2 files changed, 55 insertions, 44 deletions

diff --git a/app/scripts/lib/eth-store.js b/app/scripts/lib/account-tracker.js
index ebba98f5c..bf949597b 100644
--- a/app/scripts/lib/eth-store.js
+++ b/app/scripts/lib/account-tracker.js
@@ -1,4 +1,4 @@
-/* Ethereum Store
+/* Account Tracker
  *
  * This module is responsible for tracking any number of accounts
  * and caching their current balances & transaction counts.
@@ -18,10 +18,6 @@ class EthereumStore extends ObservableStore {
   constructor (opts = {}) {
     super({
       accounts: {},
-      transactions: {},
-      currentBlockNumber: '0',
-      currentBlockHash: '',
-      currentBlockGasLimit: '',
     })
     this._provider = opts.provider
     this._query = new EthQuery(this._provider)
@@ -50,21 +46,6 @@ class EthereumStore extends ObservableStore {
     this.updateState({ accounts })
   }
 
-  addTransaction (txHash) {
-    const transactions = this.getState().transactions
-    transactions[txHash] = {}
-    this.updateState({ transactions })
-    if (!this._currentBlockNumber) return
-    this._updateTransaction(this._currentBlockNumber, txHash, noop)
-  }
-
-  removeTransaction (txHash) {
-    const transactions = this.getState().transactions
-    delete transactions[txHash]
-    this.updateState({ transactions })
-  }
-
-
   //
   // private
   //
@@ -72,12 +53,9 @@ class EthereumStore extends ObservableStore {
   _updateForBlock (block) {
     const blockNumber = '0x' + block.number.toString('hex')
     this._currentBlockNumber = blockNumber
-    this.updateState({ currentBlockNumber: parseInt(blockNumber) })
-    this.updateState({ currentBlockHash: `0x${block.hash.toString('hex')}`})
-    this.updateState({ currentBlockGasLimit: `0x${block.gasLimit.toString('hex')}` })
+
     async.parallel([
       this._updateAccounts.bind(this),
-      this._updateTransactions.bind(this, blockNumber),
     ], (err) => {
       if (err) return console.error(err)
       this.emit('block', this.getState())
@@ -104,26 +82,6 @@ class EthereumStore extends ObservableStore {
     })
   }
 
-  _updateTransactions (block, cb = noop) {
-    const transactions = this.getState().transactions
-    const txHashes = Object.keys(transactions)
-    async.each(txHashes, this._updateTransaction.bind(this, block), cb)
-  }
-
-  _updateTransaction (block, txHash, cb = noop) {
-    // would use the block here to determine how many confirmations the tx has
-    const transactions = this.getState().transactions
-    this._query.getTransaction(txHash, (err, result) => {
-      if (err) return cb(err)
-      // only populate if the entry is still present
-      if (transactions[txHash]) {
-        transactions[txHash] = result
-        this.updateState({ transactions })
-      }
-      cb(null, result)
-    })
-  }
-
   _getAccount (address, cb = noop) {
     const query = this._query
     async.parallel({
diff --git a/app/scripts/lib/pending-balance-calculator.js b/app/scripts/lib/pending-balance-calculator.js
new file mode 100644
index 000000000..c66bffbbb
--- /dev/null
+++ b/app/scripts/lib/pending-balance-calculator.js
@@ -0,0 +1,53 @@
+const BN = require('ethereumjs-util').BN
+const normalize = require('eth-sig-util').normalize
+
+class PendingBalanceCalculator {
+
+  // Must be initialized with two functions:
+  // getBalance => Returns a promise of a BN of the current balance in Wei
+  // getPendingTransactions => Returns an array of TxMeta Objects,
+  // which have txParams properties, which include value, gasPrice, and gas,
+  // all in a base=16 hex format.
+  constructor ({ getBalance, getPendingTransactions }) {
+    this.getPendingTransactions = getPendingTransactions
+    this.getNetworkBalance = getBalance
+  }
+
+  async getBalance() {
+    const results = await Promise.all([
+      this.getNetworkBalance(),
+      this.getPendingTransactions(),
+    ])
+
+    const balance = results[0]
+    const pending = results[1]
+
+    if (!balance) return undefined
+
+    const pendingValue = pending.reduce((total, tx) => {
+      return total.add(this.valueFor(tx))
+    }, new BN(0))
+
+    return `0x${balance.sub(pendingValue).toString(16)}`
+  }
+
+  valueFor (tx) {
+    const txValue = tx.txParams.value
+    const value = this.hexToBn(txValue)
+    const gasPrice = this.hexToBn(tx.txParams.gasPrice)
+
+    const gas = tx.txParams.gas
+    const gasLimit = tx.txParams.gasLimit
+    const gasLimitBn = this.hexToBn(gas || gasLimit)
+
+    const gasCost = gasPrice.mul(gasLimitBn)
+    return value.add(gasCost)
+  }
+
+  hexToBn (hex) {
+    return new BN(normalize(hex).substring(2), 16)
+  }
+
+}
+
+module.exports = PendingBalanceCalculator