passepartout/org/gateway-tui-view.org

#+TITLE: Passepartout TUI — View
#+PROPERTY: header-args:lisp :tangle ../lisp/gateway-tui-view.lisp

* View

Pure render functions. Each takes a Croatoan window and current state.
State is read via ~(st :key)~ — no mutation here.

** Contract

1. (view-status win): renders the status bar with connection info,
   version, and timestamp.
2. (view-chat win h): renders the scrolled chat message list. Takes
   window and available height. Messages are color-coded: green (user),
   white (agent), yellow (system).
3. (view-input win): renders the input line with cursor and typing
   indicator.
4. (redraw sw cw ch iw): dispatches redraws based on ~(st :dirty)~
   flags (status, chat, input). Minimizes terminal writes.

** Status Bar
#+begin_src lisp
(in-package :passepartout.gateway-tui)

(defun view-status (win)
  (clear win)
  (box win 0 0)
  (add-string win
   (format nil " Passepartout  ~a  [~a]  msgs:~a  scroll:~a~a"
           (if (st :connected) "● Connected" "○ Disconnected")
           (string-upcase (string (st :mode)))
           (length (st :messages))
           (if (> (st :scroll-offset) 0) (format nil "~a↑" (st :scroll-offset)) "0")
           (if (st :busy) "  …thinking" ""))
   :y 1 :x 1 :fgcolor (theme-color (if (st :connected) :connected :disconnected)))
  (add-string win (format nil " ~a" (now)) :y 2 :x 1 :fgcolor (theme-color :timestamp))
  (refresh win))
#+end_src

** Chat Area
#+begin_src lisp
(defun word-wrap (text width)
  "Break text into lines at word boundaries, each <= width chars.
Returns list of trimmed strings. Single words wider than width are split."
  (let ((lines '())
        (pos 0)
        (len (length text)))
    (loop while (< pos len)
          do (let ((end (min len (+ pos width))))
               (cond
                 ((>= end len)
                  (push (string-trim '(#\Space) (subseq text pos len)) lines)
                  (setf pos len))
                 ((char= (char text (1- end)) #\Space)
                  (push (string-trim '(#\Space) (subseq text pos end)) lines)
                  (setf pos end))
                 (t
                  (let ((last-space (position #\Space text :from-end t :end (1+ end) :start pos)))
                    (if (and last-space (> last-space pos))
                        (progn
                          (push (string-trim '(#\Space) (subseq text pos last-space)) lines)
                          (setf pos (1+ last-space)))
                        (progn
                          (push (string-trim '(#\Space) (subseq text pos end)) lines)
                          (setf pos end))))))))
    (nreverse lines)))

(defun view-chat (win h)
  (clear win)
  (box win 0 0)
  (let* ((w (or (width win) 78))
         (msgs (st :messages))
         (total (length msgs))
         (max-lines (- h 2))
         (y 1))
    ;; Count visible messages from end, accounting for word wrap
    (let* ((msg-count 0)
           (lines-remaining max-lines))
      (loop for i from (1- total) downto 0
            while (> lines-remaining 0)
            do (let* ((msg (aref msgs i))
                      (role (getf msg :role))
                      (content (getf msg :content))
                      (time (or (getf msg :time) ""))
                      (prefix (case role (:user "⬆") (:agent "⬇") (t "  ")))
                      (line-text (format nil "~a [~a] ~a" prefix time content))
                      (wrapped (word-wrap line-text (- w 2)))
                      (nlines (length wrapped)))
                 (if (<= nlines lines-remaining)
                     (progn (decf lines-remaining nlines) (incf msg-count))
                     (setf lines-remaining 0))))
      ;; Render from the correct starting message
      (let* ((scroll-skip (st :scroll-offset))
             (start (max 0 (- total msg-count scroll-skip))))
        (loop for i from start below total
              while (< y (1- h))
              do (let* ((msg (aref msgs i))
                        (role (getf msg :role))
                        (content (getf msg :content))
                        (time (or (getf msg :time) ""))
                        (color (theme-color (case role (:user :user) (:agent :agent) (:system :system) (t :agent))))
                        (prefix (case role (:user "⬆") (:agent "⬇") (t "  ")))
                        (line-text (format nil "~a [~a] ~a" prefix time content))
                        (wrapped (word-wrap line-text (- w 2))))
                   (dolist (line wrapped)
                     (when (< y (1- h))
                       (add-string win line :y y :x 1 :n (1- w) :fgcolor color)
                        (incf y))))))))
  (refresh win))
#+end_src

** Input Line
#+begin_src lisp
(defun view-input (win)
  (let* ((text (input-string))
         (w (or (width win) 78))
         (pos (or (st :cursor-pos) 0))
         (display-start (max 0 (- pos (1- w))))
         (visible (subseq text display-start (min (length text) (+ display-start w)))))
    (clear win)
    (add-string win (format nil "~a " visible) :y 0 :x 0 :n (1- w) :fgcolor (theme-color :input))
    (setf (cursor-position win) (list 0 (min (- pos display-start) (1- w)))))
  (refresh win))
#+end_src

** Redraw (dirty-flag dispatch)
#+begin_src lisp
(defun redraw (sw cw ch iw)
  (destructuring-bind (sd cd id) (st :dirty)
    (when sd (view-status sw))
    (when cd (view-chat cw ch))
    (when id (view-input iw))
    (setf (st :dirty) (list nil nil nil))))
#+end_src