import { formatISO, parseISO, startOfWeek } from "date-fns";

function toDate(val: any) {
	if (val instanceof Date) return val;
	if (typeof val === "string") return parseISO(val.replace(" ", "T"));
	return new Date(val);
}

export const materialPurchases = async (data: any) => {
	/** @type {Record<string, Record<string, number>>} */
	const grouped: any = {};

	for (const r of data) {
		const mat = String(r.MaterialHumanReadableId);
		const d = toDate(r.CalDate);
		const week = formatISO(startOfWeek(d, { weekStartsOn: 1 }), {
			representation: "date",
		});

		grouped[mat] ??= {};
		grouped[mat][week] ??= 0;
		grouped[mat][week] += Number(r.DailyMaterialDemand) || 0;
	}

	const result = [];
	for (const [mat, weeks] of Object.entries(grouped)) {
		// @ts-ignore
		for (const [week, total] of Object.entries(weeks)) {
			result.push({
				MaterialHumanReadableId: mat,
				WeekStart: week,
				WeeklyDemand: Number(total).toFixed(2),
			});
		}
	}

	return result;
};