{ lib }:
let
  inherit (lib)
    mkOption
    types
    literalExpression
    ;
  colorType = types.str;

  paletteModule = types.submodule {
    options = {
      type = mkOption {
        type = types.nullOr (
          types.enum [
            "Dark"
            "Light"
            "Full"
          ]
        );
        default = null;
        description = "Color set to use for the palette. Case-sensitive.";
      };
      glyph = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Glyph for the palette. Append a trailing space to separate glyphs.";
      };
      visible = mkOption {
        type = types.nullOr types.bool;
        default = null;
        description = "Whether to show the palette.";
      };
    };
  };

  barModule = types.submodule {
    options = {
      glyph = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Glyph to use for all bars.";
      };
      symbol_open = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Opening delimiter character. Must be a single character.";
      };
      symbol_close = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Closing delimiter character. Must be a single character.";
      };
      visible = mkOption {
        type = types.nullOr types.bool;
        default = null;
        description = "Whether to show bars.";
      };
      hide_delimiters = mkOption {
        type = types.nullOr types.bool;
        default = null;
        description = "Whether to hide bar delimiters.";
      };
    };
  };

  innerMarginModule = types.submodule {
    options = {
      x = mkOption {
        type = types.nullOr types.ints.unsigned;
        default = null;
        description = "Horizontal margin between content and the box border.";
      };
      y = mkOption {
        type = types.nullOr types.ints.unsigned;
        default = null;
        description = "Vertical margin between content and the box border.";
      };
    };
  };

  boxModule = types.submodule {
    options = {
      title = mkOption {
        type = types.nullOr types.str;
        default = null;
        example = "Hydrogen";
        description = "Title displayed on the box. Omitted from config when null.";
      };
      border = mkOption {
        type = types.nullOr (
          types.enum [
            "plain"
            "thick"
            "rounded"
            "double"
          ]
        );
        default = null;
        description = "Border style for the box.";
      };
      visible = mkOption {
        type = types.nullOr types.bool;
        default = null;
        description = "Whether to show the box.";
      };
      inner_margin = mkOption {
        type = types.nullOr innerMarginModule;
        default = null;
        description = "Inner margin between content and the box border.";
      };
    };
  };

  customAsciiModule = types.submodule {
    options = {
      color = mkOption {
        type = types.nullOr colorType;
        default = null;
        example = "Cyan";
        description = ''
          Color of the ASCII art. Omitted when null.
          Accepts hex ("#00FF00"), indexed ("046"), or named colors (e.g. "Green").
        '';
      };
      path = mkOption {
        type = types.nullOr (types.either types.str types.path);
        default = null;
        example = "~/ascii/arch_linux";
        description = "Path to a file containing ASCII art. ANSI escape sequences are supported.";
      };
    };
  };

  randomizeModule = types.submodule {
    options = {
      key_color = mkOption {
        type = types.nullOr types.bool;
        default = null;
        description = "Whether to randomize the key color.";
      };
      separator_color = mkOption {
        type = types.nullOr types.bool;
        default = null;
        description = "Whether to randomize the separator color.";
      };
      pool = mkOption {
        type = types.nullOr (
          types.enum [
            "hexadecimal"
            "indexed"
            "base"
          ]
        );
        default = null;
        description = ''
          Pool of colors to draw from when randomizing. Omitted when null.
          - "hexadecimal": random color #000000–#FFFFFF
          - "indexed": random color 0–255
          - "base": random from black, white, red, green, blue, yellow, magenta, cyan
        '';
      };
    };
  };

  keysModule = types.submodule {
    options = {
      host = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Label for the Host readout.";
      };
      kernel = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Label for the Kernel readout.";
      };
      os = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Label for the OperatingSystem readout.";
      };
      machine = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Label for the Machine readout.";
      };
      de = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Label for the DesktopEnvironment readout.";
      };
      wm = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Label for the WindowManager readout.";
      };
      distro = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Label for the Distribution readout.";
      };
      terminal = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Label for the Terminal readout.";
      };
      shell = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Label for the Shell readout.";
      };
      packages = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Label for the Packages readout.";
      };
      uptime = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Label for the Uptime readout.";
      };
      local_ip = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Label for the LocalIP readout.";
      };
      memory = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Label for the Memory readout.";
      };
      battery = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Label for the Battery readout.";
      };
      backlight = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Label for the Backlight readout.";
      };
      resolution = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Label for the Resolution readout.";
      };
      cpu = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Label for the Processor readout.";
      };
      cpu_load = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Label for the ProcessorLoad readout.";
      };
      gpu = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Label for the GPU readout.";
      };
      disk_space = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Label for the DiskSpace readout.";
      };
    };
  };

