From c6d32f1f9d15c531b7160d115d7bf47d2016a859 Mon Sep 17 00:00:00 2001
From: Lars Wirzenius <liw@liw.fi>
Date: Sat, 29 May 2021 20:50:20 +0300
Subject: fix: server logic

Sponsored-by: author
---
 server.py | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 68 insertions(+), 1 deletion(-)

diff --git a/server.py b/server.py
index 369fa79..0479d1d 100755
--- a/server.py
+++ b/server.py
@@ -1,12 +1,79 @@
 #!/usr/bin/env python3
 
 import bottle
+import random
+
+
+class Max:
+    def __init__(self):
+        self.new(0)
+
+    def new(self, count):
+        if count == 1:
+            # List has length 1: we know the answer.
+            return self.done(0)
+
+        self._count = count
+        self._result = 0
+        self._pos = 0
+        self._rid = None
+        return self.next(self._result)
+
+    def decide(self, answer, rid):
+        assert rid == self._rid
+        if answer:
+            # left < right: use previous "right" item
+            return self.next(self._pos)
+        else:
+            # left >= right: use current best result
+            return self.next(self._result)
+
+    def next(self, new_result):
+        self._result = new_result
+
+        # Choose next item to compare.
+        self._pos += 1
+
+        if self._pos >= self._count:
+            # We have reached the end of the list.
+            return self.done(self._result)
+
+        # Compare newly chosen item with current result.
+        return self.compare(self._result, self._pos)
+
+    def compare(self, left, right):
+        self._rid = random.randint(1, 2 ** 30)
+        self._pos = right
+        return {
+            "type": "compare",
+            "left": left,
+            "right": right,
+            "request_id": self._rid,
+        }
+
+    def done(self, n):
+        return {"type": "done", "result": n}
+
+
+session = Max()
 
 
 @bottle.post("/")
 def root():
+    msg = bottle.request.json
+    print("request", msg)
+    msg_type = msg.get("type")
+    assert msg_type in ("compute_max", "comp_result")
+    if msg_type == "compute_max":
+        n = msg["length"]
+        assert n > 0
+        o = session.new(n)
+    else:
+        o = session.decide(msg["answer"], msg["request_id"])
+
+    print("result", o, session._pos)
     bottle.response.content_type = "application/json"
-    return {"type": "done", "result": 0}
+    return o
 
 
 bottle.run(host="localhost", port=5000)
-- 
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