<?php

/**
 * Advanced Ads
 *
 * @package   Advanced_Ads_Placements
 * @author    Thomas Maier <support@wpadvancedads.com>
 * @license   GPL-2.0+
 * @link      https://wpadvancedads.com
 * @copyright 2014 Thomas Maier, Advanced Ads GmbH
 */

/**
 * Grouping placements functions
 *
 * @since 1.1.0
 * @package Advanced_Ads_Placements
 * @author  Thomas Maier <support@wpadvancedads.com>
 */
class Advanced_Ads_Placements {

	/**
	 * Gather placeholders which later are replaced by the ads
	 *
	 * @var array $ads_for_placeholders
	 */
	private static $ads_for_placeholders = [];
	/**
	 * Temporarily change content during processing
	 *
	 * @var array $placements
	 */
	private static $replacements = [
		'gcse:search' => 'gcse__search', // Google custom search namespaced tags.
	];

	/**
	 * Return placement page description
	 *
	 * @return string
	 */
	public static function get_description() {
		return __( 'Placements are customizable ad spots on your site. Use them to see and change all the assigned ads and groups on this page. Furthermore, you can set up exclusive features like Cache Busting, Lazy Loading, AdBlocker fallbacks, or Parallax effects.', 'advanced-ads' );
	}

	/**
	 * Get placement types
	 *
	 * @return \Advanced_Ads\Placement_Type[] $types array with placement types
	 * @since 1.2.1
	 */
	public static function get_placement_types() {
		$types = [
			'post_top'       => [
				'title'       => __( 'Before Content', 'advanced-ads' ),
				'description' => __( 'Injected before the post content.', 'advanced-ads' ),
				'image'       => ADVADS_BASE_URL . 'admin/assets/img/placements/content-before.png',
				'order'       => 20,
				'options'     => [
					'show_position'    => true,
					'show_lazy_load'   => true,
					'uses_the_content' => true,
					'amp'              => true,
				],
			],
			'post_content'   => [
				'title'       => __( 'Content', 'advanced-ads' ),
				'description' => __( 'Injected into the content. You can choose the paragraph after which the ad content is displayed.', 'advanced-ads' ),
				'image'       => ADVADS_BASE_URL . 'admin/assets/img/placements/content-within.png',
				'order'       => 21,
				'options'     => [
					'show_position'    => true,
					'show_lazy_load'   => true,
					'uses_the_content' => true,
					'amp'              => true,
				],
			],
			'post_bottom'    => [
				'title'       => __( 'After Content', 'advanced-ads' ),
				'description' => __( 'Injected after the post content.', 'advanced-ads' ),
				'image'       => ADVADS_BASE_URL . 'admin/assets/img/placements/content-after.png',
				'order'       => 35,
				'options'     => [
					'show_position'    => true,
					'show_lazy_load'   => true,
					'uses_the_content' => true,
					'amp'              => true,
				],
			],
			'sidebar_widget' => [
				'title'       => __( 'Sidebar Widget', 'advanced-ads' ),
				'description' => __( 'Create a sidebar widget with an ad. Can be placed and used like any other widget.', 'advanced-ads' ),
				'image'       => ADVADS_BASE_URL . 'admin/assets/img/placements/widget.png',
				'order'       => 50,
				'options'     => [
					'show_position'  => true,
					'show_lazy_load' => true,
					'amp'            => true,
				],
			],
			'default'        => [
				'title'       => __( 'Manual Placement', 'advanced-ads' ),
				'description' => __( 'Manual placement to use as function or shortcode.', 'advanced-ads' ),
				'image'       => ADVADS_BASE_URL . 'admin/assets/img/placements/manual.png',
				'order'       => 80,
				'options'     => [
					'show_position'  => true,
					'show_lazy_load' => true,
					'amp'            => true,
				],
			],
			'header'         => [
				'title'       => __( 'Header Code', 'advanced-ads' ),
				'description' => __( 'Injected in Header (before closing &lt;/head&gt; Tag, often not visible).', 'advanced-ads' ),
				'image'       => ADVADS_BASE_URL . 'admin/assets/img/placements/header.png',
				'order'       => 3,
			],
			'footer'         => [
				'title'       => __( 'Footer Code', 'advanced-ads' ),
				'description' => __( 'Injected in Footer (before closing &lt;/body&gt; Tag).', 'advanced-ads' ),
				'image'       => ADVADS_BASE_URL . 'admin/assets/img/placements/footer.png',
				'order'       => 95,
				'options'     => [ 'amp' => true ],
			],
		];

