build(flake): split into flake modules

flake.nix

@@ -16,7 +16,6 @@
 
   outputs = inputs @ {
     flake-parts,
-    crate2nix,
     rust-overlay,
     ...
   }:
@@ -28,33 +27,22 @@
         "x86_64-linux"
       ];
 
+      imports = [
+        ./nix/wasm-bindgen.nix
+        ./nix/wordle-solver.nix
+        ./nix/wordle-solver-wasm.nix
+        ./nix/wordle-solver-wasm-pkg.nix
+        ./nix/wordle-solver-web.nix
+      ];
+
       perSystem = {
         pkgs,
         system,
         self',
         ...
       }: let
-        # Use rust-bin to generate the toolchain from rust-toolchain.toml
-        rust-toolchain = pkgs.rust-bin.fromRustupToolchainFile ./rust-toolchain.toml;
-
-        cross-pkgs = pkgs.pkgsCross.wasm32-unknown-none;
-
-        toolchain = pkgs.callPackage ./nix/with-toolchain.nix {
-          cargo = rust-toolchain;
-          rustc = rust-toolchain;
-        };
-        crossToolchain = cross-pkgs.callPackage ./nix/with-toolchain.nix {
-          cargo = rust-toolchain;
-          rustc = rust-toolchain;
-        };
-
-        wasm-bindgen = toolchain.pkgs.callPackage ./nix/wasm-bindgen.nix {};
-
-        root-crate = pkgs.callPackage ./nix/root-crate.nix {
-          cargo = rust-toolchain;
-          rustc = rust-toolchain;
-          inherit crate2nix;
-        };
+        utils = import ./nix/utils.nix;
+        rust-toolchain = utils.rust-toolchain pkgs;
       in {
         # Overlay pkgs with rust-bin
         _module.args.pkgs = import inputs.nixpkgs {
@@ -63,22 +51,13 @@
           config.allowUnsupportedSystem = true;
         };
 
-        packages = {
-          wordle-solver-web = pkgs.callPackage ./nix/wordle-solver-web.nix {inherit (self'.packages) wordle-solver-wasm-pkg;};
-          wordle-solver-wasm = crossToolchain.pkgs.callPackage ./nix/wordle-solver-wasm.nix {};
-          wordle-solver-wasm-pkg = pkgs.callPackage ./nix/wordle-solver-wasm-pkg.nix {
-            inherit wasm-bindgen root-crate;
-            inherit (self'.packages) wordle-solver-wasm;
-          };
-          wordle-solver = root-crate.build;
-          default = self'.packages.wordle-solver;
-        };
+        packages.default = self'.packages.wordle-solver;
 
         devShells.default = pkgs.mkShell {
           RA_LOG = "rust_analyzer=info";
           buildInputs = [
             rust-toolchain
-            wasm-bindgen
+            self'.packages.wasm-bindgen
             pkgs.nodejs
             pkgs.svelte-language-server
             pkgs.typescript-language-server