import { json, error } from '@sveltejs/kit';
import type { RequestHandler } from './$types';
import { db } from '$lib/server/db';
import { dailyCompletions } from '$lib/server/db/schema';
import { eq, desc } from 'drizzle-orm';

export const GET: RequestHandler = async ({ url }) => {
	const anonymousId = url.searchParams.get('anonymousId');
	const localDate = url.searchParams.get('localDate');

	if (!anonymousId || !localDate) {
		error(400, 'Missing anonymousId or localDate');
	}

	// Fetch all completion dates for this user, newest first
	const rows = await db
		.select({ date: dailyCompletions.date })
		.from(dailyCompletions)
		.where(eq(dailyCompletions.anonymousId, anonymousId))
		.orderBy(desc(dailyCompletions.date));

	const completedDates = new Set(rows.map((r) => r.date));

	// Walk backwards from localDate, counting consecutive completed days
	let streak = 0;
	let cursor = new Date(`${localDate}T00:00:00`);

	while (true) {
		const dateStr = cursor.toLocaleDateString('en-CA'); // YYYY-MM-DD
		if (!completedDates.has(dateStr)) break;
		streak++;
		cursor.setDate(cursor.getDate() - 1);
	}

	return json({ streak });
};