		$types = (array) apply_filters( 'advanced-ads-placement-types', $types );

		foreach ( $types as $type => $definition ) {
			$types[ $type ] = new \Advanced_Ads\Placement_Type( $type, $definition );
		}

		return $types;
	}

	/**
	 * Update placements if sent
	 *
	 * @since 1.5.2
	 */
	public static function update_placements() {

		// check user permissions.
		if ( ! current_user_can( Advanced_Ads_Plugin::user_cap( 'advanced_ads_manage_placements' ) ) ) {
			return;
		}

		$success = null;

		// add hook of last opened placement settings to URL.
		$hook = ! empty( $_POST['advads-last-edited-placement'] ) ? '#single-placement-' . $_POST['advads-last-edited-placement'] : '';

		if ( isset( $_POST['advads']['placement'] ) && check_admin_referer( 'advads-placement', 'advads_placement' ) ) {
			$success = self::save_new_placement( $_POST['advads']['placement'] );
		}
		// save placement data.
		if ( isset( $_POST['advads']['placements'] ) && check_admin_referer( 'advads-placement', 'advads_placement' ) ) {
			$success = self::save_placements( $_POST['advads']['placements'] );
		}

		$success = apply_filters( 'advanced-ads-update-placements', $success );

		if ( isset( $success ) ) {
			$message = $success ? 'updated' : 'error';
			wp_redirect( esc_url_raw( add_query_arg( [ 'message' => $message ] ) ) . $hook );
		}
	}

	/**
	 * Save a new placement
	 *
	 * @param array $new_placement information about the new placement.
	 *
	 * @return mixed slug if saved; false if not
	 * @since 1.1.0
	 */
	public static function save_new_placement( $new_placement ) {
		// load placements // -TODO use model.
		$placements = Advanced_Ads::get_ad_placements_array();

		// create slug.
		$new_placement['slug'] = sanitize_title( $new_placement['name'] );

		if ( isset( $placements[ $new_placement['slug'] ] ) ) {
			$i = 1;
			// try to save placement until we found an empty slug.
			do {
				$i ++;
				if ( 100 === $i ) { // prevent endless loop, just in case.
					Advanced_Ads::log( 'endless loop when injecting placement' );
					break;
				}
			} while ( isset( $placements[ $new_placement['slug'] . '_' . $i ] ) );

			$new_placement['slug'] .= '_' . $i;
			$new_placement['name'] .= ' ' . $i;
		}

		// check if slug already exists or is empty.
		if ( '' === $new_placement['slug'] || isset( $placements[ $new_placement['slug'] ] ) || ! isset( $new_placement['type'] ) ) {
			return false;
		}

		// make sure only allowed types are being saved.
		$placement_types       = self::get_placement_types();
		$new_placement['type'] = ( isset( $placement_types[ $new_placement['type'] ] ) ) ? $new_placement['type'] : 'default';
		// escape name.
		$new_placement['name'] = esc_attr( $new_placement['name'] );

		// add new place to all placements.
		$placements[ $new_placement['slug'] ] = [
			'type' => $new_placement['type'],
			'name' => $new_placement['name'],
			'item' => $new_placement['item'],
		];

		// add index options.
		if ( isset( $new_placement['options'] ) ) {
			$placements[ $new_placement['slug'] ]['options'] = $new_placement['options'];
			if ( isset( $placements[ $new_placement['slug'] ]['options']['index'] ) ) {
				$placements[ $new_placement['slug'] ]['options']['index'] = absint( $placements[ $new_placement['slug'] ]['options']['index'] );
			}
		}

