<?php

namespace Yoast\WP\SEO\Actions\Addon_Installation;

use Plugin_Upgrader;
use WP_Error;
use WPSEO_Addon_Manager;
use Yoast\WP\SEO\Exceptions\Addon_Installation\Addon_Already_Installed_Exception;
use Yoast\WP\SEO\Exceptions\Addon_Installation\Addon_Installation_Error_Exception;
use Yoast\WP\SEO\Exceptions\Addon_Installation\User_Cannot_Install_Plugins_Exception;
use Yoast\WP\SEO\Helpers\Require_File_Helper;

/**
 * Represents the endpoint for downloading and installing a zip-file from MyYoast.
 */
class Addon_Install_Action {

	/**
	 * The addon manager.
	 *
	 * @var WPSEO_Addon_Manager
	 */
	protected $addon_manager;

	/**
	 * The require file helper.
	 *
	 * @var Require_File_Helper
	 */
	protected $require_file_helper;

	/**
	 * Addon_Activate_Action constructor.
	 *
	 * @param WPSEO_Addon_Manager $addon_manager       The addon manager.
	 * @param Require_File_Helper $require_file_helper A helper that can require files.
	 */
	public function __construct(
		WPSEO_Addon_Manager $addon_manager,
		Require_File_Helper $require_file_helper
	) {
		$this->addon_manager       = $addon_manager;
		$this->require_file_helper = $require_file_helper;
	}

	/**
	 * Installs the plugin based on the given slug.
	 *
	 * @param string $plugin_slug  The plugin slug to install.
	 * @param string $download_url The plugin download URL.
	 *
	 * @return bool True when install is successful.
	 *
	 * @throws Addon_Already_Installed_Exception  When the addon is already installed.
	 * @throws Addon_Installation_Error_Exception When the installation encounters an error.
	 * @throws User_Cannot_Install_Plugins_Exception        When the user does not have the permissions to install plugins.
	 */
	public function install_addon( $plugin_slug, $download_url ) {
		if ( ! \current_user_can( 'install_plugins' ) ) {
			throw new User_Cannot_Install_Plugins_Exception( $plugin_slug );
		}

		if ( $this->is_installed( $plugin_slug ) ) {
			throw new Addon_Already_Installed_Exception( $plugin_slug );
		}

		$this->load_wordpress_classes();

		$install_result = $this->install( $download_url );
		if ( \is_wp_error( $install_result ) ) {
			throw new Addon_Installation_Error_Exception( $install_result->get_error_message() );
		}

		return $install_result;
	}

	/**
	 * Requires the files needed from WordPress itself.
	 *
	 * @codeCoverageIgnore
	 *
	 * @return void
	 */
	protected function load_wordpress_classes() {
		if ( ! \class_exists( 'WP_Upgrader' ) ) {
			$this->require_file_helper->require_file_once( \ABSPATH . 'wp-admin/includes/class-wp-upgrader.php' );
		}

		if ( ! \class_exists( 'Plugin_Upgrader' ) ) {
			$this->require_file_helper->require_file_once( \ABSPATH . 'wp-admin/includes/class-plugin-upgrader.php' );
		}

		if ( ! \class_exists( 'WP_Upgrader_Skin' ) ) {
			$this->require_file_helper->require_file_once( \ABSPATH . 'wp-admin/includes/class-wp-upgrader-skin.php' );
		}

		if ( ! \function_exists( 'get_plugin_data' ) ) {
			$this->require_file_helper->require_file_once( \ABSPATH . 'wp-admin/includes/plugin.php' );
		}

		if ( ! \function_exists( 'request_filesystem_credentials' ) ) {
			$this->require_file_helper->require_file_once( \ABSPATH . 'wp-admin/includes/file.php' );
		}
	}

	/**
	 * Checks is a plugin is installed.
	 *
	 * @param string $plugin_slug The plugin to check.
	 *
	 * @return bool True when plugin is installed.
	 */
	protected function is_installed( $plugin_slug ) {
		return $this->addon_manager->get_plugin_file( $plugin_slug ) !== false;
	}

	/**
	 * Runs the installation by using the WordPress installation routine.
	 *
	 * @param string $plugin_download The url to the download.
	 *
	 * @codeCoverageIgnore Contains WordPress specific logic.
	 *
	 * @return bool|WP_Error True when success, WP_Error when something went wrong.
	 */
	protected function install( $plugin_download ) {
		$plugin_upgrader = new Plugin_Upgrader();

		return $plugin_upgrader->install( $plugin_download );
	}
}
