From 830d723e213c2753c8f21d23f6939130b4220d4e Mon Sep 17 00:00:00 2001
From: Daniel Cousens <github@dcousens.com>
Date: Tue, 30 Jan 2018 18:46:40 +1100
Subject: [PATCH] add MTP index, resolves #9

---
 index.js              |  6 ++++--
 indexes/mediantime.js | 42 ++++++++++++++++++++++++++++++++++++++++++
 rpc.js                |  2 ++
 3 files changed, 48 insertions(+), 2 deletions(-)
 create mode 100644 indexes/mediantime.js

diff --git a/index.js b/index.js
index e9c6f65..4b563ae 100644
--- a/index.js
+++ b/index.js
@@ -5,6 +5,7 @@ let parallel = require('run-parallel')
 let rpcUtil = require('./rpc')
 
 let FeeIndex = require('./indexes/fee')
+let MtpIndex = require('./indexes/mediantime')
 let ScriptIndex = require('./indexes/script')
 let TxIndex = require('./indexes/tx')
 let TxinIndex = require('./indexes/txin')
@@ -20,11 +21,12 @@ function Indexd (db, rpc) {
   this.emitter = new EventEmitter() // TODO: bind to this
   this.emitter.setMaxListeners(Infinity)
   this.indexes = {
+    fee: new FeeIndex(),
+    mtp: new MtpIndex(),
     script: new ScriptIndex(),
     tx: new TxIndex(),
     txin: new TxinIndex(),
-    txo: new TxoIndex(),
-    fee: new FeeIndex()
+    txo: new TxoIndex()
   }
 }
 
diff --git a/indexes/mediantime.js b/indexes/mediantime.js
new file mode 100644
index 0000000..dd43964
--- /dev/null
+++ b/indexes/mediantime.js
@@ -0,0 +1,42 @@
+let typeforce = require('typeforce')
+let types = require('./types')
+let vstruct = require('varstruct')
+
+let MTPPREFIX = 0x83
+let MTPTIP = types.tip(MTPPREFIX)
+let MTP = {
+  keyType: typeforce.compile({
+    medianTime: typeforce.UInt32,
+    height: typeforce.UInt32
+  }),
+  key: vstruct([
+    ['prefix', vstruct.Value(vstruct.UInt8, MTPPREFIX)],
+    ['medianTime', vstruct.UInt32BE], // big-endian for lexicographical sort
+    ['height', vstruct.UInt32LE]
+  ]),
+  valueType: typeforce.Null
+}
+
+function MtpIndex () {}
+
+MtpIndex.prototype.tip = function (db, callback) {
+  db.get(MTPTIP, {}, callback)
+}
+
+MtpIndex.prototype.connect = function (db, atomic, block, callback) {
+  let { height, medianTime } = block
+
+  atomic.put(MTP, { medianTime, height })
+  atomic.put(MTPTIP, {}, block)
+  callback()
+}
+
+MtpIndex.prototype.disconnect = function (atomic, block) {
+  let { height, medianTime } = block
+
+  atomic.del(MTP, { medianTime, height })
+  atomic.put(MTPTIP, {}, { blockId: block.prevBlockId, height })
+}
+
+module.exports = MtpIndex
+module.exports.TYPE = MTP
diff --git a/rpc.js b/rpc.js
index 05ae88d..5b2c5af 100644
--- a/rpc.js
+++ b/rpc.js
@@ -51,6 +51,8 @@ function block (rpc, blockId, done) {
     delete block.nextblockhash
     block.prevBlockId = block.previousblockhash
     delete block.prevblockhash
+    block.medianTime = block.mediantime
+    delete block.mediantime
 
     block.transactions = block.tx.map(t => augment(t))
     delete block.tx