{
  description = "NixOS configuration of DerGrumpf";

  # the nixConfig here only affects the flake itself, not the system configuration!
  nixConfig = {
    extra-substituters = [
      "https://nix-community.cachix.org"
      "https://hyprland.cachix.org"
    ];
    extra-trusted-public-keys = [
      "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
      "hyprland.cachix.org-1:a7pgxzMz7+chwVL3/pzj6jIBMioiJM7ypFP8PwtkuGc="
    ];
  };

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

    # Desktop ENV
    hyprland.url = "github:hyprwm/Hyprland";
    hyprland-plugins = {
      url = "github:hyprwm/hyprland-plugins";
      inputs.hyprland.follows = "hyprland";
    };

    # Customization
    spicetify-nix.url = "github:Gerg-L/spicetify-nix";
    nixcord.url = "github:kaylorben/nixcord";
    catppuccin.url = "github:catppuccin/nix";

    # User Config
    home-manager.url = "github:nix-community/home-manager/release-24.11";
    home-manager.inputs.nixpkgs.follows = "nixpkgs";

  };

  outputs =
    inputs@{
      self,
      nixpkgs,
      home-manager,
      catppuccin,
      ...
    }:

    let
      system = "x86_64-linux";

      # Common Configuration
      commonModules = [
        (
          { config, ... }:
          {
            nix.settings = {
              accept-flake-config = true;
              experimental-features = [
                "nix-command"
                "flakes"
              ];
            };
          }
        )
      ];

      commonHomeManagerConfig =
        {
          username,
          monitorSetup ? "single",
        }:
        {
          home-manager = {
            useGlobalPkgs = true;
            useUserPackages = true;
            backupFileExtension = "backup";
            extraSpecialArgs = {
              inherit inputs;
              inherit username monitorSetup;
            };
            users.${username} = import ./users/${username}/home.nix;
            sharedModules = [
              inputs.catppuccin.homeModules.catppuccin
              inputs.nixcord.homeModules.nixcord
            ];
          };
        };

      # System Builder
      mkSystem =
        {
          hostname,
          username,
          system ? "x86_64-linux",
          monitorSetup ? "single",
          extraModules ? [ ],
        }:
        nixpkgs.lib.nixosSystem {
          inherit system;
          specialArgs = {
            inherit inputs;
            inherit username monitorSetup;
          };
          modules =
            commonModules
            ++ [
              ./hosts/${hostname}
              ./users/${username}/nixos.nix
              home-manager.nixosModules.home-manager
              (commonHomeManagerConfig { inherit username monitorSetup; })
            ]
            ++ extraModules;

        };

      # ISO configuration
      isoConfig = nixpkgs.lib.nixosSystem {
        inherit system;
        modules = [
          (import (nixpkgs + "/nixos/modules/installer/cd-dvd/installation-cd-minimal.nix"))
          (
            { pkgs, ... }:
            {
              environment.systemPackages = with pkgs; [
                neovim
                git
                wget
                curl
              ];
              nix.settings.experimental-features = [
                "nix-command"
                "flakes"
              ];
            }
          )
        ];
      };

    in
    {
      packages.${system}.default = self.nixosConfigurations.iso.config.system.build.isoImage;

      nixosConfigurations = {
        iso = isoConfig;

        qemu = mkSystem {
          hostname = "qemu";
          username = "phil";
          monitorSetup = "single";
        };

        m920q = mkSystem {
          hostname = "m920q";
          username = "phil";
          monitorSetup = "dual";
        };

        hp15-n028sg = mkSystem {
          hostname = "hp15-n028sg";
          username = "phil";
          monitorSetup = "dual";
        };

      };
    };
}