From f58e748263a94afae4cd33b5fc12bee8897b8225 Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Sun, 8 Jan 2017 23:05:54 -0800
Subject: [PATCH] network: add minimum chainworks.

---
 lib/blockchain/chain.js  | 26 +++++++++++++-------------
 lib/protocol/networks.js | 20 ++++++++++++++++++--
 2 files changed, 31 insertions(+), 15 deletions(-)

diff --git a/lib/blockchain/chain.js b/lib/blockchain/chain.js
index b9bdbe9b..7f4204f8 100644
--- a/lib/blockchain/chain.js
+++ b/lib/blockchain/chain.js
@@ -1731,18 +1731,6 @@ Chain.prototype.isFull = function isFull(force) {
   return !this.isInitial(force);
 };
 
-/**
- * Potentially emit a `sync` event.
- * @private
- */
-
-Chain.prototype.maybeSync = function maybeSync() {
-  if (!this.synced && this.isFull()) {
-    this.synced = true;
-    this.emit('full');
-  }
-};
-
 /**
  * Test the chain to see if it is still in the initial
  * syncing phase. Mimic's bitcoind's `IsInitialBlockDownload()`
@@ -1758,7 +1746,7 @@ Chain.prototype.isInitial = function isInitial(force) {
   if (this.height < this.network.checkpoints.lastHeight)
     return true;
 
-  if (this.height < this.bestHeight - 24 * 6)
+  if (this.tip.chainwork.cmp(this.network.pow.chainwork) < 0)
     return true;
 
   if (this.tip.ts < util.now() - this.network.block.maxTipAge)
@@ -1767,6 +1755,18 @@ Chain.prototype.isInitial = function isInitial(force) {
   return false;
 };
 
+/**
+ * Potentially emit a `sync` event.
+ * @private
+ */
+
+Chain.prototype.maybeSync = function maybeSync() {
+  if (!this.synced && this.isFull()) {
+    this.synced = true;
+    this.emit('full');
+  }
+};
+
 /**
  * Get the fill percentage.
  * @returns {Number} percent - Ranges from 0.0 to 1.0.
diff --git a/lib/protocol/networks.js b/lib/protocol/networks.js
index d9313dd7..f06bb610 100644
--- a/lib/protocol/networks.js
+++ b/lib/protocol/networks.js
@@ -180,6 +180,16 @@ main.pow = {
 
   bits: 486604799,
 
+  /**
+   * Minimum chainwork for best chain.
+   * @const {BN}
+   */
+
+  chainwork: new BN(
+    '0000000000000000000000000000000000000000002cb971dd56d1c583c20f90',
+    'hex'
+  ),
+
   /**
    * Default retarget interval.
    * @const {Number}
@@ -550,6 +560,10 @@ testnet.pow = {
     'hex'
   ),
   bits: 486604799,
+  chainwork: new BN(
+    '0000000000000000000000000000000000000000000000198b4def2baa9338d6',
+    'hex'
+  ),
   targetTimespan: 14 * 24 * 60 * 60, // two weeks
   targetSpacing: 10 * 60,
   retargetInterval: 2016,
@@ -709,6 +723,7 @@ regtest.pow = {
     'hex'
   ),
   bits: 545259519,
+  chainwork: new BN(0),
   targetTimespan: 14 * 24 * 60 * 60, // two weeks
   targetSpacing: 10 * 60,
   retargetInterval: 2016,
@@ -864,6 +879,7 @@ segnet4.pow = {
     'hex'
   ),
   bits: 503447551,
+  chainwork: new BN(0),
   targetTimespan: 14 * 24 * 60 * 60, // two weeks
   targetSpacing: 10 * 60,
   retargetInterval: 2016,
@@ -912,7 +928,7 @@ segnet4.deployments = {
     name: 'segwit',
     bit: 1,
     startTime: 0,
-    timeout: 999999999999,
+    timeout: 0xffffffff,
     force: false
   }
 };
@@ -1038,7 +1054,7 @@ simnet.block = {
 
 simnet.bip30 = {};
 
-simnet.witness = false;
+simnet.witness = true;
 
 simnet.activationThreshold = 1512; // 75% for testchains