From 07ab8e52876df4e80171bcdbeccd4bb6872bb3e5 Mon Sep 17 00:00:00 2001
From: irungentoo <irungentoo@gmail.com>
Date: Sat, 4 Oct 2014 12:03:39 -0400
Subject: [PATCH] Fixed group peer chosing algorithm.

Groups should be much more stable.
---
 toxcore/group.c | 32 +++++++++++++++++++++++++++++---
 1 file changed, 29 insertions(+), 3 deletions(-)

diff --git a/toxcore/group.c b/toxcore/group.c
index 4644b837..2fbd341c 100644
--- a/toxcore/group.c
+++ b/toxcore/group.c
@@ -198,7 +198,7 @@ static uint16_t calculate_comp_value(const uint8_t *pk1, const uint8_t *pk2)
         if (pk1[index] == pk2[index])
             continue;
 
-        cmp2 = abs((int)pk1[index] - (int)pk2[index]);
+        cmp2 = pk1[index] - pk2[index];
         break;
     }
 
@@ -244,8 +244,20 @@ static int add_to_closest(Group_Chats *g_c, int groupnumber, const uint8_t *real
         uint16_t comp_val = calculate_comp_value(g->real_pk, real_pk);
         uint16_t comp_d = 0;
 
-        for (i = 0; i < DESIRED_CLOSE_CONNECTIONS; ++i) {
-            uint16_t comp = calculate_comp_value(g->real_pk, g->closest_peers[i].real_pk);
+        for (i = 0; i < (DESIRED_CLOSE_CONNECTIONS / 2); ++i) {
+            uint16_t comp;
+            comp = calculate_comp_value(g->real_pk, g->closest_peers[i].real_pk);
+
+            if (comp > comp_val && comp > comp_d) {
+                index = i;
+                comp_d = comp;
+            }
+        }
+
+        comp_val = calculate_comp_value(real_pk, g->real_pk);
+
+        for (i = (DESIRED_CLOSE_CONNECTIONS / 2); i < DESIRED_CLOSE_CONNECTIONS; ++i) {
+            uint16_t comp = calculate_comp_value(g->closest_peers[i].real_pk, g->real_pk);
 
             if (comp > comp_val && comp > comp_d) {
                 index = i;
@@ -258,10 +270,24 @@ static int add_to_closest(Group_Chats *g_c, int groupnumber, const uint8_t *real
         return -1;
     }
 
+    uint8_t old_real_pk[crypto_box_PUBLICKEYBYTES];
+    uint8_t old_temp_pk[crypto_box_PUBLICKEYBYTES];
+    uint8_t old = 0;
+
+    if (g->closest_peers[index].entry) {
+        memcpy(old_real_pk, g->closest_peers[index].real_pk, crypto_box_PUBLICKEYBYTES);
+        memcpy(old_temp_pk, g->closest_peers[index].temp_pk, crypto_box_PUBLICKEYBYTES);
+        old = 1;
+    }
+
     g->closest_peers[index].entry = 1;
     memcpy(g->closest_peers[index].real_pk, real_pk, crypto_box_PUBLICKEYBYTES);
     memcpy(g->closest_peers[index].temp_pk, temp_pk, crypto_box_PUBLICKEYBYTES);
 
+    if (old) {
+        add_to_closest(g_c, groupnumber, old_real_pk, old_temp_pk);
+    }
+
     if (!g->changed)
         g->changed = GROUPCHAT_CLOSEST_ADDED;