1 files changed, 136 insertions, 0 deletions
diff --git a/ui/app/components/token-input/token-input.component.js b/ui/app/components/token-input/token-input.component.js
new file mode 100644
index 000000000..d1388945b
--- /dev/null
+++ b/ui/app/components/token-input/token-input.component.js
@@ -0,0 +1,136 @@
+import React, { PureComponent } from 'react'
+import PropTypes from 'prop-types'
+import UnitInput from '../unit-input'
+import CurrencyDisplay from '../currency-display'
+import { getWeiHexFromDecimalValue } from '../../helpers/conversions.util'
+import ethUtil from 'ethereumjs-util'
+import { conversionUtil, multiplyCurrencies } from '../../conversion-util'
+import { ETH } from '../../constants/common'
+
+/**
+ * Component that allows user to enter token values as a number, and props receive a converted
+ * hex value. props.value, used as a default or forced value, should be a hex value, which
+ * gets converted into a decimal value.
+ */
+export default class TokenInput extends PureComponent {
+  static contextTypes = {
+    t: PropTypes.func,
+  }
+
+  static propTypes = {
+    currentCurrency: PropTypes.string,
+    onChange: PropTypes.func,
+    onBlur: PropTypes.func,
+    value: PropTypes.string,
+    suffix: PropTypes.string,
+    showFiat: PropTypes.bool,
+    selectedToken: PropTypes.object,
+    selectedTokenExchangeRate: PropTypes.number,
+  }
+
+  constructor (props) {
+    super(props)
+
+    const { value: hexValue } = props
+    const decimalValue = hexValue ? this.getDecimalValue(props) : 0
+
+    this.state = {
+      decimalValue,
+      hexValue,
+    }
+  }
+
+  componentDidUpdate (prevProps) {
+    const { value: prevPropsHexValue } = prevProps
+    const { value: propsHexValue } = this.props
+    const { hexValue: stateHexValue } = this.state
+
+    if (prevPropsHexValue !== propsHexValue && propsHexValue !== stateHexValue) {
+      const decimalValue = this.getDecimalValue(this.props)
+      this.setState({ hexValue: propsHexValue, decimalValue })
+    }
+  }
+
+  getDecimalValue (props) {
+    const { value: hexValue, selectedToken: { decimals, symbol } = {} } = props
+
+    const multiplier = Math.pow(10, Number(decimals || 0))
+    const decimalValueString = conversionUtil(ethUtil.addHexPrefix(hexValue), {
+      fromNumericBase: 'hex',
+      toNumericBase: 'dec',
+      toCurrency: symbol,
+      conversionRate: multiplier,
+      invertConversionRate: true,
+    })
+
+    return Number(decimalValueString) || 0
+  }
+
+  handleChange = decimalValue => {
+    const { selectedToken: { decimals } = {}, onChange } = this.props
+
+    const multiplier = Math.pow(10, Number(decimals || 0))
+    const hexValue = multiplyCurrencies(decimalValue || 0, multiplier, { toNumericBase: 'hex' })
+
+    this.setState({ hexValue, decimalValue })
+    onChange(hexValue)
+  }
+
+  handleBlur = () => {
+    this.props.onBlur(this.state.hexValue)
+  }
+
+  renderConversionComponent () {
+    const { selectedTokenExchangeRate, showFiat, currentCurrency } = this.props
+    const { decimalValue } = this.state
+    let currency, numberOfDecimals
+
+    if (showFiat) {
+      // Display Fiat
+      currency = currentCurrency
+      numberOfDecimals = 2
+    } else {
+      // Display ETH
+      currency = ETH
+      numberOfDecimals = 6
+    }
+
+    const decimalEthValue = (decimalValue * selectedTokenExchangeRate) || 0
+    const hexWeiValue = getWeiHexFromDecimalValue({
+      value: decimalEthValue,
+      fromCurrency: ETH,
+      fromDenomination: ETH,
+    })
+
+    return selectedTokenExchangeRate
+      ? (
+        <CurrencyDisplay
+          className="currency-input__conversion-component"
+          currency={currency}
+          value={hexWeiValue}
+          numberOfDecimals={numberOfDecimals}
+        />
+      ) : (
+        <div className="currency-input__conversion-component">
+          { this.context.t('noConversionRateAvailable') }
+        </div>
+      )
+  }
+
+  render () {
+    const { suffix, ...restProps } = this.props
+    const { decimalValue } = this.state
+
+    return (
+      <UnitInput
+        {...restProps}
+        suffix={suffix}
+        onChange={this.handleChange}
+        onBlur={this.handleBlur}
+        value={decimalValue}
+      >
+        { this.renderConversionComponent() }
+      </UnitInput>
+    )
+  }
+}