chore: packaging hac as nix flake

Cargo.toml

@@ -3,6 +3,12 @@ members = ["hac-config", "hac-core", "hac-client", "hac-colors", "hac-cli"]
 default-members = ["hac-client"]
 resolver = "2"
 
+[workspace.metadata.crane]
+name = "hac"
+
+[workspace.package]
+version = "0.1.0"
+
 [workspace.dependencies]
 hac-config = { path = "hac-config" }
 hac-core = { path = "hac-core" }

flake.nix

@@ -0,0 +1,75 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+    crane = {
+      url = "github:ipetkov/crane";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+  outputs = {
+    nixpkgs,
+    rust-overlay,
+    crane,
+    ...
+  }: let
+    inherit (nixpkgs) lib;
+    withSystem = f:
+      lib.fold lib.recursiveUpdate {}
+      (map f ["x86_64-linux" "x86_64-darwin" "aarch64-linux" "aarch64-darwin"]);
+  in
+    withSystem (
+      system: let
+        pkgs = import nixpkgs {
+          inherit system;
+          overlays = [rust-overlay.overlays.default];
+        };
+        inherit (pkgs) stdenv lib;
+        toolchain = pkgs.rust-bin.fromRustupToolchainFile ./rust-toolchain.toml;
+        craneLib = (crane.mkLib pkgs).overrideToolchain toolchain;
+        buildDeps =
+          [pkgs.openssl]
+          ++ lib.optionals stdenv.isDarwin (with pkgs.darwin.apple_sdk.frameworks; [
+            SystemConfiguration
+          ]);
+        crate = craneLib.buildPackage {
+          # Filter src to only .rs, .toml, and .scm files to avoid needless recompiles
+          src = let
+            schemeFilter = path: _type: builtins.match ".*scm$" path != null;
+            schemeOrCargo = path: type:
+              (schemeFilter path type) || (craneLib.filterCargoSources path type);
+          in
+            lib.cleanSourceWith {
+              src = craneLib.path ./.;
+              filter = schemeOrCargo;
+            };
+          strictDeps = true;
+          buildInputs = buildDeps;
+          nativeBuildInputs = lib.optionals stdenv.isLinux [pkgs.pkg-config];
+          doNotSign = stdenv.isDarwin; # Build seems to break when this is true on Darwin
+        };
+      in {
+        apps.${system}.default = let
+          name = crate.pname or crate.name;
+          exe = crate.passthru.exePath or "/bin/${name}";
+        in {
+          type = "app";
+          program = "${crate}${exe}";
+        };
+        packages.${system}.default = crate;
+        checks.${system} = {inherit crate;};
+        devShells.${system}.default = pkgs.mkShell {
+          packages = with pkgs;
+            [
+              toolchain
+              rust-analyzer-unwrapped
+            ]
+            ++ buildDeps;
+          RUST_SRC_PATH = "${toolchain}/lib/rustlib/src/rust/library";
+        };
+      }
+    );
+}

rust-toolchain.toml

@@ -0,0 +1,4 @@
+[toolchain]
+channel = "stable"
+components = ["rust-src"]
+profile = "default"