feat(nix): create a flake (ChrisTitusTech#1154)

turns out i use nixos now so this will make the development process
wayyyy easier for me

you can now build linutil for nix with `nix build`, enter the dev
environment with `nix develop`, and format nix code with `nix fmt`

and if some crazy person was to use linutil on nixos, now they can with
`nix run github:ChrisTitusTech/linutil` or by adding linutil to their
flake

Author: koibtw

.gitignore

@@ -1,5 +1,6 @@
 /target
 /build
+/result
 rust/target
 rust/build
 /build/linutil

flake.lock

@@ -0,0 +1,27 @@
+{
+  description = "Distro-agnostic toolbox designed to simplify everyday Linux tasks";
+
+  inputs.nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
+
+  outputs =
+    { self, nixpkgs }:
+    let
+      systems = [
+        "x86_64-linux"
+        "aarch64-linux"
+      ];
+
+      forAllSystems = f: nixpkgs.lib.genAttrs systems (system: f nixpkgs.legacyPackages.${system});
+    in
+    {
+      packages = forAllSystems (pkgs: {
+        default = pkgs.callPackage ./nix/default.nix { };
+      });
+
+      devShells = forAllSystems (pkgs: {
+        default = pkgs.callPackage ./nix/shell.nix { inherit pkgs; };
+      });
+
+      formatter = forAllSystems (pkgs: pkgs.nixfmt-tree);
+    };
+}

flake.nix

@@ -0,0 +1,25 @@
+{
+  lib,
+  rustPlatform,
+}:
+
+let
+  p = (lib.importTOML ../Cargo.toml).workspace.package;
+  pTUI = (lib.importTOML ../tui/Cargo.toml).package;
+in
+rustPlatform.buildRustPackage {
+  pname = "linutil";
+  inherit (p) version;
+
+  src = ../.;
+
+  cargoLock.lockFile = ../Cargo.lock;
+
+  meta = {
+    inherit (pTUI) description;
+    homepage = pTUI.documentation;
+    license = lib.licenses.mit;
+    maintainers = with lib.maintainers; [ adamperkowski ];
+    mainProgram = "linutil";
+  };
+}

nix/default.nix

@@ -0,0 +1,31 @@
+{ pkgs }:
+
+let
+  mainPkg = if builtins.pathExists ./default.nix then pkgs.callPackage ./default.nix { } else { };
+
+  pkgInputs =
+    with pkgs;
+    [
+      clippy
+      rustfmt
+      rust-analyzer
+      bash-language-server
+      checkbashisms
+      shellcheck
+      typos
+      vhs
+    ]
+    ++ (mainPkg.nativeBuildInputs or [ ])
+    ++ (mainPkg.buildInputs or [ ]);
+in
+pkgs.mkShell {
+  packages = pkgInputs;
+
+  shellHook = ''
+    echo -ne "-----------------------------------\n "
+
+    echo -n "${toString (map (pkg: "• ${pkg.name}\n") pkgInputs)}"
+
+    echo "-----------------------------------"
+  '';
+}