better agent

cht/agent/buffer.py

@@ -0,0 +1,50 @@
+"""Streaming text buffer — smooth reveal of bursty network chunks.
+
+Accumulates text from the provider and reveals it at ~60fps with a
+~200ms target reveal pace, so the UI sees a smooth stream regardless
+of network burst patterns.
+
+All methods must be called from the GTK main thread.
+"""
+
+from typing import Callable
+
+from gi.repository import GLib
+
+
+class StreamingTextBuffer:
+    TICK_MS = 16          # ~60fps
+    REVEAL_TARGET_MS = 200
+
+    def __init__(self, on_reveal: Callable[[str], None]):
+        self._pending = ""
+        self._on_reveal = on_reveal
+        self._timer_id: int | None = None
+
+    def push(self, text: str):
+        self._pending += text
+        if self._timer_id is None:
+            self._timer_id = GLib.timeout_add(self.TICK_MS, self._tick)
+
+    def _tick(self) -> bool:
+        if not self._pending:
+            self._timer_id = None
+            return False
+        n = max(1, len(self._pending) * self.TICK_MS // self.REVEAL_TARGET_MS)
+        reveal, self._pending = self._pending[:n], self._pending[n:]
+        self._on_reveal(reveal)
+        return True
+
+    def flush(self):
+        if self._pending:
+            self._on_reveal(self._pending)
+            self._pending = ""
+        if self._timer_id is not None:
+            GLib.source_remove(self._timer_id)
+            self._timer_id = None
+
+    def cancel(self):
+        self._pending = ""
+        if self._timer_id is not None:
+            GLib.source_remove(self._timer_id)
+            self._timer_id = None