<?php
declare( strict_types=1 );

namespace CodeBold\Redirect\Core;

use CodeBold\Redirect\Monitor\Cleanup;

defined( 'ABSPATH' ) || exit;

/**
 * The two tables.
 *
 * Custom tables rather than a post type. A redirect is looked up on every front-end
 * request by the address somebody typed, and the only way to make that one indexed
 * query is a column holding exactly that address. As post meta it would be a join on
 * a longtext with no usable index, and a site with ten thousand redirects would pay
 * for it on every page view.
 */
final class Installer {

	/**
	 * Bumped whenever the schema changes. dbDelta() is re-run on the next request.
	 */
	public const DB_VERSION = '2';

	public const OPTION_DB_VERSION = 'codebold_redirect_db_version';

	public static function redirects_table(): string {
		global $wpdb;

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

	public static function not_found_table(): string {
		global $wpdb;

		return $wpdb->prefix . 'codebold_redirect_404s';
	}

	public static function maybe_upgrade(): void {
		if ( get_option( self::OPTION_DB_VERSION ) === self::DB_VERSION ) {
			return;
		}

		self::install();
	}

	public static function install(): void {
		global $wpdb;

		require_once ABSPATH . 'wp-admin/includes/upgrade.php';

		$charset   = $wpdb->get_charset_collate();
		$redirects = self::redirects_table();
		$not_found = self::not_found_table();

		// dbDelta is particular: two spaces after PRIMARY KEY, one column per line, and
		// KEY rather than INDEX. Getting any of that wrong makes it silently re-add the
		// index on every run instead of failing.
		//
		// source is VARCHAR(2000) and never indexed itself — utf8mb4 caps an index at 768
		// characters, and real addresses with long query strings are longer than that.
		// source_hash is what the lookup uses.
		dbDelta(
			"CREATE TABLE {$redirects} (
				id bigint(20) unsigned NOT NULL AUTO_INCREMENT,
				source varchar(2000) NOT NULL,
				source_hash char(32) NOT NULL,
				match_type varchar(10) NOT NULL DEFAULT 'exact',
				target text NOT NULL,
				target_type varchar(10) NOT NULL DEFAULT 'url',
				target_id bigint(20) unsigned NOT NULL DEFAULT 0,
				status_code smallint(5) unsigned NOT NULL DEFAULT 301,
				case_sensitive tinyint(1) NOT NULL DEFAULT 0,
				pass_query tinyint(1) NOT NULL DEFAULT 1,
				conditions text NULL,
				starts_at datetime NULL,
				ends_at datetime NULL,
				enabled tinyint(1) NOT NULL DEFAULT 1,
				priority int(11) NOT NULL DEFAULT 0,
				group_name varchar(100) NOT NULL DEFAULT '',
				note varchar(255) NOT NULL DEFAULT '',
				origin varchar(20) NOT NULL DEFAULT 'manual',
				post_id bigint(20) unsigned NOT NULL DEFAULT 0,
				hits bigint(20) unsigned NOT NULL DEFAULT 0,
				last_hit datetime NULL,
				created_at datetime NOT NULL,
				updated_at datetime NOT NULL,
				PRIMARY KEY  (id),
				KEY source_hash (source_hash),
				KEY match_type (match_type,enabled),
				KEY post_id (post_id),
				KEY target (target_type,target_id)
			) {$charset};"
		);

		// One row per address, not per visit. A bot asking for /wp-login.php four thousand
		// times is one row with a count of four thousand, which is what anybody reading
		// the list actually wants to know — and the table stays small enough to keep.
		//
		// No IP address column, deliberately. Knowing that an address is broken does not
		// need knowing who found it, and a log of visitor IPs is personal data the site
		// owner would then have to account for.
		dbDelta(
			"CREATE TABLE {$not_found} (
				id bigint(20) unsigned NOT NULL AUTO_INCREMENT,
				url varchar(2000) NOT NULL,
				url_hash char(32) NOT NULL,
				hits bigint(20) unsigned NOT NULL DEFAULT 1,
				first_seen datetime NOT NULL,
				last_seen datetime NOT NULL,
				referrer varchar(1000) NOT NULL DEFAULT '',
				user_agent varchar(255) NOT NULL DEFAULT '',
				is_bot tinyint(1) NOT NULL DEFAULT 0,
				ignored tinyint(1) NOT NULL DEFAULT 0,
				PRIMARY KEY  (id),
				UNIQUE KEY url_hash (url_hash),
				KEY last_seen (last_seen),
				KEY first_seen (ignored,first_seen)
			) {$charset};"
		);

		update_option( self::OPTION_DB_VERSION, self::DB_VERSION, true );

		Cleanup::schedule();
	}
}