Inventory_Presser_Allow_Inventory_As_Home_Page

class Inventory_Presser_Allow_Inventory_As_Home_Page {

	const PAGE_META_KEY = '_inventory_presser_hidden_page';

	/**
	 * create_page
	 *
	 * Creates a page so something shows up in the setting dropdown
	 *
	 * @return void
	 */
	private static function create_page() {
		// Does the page already exist?
		if ( -1 != self::find_page_id() ) {
			// Yes, abort
			return;
		}

		$id = wp_insert_post(
			array(
				'comment_status' => 'closed',
				'meta_input'     => array(
					self::PAGE_META_KEY => '1',
				),
				'post_content'   => __( 'This is not the real Inventory page. This page exists so that you can set the site\'s home page to the Inventory list in the Customizer or the Settings > Reading admin page. The Inventory "page" is actually a custom post type archive, and typically will not show up in those settings drop downs. All requests for this page will be redirected to the Inventory archive.', 'inventory-presser' ),
				'post_status'    => 'publish',
				'post_title'     => __( 'Inventory', 'inventory-presser' ),
				'post_type'      => 'page',
			)
		);
	}

	/**
	 * create_pages
	 *
	 * Are we on multi-site? If so, we need to create a page on every blog
	 * in the multisite network
	 *
	 * @return void
	 */
	static function create_pages() {
		if ( ! is_multisite() ) {
			self::create_page();
			return;
		}

		// We are on multisite, create a page for every site on the network
		$sites = get_sites(
			array(
				'network' => 1,
				'limit'   => 1000,
			)
		);
		foreach ( $sites as $site ) {
			switch_to_blog( $site->blog_id );
			self::create_page();
			restore_current_blog();
		}
	}

	/**
	 * delete_pages
	 *
	 * Are we on multi-site? If so, we need to delete the page from every
	 * blog in the multisite network
	 *
	 * @return void
	 */
	public static function delete_pages() {
		if ( ! is_multisite() ) {
			wp_delete_post( self::find_page_id(), true );
			return;
		}

		// We are on multisite, create a page for every site on the network
		$sites = get_sites(
			array(
				'network' => 1,
				'limit'   => 1000,
			)
		);
		foreach ( $sites as $site ) {
			switch_to_blog( $site->blog_id );
			wp_delete_post( self::find_page_id(), true );
			restore_current_blog();
		}
	}

	/**
	 * find_page_id
	 *
	 * Finds the ID of the page this plugin creates to allow the user to pick
	 * the inventory listing as a home page option.
	 *
	 * @return int The ID of the page or -1 if the page is not found.
	 */
	static function find_page_id() {
		$pages = get_pages(
			array(
				'meta_key'   => self::PAGE_META_KEY,
				'meta_value' => '1',
			)
		);

		if ( empty( $pages ) ) {
			return -1;
		}

		return $pages[0]->ID;
	}

	/**
	 * hide_page_from_edit_list
	 *
	 * Prevents the page this plugin creates from showing up in the list of
	 * pages while editing in the dashboard. We need a page to exist in order to
	 * allow users to choose it as their home page, but we don't want them to
	 * see an actual page in the list, because the Inventory listing is not a
	 * page, it's a custom post type archive.
	 *
	 * @param  WP_Query $query An instance of the WP_Query class
	 * @return void
	 */
	function hide_page_from_edit_list( $query ) {
		global $pagenow, $post_type;
		if ( is_admin() && 'edit.php' == $pagenow && 'page' == $post_type ) {
			$query->query_vars['post__not_in'] = array( self::find_page_id() );
		}
	}

	/**
	 * hooks
	 *
	 * Adds hooks
	 *
	 * @return void
	 */
	function hooks() {
		register_activation_hook( INVP_PLUGIN_FILE_PATH, array( 'Inventory_Presser_Allow_Inventory_As_Home_Page', 'create_pages' ) );

		add_filter( 'parse_query', array( $this, 'hide_page_from_edit_list' ) );
		add_action( 'pre_get_posts', array( $this, 'redirect_the_page' ) );
	}

	/**
	 * redirect_the_page
	 *
	 * Performs the redirect from our special page to the inventory archive
	 *
	 * @param  WP_Query $wp_query
	 * @return void
	 */
	function redirect_the_page( $wp_query ) {
		if ( is_admin() ) {
			return;
		}

		if ( $wp_query->get( 'page_id' ) == get_option( 'page_on_front' ) && $wp_query->get( 'page_id' ) == self::find_page_id() ) {
			wp_redirect( get_post_type_archive_link( INVP::POST_TYPE ) );
			exit;
		}
	}
}