Add custom apheleia function for formatting regions

Implemented a custom `apheleia` function to format selected regions or entire buffer using Apheleia, handling temp files and regions. Updated keybinding for `C-c f` to use this new function.

emacs/.emacs.d/config/init-ai.el

@@ -5,7 +5,34 @@
 
 (use-package gptel
   :commands (gptel-request)
+  :init
+  ;; Annoyingly, gptel fails to require gptel-context, so we have to do it manually
+  (autoload 'gptel-context-add "gptel-context")
+  (autoload 'gptel-context-add-file "gptel-context")
   :config
+  ;; Default to creating a new buffer when invoking gptel
+  (defun gptel-before-advice (name &optional _ initial interactivep)
+    (interactive
+     (let* ((backend (default-value 'gptel-backend))
+            (backend-name
+             (generate-new-buffer-name (format "*%s*" (gptel-backend-name backend)))))
+       (list (read-buffer "Create or choose gptel buffer: "
+                          backend-name nil                         ; DEFAULT and REQUIRE-MATCH
+                          (lambda (b)                              ; PREDICATE
+                            (buffer-local-value 'gptel-mode
+                                                (get-buffer (or (car-safe b) b)))))
+             (condition-case nil
+                 (gptel--get-api-key
+                  (gptel-backend-key backend))
+               ((error user-error)
+                (setq gptel-api-key
+                      (read-passwd
+                       (format "%s API key: " backend-name)))))
+             (and (use-region-p)
+                  (buffer-substring (region-beginning)
+                                    (region-end)))
+             t))))
+  (advice-add 'gptel :before #'gptel-before-advice)
   (defvar gptel-backend-openai (gptel-make-openai "ChatGPT"
                                  :key #'gptel-api-key-from-auth-source
                                  :stream t

emacs/.emacs.d/config/init-ide.el

@@ -282,10 +282,52 @@
 ;; Code formatting library
 (use-package apheleia
   :straight (apheleia :host github :repo "raxod502/apheleia")
+  :commands apheleia-format-buffer
+  :autoload apheleia--get-formatters
   :config
   (add-to-list 'apheleia-mode-alist '(ruby-mode . (rubocop)))
-  :general
+  (add-to-list 'apheleia-mode-alist '(ruby-ts-mode . (rubocop))))
-  (prog-mode-map "C-c f" #'apheleia-format-buffer))
+
+(defun apheleia ()
+  "Format the region or current buffer using Apheleia."
+  (interactive)
+  (let* ((buf (current-buffer))
+         (name (buffer-file-name))
+         (temp-file (make-temp-file "apheleia" nil (format ".%s" (file-name-extension name))))
+         (temp-buffer (find-file-noselect temp-file))
+         (formatters (apheleia--get-formatters))
+         (line (line-number-at-pos))
+         (col (current-column))
+         start
+         end)
+    (if (region-active-p)
+        (setq start (region-beginning)
+              end (region-end))
+      (setq start (point-min)
+            end (point-max)))
+    (with-current-buffer temp-buffer
+      (erase-buffer)
+      (insert-buffer-substring buf start end)
+      (write-file temp-file)
+      (apheleia-format-buffer formatters
+                              (lambda ()
+                                (with-current-buffer buf
+                                  (delete-region start end)
+                                  (insert-buffer-substring temp-buffer)
+                                  (goto-char (point-min))
+                                  (forward-line (1- line))
+                                  (move-to-column col)
+                                  (delete-file temp-file)
+                                  (when (get-buffer temp-buffer)
+                                    (kill-buffer temp-buffer))))
+                              :callback (lambda (&rest args)
+                                          (when-let ((error (plist-get args :error)))
+                                            (delete-file temp-file)
+                                            (when (get-buffer temp-buffer)
+                                              (kill-buffer temp-buffer))
+                                            (error "Formatting failed: %s" error)))))))
+
+(keymap-set prog-mode-map "C-c f" #'apheleia)
 
 ;; AI assistance
 (use-package copilot