src/shared/utils/highlightMatches.ts

import { escapeRegExp } from "./escapeRegExp";

export function filterMatches(
  matches: { match: string; index: number; element: string }[]
): { match: string; index: number; element: string }[] {
  const filtered: { match: string; index: number; element: string }[] = [];

  for (const current of matches) {
    const isContained = filtered.some(
      (existing) => current.index >= existing.index && current.index < existing.index + existing.match.length
    );

    if (!isContained) {
      filtered.push(current);
    }
  }

  return filtered;
}

export function getAllMatches(sortedAbbreviations: string[], input: string) {
  const allMatches: { match: string; index: number; element: string }[] = [];

  sortedAbbreviations.forEach((element) => {
    const escapedElement = escapeRegExp(element);
    const regex = new RegExp(`(?<=\\s|^|["(])(${escapedElement})(?=\\s|$|[,.!?:;")])`, "g");

    let match: RegExpExecArray | null;
    while ((match = regex.exec(input)) !== null) {
      allMatches.push({ match: match[0], index: match.index, element });
    }
  });
  return allMatches;
}

export function highlightMatches(input: string, matches: { match: string; index: number; element: string }[]): string {
  const filteredMatches = filterMatches(matches);
  filteredMatches.sort((a, b) => a.index - b.index);
  let highlightedString = input;
  let offset = 0;

  for (const match of filteredMatches) {
    const startIndex = match.index + offset;
    const endIndex = startIndex + match.match.length;
    highlightedString =
      highlightedString.slice(0, startIndex) +
      `<a href="#" class="abbreviation">${match.element}</a>` +
      highlightedString.slice(endIndex);
    offset += `<a href="#" class="abbreviation">${match.element}</a>`.length - match.match.length;
  }

  return highlightedString;
}