malice

import type { Mention } from './mentions';

export interface MarkPart {

  text: string;

  mark: boolean;

}

/** The composer text split so picked mention names and emote shortcodes can be highlighted behind the textarea. */

export function markMentions(text: string, mentions: Mention[], extra: string[] = []): MarkPart[] {

  const names = [...new Set([...mentions.map((m) => m.text), ...extra].filter(Boolean))].sort((a, b) => b.length - a.length);

  if (!names.length || !text) return [{ text, mark: false }];

  const parts: MarkPart[] = [];

  let rest = text;

  while (rest) {

    let at = -1;

    let hit = '';

    for (const name of names) {

      const i = rest.indexOf(name);

      if (i >= 0 && (at < 0 || i < at)) {

        at = i;

        hit = name;

      }

    }

    if (at < 0) {

      parts.push({ text: rest, mark: false });

      break;

    }

    if (at > 0) parts.push({ text: rest.slice(0, at), mark: false });

    parts.push({ text: hit, mark: true });

    rest = rest.slice(at + hit.length);

  }

  return parts;

}