respect eca-chat-window-side for non-side-window chat display

Author: shohi

CHANGELOG.md

@@ -1,7 +1,7 @@
 # Changelog
 
 ## Unreleased
-
+- Respect `eca-chat-window-side` (and width/height) even when `eca-chat-use-side-window` is nil, displaying the chat on that side via `display-buffer-in-direction`. To avoid overlapping/duplicate windows, placement now reuses the window already showing the chat, otherwise replaces another visible chat window in place (new-tab behavior), and only opens a new window when there is nothing to reuse.
 - Add a context-usage bar in the chat mode-line, left of the token usage, showing how full the model context window is, colored by category (system prompt, rules, skills, AGENTS.md, tool definitions, tool calls, conversation, free space), each a distinct color. In graphical frames it renders pixel-width thin segments for high granularity (small percentages stay visible); terminals fall back to block characters. Same footprint either way (`eca-chat-context-bar-width`). Colors come from the server (canonical `color`/`freeColor`) so they are consistent; hover the bar for a legend that maps each category to its server emoji swatch (`emoji`/`freeEmoji`, matching the `/context` command output), or click to run the new `/context` command. Configurable via `eca-chat-context-bar-width` and the `:context-bar` module in `eca-chat-mode-line-format`. Needs an eca server that sends `contextBreakdown` in `usage` content.
 - Auto-dismiss a pending `ask_user` question when another client (e.g. an SSE/web client in remote mode, see eca 0.139.0) answers it first. The server resolves the `ask_user` tool out from under us and sends a `toolCalled`/`toolCallRejected` for that tool-call id but no longer expects our answer (it cancels our request); we now correlate that id with `eca-chat--pending-question` and clear the stale answer-mode prompt state instead of staying stuck waiting for input.
 - Paginate long chats instead of replaying the full history on open. With `eca-chat-history-page-size` non-nil (default 50), `eca-chat-resume` opens a chat with only the newest page and shows a clickable "Load older messages" control at the top to page through earlier history on demand via the new `chat/history` request (also bound to `C-c C-S-o`). Older pages are prepended above the existing content, reusing the streaming renderer (subagent nesting included) and kept read-only like the rest of the history. Set `eca-chat-history-page-size` to nil to keep the previous full-replay behavior.

README.md

@@ -133,10 +133,10 @@ Chat
 - `eca-chat-parent-mode`: Set major-mode of chat parent, can be `markdown-mode`, `markdown-view-mode` or `gfm-view-mode` (default)
 - `eca-chat-mode-hook`: Hooks to run after entering `eca-chat-mode`.
 - `eca-chat-finished-hook`: Hooks to run after finishing a chat prompt.
-- `eca-chat-use-side-window`: Whether the chat buffer is displayed in a side window or a normal window.
-- `eca-chat-window-side`: On which side (`left`, `right`, `top`, `bottom`) the chat side window appears.
-- `eca-chat-window-width`: Width of the chat side window when on the left or right.
-- `eca-chat-window-height`: Height of the chat side window when on the top or bottom.
+- `eca-chat-use-side-window`: Whether the chat buffer is displayed in a dedicated side window or a normal window. Either way it is placed on `eca-chat-window-side`.
+- `eca-chat-window-side`: On which side (`left`, `right`, `top`, `bottom`) the chat window appears (respected for both side and normal windows).
+- `eca-chat-window-width`: Width of the chat window when on the left or right.
+- `eca-chat-window-height`: Height of the chat window when on the top or bottom.
 - `eca-chat-focus-on-open`: Whether to focus the chat window when it opens.
 - `eca-chat-auto-add-repomap`: Whether to automatically include repoMap context when opening ECA.
 - `eca-chat-auto-add-cursor`: Whether to automatically track the cursor position and add it as context.

eca-chat.el

@@ -48,8 +48,10 @@ For when chat went back to idle state."
 
