home-manager/modules/services/wlsunset.nix

{ config, lib, pkgs, ... }:

with lib;

let cfg = config.services.wlsunset;

in {
  meta.maintainers = [ hm.maintainers.matrss ];

  options.services.wlsunset = {
    enable = mkEnableOption "wlsunset";

    package = mkOption {
      type = with types; package;
      default = pkgs.wlsunset;
      defaultText = "pkgs.wlsunset";
      description = ''
        wlsunset derivation to use.
      '';
    };

    latitude = mkOption {
      type = with types; nullOr (either str (either float int));
      default = null;
      example = -74.3;
      description = ''
        Your current latitude, between `-90.0` and
        `90.0`.
      '';
    };

    longitude = mkOption {
      type = with types; nullOr (either str (either float int));
      default = null;
      example = 12.5;
      description = ''
        Your current longitude, between `-180.0` and
        `180.0`.
      '';
    };

    temperature = {
      day = mkOption {
        type = with types; int;
        default = 6500;
        description = ''
          Colour temperature to use during the day, in Kelvin (K).
          This value must be greater than `temperature.night`.
        '';
      };

      night = mkOption {
        type = with types; int;
        default = 4000;
        description = ''
          Colour temperature to use during the night, in Kelvin (K).
          This value must be smaller than `temperature.day`.
        '';
      };
    };

    gamma = mkOption {
      type = with types; (either str (either float int));
      default = 1.0;
      example = 0.6;
      description = ''
        Gamma value to use.
      '';
    };

    output = mkOption {
      type = with types; nullOr str;
      default = null;
      description = ''
        Name of output to use, by default all outputs are used.
      '';
    };

    sunrise = mkOption {
      type = with types; nullOr str;
      default = null;
      example = "06:30";
      description = ''
        The time when the sun rises (in 24 hour format).
      '';
    };

    sunset = mkOption {
      type = with types; nullOr str;
      default = null;
      example = "18:00";
      description = ''
        The time when the sun sets (in 24 hour format).
      '';
    };

    systemdTarget = mkOption {
      type = with types; str;
      default = "graphical-session.target";
      description = ''
        Systemd target to bind to.
      '';
    };
  };

  config = mkIf cfg.enable {
    assertions = [
      (lib.hm.assertions.assertPlatform "services.wlsunset" pkgs
        lib.platforms.linux)
      {
        assertion = (cfg.sunrise != null || cfg.sunset != null)
          != (cfg.latitude != null || cfg.longitude != null);
        message =
          "Either `sunrise` and `sunset` together or `longitude` and `latitude` together must be set for wlsunset";
      }
      {
        assertion = (cfg.sunrise != null) == (cfg.sunset != null);
        message =
          "Both `sunset` and `sunrise` together must be set for wlsunset";
      }
      {
        assertion = (cfg.latitude != null) == (cfg.longitude != null);
        message =
          "Both `latitude and `longitude` together must be set for wlsunset";
      }
    ];

    systemd.user.services.wlsunset = {
      Unit = {
        Description = "Day/night gamma adjustments for Wayland compositors.";
        PartOf = [ "graphical-session.target" ];
      };

      Service = {
        ExecStart = let
          args = cli.toGNUCommandLineShell { } {
            t = cfg.temperature.night;
            T = cfg.temperature.day;
            g = cfg.gamma;
            l = cfg.latitude;
            L = cfg.longitude;
            S = cfg.sunrise;
            s = cfg.sunset;
            o = cfg.output;
          };
        in "${cfg.package}/bin/wlsunset ${args}";
      };

      Install = { WantedBy = [ cfg.systemdTarget ]; };
    };
  };
}