gptel-transient: Polish gptel--read-with-prefix user experience

* gptel-transient.el (gptel--read-with-prefix-help): Drop variable.
(gptel--read-with-prefix): Enable resizing minibuffer (to make cycling
the ov meaningful). Drop `make-separator-line' which is buggy. Move
the prompt to the last line, which looks better and avoids cursor
jumping. Use `window-max-chars-per-line' instead of
`window-width' (which is incorrect in terminal). Replace newlines with
return symbol. Calculate the multi-line layoyt correctly to use all
available space on the last line. Cycle between just two modes: one
line and multiple lines (hiding one line does not add much value).
Don't show the TAB help if the whole prefix fits into one line.
(gptel--infix-add-directive): Use simple prompt.

* gptel-rewrite.el (gptel--infix-rewrite-extra): Use simple prompt.

Replace RETURN LEFT (U+2C90) with smaller RETURN SYMBOL (U+23CE),
which looks more readable (with many typefaces) between two pieces of
text.

Author: pabl0

gptel-rewrite.el

@@ -547,7 +547,7 @@ By default, gptel uses the directive associated with the `rewrite'
   :display-nil "(None)"
   :key "d"
   :format " %k %d %v"
-  :prompt (concat "Instructions " gptel--read-with-prefix-help)
+  :prompt "Instructions: "
   :reader (lambda (prompt _ history)
             (let* ((rewrite-directive
                     (car-safe (gptel--parse-directive gptel--rewrite-directive

gptel-transient.el

@@ -108,71 +108,70 @@ Meant to be called when `gptel-menu' is active."
       "\n"))
     ov))
 
-(defconst gptel--read-with-prefix-help
-  (concat
-   (propertize "(" 'face 'default)
-   (propertize "TAB" 'face 'help-key-binding)
-   (propertize ": expand, " 'face 'default)
-   (propertize "M-n" 'face 'help-key-binding)
-   (propertize "/" 'face 'default)
-   (propertize "M-p" 'face 'help-key-binding)
-   (propertize ": next/previous) " 'face 'default))
-  "Help string ;TODO: ")
-
 (defun gptel--read-with-prefix (prefix)
   "Show string PREFIX in the minibuffer after the minibuffer prompt.
 
 PREFIX is shown in an overlay.  Repeated calls to this function
-will toggle its visibility state."
+will toggle its visibility state (one line, maximum, none)."
   (unless (minibufferp)
     (user-error "This command is intended to be used in the minibuffer."))
-  (let* ((update
-         (lambda (ov s)
-           (overlay-put
-            ov 'after-string
-            (and s (concat (propertize (concat "\n" s "\n") 'face 'shadow)
-                           (make-separator-line))))))
-         (max-width (- (window-width) (minibuffer-prompt-end)))
-         (max (or max-mini-window-height 0.4))
-         (max-height (- (or (and (natnump max) max)
-                            (floor (* max (frame-height))))
-                        5)))
-    (when (and prefix (not (string-empty-p prefix)) (> max-height 1))
-      (unless visual-line-mode (visual-line-mode 1))
-      (goto-char (minibuffer-prompt-end))
-      (pcase-let ((`(,prop . ,ov)
-                   (get-char-property-and-overlay
-                    (point-min) 'gptel)))
-        (unless ov
-          (setq ov (make-overlay
-                    (point-min) (minibuffer-prompt-end) nil t)))
-        (pcase prop
-          ('partial
-           (if (> (length prefix) max-width)
-               (progn
-                 (overlay-put ov 'gptel 'prefix)
-                 (let ((disp-size
-                        (cl-loop for char across prefix
-                                 for idx upfrom 0
-                                 with n = 0 with max-length = (* max-height max-width)
-                                 if (eq char ?\n) do (cl-incf n)
-                                 if (> n max-height) return idx
-                                 if (> idx max-length)
-                                 return idx
-                                 finally return nil)))
-                   (funcall update ov
-                            (if disp-size
-                                (truncate-string-to-width
-                                 prefix disp-size  nil nil 'ellipsis)
-                              prefix))))
-             (overlay-put ov 'gptel 'hide)
-             (funcall update ov nil)))
-          ('prefix (overlay-put ov 'gptel 'hide)
-                 (funcall update ov nil))
-          (_ (overlay-put ov 'gptel 'partial)
-             (funcall update ov (truncate-string-to-width
-                                 prefix max-width nil nil
-                                 'ellipsis))))))))
+  (set (make-local-variable 'resize-mini-windows) t)
+  (cl-flet ((update (ov s)
+		    (overlay-put ov 'before-string
+				 (and s
+				      (propertize (concat
+						   s (propertize "\n"
+								 'face '(shadow default)))
+						  'rear-nonsticky t 'front-nonsticky t))))
+	    (tab-help (s)
+		      (concat
+		       (propertize "(" 'face 'default)
+		       (propertize "TAB" 'face 'help-key-binding)
+		       (propertize (concat ": " s ") ") 'face 'default))))
+    (let* ((max (or max-mini-window-height 0.4))
+	   (max-width (window-max-chars-per-line))
+	   (max (or max-mini-window-height 0.4))
+	   (max-height (- (or (and (natnump max) max)
+                              (floor (* max (frame-height))))
+			  5))
+	   (prefix (and prefix (string-replace "\n" "⏎" prefix))))
+      (when (and prefix (not (string-empty-p prefix)) (> max-height 1))
+	(pcase-let ((`(,prop . ,ov)
+                     (get-char-property-and-overlay
+                      (point-min) 'gptel)))
+          (unless ov
+            (setq ov (make-overlay
+                      (point-min) (minibuffer-prompt-end) nil t)))
+          (pcase prop
+            ('partial
+	     (overlay-put ov 'gptel 'one-line)
+	     (update ov
+		     (with-temp-buffer
+		       (insert (tab-help "shrink"))
+		       (let ((b (point)))
+			 (insert prefix)
+			 (set-text-properties b (point-max) '(face (shadow default))))
+		       (goto-char (point-min))
+		       (let ((fill-column max-width))
+			 (fill-region (point) (point-max)))
+		       (goto-line (min max-height (line-number-at-pos (point-max))))
+		       (concat (buffer-substring 1 (point))
+			       (propertize (truncate-string-to-width
+					    (buffer-substring (point) (point-max))
+					    (1- max-width) nil
+					    nil
+					    t) 'face '(shadow default))))))
+            (_ (update ov
+		       (if (>= (length prefix) max-width)
+			   (let ((he (tab-help "expand")))
+			     (overlay-put ov 'gptel 'partial)
+			     (concat he (propertize (truncate-string-to-width
+						     prefix
+						     (- max-width (length he))
+						     nil nil t)
+						    'face '(shadow default))))
+			 (overlay-put ov 'gptel 'hide)
+			 (propertize prefix 'face '(shadow default)))))))))))
 
