add module & update Install.md

INSTALL.md

@@ -2,6 +2,51 @@
 
 We have packaged `swhkd-git`. `swhkd-bin` has been packaged separately by a user of swhkd.
 
+## NixOS
+
+For now flake users only.
+
+This repo contains a NixOS Module for swhkd service.
+To enable module add an input first and import to modules:
+```nix
+{
+  inputs = {
+    swhkd.url = "github:waycrate/swhkd";
+  }
+
+  outputs = {nixpkgs, swhkd, ...} @ inputs: {
+    nixosConfigurations.HOSTNAME = nixpkgs.lib.nixosSystem {
+      specialArgs = { inherit inputs; };
+      modules = [
+        ./configuration.nix
+        swhkd.nixosModules.default
+      ];
+    };
+  } 
+}
+```
+After importing you should be able to use it in your configuration.nix file:
+```nix
+{ inputs
+, ...
+}:
+{
+  services.swhkd = {
+    enable = true;
+    package = inputs.swhkd.packages.${system}.default;
+    cooldown = 300;
+    settings = ''
+super + return
+  alacritty
+    '';
+  };
+}
+```
+* Do not forget to start/add to autostart swhkd of your system after login.
+* Replace HOSTNAME with your oun
+
+ps. this module will be updated after Security Model improve, but it is already good enough to use
+
 # Building:
 
 `swhkd` and `swhks` install to `/usr/local/bin/` by default. You can change this behaviour by editing the [Makefile](../Makefile) variable, `DESTDIR`, which acts as a prefix for all installed files. You can also specify it in the make command line, e.g. to install everything in `subdir`: `make DESTDIR="subdir" install`.

flake.nix

@@ -31,5 +31,6 @@
       default = (pkgsFor system).callPackage ./nix/shell.nix { };
     });
 
+    nixosModules.default = import ./nix/module.nix self;
   };
 }

nix/module.nix

@@ -0,0 +1,68 @@
+self: 
+{ config
+, lib
+, stdenv
+, ...
+}:
+let
+  cfg = config.services.swhkd;
+  inherit (stdenv.hostPlatform) system;
+
+  inherit (lib) types;
+  inherit (lib.modules) mkIf;
+  inherit (lib.options) mkOption mkEnableOption;
+in
+{
+  options.services.swhkd = {
+    enable = mkEnableOption "Simple Wayland HotKey Daemon";
+
+    package = mkOption {
+      description = "The package to use for `swhkd`";
+      default = self.packages.${system}.default;
+      type = types.package;
+    };
+
+    cooldown = mkOption {
+      description = "The cooldown to use for `swhkd`";
+      default = 250;
+      type = types.int;
+    };
+
+    settings = mkOption {
+      description = "The config to use for `swhkd` syntax and samples could found in [repo](https://github.com/waycrate/swhkd).";
+      default = ''
+      super + return
+        alacritty
+      '';
+      type = types.lines;
+    };
+  };
+
+  config = mkIf cfg.enable {
+    environment.systemPackages = [ cfg.package ];
+    environment.etc."swhkd/swhkdrc".text = cfg.settings;
+
+    systemd.user.services.swhkd = {
+      description = "Simple Wayland HotKey Daemon";
+      bindsTo = [ "default.target" ];
+      script = ''
+        /run/wrappers/bin/pkexec ${cfg.package}/bin/swhkd \
+          --cooldown ${toString cfg.cooldown}
+      '';
+      serviceConfig.Restart = "always";
+      wantedBy = [ "default.target" ];
+    };
+    security.polkit = {
+      enable = true;
+      extraConfig = ''
+        polkit.addRule(function(action, subject) {
+            if (action.id == "com.github.swhkd.pkexec"  &&
+                subject.local == true &&
+                subject.active == true &&) {
+                    return polkit.Result.YES;
+                }
+        });
+      '';
+    };
+  };
+}