move haproxy vaultwarden config to default.nix

vaultwarden/default.nix

@@ -1,9 +1,36 @@
 { pkgs
 , utils
 }:
-{ user ? "vaultwarden"
+{ ingress ? 18005
+, user ? "vaultwarden"
 , group ? "vaultwarden"
+
+, distribution ? {}
 }:
+let
+  addressOrLocalhost = distHaproxy: service:
+    if (builtins.head distHaproxy).properties.hostname == service.target.properties.hostname then
+      "127.0.0.1"
+    else
+      service.target.properties.hostname;
+in
 {
   inherit user group;
+
+  haproxy = service: {
+    frontend = {
+      acl = {
+        acl_vaultwarden = "hdr_beg(host) vaultwarden.";
+      };
+      use_backend = "if acl_vaultwarden";
+    };
+    backend = {
+      servers = [
+        {
+          name = "ttrss1";
+          address = "${addressOrLocalhost distribution.HaproxyConfig service}:${builtins.toString ingress}";
+        }
+      ];
+    };
+  };
 }