/**
 * @module helpers/string
 */

import { INVISIBLE_SPACE } from 'jodit/core/constants';

/**
 * Finds the position of the substring in the string, if any, and returns the length of the found subsequence.
 * Unlike `indexOf` ignores INVISIBLE_SPACE and may fail at `maxDistance` characters
 */
export function fuzzySearchIndex(
	needle: string,
	haystack: string,
	offset: number = 0,
	maxDistance: number = 1
): [number, number] {
	let i = 0,
		j = 0,
		startIndex = -1,
		len = 0,
		errorDistance = 0;

	for (j = offset; i < needle.length && j < haystack.length; ) {
		if (needle[i].toLowerCase() === haystack[j].toLowerCase()) {
			i++;
			len++;
			errorDistance = 0;

			if (startIndex === -1) {
				startIndex = j;
			}
		} else if (i > 0) {
			if (
				errorDistance >= maxDistance &&
				haystack[j] !== INVISIBLE_SPACE
			) {
				i = 0;
				startIndex = -1;
				len = 0;
				errorDistance = 0;
				j--;
			} else {
				errorDistance++;
				len++;
			}
		}

		j++;
	}

	return i === needle.length ? [startIndex, len] : [-1, 0];
}