		// save array.
		Advanced_Ads::get_instance()->get_model()->update_ad_placements_array( $placements );

		return $new_placement['slug'];
	}

	/**
	 * Save placements
	 *
	 * @param array $placement_items placements.
	 *
	 * @return mixed true if saved; error message if not
	 * @since 1.1.0
	 */
	public static function save_placements( $placement_items ) {

		// load placements // -TODO use model.
		$placements = Advanced_Ads::get_ad_placements_array();

		foreach ( $placement_items as $_placement_slug => $_placement ) {
			// remove the placement.
			if ( isset( $_placement['delete'] ) ) {
				unset( $placements[ $_placement_slug ] );
				continue;
			}
			// save item.
			if ( isset( $_placement['item'] ) ) {
				$placements[ $_placement_slug ]['item'] = $_placement['item'];
			}
			// save item options.
			if ( isset( $_placement['options'] ) ) {
				$placements[ $_placement_slug ]['options'] = $_placement['options'];
				if ( isset( $placements[ $_placement_slug ]['options']['index'] ) ) {
					$placements[ $_placement_slug ]['options']['index'] = absint( $placements[ $_placement_slug ]['options']['index'] );
				}
			} else {
				$placements[ $_placement_slug ]['options'] = [];
			}
		}

		// save array.
		Advanced_Ads::get_instance()->get_model()->update_ad_placements_array( $placements );

		return true;
	}

	/**
	 * Get items for item select field.
	 * Used for new placement form.
	 *
	 * @return array $select items for select field
	 */
	public static function items_for_select() {
		$select = [];
		$model  = Advanced_Ads::get_instance()->get_model();

		// load all ad groups.
		$groups = $model->get_ad_groups();
		foreach ( $groups as $_group ) {
			$select['groups'][ 'group_' . $_group->term_id ] = $_group->name;
		}

		// load all ads.
		$ads = $model->get_ads(
			[
				'orderby' => 'title',
				'order'   => 'ASC',
			]
		);
		foreach ( $ads as $_ad ) {
			$select['ads'][ 'ad_' . $_ad->ID ] = $_ad->post_title;
		}

		return $select;
	}

	/**
	 * Get html tags for content injection
	 *
	 * @return array $tags array with tags that can be used for content injection
	 * @since 1.3.5
	 */
	public static function tags_for_content_injection() {
		$headline_tags          = apply_filters( 'advanced-ads-headlines-for-ad-injection', [ 'h2', 'h3', 'h4' ] );
		$headline_tags_imploded = '&lt;' . implode( '&gt;, &lt;', $headline_tags ) . '&gt;';

		$tags = apply_filters(
			'advanced-ads-tags-for-injection',
			[
				// translators: %s is an html tag.
				'p'           => sprintf( __( 'paragraph (%s)', 'advanced-ads' ), '&lt;p&gt;' ),
				// translators: %s is an html tag.
				'pwithoutimg' => sprintf( __( 'paragraph without image (%s)', 'advanced-ads' ), '&lt;p&gt;' ),
				// translators: %s is an html tag.
				'h2'          => sprintf( __( 'headline 2 (%s)', 'advanced-ads' ), '&lt;h2&gt;' ),
				// translators: %s is an html tag.
				'h3'          => sprintf( __( 'headline 3 (%s)', 'advanced-ads' ), '&lt;h3&gt;' ),
				// translators: %s is an html tag.
				'h4'          => sprintf( __( 'headline 4 (%s)', 'advanced-ads' ), '&lt;h4&gt;' ),
				// translators: %s is an html tag.
				'headlines'   => sprintf( __( 'any headline (%s)', 'advanced-ads' ), $headline_tags_imploded ),
				// translators: %s is an html tag.
				'img'         => sprintf( __( 'image (%s)', 'advanced-ads' ), '&lt;img&gt;' ),
				// translators: %s is an html tag.
				'table'       => sprintf( __( 'table (%s)', 'advanced-ads' ), '&lt;table&gt;' ),
				// translators: %s is an html tag.
				'li'          => sprintf( __( 'list item (%s)', 'advanced-ads' ), '&lt;li&gt;' ),
				// translators: %s is an html tag.
				'blockquote'  => sprintf( __( 'quote (%s)', 'advanced-ads' ), '&lt;blockquote&gt;' ),
				// translators: %s is an html tag.
				'iframe'      => sprintf( __( 'iframe (%s)', 'advanced-ads' ), '&lt;iframe&gt;' ),
				// translators: %s is an html tag.
				'div'         => sprintf( __( 'container (%s)', 'advanced-ads' ), '&lt;div&gt;' ),
				// any HTML tag.
				'anyelement'  => __( 'any element', 'advanced-ads' ),
				// custom
				'custom'      => _x( 'custom', 'for the "custom" content placement option', 'advanced-ads' ),
			]
		);

