nix: add nixos module

flake.nix

@@ -14,32 +14,42 @@
     nixpkgs,
     ...
   }: let
-    supportedSystems = [
-      "aarch64-linux"
+    inherit (nixpkgs) lib;
+    genSystems = lib.genAttrs [
       "x86_64-linux"
     ];
-    genSystems = nixpkgs.lib.genAttrs supportedSystems;
     pkgsFor = nixpkgs.legacyPackages;
+    # https://github.com/NixOS/rfcs/pull/107
+    mkVersion = longDate:
+      lib.concatStrings [
+        "0.pre"
+        "+date="
+        (lib.concatStringsSep "-" [
+          (__substring 0 4 longDate)
+          (__substring 4 2 longDate)
+          (__substring 6 2 longDate)
+        ])
+      ];
   in {
     packages = genSystems (system: {
       wlroots = pkgsFor.${system}.wlroots.overrideAttrs (prev: {
-        version = inputs.wlroots.lastModifiedDate;
+        version = mkVersion inputs.wlroots.lastModifiedDate;
         src = inputs.wlroots;
       });
       default = pkgsFor.${system}.callPackage ./default.nix {
-        version = self.lastModifiedDate;
+        version = mkVersion self.lastModifiedDate;
         inherit (self.packages.${system}) wlroots;
       };
     });
 
     formatter = genSystems (system: pkgsFor.${system}.alejandra);
 
-    # TODO Provide a nixos module for easy installation and configuration
-    # nixosModules.default = import ./module.nix;
+    nixosModules.default = import ./module.nix self;
 
     # Deprecated
-    overlay = _: prev: {
+    overlays.default = _: prev: {
       hyprland = self.packages.${prev.system}.default;
     };
+    overlay = self.overlays.default;
   };
 }

module.nix

@@ -0,0 +1,62 @@
+# Copied from https://github.com/NixOS/nixpkgs/blob/master/nixos/modules/programs/sway.nix
+self: {
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+with lib; let
+  cfg = config.programs.hyprland;
+in {
+  options.programs.hyprland = {
+    enable = mkEnableOption ''
+      Hyprland, the dynamic tiling Wayland compositor that doesn't sacrifice on its looks.
+      You can manually launch Hyprland by executing "exec Hyprland" on a TTY.
+      A configuration file will be generated in ~/.config/hypr/hyprland.conf.
+      See <link xlink:href="https://github.com/vaxerski/Hyprland/wiki" /> for
+      more information.
+    '';
+
+    package = mkOption {
+      type = types.package;
+      default = self.packages.${pkgs.system}.default;
+      defaultText = literalExpression "<Hyprland flake>.packages.<system>.default";
+      example = literalExpression "<Hyprland flake>.packages.<system>.default.override { }";
+      description = ''
+        Hyprland package to use.
+      '';
+    };
+
+    extraPackages = mkOption {
+      type = with types; listOf package;
+      default = with pkgs; [
+        kitty
+        wofi
+        swaybg
+      ];
+      defaultText = literalExpression ''
+        with pkgs; [ kitty wofi swaybg ];
+      '';
+      example = literalExpression ''
+        with pkgs; [
+          alacritty wofi
+        ]
+      '';
+      description = ''
+        Extra packages to be installed system wide.
+      '';
+    };
+  };
+
+  config = mkIf cfg.enable {
+    environment.systemPackages = [cfg.package] ++ cfg.extraPackages;
+    security.polkit.enable = true;
+    hardware.opengl.enable = mkDefault true;
+    fonts.enableDefaultFonts = mkDefault true;
+    programs.dconf.enable = mkDefault true;
+    services.xserver.displayManager.sessionPackages = [cfg.package];
+    programs.xwayland.enable = mkDefault true;
+    xdg.portal.enable = mkDefault true;
+    xdg.portal.extraPortals = [pkgs.xdg-desktop-portal-wlr];
+  };
+}