 (defcustom eca-chat-window-side 'right
   "Side of the frame where the ECA chat window should appear.
-Can be `'left', `'right', `'top', or `'bottom'.  This setting will only
-be used when `eca-chat-use-side-window' is non-nil."
+Can be `'left', `'right', `'top', or `'bottom'.  This setting is respected
+both when `eca-chat-use-side-window' is non-nil (dedicated side window)
+and when it is nil (regular window displayed in the corresponding
+direction)."
   :type '(choice (const :tag "Left" left)
                  (const :tag "Right" right)
                  (const :tag "Top" top)
@@ -67,11 +69,13 @@ be used when `eca-chat-use-side-window' is non-nil."
   :group 'eca)
 
 (defcustom eca-chat-use-side-window t
-  "Whether to display ECA chat in a side window.
+  "Whether to display ECA chat in a dedicated side window.
 When non-nil (default), ECA chat opens in a dedicated side window
 controlled by `eca-chat-window-side' and related settings.  When nil,
-ECA chat opens in a regular buffer that follows standard
-`display-buffer' behavior."
+ECA chat opens in a regular window, still placed on the side given by
+`eca-chat-window-side' with the corresponding width/height, but without
+the side-window restrictions (so it can be split or replaced like any
+other window)."
   :type 'boolean
   :group 'eca)
 
@@ -2522,30 +2526,42 @@ are in progress."
   (select-window (get-buffer-window (buffer-name))))
 
 (defun eca-chat--display-buffer (buffer)
-  "Display BUFFER in a side window according to customization.
-The window is displayed on the side specified by
-`eca-chat-window-side' with dimensions from
-`eca-chat-window-width' or `eca-chat-window-height'.
+  "Display BUFFER according to customization.
+BUFFER is displayed on the side given by `eca-chat-window-side'
+with the size from `eca-chat-window-width' or
+`eca-chat-window-height'.  When `eca-chat-use-side-window' is
+non-nil a dedicated side window is used, otherwise a regular
+window in the same direction.
 If `eca-chat-focus-on-open' is non-nil, the window is selected."
-  (let ((window
-         (if eca-chat-use-side-window
-             ;; Use side window
-             (let* ((side eca-chat-window-side)
-                    (slot 0)
-                    (window-parameters '((no-delete-other-windows . t)))
-                    (display-action
-                     `((display-buffer-in-side-window)
-                       (side . ,side)
-                       (slot . ,slot)
-                       (dedicated . side)
-                       ,@(when (memq side '(left right))
-                           `((window-width . ,eca-chat-window-width)))
-                       ,@(when (memq side '(top bottom))
-                           `((window-height . ,eca-chat-window-height)))
-                       (window-parameters . ,window-parameters))))
-               (display-buffer buffer display-action))
-           ;; Use regular buffer
-           (display-buffer buffer))))
+  (let* ((side eca-chat-window-side)
+         (size (if (memq side '(left right))
+                   `((window-width . ,eca-chat-window-width))
+                 `((window-height . ,eca-chat-window-height))))
+         (display-action
+          (if eca-chat-use-side-window
+              ;; Dedicated side window.
+              `((display-buffer-in-side-window)
+                (side . ,side)
+                (slot . 0)
+                (dedicated . side)
+                ,@size
+                (window-parameters . ((no-delete-other-windows . t))))
+            ;; Regular window in the same direction.
+            `((display-buffer-in-direction)
+              (direction . ,(pcase side ('top 'above) ('bottom 'below) (_ side)))
+              ,@size)))
+         (window
+          (or
+           ;; Already visible: keep it where it is.
+           (get-buffer-window buffer)
+           ;; Another chat is visible: replace it (new-tab behavior).
+           (when-let* ((win (get-window-with-predicate
+                             (lambda (w)
+                               (buffer-local-value 'eca-chat--id (window-buffer w))))))
+             (set-window-buffer win buffer)
+             win)
+           ;; Nothing to reuse: open a new window.
+           (display-buffer buffer display-action))))
     ;; Select the window to give it focus if configured to do so
     (when (and window eca-chat-focus-on-open)
       (select-window window))