function bp_legacy_theme_ajax_messages_send_reply() {
	if ( ! bp_is_post_request() ) {
		return;
	}

	check_ajax_referer( 'messages_send_message' );

	$thread_id = (int) $_POST['thread_id'];

	// Cannot respond to a thread you're not already a recipient on.
	if ( ! bp_current_user_can( 'bp_moderate' ) && ( ! messages_is_valid_thread( $thread_id ) || ! messages_check_thread_access( $thread_id ) ) ) {
		echo "-1<div id='message' class='error'><p>" . __( 'There was a problem sending that reply. Please try again.', 'buddypress' ) . '</p></div>';
		die;
	}

	$result = messages_new_message( array( 'thread_id' => $thread_id, 'content' => $_REQUEST['content'] ) );

	if ( !empty( $result ) ) {

		// Pretend we're in the message loop.
		global $thread_template;

		bp_thread_has_messages( array( 'thread_id' => $thread_id ) );

		// Set the current message to the 2nd last.
		$thread_template->message = end( $thread_template->thread->messages );
		$thread_template->message = prev( $thread_template->thread->messages );

		// Set current message to current key.
		$thread_template->current_message = key( $thread_template->thread->messages );

		// Now manually iterate message like we're in the loop.
		bp_thread_the_message();

		// Manually call oEmbed
		// this is needed because we're not at the beginning of the loop.
		bp_messages_embed();

		// Add new-message css class.
		add_filter( 'bp_get_the_thread_message_css_class', function( $retval ) {
			$retval[] = 'new-message';
			return $retval;
		} );

		// Output single message template part.
		bp_get_template_part( 'members/single/messages/message' );

		// Clean up the loop.
		bp_thread_messages();

	} else {
		echo "-1<div id='message' class='error'><p>" . __( 'There was a problem sending that reply. Please try again.', 'buddypress' ) . '</p></div>';
	}

	exit;
}