hour.toString().padStart(2, '0')}:00`;

        const perDay = days.map(([, { events }]) =>
            events
                .filter(e => e.hour === hour)
                .sort((a, b) => a.minute - b.minute)
        );

        const maxRows = Math.max(0, ...perDay.map(list => list.length));
        if (maxRows === 0) continue;

        for (let i = 0; i < maxRows; i++) {
            const rowCells = perDay.map(list => list[i] ? list[i].md : '-');
            const zeit = i === 0 ? hourLabel : '';
            md += `| ${zeit} | ${rowCells.join(' | ')} |\n`;
        }
    }

    return md;
}