Introduce Base_Admin_Page_Collection class.

Author: Felix Arntz

src/Admin_Page_Collection/Base_Admin_Page_Collection.php

@@ -0,0 +1,126 @@
+<?php
+/**
+ * Base_Admin_Page_Collection class
+ *
+ * @package Leaves_And_Love\OOP_Admin_Pages\Admin_Page_Collection
+ * @since 1.0.0
+ */
+
+namespace Leaves_And_Love\OOP_Admin_Pages\Admin_Page_Collection;
+
+use Leaves_And_Love\OOP_Admin_Pages\Admin_Page;
+use Leaves_And_Love\OOP_Admin_Pages\Admin_Page_Collection;
+use Leaves_And_Love\OOP_Admin_Pages\Admin_Page_Factory;
+use Leaves_And_Love\OOP_Admin_Pages\Exception\Admin_Page_Not_Found_Exception;
+use Leaves_And_Love\OOP_Admin_Pages\Exception\Config_Invalid_Exception;
+use BrightNucleus\Config\ConfigInterface as Config;
+use BrightNucleus\Config\ConfigTrait;
+use BrightNucleus\Config\Config as BaseConfig;
+
+/**
+ * Class to manage admin page instances.
+ *
+ * @since 1.0.0
+ */
+class Base_Admin_Page_Collection implements Admin_Page_Collection {
+
+	use ConfigTrait;
+
+	const PAGES   = 'pages';
+	const FACTORY = 'factory';
+
+	/**
+	 * Admin pages in the collection.
+	 *
+	 * @since 1.0.0
+	 * @var array
+	 */
+	protected $pages = array();
+
+	/**
+	 * Factory to create admin pages for this collection.
+	 *
+	 * @since 1.0.0
+	 * @var Admin_Page_Factory
+	 */
+	protected $factory;
+
+	/**
+	 * Constructor.
+	 *
+	 * Sets the configuration and instantiates the admin page factory for the collection.
+	 *
+	 * @since 1.0.0
+	 *
+	 * @param Config $config Admin page collection configuration. Must contain the keys 'pages' (array of admin page
+	 *                       configurations) and 'factory' (admin page factory instance to use).
+	 *
+	 * @throws Config_Invalid_Exception Thrown when the configuration is invalid.
+	 */
+	public function __construct( Config $config ) {
+		$this->processConfig( $config );
+
+		if ( ! $this->hasConfigKey( self::FACTORY ) ) {
+			throw new Config_Invalid_Exception( sprintf( 'The required configuration key %s is missing.', self::FACTORY ) );
+		}
+
+		$factory = $this->getConfigKey( self::FACTORY );
+
+		if ( ! is_a( $factory, Admin_Page_Factory::class ) ) {
+			throw new Config_Invalid_Exception( sprintf( 'The class %1$s does not implement the interface %2$s.', $factory_class, Admin_Page_Factory::class ) );
+		}
+
+		$this->factory = $factory;
+	}
+
+	/**
+	 * Registers the admin pages in the collection within the environment.
+	 *
+	 * @since 1.0.0
+	 */
+	public function register() {
+		if ( ! $this->hasConfigKey( self::PAGES ) ) {
+			return;
+		}
+
+		$pages = $this->getConfigKey( self::PAGES );
+
+		foreach ( $pages as $page_config ) {
+			$page = $this->factory->create_page( new BaseConfig( $page_config ) );
+
+			$this->pages[ $page->get_slug() ] = $page;
+
+			$page->register();
+		}
+	}
+
+	/**
+	 * Checks whether an admin page is part of the collection.
+	 *
+	 * @since 1.0.0
+	 *
+	 * @param string $slug Identifier of the admin page to check for.
+	 * @return bool True if the admin page is part of the collection, false otherwise.
+	 */
+	public function has_page( string $slug ) : bool {
+		return isset( $this->pages[ $slug ] );
+	}
+
+	/**
+	 * Gets an admin page instance that is part of the collection.
+	 *
+	 * @since 1.0.0
+	 *
+	 * @param string $slug Identifier of the admin page to get.
+	 * @return Admin_Page Admin page instance.
+	 *
+	 * @throws Admin_Page_Not_Found_Exception Thrown when the admin page is not found.
+	 */
+	public function get_page( string $slug ) : Admin_Page {
+		if ( ! $this->has_page( $slug ) ) {
+			throw new Admin_Page_Not_Found_Exception( sprintf( 'No admin page with the identifier %s exists in the collection.', $slug ) );
+		}
+
+		return $this->pages[ $slug ];
+	}
+}