initial commit

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

core/limiter.py

@@ -0,0 +1,26 @@
+import asyncio,time
+BASE,MAX,STEP,CALM,CAP=0.5,2.0,0.25,5.0,20
+class State:
+    __slots__=("slot","interval","last","tasks")
+    def __init__(s):s.slot=0.0;s.interval=BASE;s.last=0.0;s.tasks=set()
+class Limiter:
+    def __init__(s):s.users={}
+    def admit(s,uid):
+        now=time.monotonic();st=s.users.get(uid)
+        if st is None:st=s.users[uid]=State()
+        if len(st.tasks)>=CAP:return st,None,True
+        if now-st.last>CALM:st.interval=BASE
+        wait=max(0.0,st.slot-now)
+        if wait>0:st.interval=min(MAX,st.interval+STEP)
+        st.slot=max(now,st.slot)+st.interval;st.last=now
+        return st,wait,False
+    def flush(s,st):
+        n=len(st.tasks)
+        for t in list(st.tasks):t.cancel()
+        st.tasks.clear();st.slot=0.0;st.interval=BASE;return n
+    def track(s,uid,st,task):
+        st.tasks.add(task)
+        def done(t):
+            st.tasks.discard(t)
+            if not st.tasks and time.monotonic()-st.last>CALM*2 and s.users.get(uid) is st:s.users.pop(uid,None)
+        task.add_done_callback(done)