feat: derive desktop input and SDDM scale from host metadata

modules/features/input.nix

@@ -0,0 +1,69 @@
+{
+  flake.modules.nixos.input =
+    {
+      lib,
+      config,
+      ...
+    }:
+    let
+      hostInput = config.meta.host.input;
+
+      hasAnyConfiguredValue = attrs: lib.any (value: value != null) (lib.attrValues attrs);
+      libinputScrollMethodMap = {
+        edge = "edge";
+        "no-scroll" = "none";
+        "on-button-down" = "button";
+        "two-finger" = "twofinger";
+      };
+      libinputClickMethodMap = {
+        "button-areas" = "buttonareas";
+        clickfinger = "clickfinger";
+      };
+
+      hasMouseConfig = hasAnyConfiguredValue hostInput.mouse;
+      hasTouchpadConfig = hasAnyConfiguredValue hostInput.touchpad;
+      hasPointerConfig = hasMouseConfig || hasTouchpadConfig;
+
+      mouseConfig = lib.filterAttrs (_: value: value != null) {
+        accelProfile = hostInput.mouse.accelProfile;
+        accelSpeed =
+          if hostInput.mouse.accelSpeed == null then null else toString hostInput.mouse.accelSpeed;
+        leftHanded = hostInput.mouse.leftHanded;
+        middleEmulation = hostInput.mouse.middleEmulation;
+        naturalScrolling = hostInput.mouse.naturalScrolling;
+        scrollMethod =
+          if hostInput.mouse.scrollMethod == null then
+            null
+          else
+            libinputScrollMethodMap.${hostInput.mouse.scrollMethod};
+      };
+
+      touchpadConfig = lib.filterAttrs (_: value: value != null) {
+        accelProfile = hostInput.touchpad.accelProfile;
+        accelSpeed =
+          if hostInput.touchpad.accelSpeed == null then null else toString hostInput.touchpad.accelSpeed;
+        clickMethod =
+          if hostInput.touchpad.clickMethod == null then
+            null
+          else
+            libinputClickMethodMap.${hostInput.touchpad.clickMethod};
+        disableWhileTyping = hostInput.touchpad.disableWhileTyping;
+        leftHanded = hostInput.touchpad.leftHanded;
+        middleEmulation = hostInput.touchpad.middleEmulation;
+        naturalScrolling = hostInput.touchpad.naturalScrolling;
+        scrollMethod =
+          if hostInput.touchpad.scrollMethod == null then
+            null
+          else
+            libinputScrollMethodMap.${hostInput.touchpad.scrollMethod};
+        tapping = hostInput.touchpad.tapping;
+      };
+    in
+    {
+      services.libinput = lib.mkIf hasPointerConfig {
+        enable = true;
+        mouse = mouseConfig;
+        touchpad = touchpadConfig;
+      };
+    };
+}

modules/features/meta.nix

@@ -1,5 +1,12 @@
 { lib, ... }:
 let
+  mkNullableOption =
+    type:
+    lib.mkOption {
+      inherit type;
+      default = null;
+    };
+
   emailType = lib.types.submodule (
     { ... }:
     {
@@ -100,6 +107,73 @@ let
     }
   );
 
+  mouseInputType = lib.types.submodule (
+    { ... }:
+    {
+      options = {
+        accelProfile = mkNullableOption (lib.types.nullOr (lib.types.enum [
+          "adaptive"
+          "flat"
+        ]));
+        accelSpeed = mkNullableOption (lib.types.nullOr lib.types.float);
+        leftHanded = mkNullableOption (lib.types.nullOr lib.types.bool);
+        middleEmulation = mkNullableOption (lib.types.nullOr lib.types.bool);
+        naturalScrolling = mkNullableOption (lib.types.nullOr lib.types.bool);
+        scrollMethod = mkNullableOption (lib.types.nullOr (lib.types.enum [
+          "no-scroll"
+          "two-finger"
+          "edge"
+          "on-button-down"
+        ]));
+      };
+    }
+  );
+
+  touchpadInputType = lib.types.submodule (
+    { ... }:
+    {
+      options = {
+        accelProfile = mkNullableOption (lib.types.nullOr (lib.types.enum [
+          "adaptive"
+          "flat"
+        ]));
+        accelSpeed = mkNullableOption (lib.types.nullOr lib.types.float);
+        clickMethod = mkNullableOption (lib.types.nullOr (lib.types.enum [
+          "button-areas"
+          "clickfinger"
+        ]));
+        disableWhileTyping = mkNullableOption (lib.types.nullOr lib.types.bool);
+        leftHanded = mkNullableOption (lib.types.nullOr lib.types.bool);
+        middleEmulation = mkNullableOption (lib.types.nullOr lib.types.bool);
+        naturalScrolling = mkNullableOption (lib.types.nullOr lib.types.bool);
+        scrollMethod = mkNullableOption (lib.types.nullOr (lib.types.enum [
+          "no-scroll"
+          "two-finger"
+          "edge"
+          "on-button-down"
+        ]));
+        tapping = mkNullableOption (lib.types.nullOr lib.types.bool);
+      };
+    }
+  );
+
+  inputType = lib.types.submodule (
+    { ... }:
+    {
+      options = {
+        mouse = lib.mkOption {
+          type = mouseInputType;
+          default = { };
+        };
+
+        touchpad = lib.mkOption {
+          type = touchpadInputType;
+          default = { };
+        };
+      };
+    }
+  );
+
   hostType = lib.types.submodule (
     { ... }:
     {
@@ -113,6 +187,11 @@ let
           default = { };
         };
 
