From 2d77bf0da98a115e81b9480206667a312300796c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ga=C3=ABtan=20Renaudeau?= <gaetan.renaudeau@ledger.fr>
Date: Fri, 15 Jun 2018 10:09:39 +0200
Subject: [PATCH] Improve InputCurrency

- you have more control on what you type, no more weird "empty input" cases
- it prevents to type more digits than the currency allows of magnitude
- it do everything to prevent you from typing weird things
---
 src/components/base/InputCurrency/index.js | 85 ++++++++++++----------
 1 file changed, 47 insertions(+), 38 deletions(-)

diff --git a/src/components/base/InputCurrency/index.js b/src/components/base/InputCurrency/index.js
index 97623746..da1963b0 100644
--- a/src/components/base/InputCurrency/index.js
+++ b/src/components/base/InputCurrency/index.js
@@ -6,7 +6,6 @@ import styled from 'styled-components'
 import { formatCurrencyUnit } from '@ledgerhq/live-common/lib/helpers/currencies'
 
 import noop from 'lodash/noop'
-import isNaN from 'lodash/isNaN'
 
 import Box from 'components/base/Box'
 import Input from 'components/base/Input'
@@ -14,6 +13,43 @@ import Select from 'components/base/LegacySelect'
 
 import type { Unit } from '@ledgerhq/live-common/lib/types'
 
+// TODO move this back to live common
+const numbers = '0123456789'
+const sanitizeValueString = (
+  unit: Unit,
+  valueString: string,
+): {
+  display: string,
+  value: string,
+} => {
+  let display = ''
+  let value = ''
+  let decimals = -1
+  for (let i = 0; i < valueString.length; i++) {
+    const c = valueString[i]
+    if (numbers.indexOf(c) !== -1) {
+      if (decimals >= 0) {
+        decimals++
+        if (decimals > unit.magnitude) break
+        value += c
+        display += c
+      } else if (value !== '0') {
+        value += c
+        display += c
+      }
+    } else if (decimals === -1 && (c === ',' || c === '.')) {
+      if (i === 0) display = '0'
+      decimals = 0
+      display += '.'
+    }
+  }
+  for (let i = decimals; i < unit.magnitude; ++i) {
+    value += '0'
+  }
+  if (!value) value = '0'
+  return { display, value }
+}
+
 function format(unit: Unit, value: number, { isFocused, showAllDigits, subMagnitude }) {
   // FIXME do we need locale for the input too ?
   return formatCurrencyUnit(unit, value, {
@@ -81,9 +117,10 @@ class InputCurrency extends PureComponent<Props, State> {
   componentWillReceiveProps(nextProps: Props) {
     const { value, showAllDigits, unit } = this.props
     const needsToBeReformatted =
-      value !== nextProps.value ||
-      showAllDigits !== nextProps.showAllDigits ||
-      unit !== nextProps.unit
+      !this.state.isFocused &&
+      (value !== nextProps.value ||
+        showAllDigits !== nextProps.showAllDigits ||
+        unit !== nextProps.unit)
     if (needsToBeReformatted) {
       const { isFocused } = this.state
       this.setState({
@@ -100,31 +137,13 @@ class InputCurrency extends PureComponent<Props, State> {
   }
 
   handleChange = (v: string) => {
-    // FIXME this is to refactor. this is hacky and don't cover everything..
-
-    v = v.toString().replace(/,/g, '.')
-
-    // allow to type directly `.` in input to have `0.`
-    if (v.startsWith('.')) {
-      v = `0${v}`
-    }
-
-    // forbid multiple 0 at start
-    if (v === '' || v.startsWith('00')) {
-      const { onChange, unit } = this.props
-      onChange(0, unit)
-      this.setState({ displayValue: '' })
-      return
-    }
-
-    // Check if value is valid Number
-    const asNumber = parseFloat(v)
-    if (isNaN(asNumber) || !isFinite(asNumber) || asNumber < 0) {
-      return
+    const { onChange, unit, value } = this.props
+    const r = sanitizeValueString(unit, v)
+    const satoshiValue = parseInt(r.value, 10)
+    if (value !== satoshiValue) {
+      onChange(satoshiValue, unit)
     }
-
-    this.emitOnChange(v)
-    this.setState({ displayValue: v || '' })
+    this.setState({ displayValue: r.display })
   }
 
   handleBlur = () => {
@@ -148,16 +167,6 @@ class InputCurrency extends PureComponent<Props, State> {
     })
   }
 
-  emitOnChange = (v: string) => {
-    const { onChange, unit } = this.props
-    const { displayValue } = this.state
-
-    if (displayValue.toString() !== v.toString()) {
-      const satoshiValue = Number(v) * 10 ** unit.magnitude
-      onChange(satoshiValue, unit)
-    }
-  }
-
   renderItem = item => item.code
 
   renderSelected = item => <Currency>{item.code}</Currency>