From 7754bc246f72e03c09de0e1ece58d5bb212adbb7 Mon Sep 17 00:00:00 2001
From: atagen <boss@atagen.co>
Date: Wed, 21 May 2025 17:03:16 +1000
Subject: [PATCH] feat: init

---
 flake.lock  | 43 ++++++++++++++++++++++++++++++++++
 flake.nix   | 41 ++++++++++++++++++++++++++++++++
 module.nix  | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 smooooth.sh | 39 +++++++++++++++++++++++++++++++
 4 files changed, 190 insertions(+)
 create mode 100644 flake.lock
 create mode 100644 flake.nix
 create mode 100644 module.nix
 create mode 100755 smooooth.sh

diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..aa97b79
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,43 @@
+{
+  "nodes": {
+    "nix-systems": {
+      "locked": {
+        "lastModified": 1689347949,
+        "narHash": "sha256-12tWmuL2zgBgZkdoB6qXZsgJEH9LR3oUgpaQq2RbI80=",
+        "owner": "nix-systems",
+        "repo": "default-linux",
+        "rev": "31732fcf5e8fea42e59c2488ad31a0e651500f68",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default-linux",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1747728033,
+        "narHash": "sha256-NnXFQu7g4LnvPIPfJmBuZF7LFy/fey2g2+LCzjQhTUk=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "2f9173bde1d3fbf1ad26ff6d52f952f9e9da52ea",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nix-systems": "nix-systems",
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..3e07230
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,41 @@
+{
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
+    nix-systems.url = "github:nix-systems/default-linux";
+  };
+
+  outputs =
+    inputs:
+    with inputs;
+    let
+      forAllSystems =
+        function:
+        nixpkgs.lib.genAttrs (import nix-systems) (
+          system: function system nixpkgs.legacyPackages.${system}
+        );
+    in
+    {
+      packages =
+        preferredNix:
+        forAllSystems (
+          _: pkgs: {
+            default = pkgs.writeShellApplication {
+              name = "smooooth";
+              runtimeInputs = builtins.getAttrs {
+                inherit (pkgs)
+                  polkit
+                  gnugrep
+                  coreutils
+                  libnotify
+                  ;
+                inherit preferredNix;
+              };
+              text = builtins.readFile ./smooooth.sh;
+            };
+          }
+        );
+      nixosModules = forAllSystems (
+        system: _: import ./module.nix { smooooth = self.packages.${system}.default; }
+      );
+    };
+}
diff --git a/module.nix b/module.nix
new file mode 100644
index 0000000..0199957
--- /dev/null
+++ b/module.nix
@@ -0,0 +1,67 @@
+{
+  pkgs,
+  lib,
+  config,
+  smooooth,
+  ...
+}:
+let
+  inherit (lib.options) types mkEnable mkOption;
+  cfg = config.smooooth;
+in
+{
+  options.smooooth = {
+    enable = mkEnable "the smooooth nixos hot reloader";
+    blockers = mkOption {
+      description = "Names of processes that may block reloading when holding a flake (sub)path open.";
+      default = [
+        "nano"
+        "nvim"
+        "vim"
+        "vi"
+        "hx"
+      ];
+      example = ''
+        [ "hx" ]
+      '';
+      type = types.listOf types.str;
+    };
+    path = mkOption {
+      description = "Path to the root of your flake.";
+      type = types.str;
+    };
+    pollingRate = mkOption {
+      description = "How frequently to poll for blockers when waiting on a reload.";
+      default = 10;
+      type = types.int;
+    };
+    preferredNix = mkOption {
+      description = "Your preferred package that provides a nix-compatible executable.";
+      default = pkgs.nix;
+      type = types.package;
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    systemd.user = {
+      services.smooooth = {
+        serviceConfig = {
+          Type = "oneshot";
+          ExecStart =
+            let
+              blockers = builtins.concatStringsSep "|" cfg.blockers;
+            in
+            "smooooth ${cfg.path} ${blockers} ${toString cfg.pollingRate}";
+        };
+      };
+      paths.smooooth = {
+        path = [ (smooooth cfg.preferredNix) ];
+        pathConfig = {
+          PathChanged = cfg.path;
+          Unit = "smoooth.service";
+          TriggerLimitIntervalSec = cfg.pollingRate * 2;
+        };
+      };
+    };
+  };
+}
diff --git a/smooooth.sh b/smooooth.sh
new file mode 100755
index 0000000..c17ffb5
--- /dev/null
+++ b/smooooth.sh
@@ -0,0 +1,39 @@
+SACRED_SPACE="$1"
+BLOCKERS="$2"
+PERIOD="$3"
+
+scrapePids() {
+	for pid in $(ls /proc); do
+	  if [[ "$pid" =~ ^[0-9]*$ ]]; then
+	    if egrep -q $BLOCKERS /proc/$pid/comm; then
+	      cat /proc/$pid/comm
+	      readlink /proc/$pid/cwd
+	      if [[ "$(readlink /proc/$pid/cwd)" == "$SACRED_SPACE"* ]]; then
+          return 0
+        fi
+      fi
+  	fi
+	done
+	return 1
+}
+
+notify-send "smooooth" "config change detected. waiting for blockers to resolve.."
+while scrapePids; do
+  echo "found blocker in $SACRED_SPACE, waiting.."
+  sleep $PERIOD
+done
+
+echo "building system"
+notify-send "smooooth" "rebuilding your nixos config - please stand by"
+temp="$(mktemp -d)"
+build="$temp/system"
+nix build --out-link $build $SACRED_SPACE#nixosConfigurations.$HOSTNAME.config.system.build.toplevel
+
+echo "built - attempting to activate system"
+notify-send "smooooth" "activating your new config"
+switch="$(readlink $build)/bin/switch-to-configuration"
+pkexec $switch switch
+
+echo "cleaning up"
+rm -r $temp
+