feat(completion/copilot): add accept completion "mods" concept

Essentially, if accepted completion string matches a given regexp
pattern, text can be inserted both before and after point.

This is useful in certain situations where Copilot suggests the opening
line to a if statement, for loop, etc., which leads to unbalanced curly
brackets. This can help reduce the annoyance of unbalanced brackets.

modules/completion/siren-copilot.el

@@ -6,6 +6,8 @@
 
 ;;; Code:
 
+(require 'cl-lib)
+
 (use-package copilot
   :straight (:host github :repo "zerolfx/copilot.el"
                    :files ("dist" "*.el"))
@@ -13,15 +15,16 @@
   (prog-mode . copilot-mode)
 
   :general
-  ("C-<tab>" 'siren-copilot-accept-completion-dwim)
-  ("<backtab>" 'siren-copilot-accept-completion-dwim)
-  ("M-F" 'siren-copilot-accept-completion-by-word-dwim)
-  ("M-E" 'siren-copilot-accept-completion-by-line-dwim)
+  ("C-<tab>" 'siren-copilot-dwim-with-mods)
+  ("<backtab>" 'siren-copilot-dwim-with-mods)
+  ("M-F" 'siren-copilot-dwim-by-word)
+  ("M-E" 'siren-copilot-dwim-by-line)
   (:keymaps 'copilot-completion-map
             "M-N" 'copilot-next-completion
             "M-P" 'copilot-previous-completion)
 
   :custom
+  (copilot-auto-balance t)
   (copilot-disable-predicates '(siren-copilot-disable-predicate))
 
   :preface
@@ -29,41 +32,84 @@
     (when buffer-file-name
       (let ((base (file-name-nondirectory buffer-file-name))
             (dir (file-name-directory buffer-file-name)))
-        (or (string-prefix-p ".env" base)))))
+        (or (string-prefix-p ".env" base)
+            (string-match-p "\/\.ansible\/tmp\/ansible-local-.+$" dir)))))
 
-  (defun siren-copilot-accept-completion-dwim ()
-    "Accept the current completion or trigger copilot-compilot."
+  (defun siren-copilot-dwim ()
+    "Trigger or accept completion."
     (interactive)
-    (siren-copilot-complete-or-call
-     'siren-copilot-accept-completion-with-balanced-brackets))
+    (siren-copilot--complete-or-call
+     'copilot-accept-completion))
 
-  (defun siren-copilot-accept-completion-by-word-dwim ()
-    "Accept the current completion by word, or trigger copilot-compilot."
+  (defun siren-copilot-dwim-by-word (n-word)
+    "Trigger or accept N-WORD words from current completion."
+    (interactive "p")
+    (siren-copilot--complete-or-call
+     'copilot-accept-completion-by-word n-word))
+
+  (defun siren-copilot-dwim-by-line (n-line)
+    "Trigger or accept N-LINE lines from current completion."
+    (interactive "p")
+    (siren-copilot--complete-or-call
+     'copilot-accept-completion-by-line n-line))
+
+  (defun siren-copilot-dwim-with-mods ()
+    "Trigger or accept completion."
     (interactive)
-    (siren-copilot-complete-or-call 'copilot-accept-completion-by-word 1))
+    (if (copilot--overlay-visible)
+        (siren-copilot-accept-with-mods)
+      (copilot-complete)))
 
-  (defun siren-copilot-accept-completion-by-line-dwim ()
-    "Accept the current completion by word, or trigger copilot-compilot."
-    (interactive)
-    (siren-copilot-complete-or-call 'copilot-accept-completion-by-line 1))
-
-  (defun siren-copilot-complete-or-call (f &rest args)
+  (defun siren-copilot--complete-or-call (f &rest args)
     "Trigger copilot-complete or call F."
-    (if (copilot-current-completion)
+    (if (copilot--overlay-visible)
         (apply f args)
       (copilot-complete)))
 
-  (defun siren-copilot-accept-completion-with-balanced-brackets ()
-    "Accept completion, add '}' after point if completion ends with '{'."
+  (defgroup siren-copilot nil
+    "Siren: copilot customization."
+    :group 'copilot)
+
+  (defcustom siren-copilot-accept-mods
+    '((ruby-mode . ((" do\\( |.+|\\)?" . ("\n" "\nend"))))
+      (t . (("\{$" . ("\n" "\n}"))
+            ("\\[$" . ("\n" "\n]"))
+            ("\($" . ("\n" "\n)")))))
+    "List of mods of characters to balance."
+    :type '(alist :key-type symbol
+                  :value-type (alist :key-type string
+                                     :value-type (list string string)))
+    :group 'siren-copilot)
+
+  (defun siren-copilot-accept-with-mods ()
+    "Accept completion, and add balance text after point if needed."
     (interactive)
-    (let ((bracket-open nil))
+    (let ((mod nil))
       (copilot-accept-completion (lambda (completion)
-                                   (setq bracket-open
-                                         (string-suffix-p "{" completion))
+                                   (setq mod (siren-copilot--get-mod completion))
                                    completion))
-      (when bracket-open
-        (insert "}")
-        (backward-char))))
+      (siren-copilot--insert-mod mod)))
+
+  (defun siren-copilot--get-mod (text)
+    (let ((mods (append (cdr (assoc major-mode siren-copilot-accept-mods))
+                        (cdr (assoc t siren-copilot-accept-mods)))))
+      (when (length> mods 0)
+        (cl-loop for (open . mod) in mods
+                 when (string-match-p open text)
+                 return mod))))
+
+  (defun siren-copilot--insert-mod (mod)
+    (when mod
+      (let ((before (if (length> mod 1) (car mod)))
+            (after (if (length> mod 1) (cadr mod) (car mod))))
+        (let ((start (point))
+              (end (point)))
+          (if before (insert before))
+          (save-excursion
+            (insert after)
+            (setq end (point)))
+          (indent-region start end)
+          (indent-according-to-mode)))))
 
   :config
   (with-eval-after-load 'company