hjem/collection: add systemd module

This adds a systemd module locally, allowing to define your own services
at hjem level rather than systemd level.

modules/programs/waybar.nix

@@ -270,23 +270,28 @@ in {
             }
           '';
       };
+
+      systemd.services.waybar.settings = {
+        Unit = {
+          Description = "Highly customizable Wayland bar for Sway and Wlroots based compositors.";
+          Documentation = ["https://github.com/Alexays/Waybar/wiki/"];
+          After = ["graphical-session.target"];
+          PartOf = ["graphical-session.target"];
+          Requisite = ["graphical-session.target"];
+          X-Reload-Triggers = ["${config.hjem.users.${username}.files.".config/waybar/config".text}"];
         };
 
-    systemd.user.services.waybar = {
-      description = "Highly customizable Wayland bar for Sway and Wlroots based compositors.";
-      documentation = ["https://github.com/Alexays/Waybar/wiki/"];
-      after = ["graphical-session.target"];
-      partOf = ["graphical-session.target"];
-      requisite = ["graphical-session.target"];
-      wantedBy = ["graphical-session.target"];
-
-      reloadTriggers = ["${config.hjem.users.${username}.files.".config/waybar/config".text}"];
-      serviceConfig = {
+        Service = {
           ExecStart = "${pkgs.waybar}/bin/waybar";
           ExecReload = "kill -SIGUSR2 $MAINPID";
           Restart = "on-failure";
           Slice = "app-graphical.slice";
         };
+
+        Install = {
+          WantedBy = ["graphical-session.target"];
+        };
+      };
     };
   };
 }

shared/modules/hjem/collection/systemd-services.nix

@@ -0,0 +1,57 @@
+{
+  lib,
+  config,
+  ...
+}: let
+  inherit (builtins) toString;
+  inherit (lib.attrsets) nameValuePair mapAttrs';
+  inherit (lib.modules) mkIf;
+  inherit (lib.options) mkOption;
+  inherit (lib.types) attrs attrsOf submodule;
+  inherit (lib.trivial) isBool boolToString;
+  inherit (lib.generators) toINI;
+
+  cfg = config.systemd;
+
+  toSystemdUnitFiles = services: let
+    toSystemdUnit = arg:
+      toINI {
+        listsAsDuplicateKeys = true;
+        mkKeyValue = key: value: let
+          value' =
+            if isBool value
+            then boolToString value
+            else toString value;
+        in "${key}=${value'}";
+      }
+      arg;
+  in
+    mapAttrs' (name: service:
+      nameValuePair ".config/systemd/user/${name}.service" {text = toSystemdUnit service.settings;})
+    services;
+in {
+  options.systemd = {
+    services = mkOption {
+      type = attrsOf (submodule {
+        options = {
+          settings = mkOption {
+            type = attrs;
+            default = {};
+            description = ''
+              The configuration of this unit. Each attribute in this set specifies an option
+              (documentation for available options can be found [here](https://www.freedesktop.org/software/systemd/man/latest/systemd.service.html)).
+            '';
+          };
+        };
+      });
+      default = {};
+      description = ''
+        Definition of systemd user service units.
+      '';
+    };
+  };
+
+  config = mkIf (cfg.services != {}) {
+    files = toSystemdUnitFiles cfg.services;
+  };
+}