expose *some* of the options as nixos config

modules/default.nix

@@ -25,6 +25,38 @@ in
         '';
       };
 
+      templateDir = mkOption {
+        type = types.path;
+        default = "${cfg.package}/var/lib/bespoke/templates";
+        description = ''
+          Where to load Tera templates from.
+        '';
+      };
+
+      listenAddr = mkOption {
+        type = types.str;
+        default = "127.0.0.1";
+        description = ''
+          HTTP listen address.
+        '';
+      };
+
+      listenPort = mkOption {
+        type = types.int;
+        default = 3000;
+        description = ''
+          HTTP listen port.
+        '';
+      };
+
+      rootUrl = mkOption {
+        type = types.str;
+        default = "http://localhost:3000";
+        description = ''
+          Public root URL of bespoke server.
+        '';
+      };
+
       package = mkOption {
         type = types.package;
         default = flake.defaultPackage.x86_64-linux;
@@ -53,14 +85,15 @@ in
         User = "bespoke";
         Group = "bespoke";
         Restart = "on-failure";
-        ExecStart = "${cfg.package}/bin/bespoke";
+        ExecStart = "${cfg.package}/bin/bespoke -c ${cfg.configFile}";
         WorkingDirectory = "${cfg.dataDir}";
       };
 
-      preStart = ''
-        cp -rf "${cfg.package}/var/lib/bespoke/templates" "${cfg.dataDir}"
-        cp -f "${cfg.configFile}" "${cfg.dataDir}/bespoke.toml"
-      '';
+      environment = {
+        BESPOKE_TEMPLATE_DIR = cfg.templateDir;
+        BESPOKE_LISTEN_ADDR = "${cfg.listenAddr}:${toString cfg.listenPort}";
+        BESPOKE_REDIRECT_URL = "${cfg.rootUrl}/auth/authorized";
+      };
 
     };
     systemd.tmpfiles.rules = [