begin to modularise

lib/modules/display.nix

@@ -0,0 +1,82 @@
+{ user }: { lib, pkgs, config, ... }:
+with lib;
+let
+  cfg = config.displays;
+
+  renderDisplaysForHyprland = displays:
+    "# === DISPLAY MODULE ===\n"
+    + concatStringsSep "\n" (map displayHyprlandSetting displays);
+
+  displayHyprlandSetting = display:
+    "monitor = " + display.name +
+    ", " + resToString display.resolution +
+    ", " + display.position +
+    ", " + toString display.scaling;
+
+  resolutionType = types.submodule ({ x, y, freq, ... }:
+    {
+      options = {
+        x = mkOption {
+          description = "x";
+          type = types.int;
+          default = 0;
+        };
+        y = mkOption {
+          description = "y";
+          type = types.int;
+          default = 0;
+        };
+        freq = mkOption {
+          description = "frequency";
+          type = types.int;
+          default = 0;
+        };
+      };
+    });
+  displayType = types.submodule
+    ({ ... }: {
+      options = {
+        name = mkOption {
+          description = "name of the display";
+        };
+        scaling = mkOption {
+          type = types.float;
+          default = 1.0;
+        };
+        resolution = mkOption {
+          description = "res";
+          type = resolutionType;
+          default = { };
+        };
+        position = mkOption {
+          description = "XxY";
+          default = "auto";
+        };
+      };
+    });
+
+  resToString = res:
+    if res.x == 0 || res.y == 0 || res.freq == 0
+    then "preferred"
+    else "${toString res.x}x${toString res.y}@${toString res.freq}";
+in
+{
+  options.displays =
+    {
+      enable = mkEnableOption "manage displays";
+      displays = mkOption {
+        type = types.listOf displayType;
+        default = [ ];
+      };
+    };
+
+  config = mkIf cfg.enable {
+    home-manager.users.${user}.imports = [
+      {
+        wayland.windowManager.hyprland.extraConfig = mkIf (cfg.displays != [ ])
+          (renderDisplaysForHyprland cfg.displays);
+      }
+    ];
+  };
+}
+