core: fix url helper for custom domain (#1162)

Co-authored-by: undefined <i@undefined.moe>

Author: renbaoshuo

packages/hydrooj/src/service/server.ts

@@ -144,19 +144,14 @@ export async function apply(ctx: Context) {
                 }
                 try {
                     const { anchor } = args;
-                    let withDomainId = args.domainId || false;
-                    const domainId = this.args.domainId;
-                    const host = this.domain?.host;
-                    if (domainId !== 'system' && (
-                        !this.request.host
-                        || (host instanceof Array
-                            ? (!host.includes(this.request.host))
-                            : this.request.host !== host)
-                    )) withDomainId ||= domainId;
+                    const host = this.domain?.host || [];
+                    const target = args.domainId || this.args.domainId;
+                    const rootDomainId = (this.request.host && host?.length && host?.includes(this.request.host))
+                        ? this.args.domainId : 'system';
                     delete args.query;
                     res = server.router.url(name, args, { query }).toString();
                     if (anchor) res = `${res}#${anchor}`;
-                    if (withDomainId) res = `/d/${withDomainId}${res}`;
+                    if (target !== rootDomainId) res = `/d/${target}${res}`;
                 } catch (e) {
                     logger.warn(e.message);
                     logger.info('%s %o', name, args);