refactor: rebuild app skeleton

Create skeleton for a complete rebuild of the prototype as a production
ready product.

Includes design patterns for:
 - dependency injection
 - unit testing with dependency mocking
 - integration testing
 - error handling
 - config storage

BREAKING-CHANGE: ground-up redesign with incompatible protocol standards

1 files changed, 52 insertions, 0 deletions

diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..7c36e2d
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,52 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    rust-overlay.url = "github:oxalica/rust-overlay";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, rust-overlay, flake-utils, ... }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        overlays = [ (import rust-overlay) ];
+        pkgs = import nixpkgs {
+          inherit system overlays;
+        };
+      in
+      with pkgs;
+      {
+        devShells.default = mkShell {
+
+          nativeBuildInputs = [
+            # stable to be introduced when the following issue is resolved
+            # https://github.com/oxalica/rust-overlay/issues/136
+            # rust-bin.stable.latest.default
+            # nightly for rustfmt
+            (
+              rust-bin.selectLatestNightlyWith (toolchain: toolchain.default.override {
+                extensions = [
+                  "rust-src"
+                  "rustfmt"
+                  "clippy"
+                ];
+              })
+            )
+          ];
+
+          buildInputs = [
+            rust-analyzer
+            gitlint
+          ];
+          shellHook = ''
+            # auto-install git hooks
+            dot_git="$(git rev-parse --git-common-dir)"
+            if [[ ! -d "$dot_git/hooks" ]]; then mkdir "$dot_git/hooks"; fi
+            for hook in git_hooks/* ; do ln -sf "$(pwd)/$hook" "$dot_git/hooks/" ; done
+
+            # For rust-analyzer 'hover' tooltips to work.
+            export RUST_SRC_PATH=${pkgs.rustPlatform.rustLibSrc}
+          '';
+        };
+      }
+    );
+}