satellite/modules/home-manager/compat/hyprpaper.nix

{ config, lib, pkgs, ... }:
with lib;
let
  cfg = config.services.hyprpaper;
  toHyprconf = { attrs, indentLevel ? 0, importantPrefixes ? [ "$" ], }:
    let
      inherit (lib)
        all concatMapStringsSep concatStrings concatStringsSep filterAttrs foldl
        generators hasPrefix isAttrs isList mapAttrsToList replicate;

      initialIndent = concatStrings (replicate indentLevel "  ");

      toHyprconf' = indent: attrs:
        let
          sections =
            filterAttrs (n: v: isAttrs v || (isList v && all isAttrs v)) attrs;

          mkSection = n: attrs:
            if lib.isList attrs then
              (concatMapStringsSep "\n" (a: mkSection n a) attrs)
            else ''
              ${indent}${n} {
              ${toHyprconf' "  ${indent}" attrs}${indent}}
            '';

          mkFields = generators.toKeyValue {
            listsAsDuplicateKeys = true;
            inherit indent;
          };

          allFields =
            filterAttrs (n: v: !(isAttrs v || (isList v && all isAttrs v)))
              attrs;

          isImportantField = n: _:
            foldl (acc: prev: if hasPrefix prev n then true else acc) false
              importantPrefixes;

          importantFields = filterAttrs isImportantField allFields;

          fields = builtins.removeAttrs allFields
            (mapAttrsToList (n: _: n) importantFields);
        in
        mkFields importantFields
        + concatStringsSep "\n" (mapAttrsToList mkSection sections)
        + mkFields fields;
    in
    toHyprconf' initialIndent attrs;
in
{
  meta.maintainers = [ maintainers.khaneliman maintainers.fufexan ];

  options.services.hyprpaper = {
    enable = mkEnableOption "Hyprpaper, Hyprland's wallpaper daemon";

    package = mkPackageOption pkgs "hyprpaper" { };

    settings = lib.mkOption {
      type = with lib.types;
        let
          valueType = nullOr
            (oneOf [
              bool
              int
              float
              str
              path
              (attrsOf valueType)
              (listOf valueType)
            ]) // {
            description = "Hyprpaper configuration value";
          };
        in
        valueType;
      default = { };
      description = ''
        hyprpaper configuration written in Nix. Entries with the same key
        should be written as lists. Variables' and colors' names should be
        quoted. See <https://wiki.hyprland.org/Hypr-Ecosystem/hyprpaper/> for more examples.
      '';
      example = lib.literalExpression ''
        {
          ipc = "on";
          splash = false;
          splash_offset = 2.0;

          preload =
            [ "/share/wallpapers/buttons.png" "/share/wallpapers/cat_pacman.png" ];

          wallpaper = [
            "DP-3,/share/wallpapers/buttons.png"
            "DP-1,/share/wallpapers/cat_pacman.png"
          ];
        }
      '';
    };

    importantPrefixes = lib.mkOption {
      type = with lib.types; listOf str;
      default = [ "$" ];
      example = [ "$" ];
      description = ''
        List of prefix of attributes to source at the top of the config.
      '';
    };
  };

  config = mkIf cfg.enable {
    xdg.configFile."hypr/hyprpaper.conf" = mkIf (cfg.settings != { }) {
      text = toHyprconf {
        attrs = cfg.settings;
        inherit (cfg) importantPrefixes;
      };
    };

    systemd.user.services.hyprpaper = {
      Install = { WantedBy = [ "graphical-session.target" ]; };

      Unit = {
        ConditionEnvironment = "WAYLAND_DISPLAY";
        Description = "hyprpaper";
        After = [ "graphical-session-pre.target" ];
        PartOf = [ "graphical-session.target" ];
        X-Restart-Triggers =
          [ "${config.xdg.configFile."hypr/hyprpaper.conf".source}" ];
      };

      Service = {
        ExecStart = "${getExe cfg.package}";
        Restart = "always";
        RestartSec = "10";
      };
    };
  };
}