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

let
  moduleName   = "emacs";
  username     = config.defaultUser or "henrov";

  # Paths to your init files (relative to this module)
  emacsAssets  = ../../../assets/system/conf/emacs;
  initFile     = "${emacsAssets}/init.el";
  earlyInitFile = "${emacsAssets}/early-init.el";

  # Toggle for this module
  enableProgram = config.enableEmacs or false;
in
{
  # Top-level toggle option
  options.enableEmacs = lib.mkEnableOption "Enable Emacs configuration";

  config = lib.mkIf enableProgram {

    # Minimal system-wide Emacs package
    environment.systemPackages = [
      pkgs.emacs-pgtk.override { withTreeSitter = true; }
    ];

    # Home Manager Emacs config
    home-manager.users.${username} = {
      programs.emacs = {
        enable = true;
        package = pkgs.emacs-pgtk.override { withTreeSitter = true; };

        extraPackages = epkgs: with epkgs; [
          # Core dev and language support
          manualPackages.treesit-grammars.with-all-grammars
          rust-mode
          rustic
          nix-mode
          hcl-mode

          # UI & workflow
          nerd-icons
          doom-modeline
          diminish
          eldoc
          eldoc-box
          pulsar
          which-key
          avy
          consult
          vertico
          marginalia
          crux
          shell-pop

          # Completion/snippets
          nerd-icons-corfu
          corfu
          cape
          orderless
          yasnippet
          yasnippet-snippets

          # Utilities
          rg
          exec-path-from-shell
          eat
          f
          gptel
          nixpkgs-fmt
          envrc

          # Theming
          catppuccin-theme

          # Git
          magit

          # Editing/workflow
          expreg
          vundo
          puni

          # Error/side panels
          sideline
          sideline-flymake
          sideline-eglot
        ];

        # Load your init files from assets
        initFile       = initFile;
        earlyInitFile  = earlyInitFile;
      };

      # Useful session variables
      home.sessionVariables = {
        EDITOR = "emacs";
        XDG_SCREENSHOTS_DIR = "~/screenshots";
      };
    };
  };
}