import { fail, redirect } from '@sveltejs/kit';
import { getSessionUser } from '$lib/server/auth/session';
import { getDatabase } from '$lib/server/database';
import { getPagination } from '$lib/server/pagination';
import { NOTIFICATION_CATEGORIES } from '$lib/server/notifications';
import type { Actions, PageServerLoad } from './$types';

export const load: PageServerLoad = async ({ cookies, url }) => {
	const user = await getSessionUser(cookies);
	if (!user) redirect(303, '/sign-in');
	const database = await getDatabase();
	const filtering = url.searchParams.get('filtering') === '1';
	const categories = filtering
		? url.searchParams.getAll('channel').filter((value) => NOTIFICATION_CATEGORIES.includes(value as any))
		: [...NOTIFICATION_CATEGORIES];
	const states = filtering
		? url.searchParams.getAll('state').filter((value) => value === 'unread' || value === 'read')
		: ['unread', 'read'];
	const conditions = ['n.user_id=?', '(n.mandatory=1 OR COALESCE(p.in_app_enabled,1)=1)'];
	const args: unknown[] = [user.id];
	if (categories.length === 0 || states.length === 0) {
		conditions.push('1=0');
	} else {
		if (categories.length < NOTIFICATION_CATEGORIES.length) {
			conditions.push(`n.category IN (${categories.map(() => '?').join(',')})`);
			args.push(...categories);
		}
		if (states.length === 1) conditions.push(states[0] === 'unread' ? 'n.read_at IS NULL' : 'n.read_at IS NOT NULL');
	}
	const where = `WHERE ${conditions.join(' AND ')}`;
	const total = Number((await (await database.prepare(`SELECT COUNT(*) AS total FROM notifications n LEFT JOIN notification_preferences p ON p.user_id=n.user_id AND p.category=n.category ${where}`)).get(...args))?.total ?? 0);
	const pagination = getPagination(url, total);
	const notifications = await (await database.prepare(`SELECT n.* FROM notifications n
		LEFT JOIN notification_preferences p ON p.user_id=n.user_id AND p.category=n.category
		${where} ORDER BY n.created_at DESC LIMIT ? OFFSET ?`)).all(...args, pagination.perPage, pagination.offset);
	const preferenceRows = await (await database.prepare('SELECT * FROM notification_preferences WHERE user_id=?')).all(user.id);
	const preferences = NOTIFICATION_CATEGORIES.map((name) => {
		const stored = preferenceRows.find((row) => row.category === name);
		return {
			category: name,
			inApp: name === 'isac' ? true : stored?.in_app_enabled === undefined ? true : Boolean(stored.in_app_enabled),
			browser: Boolean(stored?.browser_enabled),
			emailFrequency: String(stored?.email_frequency ?? 'none')
		};
	});
	const unread = Number((await (await database.prepare(`SELECT COUNT(*) AS count FROM notifications n
		LEFT JOIN notification_preferences p ON p.user_id=n.user_id AND p.category=n.category
		WHERE n.user_id=? AND n.read_at IS NULL AND (n.mandatory=1 OR COALESCE(p.in_app_enabled,1)=1)`)).get(user.id))?.count ?? 0);
	return { notifications, preferences, pagination, filters: { categories, states }, unread, hasVerifiedEmail: Boolean(await (await database.prepare('SELECT 1 FROM user_emails WHERE user_id=?')).get(user.id)) };
};

export const actions: Actions = {
	markRead: async ({ cookies, request }) => {
		const user = await getSessionUser(cookies);
		if (!user) redirect(303, '/sign-in');
		const id = String((await request.formData()).get('id') ?? '');
		await (await (await getDatabase()).prepare('UPDATE notifications SET read_at=COALESCE(read_at,?) WHERE id=? AND user_id=?')).run(new Date().toISOString(), id, user.id);
		return { notificationUpdated: true };
	},
	markAllRead: async ({ cookies }) => {
		const user = await getSessionUser(cookies);
		if (!user) redirect(303, '/sign-in');
		await (await (await getDatabase()).prepare('UPDATE notifications SET read_at=? WHERE user_id=? AND read_at IS NULL')).run(new Date().toISOString(), user.id);
		return { notificationsCleared: true };
	},
	savePreferences: async ({ cookies, request }) => {
		const user = await getSessionUser(cookies);
		if (!user) redirect(303, '/sign-in');
		const form = await request.formData();
		const database = await getDatabase();
		const now = new Date().toISOString();
		const hasEmail = Boolean(await (await database.prepare('SELECT 1 FROM user_emails WHERE user_id=?')).get(user.id));
		for (const category of NOTIFICATION_CATEGORIES) {
			const inApp = category === 'isac' || form.get(`inApp:${category}`) === 'on';
			const browser = form.get(`browser:${category}`) === 'on';
			const emailFrequency = String(form.get(`email:${category}`) ?? 'none');
			if (!['none', 'immediate', 'daily'].includes(emailFrequency)) return fail(400, { notificationPreferenceError: 'Choose a valid email frequency.' });
			if (emailFrequency !== 'none' && !hasEmail) return fail(400, { notificationPreferenceError: 'Add and verify a magic-link email before enabling email notifications.' });
			await (await database.prepare(`INSERT INTO notification_preferences(user_id,category,in_app_enabled,browser_enabled,email_frequency,updated_at)
				VALUES(?,?,?,?,?,?) ON CONFLICT(user_id,category) DO UPDATE SET
				in_app_enabled=excluded.in_app_enabled,browser_enabled=excluded.browser_enabled,email_frequency=excluded.email_frequency,updated_at=excluded.updated_at`))
				.run(user.id, category, inApp ? 1 : 0, browser ? 1 : 0, emailFrequency, now);
		}
		return {
			notificationPreferencesSaved: true,
			notificationPreferenceSaveToken: crypto.randomUUID()
		};
	}
};