# This shouldn't be a part of the foodogsquared's library set. These are simply
# environment builders used to build consistent environments throughout flake-
# and non-flake-based Nix environments. Much of the things here are unofficial
# and basically redoing what the upstream projects are doing so maintenance is
# pretty much higher here.
#
# Anyways, all we're doing here is to see how much of a pain to use those Nix
# projects especially those that are entirely relying on flakes.
#
# Despite named similarly to npins `sources` convention, it should also work
# for flake-based setups as long as the inputs attrset from the flake output
# function is the one that is passed.
{ lib, foodogsquaredLib, sources }:

let
  # A set of nixos-generators modules including our custom ones.
  nixosGeneratorModules = let
    officialFormats = builtins.readDir "${sources.nixos-generators}/formats";
    unofficialFormats = builtins.readDir ../modules/nixos-generators;
    formats = officialFormats // unofficialFormats;
  in lib.mapAttrs' (n: _:
    lib.nameValuePair (lib.removeSuffix ".nix" n) {
      imports = [
        "${sources.nixos-generators}/format-module.nix"
        (if (lib.hasAttr n officialFormats) then
          "${sources.nixos-generators}/formats/${n}"
        else
          "${../modules/nixos-generators}/${n}")
      ];
    }) formats;
in rec {
  mkNixosSystem =
    { pkgs, lib ? pkgs.lib, system, extraModules ? [ ], specialArgs ? { }, }:
    let
      nixosModules = ../modules/nixos;

      # Evaluating the system ourselves (which is trivial) instead of relying
      # on nixpkgs.lib.nixosSystem flake output.
      nixosSystem = args: import "${pkgs.path}/nixos/lib/eval-config.nix" args;
    in (lib.makeOverridable nixosSystem) {
      inherit pkgs;
      specialArgs = specialArgs // {
        foodogsquaredUtils = import ./utils/nixos.nix { inherit lib; };
        foodogsquaredModulesPath = builtins.toString nixosModules;
      };
      modules = extraModules ++ [
        nixosModules
        ../modules/nixos/_private
        ({ lib, ... }: { nixpkgs.hostPlatform = lib.mkForce system; })
      ];

      # Since we're setting it through nixpkgs.hostPlatform, we'll have to pass
      # this as null.
      system = null;
    };

  # A very very thin wrapper around `mkNixosSystem` to build with the given format.
  mkNixosImage = { pkgs, system, lib ? pkgs.lib, extraModules ? [ ]
    , specialArgs ? { }, format ? "iso", }:
    let
      extraModules' = extraModules ++ [ nixosGeneratorModules.${format} ];
      nixosSystem = mkNixosSystem {
        inherit pkgs lib system specialArgs;
        extraModules = extraModules';
      };
    in nixosSystem.config.system.build.${nixosSystem.config.formatAttr};

  mkHome =
    { pkgs, homeManagerSrc, lib ? pkgs.lib, modules ? [ ], specialArgs ? { }, }:
    let homeModules = ../modules/home-manager;
    in import "${homeManagerSrc}/modules" {
      inherit pkgs lib;
      check = true;
      extraSpecialArgs = specialArgs // {
        foodogsquaredModulesPath = builtins.toString homeModules;
      };
      configuration = { lib, ... }: {
        imports = modules ++ [ homeModules ../modules/home-manager/_private ];

        config = {
          programs.home-manager.path = homeManagerSrc;
          inherit (pkgs) overlays;
          nixpkgs.config = lib.mkDefault pkgs.config;
        };
      };
    };

  mkWrapper = { pkgs, lib ? pkgs.lib, wrapperManagerSrc, modules ? [ ]
    , specialArgs ? { }, }:
    let
      wrapperManagerModules = ../modules/wrapper-manager;
      wrapperManager = import wrapperManagerSrc { };
    in wrapperManager.lib.build {
      inherit pkgs lib;
      specialArgs = specialArgs // {
        foodogsquaredModulesPath = builtins.toString wrapperManagerModules;
      };
      modules = modules
        ++ [ wrapperManagerModules ../modules/wrapper-manager/_private ];
    };
}
