Merge pull request #2510 from danjm/NewUI-flat-token-balance

[NewUI] Improving gas precision and send (token) balance validation; max amount feature

17 files changed, 387 insertions, 82 deletions

diff --git a/ui/app/actions.js b/ui/app/actions.js
index 5d3befa63..93cd40ed6 100644
--- a/ui/app/actions.js
+++ b/ui/app/actions.js
@@ -140,6 +140,7 @@ var actions = {
   UPDATE_GAS_PRICE: 'UPDATE_GAS_PRICE',
   UPDATE_GAS_TOTAL: 'UPDATE_GAS_TOTAL',
   UPDATE_SEND_FROM: 'UPDATE_SEND_FROM',
+  UPDATE_SEND_TOKEN_BALANCE: 'UPDATE_SEND_TOKEN_BALANCE',
   UPDATE_SEND_TO: 'UPDATE_SEND_TO',
   UPDATE_SEND_AMOUNT: 'UPDATE_SEND_AMOUNT',
   UPDATE_SEND_MEMO: 'UPDATE_SEND_MEMO',
@@ -148,6 +149,7 @@ var actions = {
   updateGasLimit,
   updateGasPrice,
   updateGasTotal,
+  updateSendTokenBalance,
   updateSendFrom,
   updateSendTo,
   updateSendAmount,
@@ -584,6 +586,13 @@ function updateGasTotal (gasTotal) {
   }
 }
 
+function updateSendTokenBalance (tokenBalance) {
+  return {
+    type: actions.UPDATE_SEND_TOKEN_BALANCE,
+    value: tokenBalance,
+  }
+}
+
 function updateSendFrom (from) {
   return {
     type: actions.UPDATE_SEND_FROM,
diff --git a/ui/app/components/currency-input.js b/ui/app/components/currency-input.js
new file mode 100644
index 000000000..5e534d87b
--- /dev/null
+++ b/ui/app/components/currency-input.js
@@ -0,0 +1,93 @@
+const Component = require('react').Component
+const h = require('react-hyperscript')
+const inherits = require('util').inherits
+
+module.exports = CurrencyInput
+
+inherits(CurrencyInput, Component)
+function CurrencyInput (props) {
+  Component.call(this)
+
+  this.state = {
+    value: sanitizeValue(props.value),
+  }
+}
+
+function removeNonDigits (str) {
+  return str.match(/\d|$/g).join('')
+}
+
+// Removes characters that are not digits, then removes leading zeros
+function sanitizeInteger (val) {
+  return String(parseInt(removeNonDigits(val) || '0', 10))
+}
+
+function sanitizeDecimal (val) {
+  return removeNonDigits(val)
+}
+
+// Take a single string param and returns a non-negative integer or float as a string.
+// Breaks the input into three parts: the integer, the decimal point, and the decimal/fractional part.
+// Removes leading zeros from the integer, and non-digits from the integer and decimal
+// The integer is returned as '0' in cases where it would be empty. A decimal point is
+// included in the returned string if one is included in the param
+// Examples:
+//  sanitizeValue('0') -> '0'
+//  sanitizeValue('a') -> '0'
+//  sanitizeValue('010.') -> '10.'
+//  sanitizeValue('0.005') -> '0.005'
+//  sanitizeValue('22.200') -> '22.200'
+//  sanitizeValue('.200') -> '0.200'
+//  sanitizeValue('a.b.1.c,89.123') -> '0.189123'
+function sanitizeValue (value) {
+  let [,integer, point, decimal] = (/([^.]*)([.]?)([^.]*)/).exec(value)
+
+  integer = sanitizeInteger(integer) || '0'
+  decimal = sanitizeDecimal(decimal)
+
+  return `${integer}${point}${decimal}`
+}
+
+CurrencyInput.prototype.handleChange = function (newValue) {
+  const { onInputChange } = this.props
+
+  this.setState({ value: sanitizeValue(newValue) })
+
+  onInputChange(sanitizeValue(newValue))
+}
+
+// If state.value === props.value plus a decimal point, or at least one
+// zero or a decimal point and at least one zero, then this returns state.value
+// after it is sanitized with getValueParts
+CurrencyInput.prototype.getValueToRender = function () {
+  const { value } = this.props
+  const { value: stateValue } = this.state
+
+  const trailingStateString = (new RegExp(`^${value}(.+)`)).exec(stateValue)
+  const trailingDecimalAndZeroes = trailingStateString && (/^[.0]0*/).test(trailingStateString[1])
+
+  return sanitizeValue(trailingDecimalAndZeroes
+    ? stateValue
+    : value)
+}
+
+CurrencyInput.prototype.render = function () {
+  const {
+    className,
+    placeholder,
+    readOnly,
+  } = this.props
+
+  const inputSizeMultiplier = readOnly ? 1 : 1.2
+
+  const valueToRender = this.getValueToRender()
+
+  return h('input', {
+    className,
+    value: valueToRender,
+    placeholder,
+    size: valueToRender.length * inputSizeMultiplier,
+    readOnly,
+    onChange: e => this.handleChange(e.target.value),
+  })
+}
diff --git a/ui/app/components/customize-gas-modal/index.js b/ui/app/components/customize-gas-modal/index.js
index 101a19d9f..b77e1990f 100644
--- a/ui/app/components/customize-gas-modal/index.js
+++ b/ui/app/components/customize-gas-modal/index.js
@@ -73,6 +73,8 @@ function getOriginalState (props) {
     gasLimit,
     gasTotal,
     error: null,
+    priceSigZeros: '',
+    priceSigDec: '',
   }
 }
 
