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

let
  cfg = config.theme;
  init = pkgs.writeShellApplication {
    name = "theme";
    runtimeInputs = with pkgs; [ coreutils-full ];
    bashOptions = [ "nounset" "pipefail" ];
    text = ''
      if [ -z "''${WAYLAND_DISPLAY:-}" ]; then
        echo "No Wayland session active. Exiting."
        exit 0
      fi

      [ ! -L "${cfg.configDir}/wallpaper" ] && ln -sf "${cfg.wallpaper}" "${cfg.configDir}/wallpaper"
      [ ! -f "${cfg.configDir}/mode" ] && echo "${cfg.mode}" > "${cfg.configDir}/mode"

      set_wallpaper() {
        if [ -f "$1" ]; then
          WALLPAPER="$1"
        else
          echo "Invalid wallpaper path: $1"
          exit 1
        fi
      }

      set_mode() {
        if [ "$1" = "light" ] || [ "$1" = "dark" ]; then
          MODE="$1"
        else
          echo "Invalid mode: $1. Use 'light' or 'dark'."
          exit 1
        fi
      }

      toggle_mode() {
        if [ "$(cat "${cfg.configDir}/mode")" = "light" ]; then
          MODE="dark"
        else
          MODE="light"
        fi
      }

      show_usage() {
        echo "Usage: theme {toggle|light|dark|mode <mode>|wallpaper <file> [mode]}"
      }

      finish() {
        [ -n "$WALLPAPER" ] && ln -sf "$WALLPAPER" "${cfg.configDir}/wallpaper"
        [ -n "$MODE" ] && echo "$MODE" > "${cfg.configDir}/mode"

        {
          ${cfg.extraConfig}
        } > /dev/null
      }

      WALLPAPER=""
      MODE=""

      if [ $# -eq 0 ]; then
        finish
      else
        case "$1" in
          toggle)
            if [ $# -eq 1 ]; then
              toggle_mode
            else
              show_usage
              exit 1
            fi
            ;;
          light)
            if [ $# -eq 1 ]; then
              set_mode "light"
            else
              show_usage
              exit 1
            fi
            ;;
          dark)
            if [ $# -eq 1 ]; then
              set_mode "dark"
            else
              show_usage
              exit 1
            fi
            ;;
          mode)
            if [ $# -eq 2 ]; then
              set_mode "$2"
            else
              show_usage
              exit 1
            fi
            ;;
          wallpaper)
            if [ $# -ge 2 ] && [ $# -le 3 ]; then
              set_wallpaper "$2"
              [ $# -eq 3 ] && set_mode "$3"
            else
              show_usage
              exit 1
            fi
            ;;
          *)
            show_usage
            exit 1
            ;;
        esac

        finish
      fi
    '';
  };
in
{
  # https://github.com/Theaninova/TheaninovOS/blob/master/modules/home-manager/theme/md3-evo.nix
  options.theme = with lib; with types; {
    enable = mkEnableOption "theme";

    configDir = mkOption {
      type = str;
      default = "${config.xdg.configHome}/theme";
      description = "The path to the theme config directory.";
    };

    wallpaper = mkOption {
      type = path;
      description = "The path to the default wallpaper";
    };

    pkg = mkOption {
      type = package;
      default = init;
      readOnly = true;
      description = "The package containing the `theme` script";
    };

    extraConfig = mkOption {
      type = lines;
      default = "";
      description = "Extra configuration lines to add to the theme script.";
    };

    flavour = mkOption {
      type = enum [
        "content"
        "expressive"
        "fidelity"
        "fruit-salad"
        "monochrome"
        "neutral"
        "rainbow"
        "tonal-spot"
      ];
      default = "tonal-spot";
      description = "The flavour of the theme.";
    };

    mode = mkOption {
      type = enum [ "dark" "light" ];
      default = "dark";
      description = "The default mode of the theme.";
    };

    contrast = mkOption {
      type = numbers.between (-1) 1;
      default = 0;
      description = "Use a modified contrast.";
    };

    opacity = mkOption {
      type = numbers.between 0 1;
      default = 1;
      description = "The opacity of apps.";
    };

    radius = mkOption {
      type = ints.unsigned;
      default = 24;
      description = "The radius of corners.";
    };

    padding = mkOption {
      type = ints.unsigned;
      default = 12;
      description = "The padding of windows.";
    };

    blur = mkOption {
      type = ints.unsigned;
      default = 0;
      description = "The blur amount of windows.";
    };

    color = {
      semantic = {
        blend = mkOption {
          type = bool;
          default = false;
          description = "Blend the colors.";
        };

        danger = mkOption {
          type = str;
          default = "#ff0000";
          description = "The color of danger.";
        };

        warning = mkOption {
          type = str;
          default = "#ffff00";
          description = "The color of warning.";
        };

        success = mkOption {
          type = str;
          default = "#00ff00";
          description = "The color of success.";
        };

        info = mkOption {
          type = str;
          default = "#0000ff";
          description = "The color of info.";
        };
      };

      syntax = {
        blend = mkOption {
          type = bool;
          default = true;
          description = "Blend the colors.";
        };

        keywords = mkOption {
          type = str;
          default = "#ff8000";
          description = "The color of keywords.";
        };

        functions = mkOption {
          type = str;
          default = "#0000ff";
          description = "The color of functions.";
        };

        properties = mkOption {
          type = str;
          default = "#ff00ff";
          description = "The color of properties.";
        };

        constants = mkOption {
          type = str;
          default = "#ff00ff";
          description = "The color of constants.";
        };

        strings = mkOption {
          type = str;
          default = "#00ff00";
          description = "The color of variables.";
        };

        numbers = mkOption {
          type = str;
          default = "#00ffff";
          description = "The color of numbers.";
        };

        structures = mkOption {
          type = str;
          default = "#ffff00";
          description = "The color of structures.";
        };

        types = mkOption {
          type = str;
          default = "#00ffff";
          description = "The color of types.";
        };
      };

      ansi = {
        blend = mkOption {
          type = bool;
          default = true;
          description = "Blend the colors.";
        };

        red = mkOption {
          type = str;
          default = "#ff0000";
          description = "The color of red.";
        };

        green = mkOption {
          type = str;
          default = "#00ff00";
          description = "The color of green.";
        };

        yellow = mkOption {
          type = str;
          default = "#ffff00";
          description = "The color of yellow.";
        };

        orange = mkOption {
          type = str;
          default = "#ff8000";
          description = "The color of orange.";
        };

        blue = mkOption {
          type = str;
          default = "#0000ff";
          description = "The color of blue.";
        };

        magenta = mkOption {
          type = str;
          default = "#ff00ff";
          description = "The color of magenta.";
        };

        cyan = mkOption {
          type = str;
          default = "#00ffff";
          description = "The color of cyan.";
        };
      };
    };

    cursor = {
      package = mkOption {
        type = package;
        default = pkgs.gnome.adwaita-icon-theme;
        description = "The package providing the cursor theme.";
      };

      name = mkOption {
        type = str;
        default = "Adwaita";
        description = "The cursor name within the package.";
      };

      size = mkOption {
        type = ints.positive;
        default = 32;
        description = "The cursor size.";
      };
    };
  };

  config = lib.mkIf cfg.enable {
    home = {
      packages = [ cfg.pkg ];

      pointerCursor = {
        inherit (cfg.cursor) package name size;
        gtk.enable = true;
        x11.enable = true;
      };
    };
  };
}