From 200cc00129048db304a4fefab5cf7f6043982b78 Mon Sep 17 00:00:00 2001
From: Jared Miller <jared@smell.flowers>
Date: Thu, 12 Feb 2026 16:31:17 -0500
Subject: [PATCH] Dedupe MSDP vitals to avoid spamming idle clients

Cache last-sent values on Player and skip send_msdp() when
nothing changed. Idle players no longer get a packet every second.
---
 src/mudlib/gmcp.py   | 23 ++++++++++++++---------
 src/mudlib/player.py |  1 +
 tests/test_gmcp.py   | 15 +++++++++++++++
 3 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/src/mudlib/gmcp.py b/src/mudlib/gmcp.py
index 4654d30..432a1a0 100644
--- a/src/mudlib/gmcp.py
+++ b/src/mudlib/gmcp.py
@@ -115,14 +115,19 @@ def send_map_data(player: Player) -> None:
 
 
 def send_msdp_vitals(player: Player) -> None:
-    """Send MSDP variable updates for real-time gauges."""
+    """Send MSDP variable updates for real-time gauges.
+
+    Skips sending if values haven't changed since last send.
+    """
     if not player.msdp_enabled:
         return
-    player.send_msdp(
-        {
-            "HEALTH": str(round(player.pl, 1)),
-            "HEALTH_MAX": str(round(player.max_pl, 1)),
-            "STAMINA": str(round(player.stamina, 1)),
-            "STAMINA_MAX": str(round(player.max_stamina, 1)),
-        }
-    )
+    data = {
+        "HEALTH": str(round(player.pl, 1)),
+        "HEALTH_MAX": str(round(player.max_pl, 1)),
+        "STAMINA": str(round(player.stamina, 1)),
+        "STAMINA_MAX": str(round(player.max_stamina, 1)),
+    }
+    if data == player._last_msdp:
+        return
+    player._last_msdp = data
+    player.send_msdp(data)
diff --git a/src/mudlib/player.py b/src/mudlib/player.py
index 558e0b0..6c242a3 100644
--- a/src/mudlib/player.py
+++ b/src/mudlib/player.py
@@ -30,6 +30,7 @@ class Player(Entity):
     paint_mode: bool = False
     painting: bool = False
     paint_brush: str = "."
+    _last_msdp: dict = field(default_factory=dict, repr=False)
 
     @property
     def mode(self) -> str:
diff --git a/tests/test_gmcp.py b/tests/test_gmcp.py
index fa5aafb..106aeca 100644
--- a/tests/test_gmcp.py
+++ b/tests/test_gmcp.py
@@ -231,6 +231,21 @@ def test_send_msdp_vitals(player):
     )
 
 
+def test_send_msdp_vitals_dedup(player):
+    """Test MSDP skips sending when values haven't changed."""
+    send_msdp_vitals(player)
+    assert player.writer.send_msdp.call_count == 1
+
+    # second call with same values — should be suppressed
+    send_msdp_vitals(player)
+    assert player.writer.send_msdp.call_count == 1
+
+    # change a value — should send again
+    player.pl = 80.0
+    send_msdp_vitals(player)
+    assert player.writer.send_msdp.call_count == 2
+
+
 def test_player_send_gmcp(player):
     """Test Player.send_gmcp convenience method."""
     player.send_gmcp("Test.Package", {"key": "value"})