import { Task } from "@/model/task";

export const TaskSortDirection = {
	/** Oldest first (by created). */
	ASC: "asc",
	/** Newest first (by created). */
	DESC: "desc",
} as const;

export type TaskSortDirection =
	(typeof TaskSortDirection)[keyof typeof TaskSortDirection];

export const TASK_SORT_DIRECTION_ORDER: TaskSortDirection[] = [
	TaskSortDirection.ASC,
	TaskSortDirection.DESC,
];

export function isTaskSortDirection(
	value: unknown,
): value is TaskSortDirection {
	return (
		typeof value === "string" &&
		(TASK_SORT_DIRECTION_ORDER as string[]).includes(value)
	);
}

const SORT_ASC_SIGN = 1;
const SORT_DESC_SIGN = -1;

/** Sort by `created`. Default: oldest first. Does not mutate input. */
export function sortTasks(
	tasks: Task[],
	direction: TaskSortDirection = TaskSortDirection.ASC,
): Task[] {
	const sign =
		direction === TaskSortDirection.ASC ? SORT_ASC_SIGN : SORT_DESC_SIGN;
	return [...tasks].sort(
		(a, b) =>
			sign * (new Date(a.created).getTime() - new Date(b.created).getTime()),
	);
}