{
  description = "InvenTree App Development Environment - CTBK";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    flake-utils.url = "github:numtide/flake-utils";
    nixpkgs-flutter.url = "github:NixOS/nixpkgs/b9c03fbbaf84d85bb28eee530c7e9edc4021ca1b";
  };

  outputs =
    {
      self,
      nixpkgs,
      flake-utils,
      nixpkgs-flutter,
    }:
    flake-utils.lib.eachDefaultSystem (
      system:
      let

        pkgs = import nixpkgs {
          inherit system;
          config = {
            allowUnfree = true;
            android_sdk.accept_license = true;
          };
          overlays = [
            (final: prev: {
              flutter-pkg = import (self.inputs.nixpkgs-flutter) { inherit system; };
            })
          ];
        };

        androidSdk =
          (pkgs.androidenv.composeAndroidPackages {
            platformVersions = [
              "36"
              "35"
              "34"
            ];
            buildToolsVersions = [
              "36.0.0"
              "34.0.0"
            ];
            includeEmulator = true;
            includeNDK = true;
            ndkVersions = [ "26.1.10909125" ];
            cmakeVersions = [
              "3.31.6"
              "3.22.1"
            ];
          }).androidsdk;

        # FVM wrapper for NixOS - maps fvm commands to Nix-managed Flutter
        fvm-wrapper = pkgs.writeShellScriptBin "fvm" ''
          case "$1" in
            use)
              # 'fvm use' is a no-op on NixOS since Flutter is version-managed by Nix
              echo "✓ Using Flutter from Nix ($(flutter --version | head -n1))"
              exit 0
              ;;
            flutter)
              # 'fvm flutter ...' becomes 'flutter ...'
              shift
              exec flutter "$@"
              ;;
            *)
              echo "fvm wrapper: command '$1' not implemented (using Nix-managed Flutter)" >&2
              exit 1
              ;;
          esac
        '';
      in
      {
        devShells.default = pkgs.mkShell {
          buildInputs =
            with pkgs;
            [
              # Mobile development
              pkgs.flutter-pkg.flutter
              fvm-wrapper
              jdk17

              # Build tools
              android-tools
              gradle

              # Python & task runner
              python3
              python3Packages.invoke
              jq

              # System dependencies for Flutter on Linux
              git
              curl
              unzip
              which
            ]
            ++ lib.optionals stdenv.isLinux [
              gtk3
              glib
              pcre
              libepoxy
              libxkbcommon
              dbus
              at-spi2-core
              file
            ];

          shellHook = ''
            export ANDROID_HOME="${androidSdk}/libexec/android-sdk"
            export ANDROID_SDK_ROOT="$ANDROID_HOME"
            export PATH="$ANDROID_HOME/platform-tools:$ANDROID_HOME/tools/bin:$PATH"
            export JAVA_HOME="${pkgs.jdk17}"
            export GRADLE_OPTS="-Dorg.gradle.project.android.aapt2FromMavenOverride=$ANDROID_HOME/build-tools/34.0.0/aapt2"

            echo "🚀 InvenTree App Development Environment - CTBK" 
            echo "📦 Tools: Flutter, FVM, JDK17, Android SDK"
            echo "📋 Run: invoke android  # Build Android app"
          '';

          LD_LIBRARY_PATH = pkgs.lib.makeLibraryPath (
            with pkgs;
            [
              gtk3
              glib
              pcre
              libepoxy
              libxkbcommon
              dbus
              at-spi2-core
            ]
          );
        };
      }
    );
}