From 1d84c76f5c4f1cb710a250faca3ecc80a1edb9d1 Mon Sep 17 00:00:00 2001
From: Fernando Ayats <fernando.ayats-llamas@inria.fr>
Date: Mon, 11 Mar 2024 09:05:40 +0100
Subject: [PATCH] nixos/nh: init

---
 .../manual/release-notes/rl-2405.section.md   |  2 +
 nixos/modules/module-list.nix                 |  1 +
 nixos/modules/programs/nh.nix                 | 96 +++++++++++++++++++
 3 files changed, 99 insertions(+)
 create mode 100644 nixos/modules/programs/nh.nix

diff --git a/nixos/doc/manual/release-notes/rl-2405.section.md b/nixos/doc/manual/release-notes/rl-2405.section.md
index 065b0101691f..34c1dbaa902e 100644
--- a/nixos/doc/manual/release-notes/rl-2405.section.md
+++ b/nixos/doc/manual/release-notes/rl-2405.section.md
@@ -147,6 +147,8 @@ The pre-existing [services.ankisyncd](#opt-services.ankisyncd.enable) has been m
 
 - binfmt option for AppImage-run to support running [AppImage](https://appimage.org/)'s seamlessly on NixOS.. Available as [programs.appimage.binfmt](#opt-programs.appimage.binfmt).
 
+- [nh](https://github.com/viperML/nh), yet another Nix CLI helper. Available as [programs.nh](#opt-programs.nh.enable).
+
 - [ALVR](https://github.com/alvr-org/alvr), a VR desktop streamer. Available as [programs.alvr](#opt-programs.alvr.enable)
 
 - [RustDesk](https://rustdesk.com), a full-featured open source remote control alternative for self-hosting and security with minimal configuration. Alternative to TeamViewer.
diff --git a/nixos/modules/module-list.nix b/nixos/modules/module-list.nix
index b361e9ee5e41..8f900c150a09 100644
--- a/nixos/modules/module-list.nix
+++ b/nixos/modules/module-list.nix
@@ -230,6 +230,7 @@
   ./programs/neovim.nix
   ./programs/nethoscope.nix
   ./programs/nexttrace.nix
+  ./programs/nh.nix
   ./programs/nix-index.nix
   ./programs/nix-ld.nix
   ./programs/nm-applet.nix
diff --git a/nixos/modules/programs/nh.nix b/nixos/modules/programs/nh.nix
new file mode 100644
index 000000000000..c42fb2fc724a
--- /dev/null
+++ b/nixos/modules/programs/nh.nix
@@ -0,0 +1,96 @@
+{ config
+, lib
+, pkgs
+, ...
+}:
+let
+  cfg = config.programs.nh;
+in
+{
+  meta.maintainers = [ lib.maintainers.viperML ];
+
+  options.programs.nh = {
+    enable = lib.mkEnableOption "nh, yet another Nix CLI helper";
+
+    package = lib.mkPackageOption pkgs "nh" { };
+
+    flake = lib.mkOption {
+      type = lib.types.nullOr lib.types.path;
+      default = null;
+      description = ''
+        The path that will be used for the `FLAKE` environment variable.
+
+        `FLAKE` is used by nh as the default flake for performing actions, like `nh os switch`.
+      '';
+    };
+
+    clean = {
+      enable = lib.mkEnableOption "periodic garbage collection with nh clean all";
+
+      dates = lib.mkOption {
+        type = lib.types.singleLineStr;
+        default = "weekly";
+        description = ''
+          How often cleanup is performed. Passed to systemd.time
+
+          The format is described in
+          {manpage}`systemd.time(7)`.
+        '';
+      };
+
+      extraArgs = lib.mkOption {
+        type = lib.types.singleLineStr;
+        default = "";
+        example = "--keep 5 --keep-since 3d";
+        description = ''
+          Options given to nh clean when the service is run automatically.
+
+          See `nh clean all --help` for more information.
+        '';
+      };
+    };
+  };
+
+  config = {
+    warnings =
+      if (!(cfg.clean.enable -> !config.nix.gc.automatic)) then [
+        "programs.nh.clean.enable and nix.gc.automatic are both enabled. Please use one or the other to avoid conflict."
+      ] else [ ];
+
+    assertions = [
+      # Not strictly required but probably a good assertion to have
+      {
+        assertion = cfg.clean.enable -> cfg.enable;
+        message = "programs.nh.clean.enable requires programs.nh.enable";
+      }
+
+      {
+        assertion = (cfg.flake != null) -> !(lib.hasSuffix ".nix" cfg.flake);
+        message = "nh.flake must be a directory, not a nix file";
+      }
+    ];
+
+    environment = lib.mkIf cfg.enable {
+      systemPackages = [ cfg.package ];
+      variables = lib.mkIf (cfg.flake != null) {
+        FLAKE = cfg.flake;
+      };
+    };
+
+    systemd = lib.mkIf cfg.clean.enable {
+      services.nh-clean = {
+        description = "Nh clean";
+        script = "exec ${lib.getExe cfg.package} clean all ${cfg.clean.extraArgs}";
+        startAt = cfg.clean.dates;
+        path = [ config.nix.package ];
+        serviceConfig.Type = "oneshot";
+      };
+
+      timers.nh-clean = {
+        timerConfig = {
+          Persistent = true;
+        };
+      };
+    };
+  };
+}