From 7e72a4d79dff125867cfc0acc7a014f346d652cc Mon Sep 17 00:00:00 2001
From: Fedor Indutny <fedor@indutny.com>
Date: Thu, 15 May 2014 02:59:07 +0400
Subject: [PATCH] utils: `toBTC()`

---
 lib/bcoin/utils.js | 18 ++++++++++++++++--
 test/utils-test.js | 10 ++++++++++
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/lib/bcoin/utils.js b/lib/bcoin/utils.js
index e8cf23d8..f09e9596 100644
--- a/lib/bcoin/utils.js
+++ b/lib/bcoin/utils.js
@@ -365,9 +365,23 @@ utils.revHex = function revHex(s) {
 utils.assert = function assert(val, msg) {
   if (!val)
     throw new Error(msg || 'Assertion failed');
-}
+};
 
 utils.assert.equal = function assertEqual(l, r, msg) {
   if (l != r)
     throw new Error(msg || ('Assertion failed: ' + l + ' != ' + r));
-}
+};
+
+utils.toBTC = function toBTC(satoshi) {
+  var m = new bn(10000000).mul(new bn(10));
+  var lo = satoshi.mod(m);
+  if (lo.cmpn(0) !== 0) {
+    lo = lo.toString(10);
+    while (lo.length < 8)
+      lo = '0' + lo;
+    lo = '.' + lo;
+  } else {
+    lo = '';
+  }
+  return satoshi.div(m).toString(10) + lo.replace(/0+$/, '');
+};
diff --git a/test/utils-test.js b/test/utils-test.js
index d0371998..d5fa8320 100644
--- a/test/utils-test.js
+++ b/test/utils-test.js
@@ -1,4 +1,5 @@
 var assert = require('assert');
+var bn = require('bn.js');
 var bcoin = require('../');
 
 describe('Utils', function() {
@@ -18,4 +19,13 @@ describe('Utils', function() {
     var target = bcoin.utils.bitsToTarget(bits);
     assert(bcoin.utils.testTarget(target, hash));
   });
+
+  it('should convert satoshi to btc', function() {
+    var btc = bcoin.utils.toBTC(new bn(5460));
+    assert.equal(btc, '0.0000546');
+    var btc = bcoin.utils.toBTC(new bn(54678).mul(new bn(1000000)));
+    assert.equal(btc, '546.78');
+    var btc = bcoin.utils.toBTC(new bn(5460).mul(new bn(10000000)));
+    assert.equal(btc, '546');
+  });
 });