@@ -107,19 +109,17 @@ CustomizeGasModal.prototype.validate = function ({ gasTotal, gasLimit }) {
   const {
     amount,
     balance,
-    primaryCurrency,
     selectedToken,
     amountConversionRate,
     conversionRate,
   } = this.props
 
   let error = null
-
+  
   const balanceIsSufficient = isBalanceSufficient({
     amount,
     gasTotal,
     balance,
-    primaryCurrency,
     selectedToken,
     amountConversionRate,
     conversionRate,
@@ -170,6 +170,13 @@ CustomizeGasModal.prototype.convertAndSetGasLimit = function (newGasLimit) {
 
 CustomizeGasModal.prototype.convertAndSetGasPrice = function (newGasPrice) {
   const { gasLimit } = this.state
+  const sigZeros = String(newGasPrice).match(/^\d+[.]\d*?(0+)$/)
+  const sigDec = String(newGasPrice).match(/^\d+([.])0*$/)
+
+  this.setState({
+    priceSigZeros: sigZeros && sigZeros[1] || '',
+    priceSigDec: sigDec && sigDec[1] || '',
+  })
 
   const gasPrice = conversionUtil(newGasPrice, {
     fromNumericBase: 'dec',
@@ -191,15 +198,17 @@ CustomizeGasModal.prototype.convertAndSetGasPrice = function (newGasPrice) {
 
 CustomizeGasModal.prototype.render = function () {
   const { hideModal } = this.props
-  const { gasPrice, gasLimit, gasTotal, error } = this.state
+  const { gasPrice, gasLimit, gasTotal, error, priceSigZeros, priceSigDec } = this.state
 
-  const convertedGasPrice = conversionUtil(gasPrice, {
+  let convertedGasPrice = conversionUtil(gasPrice, {
     fromNumericBase: 'hex',
     toNumericBase: 'dec',
     fromDenomination: 'WEI',
     toDenomination: 'GWEI',
   })
 
+  convertedGasPrice += convertedGasPrice.match(/[.]/) ? priceSigZeros : `${priceSigDec}${priceSigZeros}`
+
   const convertedGasLimit = conversionUtil(gasLimit, {
     fromNumericBase: 'hex',
     toNumericBase: 'dec',
@@ -224,7 +233,7 @@ CustomizeGasModal.prototype.render = function () {
           value: convertedGasPrice,
           min: MIN_GAS_PRICE_GWEI,
           // max: 1000,
-          step: MIN_GAS_PRICE_GWEI,
+          step: multiplyCurrencies(MIN_GAS_PRICE_GWEI, 10),
           onChange: value => this.convertAndSetGasPrice(value),
           title: 'Gas Price (GWEI)',
           copy: 'We calculate the suggested gas prices based on network success rates.',
diff --git a/ui/app/components/input-number.js b/ui/app/components/input-number.js
index e28807c13..12dec2957 100644
--- a/ui/app/components/input-number.js
+++ b/ui/app/components/input-number.js
@@ -5,7 +5,7 @@ const {
   addCurrencies,
   conversionGTE,
   conversionLTE,
-  toNegative,
+  subtractCurrencies,
 } = require('../conversion-util')
 
 module.exports = InputNumber
@@ -17,18 +17,24 @@ function InputNumber () {
   this.setValue = this.setValue.bind(this)
 }
 
+function isValidInput (text) {
+  const re = /^([1-9]\d*|0)(\.|\.\d*)?$/
+  return re.test(text)
+}
+
 InputNumber.prototype.setValue = function (newValue) {
+  if (newValue && !isValidInput(newValue)) return
   const { fixed, min = -1, max = Infinity, onChange } = this.props
 