		return $tags;
	}

	/**
	 * Return content of a placement
	 *
	 * @param string $id slug of the display.
	 * @param array  $args optional arguments (passed to child).
	 *
	 * @return string
	 */
	public static function output( $id = '', $args = [] ) {
		// get placement data for the slug.
		if ( '' == $id ) {
			return;
		}

		$placements = Advanced_Ads::get_ad_placements_array();
		$placement  = ( isset( $placements[ $id ] ) && is_array( $placements[ $id ] ) ) ? $placements[ $id ] : [];

		if ( isset( $args['change-placement'] ) ) {
			// some options was provided by the user.
			$placement = Advanced_Ads_Utils::merge_deep_array( [ $placement, $args['change-placement'] ] );
		}

		if ( isset( $placement['item'] ) && '' !== $placement['item'] ) {
			$_item = explode( '_', $placement['item'] );

			if ( ! isset( $_item[1] ) || empty( $_item[1] ) ) {
				return;
			}

			// inject options.
			if ( isset( $placement['options'] ) && is_array( $placement['options'] ) ) {
				foreach ( $placement['options'] as $_k => $_v ) {
					if ( ! isset( $args[ $_k ] ) ) {
						$args[ $_k ] = $_v;
					}
				}
			}

			// inject placement type.
			if ( isset( $placement['type'] ) ) {
				$args['placement_type'] = $placement['type'];
			}

			// options.
			$prefix = Advanced_Ads_Plugin::get_instance()->get_frontend_prefix();

			// return either ad or group content.
			switch ( $_item[0] ) {
				case 'ad':
				case Advanced_Ads_Select::AD:
					// create class from placement id (not if header injection).
					if ( ! isset( $placement['type'] ) || 'header' !== $placement['type'] ) {
						if ( ! isset( $args['output'] ) ) {
							$args['output'] = [];
						}
						if ( ! isset( $args['output']['class'] ) ) {
							$args['output']['class'] = [];
						}
						$class = $prefix . $id;
						if ( ! in_array( $class, $args['output']['class'] ) ) {
							$args['output']['class'][] = $class;
						}
					}

					// fix method id.
					$_item[0] = Advanced_Ads_Select::AD;

					/**
					 * Deliver the translated version of an ad if set up with WPML.
					 * If an ad is not translated, show the ad in the original language when this is the selected option in the WPML settings.
					 *
					 * @source https://wpml.org/wpml-hook/wpml_object_id/
					 * @source https://wpml.org/forums/topic/backend-custom-post-types-page-overview-with-translation-options/
					 *
					 */
					if ( defined( 'ICL_SITEPRESS_VERSION' ) ) {
						global $sitepress;
						$_item[1] = apply_filters( 'wpml_object_id', $_item[1], 'advanced_ads', $sitepress->is_display_as_translated_post_type( 'advanced_ads' ) );
					}
					break;

				case Advanced_Ads_Select::PLACEMENT:
					// avoid loops (programmatical error).
					return;

				case Advanced_Ads_Select::GROUP:
					$class = $prefix . $id;
					if ( ( isset( $placement['type'] ) && $placement['type'] !== 'header' )
						 && ( ! isset( $args['output']['class'] )
							  || ! is_array( $args['output']['class'] )
							  || ! in_array( $class, $args['output']['class'] ) ) ) {
						$args['output']['class'][] = $class;
					}
				default:
			}

