sendou.ink/app/features/tier-list-maker/tier-list-maker-utils.ts

import type { TierListItem, TierListState } from "./tier-list-maker-schemas";

export function tierListItemId(item: TierListItem) {
	return `${item.type}:${item.id}${item.nth ? `:${item.nth}` : ""}`;
}

/**
 * Finds the next nth value for a duplicate item in the tier list.
 * Searches through all tiers to find the maximum nth value for items
 * with the same id and type, then returns max + 1.
 */
export function getNextNthForItem(
	item: TierListItem,
	tiers: TierListState,
): number {
	return (
		Array.from(tiers.tierItems.values()).reduce((maxNth, items) => {
			const matchingItems = items.filter(
				(i) => i.id === item.id && i.type === item.type,
			);
			const currentMax = Math.max(
				...matchingItems.map((i) => i.nth ?? 0),
				maxNth,
			);
			return currentMax;
		}, 0) + 1
	);
}