-  newValue = Number(fixed ? newValue.toFixed(4) : newValue)
+  newValue = fixed ? newValue.toFixed(4) : newValue
 
   const newValueGreaterThanMin = conversionGTE(
-    { value: newValue, fromNumericBase: 'dec' },
+    { value: newValue || '0', fromNumericBase: 'dec' },
     { value: min, fromNumericBase: 'hex' },
   )
 
   const newValueLessThanMax = conversionLTE(
-    { value: newValue, fromNumericBase: 'dec' },
+    { value: newValue || '0', fromNumericBase: 'dec' },
     { value: max, fromNumericBase: 'hex' },
   )
   if (newValueGreaterThanMin && newValueLessThanMax) {
@@ -46,8 +52,8 @@ InputNumber.prototype.render = function () {
   return h('div.customize-gas-input-wrapper', {}, [
     h('input.customize-gas-input', {
       placeholder,
-      type: 'number',
       value,
+      step,
       onChange: (e) => this.setValue(e.target.value),
     }),
     h('span.gas-tooltip-input-detail', {}, [unitLabel]),
@@ -57,7 +63,7 @@ InputNumber.prototype.render = function () {
       }),
       h('i.fa.fa-angle-down', {
         style: { cursor: 'pointer' },
-        onClick: () => this.setValue(addCurrencies(value, toNegative(step))),
+        onClick: () => this.setValue(subtractCurrencies(value, step)),
       }),
     ]),
   ])
diff --git a/ui/app/components/pending-tx/confirm-send-token.js b/ui/app/components/pending-tx/confirm-send-token.js
index 3b8ae7f7f..f14da38ef 100644
--- a/ui/app/components/pending-tx/confirm-send-token.js
+++ b/ui/app/components/pending-tx/confirm-send-token.js
@@ -15,6 +15,9 @@ const {
   multiplyCurrencies,
   addCurrencies,
 } = require('../../conversion-util')
+const {
+  calcTokenAmount,
+} = require('../../token-util')
 
 const { MIN_GAS_PRICE_HEX } = require('../send/send-constants')
 
@@ -73,8 +76,7 @@ ConfirmSendToken.prototype.getAmount = function () {
   const { params = [] } = tokenData
   const { value } = params[1] || {}
   const { decimals } = token
-  const multiplier = Math.pow(10, Number(decimals || 0))
-  const sendTokenAmount = Number(value / multiplier)
+  const sendTokenAmount = calcTokenAmount(value, decimals)
 
   return {
     fiat: tokenExchangeRate
diff --git a/ui/app/components/send/currency-display.js b/ui/app/components/send/currency-display.js
index 45986e371..8b72b3e6d 100644
--- a/ui/app/components/send/currency-display.js
+++ b/ui/app/components/send/currency-display.js
@@ -1,6 +1,7 @@
 const Component = require('react').Component
 const h = require('react-hyperscript')
 const inherits = require('util').inherits
+const CurrencyInput = require('../currency-input')
 const { conversionUtil, multiplyCurrencies } = require('../../conversion-util')
 
 module.exports = CurrencyDisplay
@@ -8,10 +9,6 @@ module.exports = CurrencyDisplay
 inherits(CurrencyDisplay, Component)
 function CurrencyDisplay () {
   Component.call(this)
-
-  this.state = {
-    value: null,
-  }
 }
 
 function isValidInput (text) {
@@ -49,13 +46,11 @@ CurrencyDisplay.prototype.render = function () {
     convertedCurrency,
     readOnly = false,
     inError = false,
-    value: initValue,
+    value,
     handleChange,
-    validate,
   } = this.props
-  const { value } = this.state
 
-  const initValueToRender = conversionUtil(initValue, {
+  const valueToRender = conversionUtil(value, {
     fromNumericBase: 'hex',
     toNumericBase: 'dec',
     fromDenomination: 'WEI',
@@ -63,7 +58,7 @@ CurrencyDisplay.prototype.render = function () {
     conversionRate,
   })
 