			// create placement id for various features.
			$args['output']['placement_id'] = $id;

			// add the placement to the global output array.
			$advads = Advanced_Ads::get_instance();
			$name   = isset( $placement['name'] ) ? $placement['name'] : $id;

			$result = Advanced_Ads_Select::get_instance()->get_ad_by_method( (int) $_item[1], $_item[0], $args );

			if ( $result && ( ! isset( $args['global_output'] ) || $args['global_output'] ) ) {
				$advads->current_ads[] = [
					'type'  => 'placement',
					'id'    => $id,
					'title' => $name,
				];
			}

			return $result;
		}

		return;
	}

	/**
	 * Inject ads directly into the content
	 *
	 * @param string $placement_id Id of the placement.
	 * @param array  $placement_opts Placement options.
	 * @param string $content Content to inject placement into.
	 *
	 * @return string $content Content with injected placement.
	 * @since 1.2.1
	 */
	public static function &inject_in_content( $placement_id, $placement_opts, &$content ) {
		return Advanced_Ads_In_Content_Injector::inject_in_content( $placement_id, $placement_opts, $content );
	}

	/**
	 * Check if the placement can be displayed
	 *
	 * @param int $id placement id.
	 *
	 * @return bool true if placement can be displayed
	 * @since 1.6.9
	 */
	public static function can_display( $id = 0 ) {
		if ( ! isset( $id ) || 0 === $id ) {
			return true;
		}

		return apply_filters( 'advanced-ads-can-display-placement', true, $id );
	}

	/**
	 * Get the placements that includes the ad or group.
	 *
	 * @param string $type 'ad' or 'group'.
	 * @param int    $id Id.
	 *
	 * @return array
	 */
	public static function get_placements_by( $type, $id ) {
		$result = [];

		$placements = Advanced_Ads::get_ad_placements_array();
		foreach ( $placements as $_id => $_placement ) {
			if ( isset( $_placement['item'] ) && $_placement['item'] === $type . '_' . $id ) {
				$result[ $_id ] = $_placement;
			}
		}

		return $result;
	}

	/**
	 * Get the markup for the group/ad selection for each placement.
	 *
	 * @param string $slug      Slug for current placement. This is passed to the view.
	 * @param array  $placement The current placement.
	 *
	 * @return string
	 */
	public static function get_items_for_placement_markup( $slug, $placement ) {
		$placement['item'] = $placement['item'] ?? '';
		// Get the currently selected item.
		$placement_item_array = explode( '_', $placement['item'] );
		$placement_item_type  = $placement_item_array[0];
		$placement_item_id    = (int) ( $placement_item_array[1] ?? 0 );

		$items = self::get_items_for_placement( $placement['type'], $placement['item'] );

		// check for missing items
		if ( $placement_item_type && ! array_key_exists( $placement['item'], $items[ $placement_item_type . 's' ]['items'] ) ) {
			$method = $placement_item_type === 'group' ? 'get_ad_groups' : 'get_ads';
			$item   = \Advanced_Ads::get_instance()->get_model()->{$method}( [ 'include' => $placement_item_id ] )[0] ?? null;

