calculate block reward.

lib/bcoin/block.js

@@ -5,6 +5,7 @@
  */
 
 var bcoin = require('../bcoin');
+var bn = require('bn.js');
 var utils = bcoin.utils;
 var constants = bcoin.protocol.constants;
 var network = bcoin.protocol.network;
@@ -253,18 +254,6 @@ Block.prototype._checkBlock = function checkBlock() {
   return true;
 };
 
-Block.prototype.__defineSetter__('height', function(height) {
-  return this._height = height;
-});
-
-Block.prototype.__defineGetter__('height', function() {
-  return this.getHeight(bcoin.chain.global);
-});
-
-Block.prototype.__defineGetter__('nextBlock', function() {
-  return this.getNextBlock(bcoin.chain.global);
-});
-
 Block.prototype.getHeight = function getHeight(chain) {
   if (this._height >= 0)
     return this._height;
@@ -296,19 +285,15 @@ Block.prototype.getNextBlock = function getNextBlock(chain) {
   return this._nextBlock = next;
 };
 
-Block.prototype.__defineGetter__('rhash', function() {
-  return utils.revHex(this.hash('hex'));
-});
-
 Block.reward = function reward(height) {
   var halvings = height / network.halvingInterval | 0;
   var reward;
 
   if (height < 0)
-    return utils.satoshi('0.0');
+    return new bn(0);
 
   if (halvings >= 64)
-    return utils.satoshi('0.0');
+    return new bn(0);
 
   reward = utils.satoshi('50.0');
   reward.iushrn(halvings);
@@ -316,8 +301,64 @@ Block.reward = function reward(height) {
   return reward;
 };
 
+Block.prototype.getReward = function getReward() {
+  var reward, base, fee, height;
+
+  if (this._reward)
+    return this._reward;
+
+  if (this.txs.length === 0 || !this.txs[0].isCoinbase()) {
+    return this._reward = {
+      fee: new bn(0),
+      reward: Block.reward(this.height)
+    };
+  }
+
+  reward = this.txs[0].outputs.reduce(function(total, output) {
+    total.iadd(output.value);
+    return total;
+  }, new bn(0));
+
+  base = Block.reward(this.height);
+
+  // If height is not accurate, artificially increase
+  // the reward era until base is smaller than the reward.
+  height = 0;
+  while (base.cmp(reward) > 0) {
+    base = Block.reward(height);
+    height += constants.halvingInterval;
+  }
+
+  fee = reward.sub(base);
+
+  return this._reward = {
+    fee: fee,
+    reward: reward
+  };
+};
+
+Block.prototype.__defineSetter__('height', function(height) {
+  return this._height = height;
+});
+
+Block.prototype.__defineGetter__('height', function() {
+  return this.getHeight(bcoin.chain.global);
+});
+
+Block.prototype.__defineGetter__('nextBlock', function() {
+  return this.getNextBlock(bcoin.chain.global);
+});
+
+Block.prototype.__defineGetter__('rhash', function() {
+  return utils.revHex(this.hash('hex'));
+});
+
 Block.prototype.__defineGetter__('reward', function() {
-  return Block.reward(this.height);
+  return this.getReward().reward;
+});
+
+Block.prototype.__defineGetter__('fee', function() {
+  return this.getReward().fee;
 });
 
 Block.prototype.inspect = function inspect() {
@@ -328,6 +369,8 @@ Block.prototype.inspect = function inspect() {
   copy.rhash = this.rhash;
   copy.height = this.height;
   copy.nextBlock = this.nextBlock;
+  copy.reward = utils.btc(this.reward);
+  copy.fee = utils.btc(this.fee);
   return copy;
 };