+        input = lib.mkOption {
+          type = inputType;
+          default = { };
+        };
+
         users = lib.mkOption {
           type = lib.types.attrsOf userType;
           default = { };

modules/features/niri/default.nix

@@ -23,6 +23,8 @@
       ...
     }:
     let
+      hostInput = config.meta.host.input;
+
       outputs = lib.mapAttrs (
         _: display:
         {
@@ -49,6 +51,27 @@
           rawTerminalAttrPath;
       terminalPackage = lib.attrByPath terminalAttrPath null pkgs;
       hasMainProgram = terminalPackage != null && terminalPackage ? meta.mainProgram;
+
+      mouseSettings = lib.filterAttrs (_: value: value != null) {
+        accel-profile = hostInput.mouse.accelProfile;
+        accel-speed = hostInput.mouse.accelSpeed;
+        left-handed = hostInput.mouse.leftHanded;
+        middle-emulation = hostInput.mouse.middleEmulation;
+        natural-scroll = hostInput.mouse.naturalScrolling;
+        scroll-method = hostInput.mouse.scrollMethod;
+      };
+
+      touchpadSettings = lib.filterAttrs (_: value: value != null) {
+        accel-profile = hostInput.touchpad.accelProfile;
+        accel-speed = hostInput.touchpad.accelSpeed;
+        click-method = hostInput.touchpad.clickMethod;
+        dwt = hostInput.touchpad.disableWhileTyping;
+        left-handed = hostInput.touchpad.leftHanded;
+        middle-emulation = hostInput.touchpad.middleEmulation;
+        natural-scroll = hostInput.touchpad.naturalScrolling;
+        scroll-method = hostInput.touchpad.scrollMethod;
+        tap = hostInput.touchpad.tapping;
+      };
     in
     {
       assertions = [
@@ -139,7 +162,12 @@
             repeat-rate = 50;
             xkb.options = "caps:escape";
           };
-          mouse.accel-speed = 0.4;
+        }
+        // lib.optionalAttrs (mouseSettings != { }) {
+          mouse = mouseSettings;
+        }
+        // lib.optionalAttrs (touchpadSettings != { }) {
+          touchpad = touchpadSettings;
         };
 
         binds =

modules/features/sddm.nix

@@ -1,14 +1,40 @@
 {
   flake.modules.nixos.sddm =
-    { pkgs, ... }:
+    {
+      config,
+      lib,
+      pkgs,
+      ...
+    }:
+    let
+      primaryDisplays = builtins.filter (display: display.primary or false) (builtins.attrValues config.meta.host.displays);
+      primaryDisplay = if primaryDisplays == [ ] then null else builtins.head primaryDisplays;
+      primaryScale =
+        if primaryDisplay == null then
+          null
+        else
+          primaryDisplay.scale;
+      greeterEnvironment =
+        lib.optional (primaryScale != null) "QT_SCALE_FACTOR=${toString primaryScale}";
+    in
     {
       services.displayManager.sddm = {
         enable = true;
+        enableHidpi = primaryScale == null;
         wayland.enable = true;
+        wayland.compositor = "kwin";
         theme = "${pkgs.sddm-astronaut}/share/sddm/themes/sddm-astronaut-theme";
         extraPackages = with pkgs; [
           kdePackages.qtmultimedia
         ];
+        settings = lib.optionalAttrs (greeterEnvironment != [ ]) {
+          General.GreeterEnvironment = lib.concatStringsSep "," (
+            [
+              "QT_WAYLAND_SHELL_INTEGRATION=layer-shell"
+            ]
+            ++ greeterEnvironment
+          );
+        };
       };
     };
 }

modules/features/workstation-base.nix

@@ -7,6 +7,7 @@ in
   flake.modules.nixos.workstation-base = {
     imports = [
       nixosModules.host-base
+      nixosModules.input
       nixosModules.sops-admin-key-file
       nixosModules.standard-boot
       nixosModules.sddm

modules/hosts/zenith/default.nix

@@ -26,6 +26,10 @@ in
       };
     };
 
+    input = {
+      mouse.accelSpeed = 0.4;
+    };
+
     users = {
       inherit (metaLib.users)
         ergon

modules/lib.nix

@@ -8,6 +8,7 @@ let
     {
       name,
       displays ? { },
+      input ? { },
       users ? { },
       imports ? [ ],
       stateVersion ? "24.05",
@@ -16,6 +17,7 @@ let
       meta.host = {
         inherit
           displays
+          input
           name
           users
           ;