{
  stdenv,
  stdenvNoCC,
  gccStdenv,
  lib,
  recurseIntoAttrs,
  libsForQt5,
  newScope,
  perlPackages,
}:

# To whomever it may concern:
#
# This directory menaces with spikes of Nix code. It is terrifying.
#
# If this is your first time here, you should probably install the dwarf-fortress-full package,
# for instance with:
#
# environment.systemPackages = [ pkgs.dwarf-fortress-packages.dwarf-fortress-full ];
#
# You can adjust its settings by using override, or compile your own package by
# using the other packages here.
#
# For example, you can enable the FPS indicator, disable the intro, pick a
# theme other than phoebus (the default for dwarf-fortress-full), _and_ use
# an older version with something like:
#
# environment.systemPackages = [
#   (pkgs.dwarf-fortress-packages.dwarf-fortress-full.override {
#      dfVersion = "0.44.11";
#      theme = "cla";
#      enableIntro = false;
#      enableFPS = true;
#   })
# ]
#
# Take a look at lazy-pack.nix to see all the other options.
#
# You will find the configuration files in ~/.local/share/df_linux/data/init. If
# you un-symlink them and edit, then the scripts will avoid overwriting your
# changes on later launches, but consider extending the wrapper with your
# desired options instead.

let
  inherit (lib)
    attrNames
    getAttr
    importJSON
    listToAttrs
    optionalAttrs
    recurseIntoAttrs
    replaceStrings
    versionAtLeast
    ;

  callPackage = newScope self;

  # The latest Dwarf Fortress version. Maintainers: when a new version comes
  # out, ensure that (unfuck|dfhack|twbt) are all up to date before changing
  # this. Note that unfuck and twbt are not required for 50.
  latestVersion =
    self.dfVersions.game.latest.${
      if stdenv.hostPlatform.isLinux then
        "linux"
      else if stdenv.hostPlatform.isDarwin then
        "darwin"
      else
        throw "Unsupported system"
    };

  # Converts a version to a package name.
  versionToName = version: "dwarf-fortress_${replaceStrings [ "." ] [ "_" ] version}";

  # A map of names to each Dwarf Fortress package we know about.
  df-games = listToAttrs (
    map (dfVersion: {
      name = versionToName dfVersion;
      value =
        let
          isAtLeast50 = versionAtLeast dfVersion "50.0";

          dwarf-fortress-unfuck = optionalAttrs (!isAtLeast50 && stdenv.hostPlatform.isLinux) (
            callPackage ./unfuck.nix { inherit dfVersion; }
          );

          dwarf-fortress = callPackage ./game.nix {
            inherit dfVersion;
            inherit dwarf-fortress-unfuck;
          };

          twbt = optionalAttrs (!isAtLeast50) (callPackage ./twbt { inherit dfVersion; });

          dfhack = callPackage ./dfhack {
            inherit (perlPackages) XMLLibXML XMLLibXSLT;
            inherit dfVersion;
            stdenv = gccStdenv;
          };

          mkDfWrapper =
            {
              dwarf-fortress,
              dfhack,
              dwarf-therapist ? null,
              ...
            }@args:
            callPackage ./wrapper (
              {
                inherit (self) themes;
                inherit
                  dwarf-fortress
                  twbt
                  dfhack
                  dwarf-therapist
                  ;
              }
              // args
            );

          dwarf-therapist = libsForQt5.callPackage ./dwarf-therapist/wrapper.nix {
            inherit dwarf-fortress dfhack mkDfWrapper;
            dwarf-therapist =
              (libsForQt5.callPackage ./dwarf-therapist {
                inherit (self) dfVersions;
              }).override
                (
                  optionalAttrs (!isAtLeast50) {
                    # 41.2.5 is the last version to support Dwarf Fortress 0.47.
                    version = "41.2.5";
                    maxDfVersion = "0.47.05";
                    hash = "sha256-xfYBtnO1n6OcliVt07GsQ9alDJIfWdVhtuyWwuvXSZs=";
                  }
                );
          };
        in
        mkDfWrapper { inherit dwarf-fortress dfhack dwarf-therapist; };
    }) (attrNames self.dfVersions.game.versions)
  );

  self = rec {
    dfVersions = importJSON ./df.lock.json;

    # Aliases for the latest Dwarf Fortress and the selected Therapist install
    dwarf-fortress = getAttr (versionToName latestVersion) df-games;
    dwarf-therapist = dwarf-fortress.dwarf-therapist;
    dwarf-fortress-original = dwarf-fortress.dwarf-fortress;

    dwarf-fortress-full = callPackage ./lazy-pack.nix {
      inherit df-games versionToName latestVersion;
    };

    soundSense = callPackage ./soundsense.nix { };

    legends-browser = callPackage ./legends-browser { };

    themes = recurseIntoAttrs (
      callPackage ./themes {
        stdenv = stdenvNoCC;
      }
    );

    # Theme aliases
    phoebus-theme = themes.phoebus;
    cla-theme = themes.cla;
  };

in
self // df-games