/**
 * Creates a function that returns the index of the first value matching a predicate.
 *
 * The predicate receives the value, index, and full input array. The returned function
 * returns -1 when no value matches, matching Array.prototype.findIndex.
 *
 * @template T - The type of elements in the array.
 * @param predicate - Called with each value, index, and array until it returns true.
 * @returns A function that maps a readonly array to the first matching index, or -1.
 *
 * @example
 * import { findIndex, pipe } from 'es-toolkit/fp';
 *
 * pipe([{ id: 1 }, { id: 2 }], findIndex(item => item.id === 2));
 * // => 1
 */
export function findIndex<T>(
  predicate: (value: T, index: number, array: readonly T[]) => boolean
): (array: readonly T[]) => number {
  return function (array: readonly T[]): number {
    return array.findIndex(predicate);
  };
}