			$items[ $placement_item_type . 's' ]['items'][ $placement['item'] ] = [
				'selected' => true,
				'disabled' => true,
			];

			if ( $item instanceof WP_Post ) {
				$items[ $placement_item_type . 's' ]['items'][ $placement['item'] ]['name'] = $item->post_title;
			} elseif ( $item instanceof Advanced_Ads_Group ) {
				$items[ $placement_item_type . 's' ]['items'][ $placement['item'] ]['name'] = $item->name;
			} else {
				unset( $items[ $placement_item_type . 's' ]['items'][ $placement['item'] ] );
			}

			if ( isset( $items[ $placement_item_type . 's' ]['items'][ $placement['item'] ] ) ) {
				$items = array_map( static function( $items_group ) {
					$keys = array_column( $items_group['items'], 'name' );
					array_multisort( $keys, SORT_ASC, SORT_NATURAL, $items_group['items'] );

					return $items_group;
				}, $items );
			}
		}

		$items = array_filter( $items, static function( $items_group ) {
			return ! empty( $items_group['items'] );
		} );

		ob_start();

		include ADVADS_BASE_PATH . 'admin/views/placements-item.php';

		return ob_get_clean();
	}

	/**
	 * Get the available items for the selected placement.
	 *
	 * @param string $type The current placement type.
	 * @param string $item The ad/group id.
	 *
	 * @return array[]
	 */
	public static function get_items_for_placement( string $type, string $item = 'ad_0' ) : iterable {
		$placement_type = self::get_placement_types()[ $type ];
		$items          = [
			'groups' => [
				'label' => __( 'Ad Groups', 'advanced-ads' ),
				'items' => $placement_type->get_allowed_groups(),
			],
			'ads'    => [
				'label' => __( 'Ads', 'advanced-ads' ),
				'items' => $placement_type->get_allowed_ads(),
			],
		];

		return array_map( static function( $items_group ) use ( $item ) {
			array_walk( $items_group['items'], static function( &$value, $key ) use ( $item ) {
				$value = [
					'name'     => $value,
					'selected' => $key === $item,
					'disabled' => false,
				];
			} );

			return $items_group;
		}, $items );
	}

	/**
	 * Get paths of ancestors that should not contain ads.
	 *
	 * @param object $xpath DOMXPath object.
	 *
	 * @return array Paths of ancestors.
	 */
	private static function get_ancestors_to_limit( $xpath ) {
		$query = self::get_ancestors_to_limit_query();
		if ( ! $query ) {
			return [];
		}

		$node_list          = $xpath->query( $query );
		$ancestors_to_limit = [];

		foreach ( $node_list as $a ) {
			$ancestors_to_limit[] = $a->getNodePath();
		}

		return $ancestors_to_limit;
	}


	/**
	 * Remove paragraphs that has ancestors that should not contain ads.
	 *
	 * @param array $paragraphs An array of `DOMNode` objects to insert ads before or after.
	 * @param array $ancestors_to_limit Paths of ancestor that should not contain ads.
	 *
	 * @return array $new_paragraphs An array of `DOMNode` objects to insert ads before or after.
	 */
	private static function filter_by_ancestors_to_limit( $paragraphs, $ancestors_to_limit ) {
		$new_paragraphs = [];

		foreach ( $paragraphs as $k => $paragraph ) {
			foreach ( $ancestors_to_limit as $a ) {
				if ( 0 === stripos( $paragraph->getNodePath(), $a ) ) {
					continue 2;
				}
			}

			$new_paragraphs[] = $paragraph;
		}

		return $new_paragraphs;
	}

	/**
	 * Get query to select ancestors that should not contain ads.
	 *
	 * @return string/false DOMXPath query or false.
	 */
	private static function get_ancestors_to_limit_query() {
		/**
		 * TODO:
		 * - support `%` (rand) at the start
		 * - support plain text that node should contain instead of CSS selectors
		 * - support `prev` and `next` as `type`
		 */

