WP: Generate Unique Title

class-booking.php

/**
	 * Generate Unique Title.
	 *
	 * @since 1.0.0
	 */
	public function booking_title() {

		// Generate a random number with 8 length.
		$id_length = 8;
		$uniqueid  = crypt( uniqid( rand(), 1 ) );
		$uniqueid  = strip_tags( stripslashes( $uniqueid ) );
		$uniqueid  = str_replace( ".","",$uniqueid );
		$uniqueid  = strrev( str_replace( "/","",$uniqueid ) );
		$uniqueid  = substr( $uniqueid, 0, $id_length );
		$uniqueid  = strtoupper( $uniqueid );

		// Format the title.
		$title = 'Booking: #' . $uniqueid . ' - ' . date( 'd-m-Y' );

		// Return the title.
		return $title;

	}