# XDG stands for "Cross-Desktop Group", with X used to mean "cross". 
# It's a bunch of specifications from freedesktop.org intended to standardize desktops and 
# other GUI applications on various systems (primarily Unix-like) to be interoperable: 
#   https://www.freedesktop.org/wiki/Specifications/
{config, pkgs, ...}: let
  browser = ["firefox.desktop"];

  # XDG MIME types
  associations = {
    "application/x-extension-htm" = browser;
    "application/x-extension-html" = browser;
    "application/x-extension-shtml" = browser;
    "application/x-extension-xht" = browser;
    "application/x-extension-xhtml" = browser;
    "application/xhtml+xml" = browser;
    "text/html" = browser;
    "x-scheme-handler/about" = browser;
    "x-scheme-handler/ftp" = browser;
    "x-scheme-handler/http" = browser;
    "x-scheme-handler/https" = browser;
    "x-scheme-handler/unknown" = browser;

    "audio/*" = ["mpv.desktop"];
    "video/*" = ["mpv.dekstop"];
    "image/*" = ["imv.desktop"];
    "application/json" = browser;
    "application/pdf" = browser;  # TODO: pdf viewer
    "x-scheme-handler/discord" = ["discord.desktop"];
    "x-scheme-handler/tg" = ["telegramdesktop.desktop"];
  };
in {
  home.packages = with pkgs; [
    xdg-utils
    xdg-user-dirs
  ];

  xdg = {
    enable = true;
    cacheHome = config.home.homeDirectory + "/.local/cache";

    mimeApps = {
      enable = true;
      defaultApplications = associations;
    };

    userDirs = {
      enable = true;
      createDirectories = true;
      extraConfig = {
        XDG_SCREENSHOTS_DIR = "${config.xdg.userDirs.pictures}/Screenshots";
      };
    };
  };
}