{ lib, pkgs, ... }@attrs:
let
  osConfig = attrs.osConfig or null;
  inherit (lib) types;
  fromOs =
    let
      get =
        path: set:
        if path == [ ] then set else get (builtins.tail path) (builtins.getAttr (builtins.head path) set);
    in
    path: default: if osConfig == null then default else get path osConfig;
  fromConfig = path: default: fromOs ([ "jconfig" ] ++ path) default;

  mkExtraPackagesOption =
    name: defaultPkgsPath:
    let
      text = lib.strings.concatMapStringsSep " " (
        pkgPath: "pkgs." + (lib.strings.concatStringsSep "." pkgPath)
      ) defaultPkgsPath;
      defaultText = lib.literalExpression "[ ${text} ]";
      default = builtins.map (pkgPath: lib.attrsets.getAttrFromPath pkgPath pkgs) defaultPkgsPath;
    in
    lib.mkOption {
      description = "Extra ${name} Packages.";
      type = types.listOf types.package;
      inherit default defaultText;
      example = [ ];
    };

  identity.options = {
    email = lib.mkOption {
      description = "Primary email address";
      type = types.str;
      example = "email@example.org";
    };
    name = lib.mkOption {
      description = "The default name you use.";
      type = types.str;
      example = "John Doe";
    };
    signingKey = lib.mkOption {
      description = "The signing key programs should use (i.e. git).";
      type = types.nullOr types.str;
      default = null;
      example = "F016B9E770737A0B";
    };
    encryptionKey = lib.mkOption {
      description = "The encryption key programs should use (i.e. pass).";
      type = types.nullOr types.str;
      default = null;
      example = "F016B9E770737A0B";
    };
  };

  user.options = {
    enable = lib.mkEnableOption "Jalil's default user configuration";
    gpg = lib.mkOption {
      description = "GnuPG Configuration.";
      default = { };
      type = types.submodule {
        options.unlockKeys = lib.mkOption {
          description = "Keygrips of keys to unlock through `pam-gnupg` when logging in.";
          default = [ ];
          example = [ "6F4ABB77A88E922406BCE6627AFEEE2363914B76" ];
          type = types.listOf types.str;
        };
      };
    };
    defaultIdentity = lib.mkOption {
      description = "The default identity to use in things like git.";
      type = types.submodule identity;
    };
  };

  tempInfo.options.hwmon-path = lib.mkOption {
    description = "Path to the hardware sensor whose temperature to monitor.";
    type = types.str;
    example = "/sys/class/hwmon/hwmon2/temp1_input";
  };

  sway.options = {
    enable = lib.mkEnableOption "sway" // {
      default = fromConfig [
        "gui"
        "sway"
      ] true;
    };
    background = lib.mkOption {
      description = "The wallpaper to use.";
      type = types.path;
      default =
        fromConfig
          [
            "styling"
            "wallpaper"
          ]
          (
            builtins.fetchurl {
              url = "https://raw.githubusercontent.com/lunik1/nixos-logo-gruvbox-wallpaper/d4937c424fad79c1136a904599ba689fcf8d0fad/png/gruvbox-dark-rainbow.png";
              sha256 = "036gqhbf6s5ddgvfbgn6iqbzgizssyf7820m5815b2gd748jw8zc";
            }
          );
    };
    autostart = lib.mkOption {
      description = ''
        Autostart Sway when logging in to /dev/tty1.

        This will make it so `exec sway` is run when logging in to TTY1, if
        you want a non-graphical session (ie. your GPU drivers are broken)
        you can switch TTYs when logging in by using CTRL+ALT+F2 (for TTY2,
        F3 for TTY3, etc).
      '';
      type = types.bool;
      default = true;
      example = false;
    };
    exec = lib.mkOption {
      description = "Run commands when starting sway.";
      default = { };
      type = types.submodule {
        options = {
          once = lib.mkOption {
            description = "Programs to start only once (`exec`).";
            type = types.listOf types.str;
            default = [ ];
            example = [ "signal-desktop --start-in-tray" ];
          };
          always = lib.mkOption {
            description = "Programs to start whenever the config is sourced (`exec_always`).";
            type = types.listOf types.str;
            default = [ ];
            example = [ "signal-desktop --start-in-tray" ];
          };
        };
      };
    };
  };

  gui.options = {
    enable = lib.mkEnableOption "GUI applications" // {
      default = fromConfig [
        "gui"
        "enable"
      ] false;
    };
    tempInfo = lib.mkOption {
      description = "Temperature info to display in the statusbar.";
      default = null;
      type = types.nullOr (types.submodule tempInfo);
    };
    sway = lib.mkOption {
      description = "Sway window manager configuration.";
      default = { };
      type = types.submodule sway;
    };
    terminal = lib.mkOption {
      description = "The terminal emulator to use.";
      default = "wezterm";
      example = "alacritty";
      type = types.enum [
        "wezterm"
        "alacritty"
      ];
    };
  };
in
{
  options.jhome = lib.mkOption {
    description = "Jalil's default home-manager configuration.";
    default = { };
    type = types.submodule {
      options = {
        enable = lib.mkEnableOption "jalil's home defaults";
        hostName = lib.mkOption {
          description = "The hostname of this system.";
          type = types.str;
          default = fromOs [
            "networking"
            "hostName"
          ] "nixos";
          example = "my pc";
        };
        dev = lib.mkOption {
          description = "Setup development environment for programming languages.";
          default = { };
          type = types.submodule {
            options = {
              enable = lib.mkEnableOption "development settings" // {
                default = fromConfig [
                  "dev"
                  "enable"
                ] false;
              };
              neovimAsManPager = lib.mkEnableOption "neovim as the man pager";
              extraPackages = mkExtraPackagesOption "dev" [
                [ "devenv" ] # a devshell alternative
                [ "jq" ] # json parser
                [ "just" ] # just a command runner
                [ "typos" ] # low false positive rate typo checker
                [ "gcc" ] # GNU Compiler Collection
                [ "git-absorb" ] # fixup! but automatic
                [ "man-pages" ] # gimme the man pages
                [ "man-pages-posix" ] # I said gimme the man pages!!!
              ];
              rust = lib.mkOption {
                description = "Jalil's default rust configuration.";
                default = { };
                type = types.submodule {
                  options.enable = lib.mkEnableOption "rust development settings";
                  options.extraPackages = mkExtraPackagesOption "Rust" [
                    [ "cargo-insta" ] # snapshot testing
                    [ "cargo-nextest" ] # better testing harness
                    [ "cargo-udeps" ] # check for unused dependencies (requires nightly)
                    [ "cargo-watch" ] # watch for file changes and run commands
                  ];
                };
              };
            };
          };
        };
        user = lib.mkOption {
          description = "User settings.";
          default = null;
          type = types.nullOr (types.submodule user);
        };
        gui = lib.mkOption {
          description = "Jalil's default GUI configuration.";
          default = { };
          type = types.submodule gui;
        };
        styling = lib.mkOption {
          description = "My custom styling (uses stylix)";
          default = { };
          type = types.submodule {
            options = {
              enable = lib.mkEnableOption "styling" // {
                default = fromConfig [
                  "styling"
                  "enable"
                ] true;
              };
            };
          };
        };
      };
    };
  };
}