{ core-inputs
, user-inputs
, snowfall-lib
, snowfall-config
}:

let
  inherit (core-inputs.nixpkgs.lib) assertMsg fix fold filterAttrs callPackageWith;

  core-inputs-libs = snowfall-lib.flake.get-libs (snowfall-lib.flake.without-self core-inputs);
  user-inputs-libs = snowfall-lib.flake.get-libs (snowfall-lib.flake.without-self user-inputs);

  snowfall-top-level-lib = filterAttrs (name: value: !builtins.isAttrs value) snowfall-lib;

  base-lib = snowfall-lib.attrs.merge-shallow [
    core-inputs.nixpkgs.lib
    core-inputs-libs
    user-inputs-libs
    snowfall-top-level-lib
    { snowfall = snowfall-lib; }
  ];

  user-lib-root = snowfall-lib.fs.get-file "lib";
  user-lib-modules = snowfall-lib.fs.get-default-nix-files-recursive user-lib-root;

  user-lib = fix (user-lib:
    let
      attrs = {
        inputs = snowfall-lib.flake.without-snowfall-inputs user-inputs;
        snowfall-inputs = core-inputs;
        lib = snowfall-lib.attrs.merge-shallow [
          base-lib
          { internal = user-lib; }
        ];
      };
      libs = builtins.map
        (path: callPackageWith attrs path { })
        user-lib-modules;
    in
    snowfall-lib.attrs.merge-deep libs
  );

  system-lib = snowfall-lib.attrs.merge-shallow [
    base-lib
    { internal = user-lib; }
  ];
in
{
  internal = {
    inherit system-lib user-lib;
  };
}