Add a company taxonomy to ads managed by the Advanced Ads plugin.

advanced-ads-company-category.php

<?php
/**
 * Advanced Ads – Company Category
 *
 * @wordpress-plugin
 * Plugin Name:       Advanced Ads – Company Category
 * Plugin URI:        https://wpadvancedads.com
 * Description:       Add a Company category to ads so that you can group them.
 * Version:           0.1
 * Author:            Thomas Maier
 * Author URI:        https://wpadvancedads.com
 * Domain Path:       /languages
 * License:           GPL-2.0+
 * License URI:       https://www.gnu.org/licenses/gpl-2.0.txt
 *
 * Features:
 *
 * - adds a "Company" categorization to ads
 * - adds a category-like meta box to the ad edit screen to choose the company
 * - lists the company in a dedicated column in the ad overview list
 *
 * Limitations:
 *
 * - the ad overview list can’t be filtered by the company => needs a fix
 *
 */

// If this file is called directly, abort.
if ( ! defined( 'WPINC' ) ) {
	die;
}

/**
 * Register the Company taxonomy
 */
function advanced_ads_company_category_register_taxonomy() {
	if ( ! taxonomy_exists( 'advanced_ads_company_taxonomy' ) ) {
		$labels = array(
			'name'              => 'Companies',
			'singular_name'     => 'Company',
			'search_items'      => 'Search Company',
			'all_items'         => 'All Companies',
			'parent_item'       => 'Parent Companies',
			'parent_item_colon' => 'Parent Companies:',
			'edit_item'         => 'Edit Company',
			'update_item'       => 'Update Company',
			'add_new_item'      => 'Add New Company',
			'new_item_name'     => 'New Company Name',
			'menu_name'         => 'Companies',
			'not_found'         => 'No Company found',
		);

		$args = array(
			'public'            => false,
			'hierarchical'      => true,
			'labels'            => $labels,
			'show_ui'           => true,
			'show_in_nav_menus' => false,
			'show_tagcloud'     => false,
			'show_admin_column' => true,
			'query_var'         => false,
			'rewrite'           => false,
		);

		register_taxonomy( 'advanced_ads_company_taxonomy', array( 'advanced_ads' ), $args );
	}
}

add_action( 'init', 'advanced_ads_company_category_register_taxonomy' );

/**
 * Whitelist the Company taxonomy box on the ad edit page
 */
function advanced_ads_company_category_whitelist_metabox( $metaboxes ) {
	$metaboxes[] = 'advanced_ads_company_taxonomydiv';

	return $metaboxes;
}

add_filter( 'advanced-ads-ad-edit-allowed-metaboxes', 'advanced_ads_company_category_whitelist_metabox' );

/**
 * Whitelist Company column in ad overview list
 */
function advanced_ads_company_category_whitelist_column( $columns ) {
	$columns[] = 'taxonomy-advanced_ads_company_taxonomy';

	return $columns;
}

add_filter( 'advanced-ads-ad-list-allowed-columns', 'advanced_ads_company_category_whitelist_column' );

/**
 * Create a company list that will be displayed in the filter list
 */
function advanced_ads_company_category_collect_filters( $all_filters, $post, $ad_option ) {

	$anc = advanced_ads_company_storage::get_ads_and_company();

	// no companies.
	if ( false === $anc ) {
		return $all_filters;
	}

	foreach ( $anc['ads_by_company'] as $comp_id => $ad_ids ) {
		if ( in_array( $post->ID, $ad_ids, true ) ) {
			if ( ! isset( $all_filters['all_companies'] ) ) {
				$all_filters['all_companies'] = array();
			}
			if ( ! isset( $all_filters['all_companies'][ $comp_id ] ) ) {
				$all_filters['all_companies'][ $comp_id ] = $anc['all_companies'][ $comp_id ]['slug'];
			}
		}
	}

	return $all_filters;

}

add_filter( 'advanced-ads-ad-list-column-filter', 'advanced_ads_company_category_collect_filters', 10, 3 );

/**
 * Add a select box for companies
 */
function advanced_ads_company_add_markup( $all_filters ) {
	if ( ! empty( $all_filters['all_companies'] ) ) {

		$anc = advanced_ads_company_storage::get_ads_and_company();

		echo '<select id="advads-filter-company" name="adcompany">';
		echo '<option value="">- All companies -</option>';
		foreach ( $all_filters['all_companies'] as $id => $slug ) {
			echo '<option value="' . esc_attr( $id ) . '">' . esc_html( $anc['all_companies'][ $id ]['name'] ) . '</option>';
		}
		echo '</select>';
	}
}

add_action( 'advanced-ads-ad-list-filter-markup', 'advanced_ads_company_add_markup' );

/**
 * Add company filter on ad overview page
 *
 * @param array $posts list of posts.
 * @param array $all_ads_options additional options.
 *
 * @return array filtered posts
 */
function advanced_ads_company_filter( $posts, $all_ads_options ) {

	$request = wp_unslash( $_REQUEST );
	if ( isset( $request['adcompany'] ) && ! empty( $request['adcompany'] ) ) {

		$anc = advanced_ads_company_storage::get_ads_and_company();
		if ( false === $anc ) {
			return $posts;
		}

		$new_posts = array();
		foreach ( $posts as $post ) {
			if ( in_array( $post->ID, $anc['ads_by_company'][ absint( $request['adcompany'] ) ], true ) ) {
				$new_posts[] = $post;
			}
		}
		$posts = $new_posts;

	}

	return $posts;

}

add_filter( 'advanced-ads-ad-list-filter', 'advanced_ads_company_filter', 10, 2 );

if ( ! class_exists( 'advanced_ads_company_storage' ) ) {
	class advanced_ads_company_storage {
		private static $ads_company = null;

		public static function get_ads_and_company() {
			if ( null === self::$ads_company ) {

				global $wpdb;
				$q1 = "SELECT `term_id`, `name`, `slug` FROM `{$wpdb->prefix}terms` WHERE `term_id` IN " .
				      "( SELECT `term_id` FROM `{$wpdb->prefix}term_taxonomy` WHERE `taxonomy` = 'advanced_ads_company_taxonomy' )";

				/**
				 * All companies
				 */
				$_all_companies = $wpdb->get_results( $q1, 'ARRAY_A' );

				if ( empty( $_all_companies ) ) {
					self::$ads_company = false;

					return false;
				}

				$all_companies = array();
				foreach ( $_all_companies as $c ) {
					$all_companies[ absint( $c['term_id'] ) ] = array(
						'name' => $c['name'],
						'slug' => $c['slug'],
					);
				}

				$q2 = "SELECT `object_id`, `term_taxonomy_id` FROM `{$wpdb->prefix}term_relationships` WHERE `term_taxonomy_id` IN " .
				      "( SELECT `term_id` FROM `{$wpdb->prefix}term_taxonomy` WHERE `taxonomy` = 'advanced_ads_company_taxonomy' )";

				$ads = $wpdb->get_results( $q2, 'ARRAY_A' );

				/**
				 * Group the ad id-s by company.
				 */
				$anc = array();
				foreach ( $ads as $ad ) {
					if ( ! isset( $anc[ absint( $ad['term_taxonomy_id'] ) ] ) ) {
						$anc[ absint( $ad['term_taxonomy_id'] ) ] = array();
					}
					$anc[ absint( $ad['term_taxonomy_id'] ) ][] = absint( $ad['object_id'] );
				}

				$results           = array(
					'ads_by_company' => $anc,
					'all_companies'  => $all_companies,
				);
				self::$ads_company = $results;

				return $results;

			} else {
				return self::$ads_company;
			}
		}
	}
}