		/**
		 * Filter the nodes that limit injection.
		 *
		 * @param array An array of arrays, each of which contains:
		 *
		 * @type string $type Accept: `ancestor` - limit injection inside the ancestor.
		 * @type string $node A "class selector" which targets one class (.) or "id selector" which targets one id (#),
		 *                        optionally with `%` at the end.
		 */
		$items = apply_filters(
			'advanced-ads-content-injection-nodes-without-ads',
			[
				[
					// a class anyone can use to prevent automatic ad injection into a specific element.
					'node' => '.advads-stop-injection',
					'type' => 'ancestor',
				],
				[
					// Product Slider for Beaver Builder by WooPack.
					'node' => '.woopack-product-carousel',
					'type' => 'ancestor',
				],
				[
					// WP Author Box Lite.
					'node' => '#wpautbox-%',
					'type' => 'ancestor',
				],
				[
					// GeoDirectory Post Slider.
					'node' => '.geodir-post-slider',
					'type' => 'ancestor',
				],
			]
		);

		$query = [];
		foreach ( $items as $p ) {
			$sel = $p['node'];

			$sel_type = substr( $sel, 0, 1 );
			$sel      = substr( $sel, 1 );

			$rand_pos = strpos( $sel, '%' );
			$sel      = str_replace( '%', '', $sel );
			$sel      = sanitize_html_class( $sel );

			if ( '.' === $sel_type ) {
				if ( false !== $rand_pos ) {
					$query[] = "@class and contains(concat(' ', normalize-space(@class), ' '), ' $sel')";
				} else {
					$query[] = "@class and contains(concat(' ', normalize-space(@class), ' '), ' $sel ')";
				}
			}
			if ( '#' === $sel_type ) {
				if ( false !== $rand_pos ) {
					$query[] = "@id and starts-with(@id, '$sel')";
				} else {
					$query[] = "@id and @id = '$sel'";
				}
			}
		}

		if ( ! $query ) {
			return false;
		}

		return '//*[' . implode( ' or ', $query ) . ']';
	}

	/**
	 * Sort placements
	 *
	 * @param array  $placements Existing placements.
	 * @param string $orderby The field to order by. Accept `name` or `type`.
	 * @return array $placements Sorted placements.
	 */
	public static function sort( $placements, $orderby = 'name' ) {
		if ( ! is_array( $placements ) ) {
			return [];
		}
		if ( 'name' === $orderby ) {
			ksort( $placements, SORT_NATURAL );
			return $placements;
		}
		uasort( $placements, [ 'Advanced_Ads_Placements', 'sort_by_type_callback' ] );
		return $placements;

	}

	/**
	 * Callback to sort placements by type.
	 *
	 * @param array $f First placement.
	 * @param array $s Second placement.
	 * @return int 0 If placements are equal, -1 if the first should come first, 1 otherwise.
	 */
	private static function sort_by_type_callback( $f, $s ) {
		// A placement with the "Words Between Ads" option set to non-zero gets injected after others
		// because it reads existing ads.
		if ( ! empty( $f['options']['words_between_repeats'] ) xor ! empty( $s['options']['words_between_repeats'] ) ) {
			return ! empty( $f['options']['words_between_repeats'] ) ? 1 : -1;
		}

		$types = self::get_placement_types();

		$f_o = ( isset( $f['type'] ) && isset( $types[ $f['type'] ]['order'] ) ) ? $types[ $f['type'] ]['order'] : 100;
		$s_o = ( isset( $s['type'] ) && isset( $types[ $s['type'] ]['order'] ) ) ? $types[ $s['type'] ]['order'] : 100;

		if ( $f_o === $s_o ) {
			// Sort by index.
			if ( 'post_content' === $f['type'] && isset( $f['options']['index'] ) && isset( $s['options']['index'] )
				&& $f['options']['index'] !== $s['options']['index'] ) {
				return ( $f['options']['index'] < $s['options']['index'] ) ? -1 : 1;
			}

			// Sort by name.
			if ( isset( $f['name'] ) && isset( $s['name'] ) ) {
				return 0 > strnatcmp( $f['name'], $s['name'] ) ? -1 : 1;
			}
			return 0;
		}

		// Sort by order.
		return ( $f_o < $s_o ) ? -1 : 1;

	}


}