refactor: use flake instead of devbox (#45)

* refactor: remove devbox

* chore: remove rust-toolchain

* chore: init devenv

* fix(devenv): fix typo

* fix(devenv): set root

* fix(devenv): fix imports

* fix(ci): add rust-toolchain

* fix(devenv): add fenix

* fix: use nightly rust

.envrc

@@ -1,7 +1 @@
-# Automatically sets up your devbox environment whenever you cd into this
-# directory via our direnv integration:
-
-eval "$(devbox generate direnv --print-envrc)"
-
-# check out https://www.jetpack.io/devbox/docs/ide_configuration/direnv/
-# for more details
+use flake . --override-input devenv-root "file+file://"<(printf %s "$PWD")

.gitignore

@@ -23,5 +23,6 @@ target/
 # mdBook
 docs/book
 
-# devbox
-.devbox
+# direnv / devenv
+.direnv
+.devenv

devenv.nix

@@ -0,0 +1,32 @@
+# https://devenv.sh/basics/
+{ lib, pkgs, ... }:
+let rust_toolchain = lib.importTOML ./rust-toolchain.toml;
+in {
+  name = "hatsu";
+
+  # https://devenv.sh/languages/
+  languages.rust = {
+    enable = true;
+    channel = rust_toolchain.toolchain.channel;
+    components = rust_toolchain.toolchain.components;
+  };
+
+  imports = [
+    # This is just like the imports in devenv.nix.
+    # See https://devenv.sh/guides/using-with-flake-parts/#import-a-devenv-module
+    # ./devenv-foo.nix
+  ];
+
+  # https://devenv.sh/packages/
+  packages = with pkgs; [
+    # cargo-*
+    cargo-watch
+
+    mold
+    sccache
+  ];
+
+  # enterShell = ''
+  #   hello
+  # '';
+}