Add syncthing systemd dependencies

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

hosts/common/user/configs/console/syncthing/default.nix

@@ -1,7 +1,17 @@
 {
   username ? throw "username argument is required",
 }:
-{ config, ... }:
+{
+  config,
+  inputs,
+  lib,
+  pkgs,
+  ...
+}:
+let
+  userConfig = config.users.users.${username};
+  hmConfig = config.home-manager.users.${username};
+in
 {
   networking.firewall = {
     allowedTCPPorts = [ 22000 ];
@@ -24,7 +34,8 @@
     };
   };
 
-  home-manager.users.${username}.services.syncthing = {
+  home-manager.users.${username} = {
+    services.syncthing = {
       enable = true;
       key = config.sops.secrets."syncthing/key".path;
       cert = config.sops.secrets."syncthing/cert".path;
@@ -38,4 +49,26 @@
         };
       };
     };
+
+    systemd.user.services.syncthing.Unit.After =
+      let
+        inherit (pkgs.callPackage "${inputs.impermanence}/lib.nix" { }) mkServiceName parentsOf;
+        removeHomePrefix =
+          path: lib.strings.removePrefix "~/" (lib.strings.removePrefix "${userConfig.home}/" path);
+        syncthingFolders = builtins.map (folder: removeHomePrefix folder.path) (
+          builtins.attrValues hmConfig.services.syncthing.settings.folders
+        );
+      in
+      lib.lists.flatten (
+        builtins.map (
+          persistence:
+          builtins.map (folder: "${mkServiceName persistence.persistentStoragePath folder}.service") (
+            builtins.filter (folder: builtins.elem folder persistence.directories) (
+              lib.lists.unique (lib.lists.flatten (builtins.map parentsOf syncthingFolders))
+            )
+          )
+        ) (builtins.attrValues hmConfig.home.persistence)
+      )
+      ++ [ "sops-nix.service" ];
+  };
 }