-  const convertedValue = conversionUtil(value || initValueToRender, {
+  const convertedValue = conversionUtil(valueToRender, {
     fromNumericBase: 'dec',
     fromCurrency: primaryCurrency,
     toCurrency: convertedCurrency,
@@ -84,29 +79,14 @@ CurrencyDisplay.prototype.render = function () {
 
       h('div.currency-display__input-wrapper', [
 
-        h('input', {
+        h(CurrencyInput, {
           className: primaryBalanceClassName,
-          value: `${value || initValueToRender}`,
+          value: `${valueToRender}`,
           placeholder: '0',
-          size: (value || initValueToRender).length * inputSizeMultiplier,
           readOnly,
-          onChange: (event) => {
-            let newValue = event.target.value
-
-            if (newValue === '') {
-              newValue = '0'
-            } else if (newValue.match(/^0[1-9]$/)) {
-              newValue = newValue.match(/[1-9]/)[0]
-            }
-
-            if (newValue && !isValidInput(newValue)) {
-              event.preventDefault()
-            } else {
-              validate(this.getAmount(newValue))
-              this.setState({ value: newValue })
-            }
+          onInputChange: newValue => {
+            handleChange(this.getAmount(newValue))
           },
-          onBlur: event => !readOnly && handleChange(this.getAmount(event.target.value)),
         }),
 
         h('span.currency-display__currency-symbol', primaryCurrency),
diff --git a/ui/app/components/send/send-constants.js b/ui/app/components/send/send-constants.js
index 0a4f85bc9..a961ffcd8 100644
--- a/ui/app/components/send/send-constants.js
+++ b/ui/app/components/send/send-constants.js
@@ -11,6 +11,7 @@ const MIN_GAS_PRICE_GWEI = ethUtil.addHexPrefix(conversionUtil(MIN_GAS_PRICE_HEX
   toDenomination: 'GWEI',
   fromNumericBase: 'hex',
   toNumericBase: 'hex',
+  numberOfDecimals: 1,
 }))
 
 const MIN_GAS_TOTAL = multiplyCurrencies(MIN_GAS_LIMIT_HEX, MIN_GAS_PRICE_HEX, {
diff --git a/ui/app/components/send/send-utils.js b/ui/app/components/send/send-utils.js
index 6ec04a223..bd1197950 100644
--- a/ui/app/components/send/send-utils.js
+++ b/ui/app/components/send/send-utils.js
@@ -1,11 +1,17 @@
-const { addCurrencies, conversionGreaterThan } = require('../../conversion-util')
+const {
+  addCurrencies,
+  conversionUtil,
+  conversionGTE,
+} = require('../../conversion-util')
+const {
+  calcTokenAmount,
+} = require('../../token-util')
 
-function isBalanceSufficient ({
-  amount,
-  gasTotal,
+function isBalanceSufficient({
+  amount = '0x0',
+  gasTotal = '0x0',
   balance,
   primaryCurrency,
-  selectedToken,
   amountConversionRate,
   conversionRate,
 }) {
@@ -15,7 +21,7 @@ function isBalanceSufficient ({
     toNumericBase: 'hex',
   })
 
-  const balanceIsSufficient = conversionGreaterThan(
+  const balanceIsSufficient = conversionGTE(
     {
       value: balance,
       fromNumericBase: 'hex',
@@ -26,13 +32,37 @@ function isBalanceSufficient ({
       value: totalAmount,
       fromNumericBase: 'hex',
       conversionRate: amountConversionRate,
-      fromCurrency: selectedToken || primaryCurrency,
+      fromCurrency: primaryCurrency,
     },
   )
 
   return balanceIsSufficient
 }
 
+function isTokenBalanceSufficient({
+  amount = '0x0',
+  tokenBalance,
+  decimals,
+}) {
+  const amountInDec = conversionUtil(amount, {
+    fromNumericBase: 'hex',
+  })
+
+  const tokenBalanceIsSufficient = conversionGTE(
+    {
+      value: tokenBalance,
+      fromNumericBase: 'dec',
+    },
+    {
+      value: calcTokenAmount(amountInDec, decimals),
+      fromNumericBase: 'dec',
+    },
+  )
+
+  return tokenBalanceIsSufficient
+}
+
 module.exports = {
   isBalanceSufficient,
+  isTokenBalanceSufficient,
 }
diff --git a/ui/app/components/send/send-v2-container.js b/ui/app/components/send/send-v2-container.js
index 5a6e83ae6..51d5c4f89 100644
--- a/ui/app/components/send/send-v2-container.js
+++ b/ui/app/components/send/send-v2-container.js
@@ -13,6 +13,7 @@ const {
   getSendFrom,
   getCurrentCurrency,
   getSelectedTokenToFiatRate,
+  getSelectedTokenContract,
 } = require('../../selectors')
 
 module.exports = connect(mapStateToProps, mapDispatchToProps)(SendEther)
@@ -48,6 +49,7 @@ function mapStateToProps (state) {
     convertedCurrency: getCurrentCurrency(state),
     data,
     amountConversionRate: selectedToken ? tokenToFiatRate : conversionRate,
+    tokenContract: getSelectedTokenContract(state),
   }
 }
 