 (defun gptel--transient-read-number (prompt initial-input history)
   "Read a numeric value from the minibuffer.
@@ -202,7 +201,7 @@ Handle formatting for system messages when the active
               (propertize "]" 'face 'transient-heading))
     (if message
         (gptel--describe-directive
-         message (max (- (window-width) 12) 14) "⮐ ")
+         message (max (- (window-width) 12) 14) "⏎")
       "[No system message set]")))
 
 (defun gptel--tools-init-value (obj)
@@ -353,7 +352,7 @@ which see."
 				       (len (length val)))
 				 (ptv (concat
                                        "\"" (string-replace
-					     "\n" "⮐"
+					     "\n" "⏎"
 					     (truncate-string-to-width
 					      val 20 nil nil t))
 				       "\"" (when (> len 20)
@@ -706,7 +705,7 @@ If EXTERNAL is non-nil, include external sources of directives."
                           (concat "(" (gptel--describe-directive prompt (- width 30)) ")")
                           'face 'shadow))
                  `(lambda () (interactive)
-                    (message "%s: %s" ,msg ,(gptel--describe-directive prompt 100 "⮐ "))
+                    (message "%s: %s" ,msg ,(gptel--describe-directive prompt 100 "⏎"))
                     (gptel--set-with-scope ',sym ',prompt gptel--set-buffer-locally))
 	         :transient 'transient--do-return)
            into prompt-suffixes
@@ -1076,19 +1075,18 @@ Or in an extended conversation:
   :display-nil 'none
   :overlay nil
   :argument ":"
-  :prompt (concat "Add instructions for next request only "
-                  gptel--read-with-prefix-help)
+  :prompt "Instruction for next request: "
   :reader (lambda (prompt initial history)
             (let* ((directive
                     (car-safe (gptel--parse-directive gptel--system-message 'raw)))
                    (cycle-prefix (lambda () (interactive)
-                                   (gptel--read-with-prefix directive)))
+				   (gptel--read-with-prefix directive)))
                    (minibuffer-local-map
                     (make-composed-keymap
                      (define-keymap "TAB" cycle-prefix "<tab>" cycle-prefix)
                      minibuffer-local-map))
                    (extra (minibuffer-with-setup-hook cycle-prefix
-                            (read-string prompt (or initial " ") history))))
+			    (read-string prompt nil history (or initial)))))
               (unless (string-empty-p extra) extra)))
   :format " %k %d %v"
   :key "d"

gptel.el

@@ -1760,7 +1760,7 @@ buffer."
                               (format "#<lambda %#x>" (sxhash s)))
                              ((byte-code-function-p s)
                               (format "#<compiled %#x>" (sxhash s)))
-                             ((stringp s) (string-replace "\n" "⮐ " s))
+                             ((stringp s) (string-replace "\n" "⏎" s))
                              (t (prin1-to-string s)))))
            (inhibit-read-only t)
            (info (gptel-fsm-info fsm))
@@ -2827,7 +2827,7 @@ NAME and ARG-VALUES are the name and arguments for the call."
                         (cond ((stringp arg)
                                (prin1-to-string
                                 (replace-regexp-in-string
-                                 "\n" "⮐" (truncate-string-to-width
+                                 "\n" "⏎" (truncate-string-to-width
                                            arg (floor (window-width) 4)
                                            nil nil t))))
                               (t (prin1-to-string arg))))