<?php
/**
 * The plugin's admin menu.
 *
 * @package AdPix\Analytics
 */

declare( strict_types = 1 );

namespace AdPix\Analytics\Controller\Admin;

use AdPix\Analytics\Contracts\AdminPageInterface;
use AdPix\Analytics\Contracts\BootableInterface;

defined( 'ABSPATH' ) || exit;

/**
 * Mounts the plugin's screens under one top-level sidebar entry.
 *
 * The settings used to live under Settings, which is where WordPress suggests a single options page
 * belongs. It has moved because there is more than a settings page now: statistics is a screen
 * people open to read rather than to configure, and burying a daily-use report three levels into
 * Settings would mean nobody found it twice.
 *
 * This class knows nothing about any particular screen. It is given a list of pages, registers each
 * one, and hands each the hook suffix WordPress returned — which is the part worth being careful
 * about. WordPress derives a submenu's hook from `sanitize_title()` of the *parent menu title*, and
 * that title is translated: on a Persian site it is "ادپیکس", whose sanitized form is a
 * percent-encoded string. Any page that assembled its own hook name would therefore load its
 * stylesheet in English and quietly fail to in Persian. Passing the real suffix down removes the
 * guess entirely.
 */
final class MenuController implements BootableInterface {

	/**
	 * Where the top-level entry sits in the sidebar.
	 *
	 * Just below Settings, in the block WordPress leaves for plugins. A float is used because integer
	 * positions collide silently — two plugins claiming the same one means only one of them appears.
	 */
	private const POSITION = 80.7;

	/**
	 * Screens to mount, in sidebar order. The first is also what the top-level entry opens.
	 *
	 * @var AdminPageInterface[]
	 */
	private $pages;

	/**
	 * @param AdminPageInterface[] $pages Screens to mount, in order.
	 */
	public function __construct( array $pages ) {
		$this->pages = array_values( $pages );
	}

	/**
	 * Register hooks.
	 *
	 * @return void
	 */
	public function boot(): void {
		add_action( 'admin_menu', array( $this, 'register' ) );
	}

	/**
	 * Build the menu.
	 *
	 * @return void
	 */
	public function register(): void {
		if ( array() === $this->pages ) {
			return;
		}

		$first = $this->pages[0];

		// The top-level entry is the first page. WordPress would otherwise invent a submenu item
		// duplicating the parent, labelled with the menu title — "AdPix > AdPix" — so the first
		// submenu below is registered against the parent's own slug to take that duplicate's place.
		$hook = add_menu_page(
			$first->page_title(),
			$this->brand(),
			$first->capability(),
			$first->slug(),
			array( $first, 'render' ),
			$this->icon(),
			self::POSITION
		);

		$first->set_hook( is_string( $hook ) ? $hook : '' );

		foreach ( $this->pages as $page ) {
			$hook = add_submenu_page(
				$first->slug(),
				$page->page_title(),
				$page->menu_title(),
				$page->capability(),
				$page->slug(),
				array( $page, 'render' )
			);

			// A page the current user cannot open is not registered at all, and add_submenu_page()
			// returns false for it. Leaving the hook empty in that case is correct: the screen is
			// unreachable, so nothing should ever match it.
			$page->set_hook( is_string( $hook ) ? $hook : '' );
		}
	}

	/**
	 * The name shown in the sidebar.
	 *
	 * Separate from the settings page's own title so the sidebar can carry the brand as each language
	 * writes it — "AdPix" in English, "ادپیکس" in Persian — while the screen itself keeps its full name.
	 *
	 * @return string
	 */
	private function brand(): string {
		return __( 'AdPix', 'adpix-analytics' );
	}

	/**
	 * The sidebar icon, as a data URI.
	 *
	 * A data URI rather than a URL because WordPress inlines these into the menu markup, so the icon
	 * is there on first paint instead of arriving a request later and shifting the sidebar. Note that
	 * WordPress recolours dashicons to match the admin scheme but leaves an SVG exactly as given, so
	 * this is a copy of the mark with its mid-grey lightened — the brand grey is all but invisible
	 * against the dark sidebar.
	 *
	 * @return string The data URI, or a dashicon name if the file cannot be read.
	 */
	private function icon(): string {
		$path = ADPIX_ANALYTICS_PATH . 'assets/img/menu-icon.svg';

		// A bundled 800-byte file, read once per admin request while the menu is built. The fallback is
		// not defensive theatre: a hardened host with open_basedir set awkwardly can make this fail, and
		// a menu with no icon at all is harder to find than one wearing a generic chart.
		$svg = is_readable( $path ) ? file_get_contents( $path ) : false; // phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents

		if ( ! is_string( $svg ) || '' === trim( $svg ) ) {
			return 'dashicons-chart-area';
		}

		return 'data:image/svg+xml;base64,' . base64_encode( $svg ); // phpcs:ignore WordPress.PHP.DiscouragedPHPFunctions.obfuscation_base64_encode
	}
}