<?php
/**
 * Registers the Postlinkly admin menu.
 *
 * @package Postlinkly
 * @since   1.0.0
 */

declare(strict_types=1);

namespace Postlinkly\Admin;

use Postlinkly\Capabilities\CapabilityMap;
use Postlinkly\Hooks\ServiceProvider;

/**
 * Registers the Postlinkly admin menu and submenu pages.
 *
 * Owns the `admin_menu` hook. Receives the full list of `AdminPage`
 * instances at construction time and registers each one in the correct
 * position. The top-level menu entry is the Dashboard; all other pages
 * are submenus.
 *
 * Menu structure:
 *
 *   Postlinkly (top-level, icon: dashicons-admin-links)
 *   ├── Dashboard            (postlinkly)
 *   ├── Link Report          (postlinkly_report)
 *   ├── Settings             (postlinkly_settings)
 *   └── Tools                (postlinkly_tools)
 *
 * An add-on's pages (through the `postlinkly_admin_pages` filter) are
 * added in the order the filter returns them.
 *
 * Target Keywords is not in the main menu — it is accessible from
 * Settings when a supported SEO plugin is detected.
 * Internal-link rot and orphaned posts are tabs on the Report page.
 *
 * @since 1.0.0
 */
final class AdminMenu implements ServiceProvider {

	/**
	 * Slug of the top-level menu entry.
	 *
	 * Matches the Dashboard page slug so WordPress collapses the
	 * auto-generated top-level duplicate into the Dashboard entry.
	 *
	 * @since 1.1.0 Changed from 'postlinkly' to 'postlinkly_dashboard'.
	 * @since 1.3.0 Changed to 'postlinkly'; Dashboard is the landing page.
	 */
	public const TOP_LEVEL_SLUG = 'postlinkly';

	/**
	 * @var array<int, AdminPage>
	 */
	private array $pages;

	/**
	 * @since 1.0.0
	 *
	 * @param array<int, AdminPage> $pages All admin pages, in display order.
	 */
	public function __construct( array $pages ) {
		$this->pages = array_values(
			array_filter( $pages, static fn( $p ) => $p instanceof AdminPage )
		);
	}

	/**
	 * Registers Plugin service hooks.
	 *
	 * @since 1.0.0
	 *
	 * @return array<int, array<int, mixed>>
	 */
	public function get_hooks(): array {
		return array(
			array( 'admin_menu', array( $this, 'register_menu' ) ),
		);
	}

	/**
	 * Registers the top-level menu and all submenu pages.
	 *
	 * @since 1.0.0
	 * @hook  admin_menu
	 *
	 * @return void
	 */
	public function register_menu(): void {
		$top_cap = CapabilityMap::for( 'view_report' );

		// Top-level entry — points to the Report page.
		add_menu_page(
			__( 'Postlinkly', 'postlinkly' ),
			__( 'Postlinkly', 'postlinkly' ),
			$top_cap,
			self::TOP_LEVEL_SLUG,
			array( $this, 'render_top_level' ),
			$this->get_menu_icon(),
			80
		);

		// Register each page as a submenu. The first submenu replaces
		// the auto-generated duplicate of the top-level entry.
		foreach ( $this->pages as $page ) {
			add_submenu_page(
				self::TOP_LEVEL_SLUG,
				$page->get_page_title(),
				$page->get_menu_title(),
				$page->get_capability(),
				$page->get_slug(),
				array( $page, 'render' )
			);
		}
	}

	/**
	 * Returns the data URI for the menu SVG icon.
	 *
	 * WordPress accepts a base64-encoded SVG data URI as the `$icon_url`
	 * argument to `add_menu_page()`. This keeps the icon self-contained
	 * (no extra HTTP request) and lets WP tint it with the active admin
	 * colour scheme.
	 *
	 * @since 1.0.0
	 *
	 * @return string Data URI string.
	 */
	private function get_menu_icon(): string {
		$path = defined( 'POSTLINKLY_PLUGIN_DIR' )
			? (string) POSTLINKLY_PLUGIN_DIR . 'assets/images/menu-icon.svg'
			: '';

		if ( '' !== $path && is_readable( $path ) ) {
			$svg = file_get_contents( $path ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents -- Local file read; wp_remote_get is for HTTP.
			if ( is_string( $svg ) && '' !== $svg ) {
				return 'data:image/svg+xml;base64,' . base64_encode( $svg ); // phpcs:ignore WordPress.PHP.DiscouragedPHPFunctions.obfuscation_base64_encode -- Standard WP pattern for inline SVG menu icons.
			}
		}

		// Fallback to a dashicon if the SVG file is missing.
		return 'dashicons-admin-links';
	}
	/**
	 * Fallback render callback for the top-level menu entry.
	 *
	 * In practice WordPress always routes to the first submenu, so this
	 * is only called when no pages are registered.
	 *
	 * @since 1.0.0
	 *
	 * @return void
	 */
	public function render_top_level(): void {
		echo '<div class="wrap"><h1>' . esc_html__( 'Postlinkly', 'postlinkly' ) . '</h1></div>';
	}
}