<?php
defined( 'ABSPATH' ) || exit;

/**
 * Appends the Viator Structure regions (each with a dropdown of its cities)
 * to the theme's header menu, so the menu follows the structure without
 * hand-editing Appearance → Menus.
 */
class VC_Menu {
	const LOCATION = 'hoho_primary';

	public static function init() {
		add_filter( 'wp_nav_menu_objects', array( __CLASS__, 'append' ), 10, 2 );
	}

	public static function append( $items, $args ) {
		if ( empty( $args->theme_location ) || self::LOCATION !== $args->theme_location ) {
			return $items;
		}
		$extra = self::items();
		if ( ! $extra ) {
			return $items;
		}

		// Regions go right after the top-level link to the tours archive ("All
		// Tours"); without one, at the end. The walker renders top-level items
		// in array order.
		$items    = array_values( $items );
		$position = count( $items );
		$archive  = untrailingslashit( (string) get_post_type_archive_link( 'viator_tour' ) );
		foreach ( $items as $i => $item ) {
			if ( empty( $item->menu_item_parent ) && '' !== $archive && untrailingslashit( (string) $item->url ) === $archive ) {
				$position = $i + 1;
				break;
			}
		}
		array_splice( $items, $position, 0, $extra );

		foreach ( $items as $i => $item ) {
			$item->menu_order = $i + 1;
		}
		return $items;
	}

	/**
	 * Menu-item objects for the walker. The theme walker turns a parent with
	 * children into a toggle button (no link), so a region's dropdown starts
	 * with an "All of {region}" link to the region page itself.
	 *
	 * @return object[]
	 */
	public static function items() {
		$items = array();
		$n     = 0;
		foreach ( VC_Structure::get() as $region ) {
			$term = $region['term_id'] ? get_term( (int) $region['term_id'], 'viator_destination' ) : null;
			if ( ! $term instanceof WP_Term ) {
				continue;
			}
			$region_url = get_term_link( $term );
			if ( is_wp_error( $region_url ) ) {
				continue;
			}
			$parent  = self::item( ++$n, 0, $term->name, $region_url );
			$items[] = $parent;
			if ( ! $region['cities'] ) {
				continue;
			}
			/* translators: %s: region name. */
			$items[] = self::item( ++$n, $parent->db_id, sprintf( __( 'All of %s', 'viator-collector' ), $term->name ), $region_url );
			foreach ( $region['cities'] as $city ) {
				$items[] = self::item( ++$n, $parent->db_id, $city['name'], home_url( '/' . $city['slug'] . '/' ) );
			}
		}
		return $items;
	}

	private static function item( $n, $parent_id, $title, $url ) {
		$id   = -1000 - $n;
		$item = new stdClass();

		$item->ID               = $id;
		$item->db_id            = $id;
		$item->menu_item_parent = (string) $parent_id;
		$item->object_id        = (string) $id;
		$item->object           = 'custom';
		$item->type             = 'custom';
		$item->type_label       = '';
		$item->title            = $title;
		$item->url              = $url;
		$item->target           = '';
		$item->attr_title       = '';
		$item->description      = '';
		$item->classes          = array( 'menu-item', 'vc-structure-item' );
		$item->xfn              = '';
		$item->status           = 'publish';
		$item->post_parent      = 0;
		$item->menu_order       = $n;
		$item->current          = false;
		$item->current_item_ancestor = false;
		$item->current_item_parent   = false;

		return $item;
	}
}