{ config, pkgs, lib, ... }:

/*
  This module:
  * provides a central way to change the font my system uses.
*/

with lib;

let cfg = config.kw.theme; in
{
  options.kw.theme = {
    enable = mkEnableOption "kat's theme module";
    css_style = mkOption {
      type = types.enum [ "nested" "compressed" "compact" "expanded" ];
      default = "expanded";
    };
    base16 = mkOption {
      type = types.attrsOf types.str;
    };
    alpha = mkOption {
      type = types.str;
    };
    font = {
      name = mkOption {
        type = types.str;
        default = "Cozette";
      };
      size = mkOption {
        type = types.float;
        default = 9.0;
      };
      size_css = mkOption {
        type = types.str;
        default = "${toString (cfg.font.size + 3)}px";
      };
    };
  };
  config = mkIf (cfg.enable) {
    kw.theme = {
      base16 = lib.mapAttrs' (k: v: lib.nameValuePair k "#${v.hex.rgb}")
      (lib.filterAttrs (n: _: lib.hasInfix "base" n) config.lib.arc.base16.schemeForAlias.default);
      alpha = "80";
    };

    lib.kw.sassTemplate = pkgs.callPackage ({ sass, stdenv }: { name, src }: stdenv.mkDerivation ({
      inherit name src;
      nativeBuildInputs = lib.singleton sass;
      phases = [ "buildPhase" ];
      buildPhase = ''
        substituteAll $src sub.sass
        sass sub.sass $out --sourcemap=none --style=${cfg.css_style}
      '';
    } // cfg.base16 // {
      font = cfg.font.name;
      font_size = cfg.font.size_css;
      inherit (cfg) alpha;
    })) {};
    _module.args = { inherit (config.lib) kw; };
  };
}