clight: include module

nixos/modules/module-list.nix

@@ -816,6 +816,7 @@
   ./services/web-servers/varnish/default.nix
   ./services/web-servers/zope2.nix
   ./services/x11/extra-layouts.nix
+  ./services/x11/clight.nix
   ./services/x11/colord.nix
   ./services/x11/compton.nix
   ./services/x11/unclutter.nix

nixos/modules/services/x11/clight.nix

@@ -0,0 +1,115 @@
+{ config, pkgs, lib, ... }:
+
+with lib;
+
+let
+  cfg = config.services.clight;
+
+  toConf = v:
+    if builtins.isFloat v then toString v
+    else if isInt v       then toString v
+    else if isBool v      then boolToString v
+    else if isString v    then ''"${escape [''"''] v}"''
+    else if isList v      then "[ " + concatMapStringsSep ", " toConf v + " ]"
+    else abort "clight.toConf: unexpected type (v = ${v})";
+
+  clightConf = pkgs.writeText "clight.conf"
+    (concatStringsSep "\n" (mapAttrsToList
+      (name: value: "${toString name} = ${toConf value};")
+      (filterAttrs
+        (_: value: value != null)
+        cfg.settings)));
+in {
+  options.services.clight = {
+    enable = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        Whether to enable clight or not.
+      '';
+    };
+
+    temperature = {
+      day = mkOption {
+        type = types.int;
+        default = 5500;
+        description = ''
+          Colour temperature to use during the day, between
+          <literal>1000</literal> and <literal>25000</literal> K.
+        '';
+      };
+      night = mkOption {
+        type = types.int;
+        default = 3700;
+        description = ''
+          Colour temperature to use at night, between
+          <literal>1000</literal> and <literal>25000</literal> K.
+        '';
+      };
+    };
+
+    settings = let
+      validConfigTypes = with types; either int (either str (either bool float));
+    in mkOption {
+      type = with types; attrsOf (nullOr (either validConfigTypes (listOf validConfigTypes)));
+      default = {};
+      example = { captures = 20; gamma_long_transition = true; ac_capture_timeouts = [ 120 300 60 ]; };
+      description = ''
+        Additional configuration to extend clight.conf. See
+        <link xlink:href="https://github.com/FedeDP/Clight/blob/master/Extra/clight.conf"/> for a
+        sample configuration file.
+      '';
+    };
+  };
+
+  config = mkIf cfg.enable {
+    boot.kernelModules = [ "i2c_dev" ];
+    environment.systemPackages = with pkgs; [ clight clightd ];
+    services.dbus.packages = with pkgs; [ clight clightd ];
+    services.upower.enable = true;
+
+    services.clight.settings = {
+      gamma_temp = with cfg.temperature; mkDefault [ day night ];
+    } // (optionalAttrs (config.location.provider == "manual") {
+      latitude = mkDefault config.location.latitude;
+      longitude = mkDefault config.location.longitude;
+    });
+
+    services.geoclue2.appConfig."clightc" = {
+      isAllowed = true;
+      isSystem = true;
+    };
+
+    systemd.services.clightd = {
+      requires = [ "polkit.service" ];
+      wantedBy = [ "multi-user.target" ];
+
+      description = "Bus service to manage various screen related properties (gamma, dpms, backlight)";
+      serviceConfig = {
+        Type = "dbus";
+        BusName = "org.clightd.clightd";
+        Restart = "on-failure";
+        RestartSec = 5;
+        ExecStart = ''
+          ${pkgs.clightd}/bin/clightd
+        '';
+      };
+    };
+
+    systemd.user.services.clight = {
+      after = [ "upower.service" "clightd.service" ];
+      wants = [ "upower.service" "clightd.service" ];
+      partOf = [ "graphical-session.target" ];
+      wantedBy = [ "graphical-session.target" ];
+
+      description = "C daemon to adjust screen brightness to match ambient brightness, as computed capturing frames from webcam";
+      serviceConfig = {
+        Restart = "on-failure";
+        RestartSec = 5;
+        ExecStart = ''
+          ${pkgs.clight}/bin/clight --conf-file ${clightConf}
+        '';
+      };
+    };
+  };
+}