home-manager: added treemacs and emacs IDE optimizations

home/shell.nix

@@ -18,14 +18,47 @@
             org-journal
             org-roam     
             nix-mode
+            treemacs
             ])
         );
         package = pkgs.emacs-nox;
         extraConfig = ''
+            ; 4 spaces > tabs.
             (setq-default indent-tabs-mode nil)
             (setq-default tab-width 4)
             (setq indent-line-function 'insert-tab)
+
+            ; xterm mouse mode
             (xterm-mouse-mode 1)
+
+            ; Enable line numbers
+            (global-display-line-numbers-mode 1)
+            (global-hl-line-mode t)
+
+            ; Enable mouse scrolling
+            (global-set-key (kbd "<mouse-4>") 'previous-line)
+            (global-set-key (kbd "<mouse-5>") 'next-line)
+
+            ; Enable tabs
+            (tab-bar-mode 1)
+            (setq tab-bar-show 1)
+            (setq tab-bar-new-tab-choice "*dashboard*")
+
+            ; Enable treemacs
+            (add-hook 'emacs-startup-hook 'treemacs)
+            (setq treemacs-width 25)
+            (treemacs-resize-icons 16) ; Adjust the icon size according to your preference
+            (setq treemacs-follow-mode t) ; Enable follow mode
+            (setq treemacs-filewatch-mode t) ; Enable file watch mode
+            (setq treemacs-fringe-indicator-mode t) ; Enable fringe indicator mode
+            (setq treemacs-git-mode 'simple) ; Set git mode to simple
+            (setq treemacs-git-integration t) ; Enable git integration
+            (setq treemacs-show-hidden-files t) ; Show hidden files
+            (setq treemacs-icons-dired-mode t) ; Use icons in dired buffers
+
+            ; Enable column 80 line for coding
+            (setq-default fill-column 80)
+            (add-hook 'prog-mode-hook #'display-fill-column-indicator-mode)
         '';
     };