import { Router } from 'express';
import type { Response } from 'express';
import * as Sentry from '@sentry/node';
import { handleErrorAsync, clearLinkedText } from '../../src/helpers.ts';
import { createEvents } from 'ics';
import { calendar } from '../../src/calendar/calendar.ts';
import { loadSuml, loadSumlFromBase } from '../loader.ts';
import { Calendar, Day } from '../../src/calendar/helpers.ts';
import SQL from 'sql-template-strings';
import { normalise } from './user.ts';
import type { Translations } from '../../locale/translations.ts';
import type { Event } from '../../src/calendar/helpers.ts';
import type { LocaleDescription } from '../../locale/locales.ts';

// TODO caching? // import { caches } from "../../src/cache";

const translations = loadSuml('translations') as Translations;
const fallbackTranslations = loadSumlFromBase('locale/_base/translations') as Translations;

const renderEvents = (yearEvents: Record<number, Event[]>, res: Response, onlyFirstDays: boolean = false, calNameExtra: string = '') => {
    const events = [];
    let i = 1;
    for (const year in yearEvents) {
        if (!yearEvents.hasOwnProperty(year)) {
            continue;
        }
        for (const event of yearEvents[year]) {
            if (!event) {
                continue;
            }
            const ics = event.toIcs(parseInt(year), translations, fallbackTranslations, clearLinkedText, i, onlyFirstDays, calNameExtra);
            if (ics !== null) {
                events.push(ics);
            }
        }
        i++;
    }

    if (events.length === 0) {
        return res.status(404).json({ error: 'Not found' });
    }

    createEvents(
        events,
        (error, value) => {
            if (error) {
                Sentry.captureException(error);
                return res.status(500).json({ error: 'Unexpected server error' });
            }

            res.header('Content-type', 'text/calendar');
            res.send(value);
        },
    );
};

const getEventName = (name: string): string => {
    name = translations.calendar.events[name] || fallbackTranslations.calendar.events[name] || name;
    name = name.replace(/{.*?=(.*?)}/g, '$1');
    return name;
};

const buildMessage = (events: string[], locale: LocaleDescription, day: Day, link: string): string | null => {
    if (events.length === 0) {
        return null;
    }

    let message = `[${locale.name}] ${day.toString()}\n\n${translations.calendar.banner}:\n`;
    for (const event of events) {
        message += ` - ${event}\n`;
    }
    message += `\n${link}`;

    return message;
};

const eventsSummary = (day: Day, locale: LocaleDescription) => {
    const eventsRaw = calendar.getCurrentYear()!.eventsByDate[day.toString()];

    const link = `${locale.url}/${encodeURIComponent(global.config.calendar!.route!)}/${day}`;
    const image = `${locale.url}/calendar/${day}.png`;

    let message = null;
    const events = [];
    if (eventsRaw !== undefined && eventsRaw.length > 0) {
        for (const event of eventsRaw) {
            events.push(getEventName(event.name));
            delete event.daysMemoise;
        }
    }
    let eventsForMessage = [...events];
    while (true) {
        message = buildMessage(eventsForMessage, locale, day, link);

        if (message === null || message.length <= 280) {
            break;
        } else {
            eventsForMessage = eventsForMessage.slice(0, eventsForMessage.length - 1);
        }
    }

    return {
        day: day.toString(),
        link,
        image,
        message,
        events,
        eventsRaw: eventsRaw || [],
    };
};

const generateURIEncodedPathAlternative = (path: string): string[] => {
    return [path, path.replace('@', encodeURIComponent('@'))];
};

interface ProfileRaw {
    events: string;
    customEvents: string;
}

const router = Router();

router.get('/calendar/today', handleErrorAsync(async (req, res) => {
    return res.json(eventsSummary(
        Day.today(),
        req.locales[global.config.locale],
    ));
}));

router.get('/calendar/:year-:month-:day', handleErrorAsync(async (req, res) => {
    return res.json(eventsSummary(
        new Day(parseInt(req.params.year), parseInt(req.params.month), parseInt(req.params.day)),
        req.locales[global.config.locale],
    ));
}));

const routeBase = `/queer-calendar-${global.config.locale}`;

router.get(`${routeBase}.ics`, handleErrorAsync(async (req, res) => {
    const events: Record<number, Event[]> = {};
    for (const year of calendar.getAllYears()) {
        events[year.year] = year.events;
    }

    renderEvents(events, res, req.query.only_first_days !== undefined);
}));

router.get(generateURIEncodedPathAlternative(`${routeBase}-@:username.ics`), handleErrorAsync(async (req, res) => {
    const profiles = await req.db.all<Pick<ProfileRaw, 'events' | 'customEvents'>>(SQL`
        SELECT events, customEvents FROM profiles p
        LEFT JOIN users u ON p.userId = u.id
        WHERE u.usernameNorm = ${normalise(req.params.username)}
          AND p.locale = ${global.config.locale}
    `);

    if (!profiles.length) {
        return res.status(404).json({ error: 'Not found' });
    }

    const events = Calendar.generatePersonalCalendarEvents([
        ...JSON.parse(profiles[0].events),
        ...JSON.parse(profiles[0].customEvents),
    ], calendar.getCurrentYear()!);

    const groupedEvents: Record<number, Event[]> = {};
    for (const year of calendar.getAllYears()) {
        groupedEvents[year.year] = events;
    }

    renderEvents(groupedEvents, res, req.query.only_first_days !== undefined, ` (@${req.params.username})`);
}));

router.get(`${routeBase}-:year-:uuid.ics`, handleErrorAsync(async (req, res) => {
    const year = calendar.getYear(parseInt(req.params.year));
    if (!year) {
        return res.status(404).json({ error: 'Not found' });
    }

    renderEvents({ [year.year]: [year.eventsByUuid[req.params.uuid]] }, res);
}));

router.get(`${routeBase}-:year.ics`, handleErrorAsync(async (req, res) => {
    const year = calendar.getYear(parseInt(req.params.year));
    if (!year) {
        return res.status(404).json({ error: 'Not found' });
    }

    renderEvents({ [year.year]: year.events }, res);
}));

export default router;