From 855c1fd341352e140d8d7c26f52c113c1bd9e271 Mon Sep 17 00:00:00 2001
From: chiguireitor <johnvillarzavatti@gmail.com>
Date: Thu, 28 Dec 2017 22:28:00 -0400
Subject: [PATCH] Added support for a "balance" endpoint

---
 index.js          |  2 +-
 lib/express.js    | 38 ++++++++++++++++++++++++++++++++++++++
 lib/service.js    |  1 -
 package-lock.json |  5 +++++
 package.json      |  1 +
 5 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/index.js b/index.js
index 647f3ce..d919be2 100644
--- a/index.js
+++ b/index.js
@@ -21,7 +21,7 @@ service((err, adapter) => {
 
   // start the API server
   debug('starting API server')
-  app.use(api(adapter, {testnet: TESTNET}))
+  app.use(api(adapter, {testnet: TESTNET || REGTEST}))
   app.listen(process.env.SERVER_PORT);
   debug("App listening on port "+process.env.SERVER_PORT);
 })
diff --git a/lib/express.js b/lib/express.js
index 5068321..f998458 100644
--- a/lib/express.js
+++ b/lib/express.js
@@ -5,6 +5,7 @@ let express = require('express')
 let parallel = require('run-parallel')
 let rpc = require('./rpc')
 let types = require('indexd/types')
+let BN = require('bn.js')
 
 function Hex256bit (value) {
   return typeof value === 'string' &&
@@ -107,6 +108,43 @@ module.exports = function initialize (adapter, opts) {
     })
   })
 
+  router.get('/a/:address/balance', (req, res) => {
+    let scId
+    try {
+      let script = bitcoin.address.toOutputScript(req.params.address, network)
+      scId = bitcoin.crypto.sha256(script).toString('hex')
+    } catch (e) { return respond(req, res, e) }
+
+    let height = resolveHeight(req.query.height)
+
+    parallel({
+      tip: (cb) => adapter.blockchain.db.get(types.tip, {}, cb),
+      utxos: (cb) => adapter.utxosByScriptId(scId, height, cb)
+    }, (err, results) => {
+      if (err) return respond(req, res, err)
+
+      let tipHeight = results.tip.height
+      let balance = {
+        confirmed: new BN('0', 16),
+        unconfirmed: new BN('0', 16)
+      }
+
+      Object.keys(results.utxos).forEach(function (key) {
+        let utxo = results.utxos[key]
+        let height = utxo.height
+        if (height && height <= tipHeight) {
+          balance.confirmed.iadd(new BN(utxo.value))
+        } else {
+          balance.unconfirmed.iadd(new BN(utxo.value))
+        }
+      })
+      respond(req, res, null, {
+        confirmed: balance.confirmed.toString(10),
+        unconfirmed: balance.unconfirmed.toString(10)
+      })
+    })
+  })
+
   router.get('/a/:address/txs', (req, res) => {
     let scId
     try {
diff --git a/lib/service.js b/lib/service.js
index e7739de..cb026d0 100644
--- a/lib/service.js
+++ b/lib/service.js
@@ -71,4 +71,3 @@ module.exports = function initialize (callback) {
     callback(null, adapter)
   })
 }
-
diff --git a/package-lock.json b/package-lock.json
index a3e7056..43c65fe 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -111,6 +111,11 @@
         "readable-stream": "2.3.3"
       }
     },
+    "bn.js": {
+      "version": "4.11.8",
+      "resolved": "https://registry.npmjs.org/bn.js/-/bn.js-4.11.8.tgz",
+      "integrity": "sha512-ItfYfPLkWHUjckQCk8xC+LwxgK8NYcXywGigJgSwOP8Y2iyWT4f2vsZnoOXTTbo+o5yXmIUJ4gn5538SO5S3gA=="
+    },
     "body-parser": {
       "version": "1.18.2",
       "resolved": "https://registry.npmjs.org/body-parser/-/body-parser-1.18.2.tgz",
diff --git a/package.json b/package.json
index f20d5e0..cb98ea9 100644
--- a/package.json
+++ b/package.json
@@ -10,6 +10,7 @@
   "license": "MIT",
   "dependencies": {
     "bitcoinjs-lib": "^3.3.1",
+    "bn.js": "^4.11.8",
     "dotenv": "^4.0.0",
     "express": "^4.16.2",
     "indexd": "=0.8.13",