import { combinations as combinationsToolkit } from '../../array/combinations.ts';

/**
 * Creates a function that returns every combination of the configured size.
 *
 * Elements are treated as unique by position, so duplicate values can produce identical-looking
 * combinations. The returned function throws when size is not a non-negative integer.
 *
 * @template T - The type of elements in the array.
 * @param size - The number of items in each combination.
 * @returns A function that maps a readonly array to its size-length combinations.
 * @throws {Error} When size is not a non-negative integer.
 *
 * @example
 * import { combinations, pipe } from 'es-toolkit/fp';
 *
 * pipe(['A', 'B', 'C'], combinations(2));
 * // => [['A', 'B'], ['A', 'C'], ['B', 'C']]
 */
export function combinations<T>(size: number): (array: readonly T[]) => T[][] {
  return function (array: readonly T[]): T[][] {
    return combinationsToolkit(array, size);
  };
}
