<?php

namespace Yipresser\AdminOptimizer;

use Yipresser\AdminOptimizer\Modules\Settings_Assets_Interface;

// Exit if accessed directly.
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Shared option, initialization, and admin-page lifecycle for modules.
 */
abstract class Base_Module {
	/** @var string Native post type whose admin screens belong to the module. */
	const ADMIN_POST_TYPE = '';

	/** @var string|null Exact hook suffix for a conventional module submenu. */
	private $submenu_hook_suffix;

	/**
	 * The module's stored options.
	 *
	 * @var mixed
	 */
	protected $options;

	/**
	 * The module's settings handler.
	 *
	 * @var object|null
	 */
	protected $settings;

	/**
	 * Load the module's options before registering its hooks and services.
	 */
	final public function __construct() {
		$this->options = get_option( static::OPTION_NAME, $this->get_default_options() );

		if ( '' !== static::ADMIN_POST_TYPE ) {
			Module_Registry::register_admin_post_type( static::MODULE_ID, static::ADMIN_POST_TYPE );
		}

		$this->init();

		if ( ! $this->settings instanceof Settings_Assets_Interface ) {
			throw new \LogicException( static::class . ' settings must implement Settings_Assets_Interface.' );
		}

		add_action( 'adminoptimizer_add_submenu_page', [ $this, 'add_submenu_page' ] );
		add_action( 'admin_enqueue_scripts', [ $this, 'enqueue_settings_assets' ] );
	}

	/**
	 * Return the value used when the module option has not been saved yet.
	 *
	 * @return mixed
	 */
	protected function get_default_options() {
		return [];
	}

	/**
	 * Register the module's services and hooks after its options are loaded.
	 */
	abstract protected function init(): void;

	/**
	 * Use the module settings handler as the single settings-asset entry point.
	 *
	 * @param string $hook_suffix Current admin page hook suffix.
	 */
	final public function enqueue_settings_assets( string $hook_suffix ): void {
		if ( ! $this->is_settings_screen( $hook_suffix ) ) {
			return;
		}

		$this->settings->enqueue_settings_assets( $hook_suffix );
	}

	/**
	 * Determine whether the current screen belongs to this module's settings UI.
	 *
	 * @param string $hook_suffix Current admin page hook suffix.
	 */
	protected function is_settings_screen( string $hook_suffix ): bool {
		if ( null !== $this->submenu_hook_suffix && $hook_suffix === $this->submenu_hook_suffix ) {
			return true;
		}

		$screen = function_exists( 'get_current_screen' ) ? get_current_screen() : null;

		return Module_Registry::is_admin_screen_for_module( static::MODULE_ID, $screen );
	}

	/**
	 * Register the submenu and its canonical module ownership.
	 *
	 * @return string|false Hook suffix on success, false when registration fails.
	 */
	final public function add_submenu_page() {
		$submenu_config = $this->get_submenu_config();

		if ( null === $submenu_config ) {
			return false;
		}

		$config = wp_parse_args(
			$submenu_config,
			[
				'page_title' => '',
				'menu_title' => '',
				'capability' => 'manage_options',
				'menu_slug'  => '',
				'callback'   => null,
			]
		);

		if ( '' === $config['menu_slug'] || ! is_callable( $config['callback'] ) ) {
			return false;
		}

		$hook_suffix = add_submenu_page(
			ADMINOPTIMIZER_MODULES_MENU_SLUG,
			$config['page_title'],
			$config['menu_title'],
			$config['capability'],
			$config['menu_slug'],
			$config['callback']
		);

		if ( false !== $hook_suffix ) {
			$this->submenu_hook_suffix = $hook_suffix;
			Module_Registry::register_admin_screen( static::MODULE_ID, $hook_suffix );
		}

		return $hook_suffix;
	}

	/**
	 * Return the module's submenu definition.
	 *
	 * Return null when the module does not provide a submenu.
	 *
	 * @return array<string,mixed>|null
	 */
	abstract protected function get_submenu_config(): ?array;
}