Youtube embed video URL with parameters or video ID from a common URL

get_youtube_video_embed_url.php

/**
 * Returns a Youtube video ID from URL
 *
 * @link https://regex101.com/
 *
 * @param string $url - target URL, like 'https://www.youtube.com/watch?v=C0DPdy98e4c' and similar
 *
 * @return bool|string - Youtube video ID, like 'C0DPdy98e4c', or false if no matches
 *
 * @author K
 * @author 1.00
 *
 */
function get_youtube_video_id( $url ) {

	if ( empty( $url ) ) {
		return false;
	}

	$reg_exp = '/(?:https?:\/\/)?(?:www\.)?youtu\.?be(?:\.com)?\/?.*(?:watch|embed)?(?:.*v=|v\/|\/)([\w\-_]+)\&?/';
	preg_match( $reg_exp, $url, $matches );

	if ( $matches && strlen( $matches[1] ) == 11 ) {
		return $matches[1];
	}

	return false;
}

/**
 * Returns a Youtube video embed URL from a common URL or a video ID
 *
 * @param string       $target - the video URL or ID
 * @param string|array $args - parameters of the embed link
 * @param bool         $target_is_id - true if $target is a video ID, instead a video URL
 *
 * @return bool|mixed|string - the embed youtube video link or false if fail
 *
 * @author K
 * @author 1.01
 *
 */
function get_youtube_embed_url( $target, $args = null, $target_is_id = false ) {

	// Wrong parameters
	if ( empty( $target ) || ( $target_is_id && strlen( $target ) != 11 ) ) {
		return false;
	} elseif ( ! ( $video_id = ( $target_is_id ) ? $target : get_youtube_video_id( $target ) ) ) {
		return false;
	}

	// Init embed URL and string of parameters
	$embed_url   = 'https://www.youtube.com/embed/' . $video_id;
	$args_string = '';

	if ( ! empty( $args ) && is_string( $args ) && $args[0] == '?' && strlen( $args ) > 5 ) {

		// The parameters are set as a string like '?autoplay=1&showinfo=1&rel=0'
		$args_string = $args;

	} else if ( ! empty( $args ) && is_array( $args ) ) {

		// The parameters are set as an associative array
		// Look at: https://developers.google.com/youtube/player_parameters
		$allowed_params = array(
			'autoplay',
			'cc_load_policy',
			'color',
			'controls',
			'disablekb',
			'enablejsapi',
			'end',
			'fs',
			'hl',
			'iv_load_policy',
			'list',
			'listType',
			'loop',
			'modestbranding',
			'origin',
			'playlist',
			'playsinline',
			'rel',
			'showinfo',
			'start',
			'widget_referrer',
			'version',
			'vq'
		);
		// Build a params string
		foreach ( $args as $key => $arg ) {
			if ( $arg != null && in_array( $key, $allowed_params ) ) {
				$args_string .= "&{$key}={$arg}";
			}
		}
		// The first chat must be '?'
		if ( ! empty( $args_string ) && strlen( $args_string ) > 5 ) {
			$args_string[0] = '?';
		} else {
			$args_string = '';
		}
	}

	return esc_url( $embed_url . $args_string );
}