@@ -64,6 +66,9 @@ function mapDispatchToProps (dispatch) {
     setSelectedAddress: address => dispatch(actions.setSelectedAddress(address)),
     addToAddressBook: address => dispatch(actions.addToAddressBook(address)),
     updateGasTotal: newTotal => dispatch(actions.updateGasTotal(newTotal)),
+    updateGasPrice: newGasPrice => dispatch(actions.updateGasPrice(newGasPrice)),
+    updateGasLimit: newGasLimit => dispatch(actions.updateGasLimit(newGasLimit)),
+    updateSendTokenBalance: tokenBalance => dispatch(actions.updateSendTokenBalance(tokenBalance)),
     updateSendFrom: newFrom => dispatch(actions.updateSendFrom(newFrom)),
     updateSendTo: newTo => dispatch(actions.updateSendTo(newTo)),
     updateSendAmount: newAmount => dispatch(actions.updateSendAmount(newAmount)),
diff --git a/ui/app/components/tx-list-item.js b/ui/app/components/tx-list-item.js
index 26de19f15..4e76147a1 100644
--- a/ui/app/components/tx-list-item.js
+++ b/ui/app/components/tx-list-item.js
@@ -10,6 +10,7 @@ const Identicon = require('./identicon')
 const contractMap = require('eth-contract-metadata')
 
 const { conversionUtil, multiplyCurrencies } = require('../conversion-util')
+const { calcTokenAmount } = require('../token-util')
 
 const { getCurrentCurrency } = require('../selectors')
 
@@ -135,8 +136,7 @@ TxListItem.prototype.getSendTokenTotal = async function () {
   const { params = [] } = decodedData || {}
   const { value } = params[1] || {}
   const { decimals, symbol } = await this.getTokenInfo()
-  const multiplier = Math.pow(10, Number(decimals || 0))
-  const total = Number(value / multiplier)
+  const total = calcTokenAmount(value, decimals)
 
   const pair = symbol && `${symbol.toLowerCase()}_eth`
 
diff --git a/ui/app/conversion-util.js b/ui/app/conversion-util.js
index 9359d7c90..ee2950071 100644
--- a/ui/app/conversion-util.js
+++ b/ui/app/conversion-util.js
@@ -53,7 +53,7 @@ const toNormalizedDenomination = {
 }
 const toSpecifiedDenomination = {
   WEI: bigNumber => bigNumber.times(BIG_NUMBER_WEI_MULTIPLIER).round(),
-  GWEI: bigNumber => bigNumber.times(BIG_NUMBER_GWEI_MULTIPLIER).round(1),
+  GWEI: bigNumber => bigNumber.times(BIG_NUMBER_GWEI_MULTIPLIER).round(9),
 }
 const baseChange = {
   hex: n => n.toString(16),
@@ -145,6 +145,20 @@ const addCurrencies = (a, b, options = {}) => {
   })
 }
 
+const subtractCurrencies = (a, b, options = {}) => {
+  const {
+    aBase,
+    bBase,
+    ...conversionOptions
+  } = options
+  const value = (new BigNumber(a, aBase)).minus(b, bBase);
+
+  return converter({
+    value,
+    ...conversionOptions,
+  })
+}
+
 const multiplyCurrencies = (a, b, options = {}) => {
   const {
     multiplicandBase,
@@ -169,6 +183,7 @@ const conversionGreaterThan = (
 ) => {
   const firstValue = converter({ ...firstProps })
   const secondValue = converter({ ...secondProps })
+  
   return firstValue.gt(secondValue)
 }
 
@@ -202,4 +217,5 @@ module.exports = {
   conversionGTE,
   conversionLTE,
   toNegative,
+  subtractCurrencies,
 }
diff --git a/ui/app/css/itcss/components/send.scss b/ui/app/css/itcss/components/send.scss
index 4d7e6d71a..2bd192788 100644
--- a/ui/app/css/itcss/components/send.scss
+++ b/ui/app/css/itcss/components/send.scss
@@ -629,6 +629,15 @@
     }
   }
 
