{
  description = "My NixOS Configurations Flake";

  inputs = {
    # Source: https://github.com/NixOS/nixpkgs
    nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
    nixpkgs-old.url = "github:nixos/nixpkgs/nixos-24.11";
    nixpkgs-latest.url = "github:nixos/nixpkgs";

    # Source: https://github.com/nix-community/home-manager
    home-manager = {
      url = "github:nix-community/home-manager";
      inputs.nixpkgs.follows = "nixpkgs";
    };

    # Source: https://github.com/NixOS/nixos-hardware
    nixos-hardware.url = "github:nixos/nixos-hardware";

    # Source: https://github.com/Mic92/sops-nix
    sops-nix.url = "github:mic92/sops-nix";

    # Source: https://github.com/nix-community/nix-vscode-extensions
    nix-vscode-extensions.url = "github:nix-community/nix-vscode-extensions";

    # Source: https://github.com/catppuccin/nix
    catppuccin.url = "github:catppuccin/nix";

    # Source: https://github.com/helix-editor/helix
    helix.url = "github:helix-editor/helix";

    # Source: https://github.com/zedless-editor/zedless
    zedless-editor.url = "github:zedless-editor/zedless";
  };

  outputs =
    {
      nixpkgs,
      nixpkgs-old,
      nixpkgs-latest,
      ...
    }@inputs:
    let
      makeConfig = import ./lib/config.nix {
        inherit
          inputs
          nixpkgs
          nixpkgs-old
          nixpkgs-latest
          ;
      };
    in
    {
      nixosConfigurations.template-hostname = makeConfig "thinkbook" {
        hostName = "template-hostname";
        userName = "template";
        additionalOverlays = [ inputs.nix-vscode-extensions.overlays.default ];
        systemArch = "x86_64-linux";
      };

      nixosConfigurations.book = makeConfig "thinkbook" {
        hostName = "book";
        userName = "geekiot";
        additionalOverlays = [ inputs.nix-vscode-extensions.overlays.default ];
        systemArch = "x86_64-linux";
      };
    };
}