  themeModule = types.submodule {
    options = {
      spacing = mkOption {
        type = types.nullOr types.ints.unsigned;
        default = null;
        description = "Spacing between the separator and adjacent content.";
      };
      padding = mkOption {
        type = types.nullOr types.ints.unsigned;
        default = null;
        description = "Padding between content and its surroundings.";
      };
      hide_ascii = mkOption {
        type = types.nullOr types.bool;
        default = null;
        description = "Whether to disable ASCII rendering entirely.";
      };
      prefer_small_ascii = mkOption {
        type = types.nullOr types.bool;
        default = null;
        description = "Always use smaller variants of built-in ASCII art.";
      };
      separator = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Glyph to use as the separator.";
      };
      key_color = mkOption {
        type = types.nullOr colorType;
        default = null;
        example = "Cyan";
        description = ''
          Color of the keys. Omitted when null.
          Accepts hex ("#00FF00"), indexed ("046"), or named colors (e.g. "Cyan").
        '';
      };
      separator_color = mkOption {
        type = types.nullOr colorType;
        default = null;
        example = "White";
        description = ''
          Color of the separator. Omitted when null.
          Accepts hex ("#00FF00"), indexed ("046"), or named colors (e.g. "White").
        '';
      };
      palette = mkOption {
        type = types.nullOr paletteModule;
        default = null;
        description = ''
          Palette section. Displays the active colorscheme of your terminal emulator.
          Omit to exclude the [palette] section entirely.
        '';
      };
      bar = mkOption {
        type = types.nullOr barModule;
        default = null;
        description = ''
          Bar section. Replaces data ranging from 0–100% with visual bars.
          Omit to exclude the [bar] section entirely.
        '';
      };
      box = mkOption {
        type = types.nullOr boxModule;
        default = null;
        description = ''
          Box section. Renders a box around system information.
          Omit to exclude the [box] section entirely.
        '';
      };
      custom_ascii = mkOption {
        type = types.nullOr customAsciiModule;
        default = null;
        description = ''
          Custom ASCII section. Specify your own ASCII art file.
          Omit to exclude the [custom_ascii] section entirely.
        '';
      };
      randomize = mkOption {
        type = types.nullOr randomizeModule;
        default = null;
        description = ''
          Randomize section. Controls random color selection for keys and separators.
          Omit to exclude the [randomize] section entirely.
        '';
      };
      keys = mkOption {
        type = types.nullOr keysModule;
        default = null;
        description = ''
          Keys section. Overrides the display label for each readout.
          Omit to exclude the [keys] section entirely.
        '';
      };
    };
  };
in
{
  themes = mkOption {
    type = types.attrsOf themeModule;
    default = { };
    example = literalExpression ''
      {
        Hydrogen = {
          spacing = 2;
          padding = 0;
          hide_ascii = true;
          separator = ">";
          key_color = "Cyan";
          separator_color = "White";

          palette = {
            type = "Full";
            visible = false;
          };

          bar = {
            glyph = "o";
            symbol_open = "[";
            symbol_close = "]";
            hide_delimiters = true;
            visible = true;
          };

          box = {
            border = "plain";
            visible = true;
            inner_margin = { x = 1; y = 0; };
          };

          randomize = {
            key_color = false;
            separator_color = false;
          };

          keys = {
            host = "Host";
            kernel = "Kernel";
            battery = "Battery";
            os = "OS";
            de = "DE";
            wm = "WM";
            distro = "Distro";
            terminal = "Terminal";
            shell = "Shell";
            packages = "Packages";
            uptime = "Uptime";
            memory = "Memory";
            machine = "Machine";
            local_ip = "Local IP";
            backlight = "Brightness";
            resolution = "Resolution";
            cpu_load = "CPU Load";
            cpu = "CPU";
            gpu = "GPU";
            disk_space = "Disk Space";
          };
        };
      }
    '';
    description = ''
      Attribute set of macchina themes. Each entry is written to
      {file}`$XDG_CONFIG_HOME/macchina/themes/<name>.toml`.

      Theme names are case-sensitive. A theme defined here can be activated
      by setting {option}`programs.macchina.settings.theme` to its name.

      See <https://github.com/Macchina-CLI/macchina/wiki/Customization>
      for details.
    '';
  };
}