<?php
/**
 * Own tables of the plugin.
 *
 * @package GruVer\Subscribe
 */

namespace GruVer\Subscribe\Storage;

use GruVer\Subscribe\Spam\RateLimit;

/**
 * Only real configuration (the lists) lives in wp_options. What the plugin counts or notes while it runs has its own
 * tables, so that bots cannot fill wp_options and nothing outlives its purpose:
 *
 * - gruver_subscribe_rate: attempts per IP address, under a keyed hash of the address, until the window ends.
 * - gruver_subscribe_status: what GruVer last said about each list (connection check, last failed sign-up).
 *
 * The tables are created on activation and, because activation does not run on updates or for new sites of a
 * network, whenever the stored schema version differs. Expired rows go with every write and once a day by cron.
 */
final class Schema {

	public const VERSION = 1;

	/** Schema version of this site, autoloaded because it is read on every request. */
	public const OPTION = 'gruver_subscribe_db_version';

	public const CLEANUP_HOOK = 'gruver_subscribe_cleanup';

	/**
	 * Table of the limit per IP address.
	 */
	public static function rate_table(): string {
		global $wpdb;

		return $wpdb->prefix . 'gruver_subscribe_rate';
	}

	/**
	 * Table of the state of the lists.
	 */
	public static function status_table(): string {
		global $wpdb;

		return $wpdb->prefix . 'gruver_subscribe_status';
	}

	/**
	 * Create or update the tables if this site has an older schema (hook init).
	 */
	public static function maybe_install(): void {
		if ( self::VERSION !== (int) get_option( self::OPTION, 0 ) ) {
			self::install();
		}
	}

	/**
	 * Create or update the tables and schedule the daily cleanup.
	 */
	public static function install(): void {
		global $wpdb;

		if ( ! function_exists( 'dbDelta' ) ) {
			require_once ABSPATH . 'wp-admin/includes/upgrade.php';
		}
		$charset = $wpdb->get_charset_collate();
		dbDelta(
			'CREATE TABLE ' . self::rate_table() . " (
	bucket char(64) NOT NULL,
	hits smallint(5) unsigned NOT NULL DEFAULT 0,
	window_end bigint(20) unsigned NOT NULL,
	PRIMARY KEY  (bucket),
	KEY window_end (window_end)
) $charset;"
		);
		dbDelta(
			'CREATE TABLE ' . self::status_table() . " (
	list_key varchar(40) NOT NULL,
	data longtext NOT NULL,
	updated_at bigint(20) unsigned NOT NULL,
	PRIMARY KEY  (list_key)
) $charset;"
		);
		update_option( self::OPTION, self::VERSION, true );

		if ( false === wp_next_scheduled( self::CLEANUP_HOOK ) ) {
			wp_schedule_event( time() + HOUR_IN_SECONDS, 'daily', self::CLEANUP_HOOK );
		}
	}

	/**
	 * Daily cleanup (cron), in case nobody sends a form for a while.
	 */
	public static function cleanup(): void {
		RateLimit::purge( time() );
	}

	/**
	 * Stop the cleanup when the plugin is deactivated; the tables stay until it is deleted.
	 */
	public static function deactivate(): void {
		wp_clear_scheduled_hook( self::CLEANUP_HOOK );
	}
}