fix(cli): apply index updates in place instead of fetching the whole index

The interactive mode fetched and re-parsed the full index on every
index_delta, on the loop receiving the download: 67 times in 80 s while
a node enriched a library.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 29 insertions, 1 deletions

diff --git a/packages/meshbay-cli/src/meshbay_cli/tui/screens.py b/packages/meshbay-cli/src/meshbay_cli/tui/screens.py
index 39b5df3..b6fd347 100644
--- a/packages/meshbay-cli/src/meshbay_cli/tui/screens.py
+++ b/packages/meshbay-cli/src/meshbay_cli/tui/screens.py
@@ -41,6 +41,9 @@ from .panes import LocalPane, RemotePane
 from .widgets import Choice, TransferStrip
 
 PER_GROUP = 2
+# A burst of index updates that added or removed files is answered by one full
+# index, this long after the last of them.
+REFRESH_AFTER_DELTA_S = 2.0
 
 
 class SignInScreen(Screen):
@@ -118,6 +121,7 @@ class MainScreen(Screen):
         self._trees: dict[str, Tree] = {}
         self._gates: dict[str, asyncio.Semaphore] = {}
         self._watching: set[str] = set()
+        self._refreshes: dict[str, asyncio.TimerHandle] = {}
 
     def compose(self) -> ComposeResult:
         with Horizontal():
@@ -150,12 +154,36 @@ class MainScreen(Screen):
             self._trees[group["id"]] = Tree.from_index(await session.index())
             if group["id"] not in self._watching:
                 self._watching.add(group["id"])
-                session.ch.on_push("index_delta", lambda _msg, g=group: self._changed(g))
+                session.ch.on_push(
+                    "index_delta", lambda msg, g=group, s=session: self._delta(g, s, msg))
         return self._trees[group["id"]]
 
     def forget_tree(self, group: dict) -> None:
         self._trees.pop(group["id"], None)
 
+    def _delta(self, group: dict, session, msg: dict) -> None:
+        """A pushed index update, applied to the tree in place. Only one that
+        adds or removes something is drawn, and asks for the whole index — once
+        for a burst, not once per message."""
+        tree = self._trees.get(group["id"])
+        if tree is None:
+            return   # the next look asks for the whole index anyway
+        try:
+            structural = tree.apply_delta(session.open_delta(msg))
+        except CliError:
+            structural = True
+        if not structural:
+            return
+        pending = self._refreshes.pop(group["id"], None)
+        if pending is not None:
+            pending.cancel()
+        self._refreshes[group["id"]] = asyncio.get_running_loop().call_later(
+            REFRESH_AFTER_DELTA_S, self._refreshed, group)
+
+    def _refreshed(self, group: dict) -> None:
+        self._refreshes.pop(group["id"], None)
+        self._changed(group)
+
     def _changed(self, group: dict) -> None:
         """Something changed in the group: the index is asked for again, and the
         pane redrawn if it is showing that group."""