+  &__amount-max {
+    color: $curious-blue;
+    font-family: Roboto;
+    font-size: 12px;
+    left: 8px;
+    border: none;
+    cursor: pointer;
+  }
+
   &__gas-fee-display {
     width: 100%;
   }
diff --git a/ui/app/reducers/metamask.js b/ui/app/reducers/metamask.js
index 50c9712ff..3b93a1625 100644
--- a/ui/app/reducers/metamask.js
+++ b/ui/app/reducers/metamask.js
@@ -27,6 +27,7 @@ function reduceMetamask (state, action) {
       gasLimit: null,
       gasPrice: null,
       gasTotal: null,
+      tokenBalance: null,
       from: '',
       to: '',
       amount: '0x0',
@@ -196,6 +197,14 @@ function reduceMetamask (state, action) {
         },
       })
 
+    case actions.UPDATE_SEND_TOKEN_BALANCE:
+      return extend(metamaskState, {
+        send: {
+          ...metamaskState.send,
+          tokenBalance: action.value,
+        },
+      })
+
     case actions.UPDATE_SEND_FROM:
       return extend(metamaskState, {
         send: {
diff --git a/ui/app/selectors.js b/ui/app/selectors.js
index 3a15cef4c..a5f9a75d8 100644
--- a/ui/app/selectors.js
+++ b/ui/app/selectors.js
@@ -1,4 +1,5 @@
 const valuesFor = require('./util').valuesFor
+const abi = require('human-standard-token-abi')
 
 const {
   multiplyCurrencies,
@@ -22,6 +23,7 @@ const selectors = {
   getCurrentCurrency,
   getSendAmount,
   getSelectedTokenToFiatRate,
+  getSelectedTokenContract,
 }
 
 module.exports = selectors
@@ -149,3 +151,10 @@ function getSelectedTokenToFiatRate (state) {
 
   return tokenToFiatRate
 }
+
+function getSelectedTokenContract (state) {
+  const selectedToken = getSelectedToken(state)
+  return selectedToken
+    ? global.eth.contract(abi).at(selectedToken.address)
+    : null
+}
diff --git a/ui/app/send-v2.js b/ui/app/send-v2.js
index 6ce3e1b70..8c8b97a6d 100644
--- a/ui/app/send-v2.js
+++ b/ui/app/send-v2.js
@@ -2,6 +2,8 @@ const { inherits } = require('util')
 const PersistentForm = require('../lib/persistent-form')
 const h = require('react-hyperscript')
 
+const ethUtil = require('ethereumjs-util')
+
 const Identicon = require('./components/identicon')
 const FromDropdown = require('./components/send/from-dropdown')
 const ToAutoComplete = require('./components/send/to-autocomplete')
@@ -9,15 +11,24 @@ const CurrencyDisplay = require('./components/send/currency-display')
 const MemoTextArea = require('./components/send/memo-textarea')
 const GasFeeDisplay = require('./components/send/gas-fee-display-v2')
 
-const { MIN_GAS_TOTAL } = require('./components/send/send-constants')
+const {
+  MIN_GAS_TOTAL,
+  MIN_GAS_PRICE_HEX,
+  MIN_GAS_LIMIT_HEX,
+} = require('./components/send/send-constants')
 
 const {
   multiplyCurrencies,
   conversionGreaterThan,
+  subtractCurrencies,
 } = require('./conversion-util')
 const {
+  calcTokenAmount,
+} = require('./token-util')
+const {
   isBalanceSufficient,
-} = require('./components/send/send-utils.js')
+  isTokenBalanceSufficient,
+} = require('./components/send/send-utils')
 const { isValidAddress } = require('./util')
 
 module.exports = SendTransactionScreen
@@ -40,6 +51,37 @@ function SendTransactionScreen () {
   this.validateAmount = this.validateAmount.bind(this)
 }
 
+const getParamsForGasEstimate = function (selectedAddress, symbol, data) {
+  const estimatedGasParams = {
+    from: selectedAddress,
+    gas: '746a528800',
+  }
+
+  if (symbol) {
+    Object.assign(estimatedGasParams, { value: '0x0' })
+  }
+
+  if (data) {
+    Object.assign(estimatedGasParams, { data })
+  }
+
+  return estimatedGasParams
+}
+
+SendTransactionScreen.prototype.updateSendTokenBalance = function (usersToken) {
+  if (!usersToken) return
+
+  const {
+    selectedToken = {},
+    updateSendTokenBalance,
+  } = this.props
+  const { decimals } = selectedToken || {}
+
+  const tokenBalance = calcTokenAmount(usersToken.balance.toString(), decimals)
+
+  updateSendTokenBalance(tokenBalance)
+}
+
 SendTransactionScreen.prototype.componentWillMount = function () {
   const {
     updateTokenExchangeRate,
@@ -49,32 +91,24 @@ SendTransactionScreen.prototype.componentWillMount = function () {
     selectedAddress,
     data,
     updateGasTotal,
+    from,
+    tokenContract,
   } = this.props
   const { symbol } = selectedToken || {}
 
