From bb6565d9661e2405f6ff543ef5256bc8932709f3 Mon Sep 17 00:00:00 2001
From: Duke Leto <duke@leto.net>
Date: Wed, 24 Jun 2020 20:49:53 -0400
Subject: [PATCH] Block time halving at height 340000

---
 src/main.cpp | 22 ++++++++++++++++++----
 src/pow.cpp  |  5 ++++-
 2 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index 73f49eb38..5b70ed2fd 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -3350,6 +3350,8 @@ static int64_t nTimeTotal = 0;
 bool FindBlockPos(int32_t tmpflag,CValidationState &state, CDiskBlockPos &pos, unsigned int nAddSize, unsigned int nHeight, uint64_t nTime, bool fKnown = false);
 bool ReceivedBlockTransactions(const CBlock &block, CValidationState& state, CBlockIndex *pindexNew, const CDiskBlockPos& pos);
 
+int32_t nFirstHalvingHeight = 340000;
+
 bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pindex, CCoinsViewCache& view, bool fJustCheck,bool fCheckPOW)
 {
     CDiskBlockPos blockPos;
@@ -3362,15 +3364,20 @@ bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pin
     AssertLockHeld(cs_main);
 
     bool ishush3 = strncmp(ASSETCHAINS_SYMBOL, "HUSH3",5) == 0 ? true : false;
+
+    // At startup, HUSH3 doesn't know a block height yet and so we must wait until
+    // connecting a block to set our private/blocktime flags, which are height-dependent
     if(!ASSETCHAINS_PRIVATE && ishush3) {
         unsigned int nHeight       = pindex->GetHeight();
-        if(nHeight >= 340000) {
-            // At startup, HUSH3 doesn't know a block height yet and so we must wait until
-            // connecting a block
-            fprintf(stderr, "%s: Going full z2z at height %d!\n",__func__,nHeight);
+        if(nHeight >= nFirstHalvingHeight) {
+            fprintf(stderr, "%s: Going full z2z at height %d!\n",__func__,pindex->GetHeight());
             ASSETCHAINS_PRIVATE = 1;
         }
     }
+    if (ishush3 && (ASSETCHAINS_BLOCKTIME != 75) && (chainActive.Height() >= nFirstHalvingHeight)) {
+        LogPrintf("%s: Blocktime halving to 75s at height %d!\n",__func__,pindex->GetHeight());
+        ASSETCHAINS_BLOCKTIME = 75;
+    }
 
     bool fExpensiveChecks = true;
     if (fCheckpointsEnabled) {
@@ -3968,6 +3975,13 @@ void static UpdateTip(CBlockIndex *pindexNew) {
         progress = (longestchain > 0 ) ? (double) chainActive.Height() / longestchain : 1.0;
     }
 
+    if(ishush3) {
+        if (ASSETCHAINS_BLOCKTIME != 75 && (chainActive.Height() >= nFirstHalvingHeight)) {
+            LogPrintf("%s: Blocktime halving to 75s at height %d!\n",__func__,chainActive.Height());
+            ASSETCHAINS_BLOCKTIME = 75;
+        }
+    }
+
     LogPrintf("%s: new best=%s  height=%d  log2_work=%.8g  tx=%lu  date=%s progress=%f  cache=%.1fMiB(%utx)\n", __func__,
               chainActive.LastTip()->GetBlockHash().ToString(), chainActive.Height(),
               log(chainActive.Tip()->chainPower.chainWork.getdouble())/log(2.0),
diff --git a/src/pow.cpp b/src/pow.cpp
index 79c41feb4..6d0262699 100644
--- a/src/pow.cpp
+++ b/src/pow.cpp
@@ -1,6 +1,6 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2014 The Bitcoin Core developers
-// Copyright (c) 2019      The Hush developers
+// Copyright (c) 2019-2020 The Hush developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
@@ -298,6 +298,9 @@ arith_uint256 zawy_TSA_EMA(int32_t height,int32_t tipdiff,arith_uint256 prevTarg
 
 unsigned int GetNextWorkRequired(const CBlockIndex* pindexLast, const CBlockHeader *pblock, const Consensus::Params& params)
 {
+    if (pindexLast->GetHeight() == 340000) {
+        LogPrintf("%s: Using blocktime=%d\n",__func__,ASSETCHAINS_BLOCKTIME);
+    }
     if (ASSETCHAINS_ALGO != ASSETCHAINS_EQUIHASH && ASSETCHAINS_STAKED == 0)
         return lwmaGetNextWorkRequired(pindexLast, pblock, params);