snowfall-lib/snowfall-lib/module/default.nix

{
  core-inputs,
  user-inputs,
  snowfall-lib,
  snowfall-config,
}:
let
  inherit (builtins) baseNameOf;
  inherit (core-inputs.nixpkgs.lib)
    foldl
    mapAttrs
    hasSuffix
    isFunction
    splitString
    tail
    ;

  user-modules-root = snowfall-lib.fs.get-snowfall-file "modules";
in
{
  module = {
    ## Create flake output modules.
    ## Example Usage:
    ## ```nix
    ## create-modules { src = ./my-modules; overrides = { inherit another-module; }; alias = { default = "another-module" }; }
    ## ```
    ## Result:
    ## ```nix
    ## { another-module = ...; my-module = ...; default = ...; }
    ## ```
    #@ Attrs -> Attrs
    create-modules =
      {
        src ? "${user-modules-root}/nixos",
        overrides ? { },
        alias ? { },
      }:
      let
        user-modules = snowfall-lib.fs.get-default-nix-files-recursive src;
        create-module-metadata = module: {
          name = snowfall-lib.path.get-relative-module-path src module;
          path = module;
        };
        modules-metadata = builtins.map create-module-metadata user-modules;
        merge-modules =
          modules: metadata:
          modules
          // {
            # NOTE: home-manager *requires* modules to specify named arguments or it will not
            # pass values in. For this reason we must specify things like `pkgs` as a named attribute.
            ${metadata.name} =
              args@{ pkgs, ... }:
              let
                system = args.system or args.pkgs.stdenv.hostPlatform.system;
                target = args.target or system;

                format =
                  let
                    virtual-system-type = snowfall-lib.system.get-virtual-system-type target;
                  in
                  if virtual-system-type != "" then
                    virtual-system-type
                  else if snowfall-lib.system.is-darwin target then
                    "darwin"
                  else
                    "linux";

                # Replicates the specialArgs from Snowfall Lib's system builder.
                modified-args = args // {
                  inherit system target format;
                  virtual = args.virtual or (snowfall-lib.system.get-virtual-system-type target != "");
                  systems = args.systems or { };

                  lib = snowfall-lib.internal.system-lib;

                  inputs = snowfall-lib.flake.without-src user-inputs;
                  namespace = snowfall-config.namespace;
                };
                imported-user-module = import metadata.path;
                user-module =
                  if isFunction imported-user-module then
                    imported-user-module modified-args
                  else
                    imported-user-module;
              in
              user-module // { _file = metadata.path; };
          };
        modules = snowfall-lib.attrs.merge-with-aliases merge-modules modules-metadata alias // overrides;
      in
      modules;
  };
}