-  const estimateGasParams = {
-    from: selectedAddress,
-    gas: '746a528800',
-  }
-
   if (symbol) {
     updateTokenExchangeRate(symbol)
-    Object.assign(estimateGasParams, { value: '0x0' })
   }
 
-  if (data) {
-    Object.assign(estimateGasParams, { data })
-  }
+  const estimateGasParams = getParamsForGasEstimate(selectedAddress, symbol, data)
 
   Promise
     .all([
       getGasPrice(),
-      estimateGas({
-        from: selectedAddress,
-        gas: '746a528800',
-      }),
+      estimateGas(estimateGasParams),
+      tokenContract && tokenContract.balanceOf(from.address)
     ])
-    .then(([gasPrice, gas]) => {
+    .then(([gasPrice, gas, usersToken]) => {
 
       const newGasTotal = multiplyCurrencies(gas, gasPrice, {
         toNumericBase: 'hex',
@@ -82,9 +116,36 @@ SendTransactionScreen.prototype.componentWillMount = function () {
         multiplierBase: 16,
       })
       updateGasTotal(newGasTotal)
+      this.updateSendTokenBalance(usersToken)
     })
 }
 
+SendTransactionScreen.prototype.componentDidUpdate = function (prevProps) {
+  const {
+    from: { balance },
+    gasTotal,
+    tokenBalance,
+    amount,
+    selectedToken,
+  } = this.props
+  const {
+    from: { balance: prevBalance },
+    gasTotal: prevGasTotal,
+    tokenBalance: prevTokenBalance,
+  } = prevProps
+
+  const notFirstRender = [prevBalance, prevGasTotal].every(n => n !== null)
+
+  const balanceHasChanged = balance !== prevBalance
+  const gasTotalHasChange = gasTotal !== prevGasTotal
+  const tokenBalanceHasChanged = selectedToken && tokenBalance !== prevTokenBalance
+  const amountValidationChange = balanceHasChanged || gasTotalHasChange || tokenBalanceHasChanged
+
+  if (notFirstRender && amountValidationChange) {
+    this.validateAmount(amount)
+  }
+}
+
 SendTransactionScreen.prototype.renderHeaderIcon = function () {
   const { selectedToken } = this.props
 
@@ -144,12 +205,24 @@ SendTransactionScreen.prototype.renderErrorMessage = function (errorType) {
     : null
 }
 
+SendTransactionScreen.prototype.handleFromChange = async function (newFrom) {
+  const {
+    updateSendFrom,
+    tokenContract,
+  } = this.props
+
+  if (tokenContract) {
+    const usersToken = await tokenContract.balanceOf(newFrom.address)
+    this.updateSendTokenBalance(usersToken)
+  }
+  updateSendFrom(newFrom)
+}
+
 SendTransactionScreen.prototype.renderFromRow = function () {
   const {
     from,
     fromAccounts,
     conversionRate,
-    updateSendFrom,
   } = this.props
 
   const { fromDropdownOpen } = this.state
@@ -163,7 +236,7 @@ SendTransactionScreen.prototype.renderFromRow = function () {
         dropdownOpen: fromDropdownOpen,
         accounts: fromAccounts,
         selectedAccount: from,
-        onSelect: updateSendFrom,
+        onSelect: newFrom => this.handleFromChange(newFrom),
         openDropdown: () => this.setState({ fromDropdownOpen: true }),
         closeDropdown: () => this.setState({ fromDropdownOpen: false }),
         conversionRate,
@@ -227,9 +300,40 @@ SendTransactionScreen.prototype.handleAmountChange = function (value) {
   const amount = value
   const { updateSendAmount } = this.props
 
