{
  description = "Portable NixOS + Home Manager configuration with sops secrets and disko";

  inputs = {
    # Core
    nixpkgs.url = "github:nixos/nixpkgs/nixos-24.11";
    nixpkgs-unstable.url = "github:nixos/nixpkgs/nixos-unstable";

    # Flakes
    flake-utils.url = "github:numtide/flake-utils";

    # Home Manager
    home-manager = {
      url = "github:nix-community/home-manager/release-24.11";
      inputs.nixpkgs.follows = "nixpkgs";
    };

    # Secrets management
    sops-nix = {
      url = "github:mic92/sops-nix";
      inputs.nixpkgs.follows = "nixpkgs";
    };

    # Disk partitioning
    disko = {
      url = "github:nix-community/disko";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs = { self, nixpkgs, nixpkgs-unstable, flake-utils, home-manager, sops-nix, disko }:
    let
      system = "x86_64-linux";

      pkgs = import nixpkgs {
        inherit system;
        config.allowUnfree = true;
      };

      pkgs-unstable = import nixpkgs-unstable {
        inherit system;
        config.allowUnfree = true;
      };

      # Utility to overlay unstable packages
      overlayUnstable = final: prev: {
        unstable = pkgs-unstable;
      };

    in {

      # ============================================
      # NixOS System Configurations
      # ============================================

      nixosConfigurations = {

        # Example: Laptop configuration
        laptop = nixpkgs.lib.nixosSystem {
          inherit system;

          specialArgs = {
            inherit sops-nix disko;
            pkgs-unstable = pkgs-unstable;
          };

          modules = [
            overlayUnstable
            sops-nix.nixosModules.sops
            disko.nixosModules.disko

            # Machine-specific config
            ./hosts/laptop/default.nix

            # Shared system modules
            ./nixos/default.nix

            # Home Manager integration
            home-manager.nixosModules.home-manager
            {
              home-manager.useGlobalPkgs = true;
              home-manager.useUserPackages = true;
              home-manager.extraSpecialArgs = {
                inherit sops-nix pkgs-unstable;
              };
              home-manager.users.youruser = import ./home/default.nix;
            }
          ];
        };

        # Example: Server configuration
        server = nixpkgs.lib.nixosSystem {
          inherit system;

          specialArgs = {
            inherit sops-nix disko;
            pkgs-unstable = pkgs-unstable;
          };

          modules = [
            overlayUnstable
            sops-nix.nixosModules.sops
            disko.nixosModules.disko

            ./hosts/server/default.nix
            ./nixos/default.nix

            home-manager.nixosModules.home-manager
            {
              home-manager.useGlobalPkgs = true;
              home-manager.useUserPackages = true;
              home-manager.extraSpecialArgs = {
                inherit sops-nix pkgs-unstable;
              };
              home-manager.users.youruser = import ./home/default.nix;
            }
          ];
        };
      };

      # ============================================
      # Home Manager Standalone (Non-NixOS systems)
      # ============================================

      homeConfigurations = {
        "youruser@linux" = home-manager.lib.homeManagerConfiguration {
          inherit pkgs;
          extraSpecialArgs = {
            pkgs-unstable = pkgs-unstable;
            sops-nix = sops-nix;
          };
          modules = [
            overlayUnstable
            ./home/default.nix
          ];
        };
      };

      # ============================================
      # Development Shell
      # ============================================

      devShells.${system}.default = pkgs.mkShell {
        buildInputs = with pkgs; [
          nix
          nixpkgs-fmt
          sops
          age
          disko
          git
        ];

        shellHook = ''
          echo "🔧 NixOS Configuration Development Shell"
          echo "Available commands:"
          echo "  - nix flake check              # Check flake validity"
          echo "  - nix flake show               # Show all outputs"
          echo "  - sudo nixos-rebuild switch --flake .#hostname"
          echo "  - home-manager switch --flake .#youruser@linux"
          echo "  - sops secrets/secrets.yaml    # Edit encrypted secrets"
        '';
      };

      # ============================================
      # Installer Script
      # ============================================

      apps.${system}.installer = {
        type = "app";
        program = toString (pkgs.writeShellScript "installer" ''
          set -e

          if [ -z "$1" ]; then
            echo "Usage: nix run .#installer -- <hostname>"
            echo "Example: nix run .#installer -- laptop"
            exit 1
          fi

          HOSTNAME=$1

          echo "🚀 Bootstrapping NixOS: $HOSTNAME"

          # Check if on NixOS
          if [ -f /etc/os-release ]; then
            . /etc/os-release
            if [ "$ID" = "nixos" ]; then
              echo "✓ Running on NixOS"
              sudo nixos-rebuild switch --flake ".#$HOSTNAME"
              echo "✓ NixOS system configured"
            else
              echo "⚠ Not on NixOS - installing home-manager only"
              home-manager switch --flake ".#youruser@linux"
              echo "✓ Home manager configured"
            fi
          else
            echo "⚠ Cannot determine OS"
            exit 1
          fi
        '');
      };

    };
}