halloy: add module (#7034)

modules/programs/halloy.nix

@@ -0,0 +1,49 @@
+{
+  lib,
+  pkgs,
+  config,
+  ...
+}:
+let
+  inherit (lib)
+    mkIf
+    mkEnableOption
+    mkPackageOption
+    mkOption
+    ;
+
+  cfg = config.programs.halloy;
+
+  formatter = pkgs.formats.toml { };
+in
+{
+  meta.maintainers = with lib.hm.maintainers; [ aguirre-matteo ];
+
+  options.programs.halloy = {
+    enable = mkEnableOption "halloy";
+    package = mkPackageOption pkgs "halloy" { nullable = true; };
+    settings = mkOption {
+      type = formatter.type;
+      default = { };
+      example = {
+        "buffer.channel.topic".enabled = true;
+        "servers.liberachat" = {
+          nickname = "halloy-user";
+          server = "irc.libera.chat";
+          channels = [ "#halloy" ];
+        };
+      };
+      description = ''
+        Configuration settings for halloy. All available options can be
+        found here: <https://halloy.chat/configuration/index.html>.
+      '';
+    };
+  };
+
+  config = mkIf cfg.enable {
+    home.packages = mkIf (cfg.package != null) [ cfg.package ];
+    xdg.configFile."halloy/config.toml" = mkIf (cfg.settings != { }) {
+      source = formatter.generate "halloy-config" cfg.settings;
+    };
+  };
+}