+  this.validateAmount(amount)
   updateSendAmount(amount)
 }
 
+SendTransactionScreen.prototype.setAmountToMax = function () {
+  const {
+    from: { balance },
+    gasTotal,
+    updateSendAmount,
+    updateSendErrors,
+    updateGasPrice,
+    updateGasLimit,
+    updateGasTotal,
+    tokenBalance,
+    selectedToken,
+  } = this.props
+  const { decimals } = selectedToken || {}
+  const multiplier = Math.pow(10, Number(decimals || 0))
+
+  const maxAmount = selectedToken
+    ? multiplyCurrencies(tokenBalance, multiplier, {toNumericBase: 'hex'})
+    : subtractCurrencies(
+      ethUtil.addHexPrefix(balance),
+      ethUtil.addHexPrefix(gasTotal),
+      { toNumericBase: 'hex' }
+    )
+
+  updateSendErrors({ amount: null })
+  updateGasPrice(MIN_GAS_PRICE_HEX)
+  updateGasLimit(MIN_GAS_LIMIT_HEX)
+  updateGasTotal(MIN_GAS_TOTAL)
+  updateSendAmount(maxAmount)
+}
+
 SendTransactionScreen.prototype.validateAmount = function (value) {
   const {
     from: { balance },
@@ -239,21 +343,31 @@ SendTransactionScreen.prototype.validateAmount = function (value) {
     primaryCurrency,
     selectedToken,
     gasTotal,
+    tokenBalance,
   } = this.props
+  const { decimals } = selectedToken || {}
   const amount = value
 
   let amountError = null
 
   const sufficientBalance = isBalanceSufficient({
-    amount,
+    amount: selectedToken ?  '0x0' : amount,
     gasTotal,
     balance,
     primaryCurrency,
-    selectedToken,
     amountConversionRate,
     conversionRate,
   })
 
+  let sufficientTokens
+  if (selectedToken) {
+    sufficientTokens = isTokenBalanceSufficient({
+      tokenBalance,
+      amount,
+      decimals,
+    })
+  }
+
   const amountLessThanZero = conversionGreaterThan(
     { value: 0, fromNumericBase: 'dec' },
     { value: amount, fromNumericBase: 'hex' },
@@ -261,6 +375,8 @@ SendTransactionScreen.prototype.validateAmount = function (value) {
 
   if (!sufficientBalance) {
     amountError = 'Insufficient funds.'
+  } else if (selectedToken && !sufficientTokens) {
+    amountError = 'Insufficient tokens.'
   } else if (amountLessThanZero) {
     amountError = 'Can not send negative amounts of ETH.'
   }
@@ -275,15 +391,19 @@ SendTransactionScreen.prototype.renderAmountRow = function () {
     convertedCurrency,
     amountConversionRate,
     errors,
+    amount,
   } = this.props
-
-  const { amount } = this.state
-
   return h('div.send-v2__form-row', [
-
+    
     h('div.send-v2__form-label', [
       'Amount:',
       this.renderErrorMessage('amount'),
+      !errors.amount && h('div.send-v2__amount-max', {
+        onClick: (event) => {
+          event.preventDefault()
+          this.setAmountToMax()
+        },
+      }, [ 'Max' ]),
     ]),
 
     h('div.send-v2__form-field', [
@@ -292,10 +412,9 @@ SendTransactionScreen.prototype.renderAmountRow = function () {
         primaryCurrency,
         convertedCurrency,
         selectedToken,
-        value: amount,
+        value: amount || '0x0',
         conversionRate: amountConversionRate,
         handleChange: this.handleAmountChange,
-        validate: this.validateAmount,
       }),
     ]),
 
@@ -335,8 +454,7 @@ SendTransactionScreen.prototype.renderGasRow = function () {
 }
 
 SendTransactionScreen.prototype.renderMemoRow = function () {
-  const { updateSendMemo } = this.props
-  const { memo } = this.state
+  const { updateSendMemo, memo } = this.props
 
   return h('div.send-v2__form-row', [
 
@@ -383,7 +501,7 @@ SendTransactionScreen.prototype.renderFooter = function () {
     errors: { amount: amountError, to: toError },
   } = this.props
 
-  const noErrors = amountError === null && toError === null
+  const noErrors = !amountError && toError === null
   const errorClass = noErrors ? '' : '__disabled'
 
   return h('div.send-v2__footer', [
@@ -437,7 +555,7 @@ SendTransactionScreen.prototype.onSubmit = function (event) {
     errors: { amount: amountError, to: toError },
   } = this.props
 
-  const noErrors = amountError === null && toError === null
+  const noErrors = !amountError && toError === null
 
   if (!noErrors) {
     return
diff --git a/ui/app/token-tracker.js b/ui/app/token-tracker.js
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/ui/app/token-tracker.js
diff --git a/ui/app/token-util.js b/ui/app/token-util.js
index eec518556..f84051ef5 100644
--- a/ui/app/token-util.js
+++ b/ui/app/token-util.js
@@ -31,6 +31,15 @@ const tokenInfoGetter = function () {
   }
 }
 
+function calcTokenAmount (value, decimals) {
+  const multiplier = Math.pow(10, Number(decimals || 0))
+  const amount = Number(value / multiplier)
+
+  return amount
+}
+
+
 module.exports = {
   tokenInfoGetter,
+  calcTokenAmount,
 }