Add nix

.envrc

@@ -0,0 +1 @@
+use flake

.gitignore

@@ -20,3 +20,4 @@ app/src/main/res/drawable/
 app/release
 app/src/main/ic_launcher-playstore.png
 app/src/main/res/
+.direnv/

flake.nix

@@ -0,0 +1,36 @@
+{
+  description = "BranchLinkSimulatorAndroid flake";
+  inputs = {
+    branch-nix.url = "git+ssh://[email protected]/BranchMetrics/nix";
+  };
+
+  outputs = { self, branch-nix }:
+    let
+      nixpkgs = branch-nix.nixpkgs;
+      extra-pkgs = branch-nix.packages;
+      utils = branch-nix.utils;
+      system-utils = branch-nix.system-utils;
+    in
+    utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system} // {
+          extra-pkgs = extra-pkgs.${system};
+        };
+        jdk = pkgs.openjdk21;
+      in
+      {
+        devShell = pkgs.mkShell {
+          nativeBuildInputs = [
+            jdk
+          ];
+          JAVA_HOME = "${jdk}";
+          shellHook = ''
+              if [ -f $HOME/.config/bin/setup-intellij-jdk ] && [ -f ./.idea/misc.xml ]; then
+                $HOME/.config/bin/setup-intellij-jdk || echo "setup-intellij-jdk failed"
+              fi
+          '';
+        };
+        formatter = pkgs.nixpkgs-fmt;
+      }
+    );
+}