From d52f69afffdd5885c9b18b23c81336914e4fa05a Mon Sep 17 00:00:00 2001
From: Simon Warta <simon@warta.it>
Date: Thu, 30 Jan 2020 08:43:08 +0100
Subject: [PATCH] Implement Amount debugging using Decimal class

---
 packages/faucet/src/debugging.ts | 32 ++++++--------------------------
 1 file changed, 6 insertions(+), 26 deletions(-)

diff --git a/packages/faucet/src/debugging.ts b/packages/faucet/src/debugging.ts
index 5b5adc09ab..1fb4c9ab17 100644
--- a/packages/faucet/src/debugging.ts
+++ b/packages/faucet/src/debugging.ts
@@ -1,38 +1,18 @@
 import { Account, Amount } from "@iov/bcp";
+import { Decimal } from "@iov/encoding";
 import { MultiChainSigner } from "@iov/multichain";
 
 import { SendJob } from "./types";
 
-export function amountToNumber(amount: Amount): number {
-  const { quantity, fractionalDigits } = amount;
-  if (!quantity.match(/^[0-9]+$/)) {
-    throw new Error(`quantity must be a number, got ${quantity}`);
-  }
-  if (fractionalDigits < 0) {
-    throw new Error(`invalid fractional digits: ${fractionalDigits}`);
-  }
-  // let's remove those leading zeros...
-  const temp = quantity.replace(/^0+/, "");
-  // unless we need them to reach a decimal point
-  const pad = fractionalDigits - temp.length;
-  const trimmed = pad > 0 ? "0".repeat(pad) + temp : temp;
-
-  const cut = trimmed.length - fractionalDigits;
-  const whole = cut === 0 ? "0" : trimmed.slice(0, cut);
-  const decimal = fractionalDigits === 0 ? "" : `.${trimmed.slice(cut)}`;
-  const value = `${whole}${decimal}`;
-
-  return Number(value);
-}
-
 /** A string representation of a coin in a human-readable format that can change at any time */
-export function debugCoin(coin: Amount): string {
-  return `${amountToNumber(coin)} ${coin.tokenTicker}`;
+function debugAmount(amount: Amount): string {
+  const value = Decimal.fromAtomics(amount.quantity, amount.fractionalDigits).toString();
+  return `${value} ${amount.tokenTicker}`;
 }
 
 /** A string representation of a balance in a human-readable format that can change at any time */
 export function debugBalance(data: ReadonlyArray<Amount>): string {
-  return `[${data.map(debugCoin).join(", ")}]`;
+  return `[${data.map(debugAmount).join(", ")}]`;
 }
 
 /** A string representation of an account in a human-readable format that can change at any time */
@@ -53,6 +33,6 @@ export function logAccountsState(accounts: ReadonlyArray<Account>): void {
 export function logSendJob(signer: MultiChainSigner, job: SendJob): void {
   const from = signer.identityToAddress(job.sender);
   const to = job.recipient;
-  const amount = debugCoin(job.amount);
+  const amount = debugAmount(job.amount);
   console.info(`Sending ${amount} from ${from} to ${to} ...`);
 }