// index.d.ts

/**
 * Attempts to extract the YouTube Video ID from a wide variety of URL formats.
 * Covers official (standard, mobile, music, kids, nocookie, regional),
 * shorteners, embed, image links, attribution links,
 * mobile schemes, common third-party frontends (static examples), iframes,
 * and some legacy/rare patterns. Includes a generic fallback for '/watch?v='.
 *
 * @param urlString The URL or string potentially containing a YouTube video link or ID.
 * @returns The 11-character YouTube Video ID, or null if not found or invalid.
 */
export declare function getYouTubeVideoId(urlString: string | null | undefined): string | null;

/**
 * Attempts to extract the YouTube Channel ID (starting with 'UC') from URL formats.
 * Primarily looks for '/channel/UC...' patterns on YouTube and known third-party domains.
 *
 * **Important:** This function does *not* resolve custom channel URLs (e.g., `/c/ChannelName`),
 * legacy usernames (e.g., `/user/UserName`), or handles (e.g., `/@Handle`). Resolving these
 * requires API calls or scraping and is outside the scope of simple URL parsing.
 *
 * @param urlString The URL or string potentially containing a YouTube channel link.
 * @returns The 24-character YouTube Channel ID (starting with 'UC'), or null if not found or invalid.
 */
export declare function getYouTubeChannelId(urlString: string | null | undefined): string | null;

/**
 * Attempts to extract the YouTube Playlist ID (starting with 'PL') from URL formats.
 * Primarily looks for the `list=PL...` query parameter on YouTube, Music, known third-party domains.
 * Focuses on standard shareable playlist IDs.
 *
 * @param urlString The URL or string potentially containing a YouTube playlist link.
 * @returns The YouTube Playlist ID (starting with 'PL'), or null if not found or invalid.
 */
export declare function getYouTubePlaylistId(urlString: string | null | undefined): string | null;