From e180672583968188ced34b56186a8edafb584f30 Mon Sep 17 00:00:00 2001
From: sairajzero <sairaj0630@gmail.com>
Date: Sun, 23 Apr 2023 02:55:49 +0530
Subject: [PATCH] Adding reverse option to address history query

- Using option `reverse` as true will query the latest 1000 (max val) tx instead of the 1st 1000 tx.
---
 lib/services/address/index.js | 73 +++++++++++++++++++++++------------
 1 file changed, 48 insertions(+), 25 deletions(-)

diff --git a/lib/services/address/index.js b/lib/services/address/index.js
index 2b70b8f2..3c2c2044 100644
--- a/lib/services/address/index.js
+++ b/lib/services/address/index.js
@@ -195,9 +195,13 @@ AddressService.prototype.getAddressHistory = function(addresses, options, stream
     options.mempoolOnly = false;
   }
 
+  if(_.isUndefined(options.reverse)) {
+    options.reverse = false;
+  }
+
   var old_support = false;
   //Quick support for `from` and `to` options (DEPRECATED! Not recommeded to use)
-  if( !_.isUndefined(options.from) || !_.isUndefined(options.to)) { 
+  if(!_.isUndefined(options.from) || !_.isUndefined(options.to)) { 
     old_support = true;
     options.from = options.from || 0;
     options.to = options.to || 0xffffffff; //Max value of to will actually be MAX_TX_QUERY_LIMIT_HISTORY
@@ -223,13 +227,18 @@ AddressService.prototype.getAddressHistory = function(addresses, options, stream
 
         addr_count++;
 
-        if(!results.items.some(x => x.txid() === tx.txid())) //push only if tx not already in array
-          results.items.unshift(tx); //using unshift, so that recent tx (low) are at front
+        if(!results.items.some(x => x.txid() === tx.txid())) {//add only if tx not already in array
+          if(!options.reverse)
+            results.items.unshift(tx); //using unshift, so that recent tx (low) are at front
+          else
+            results.items.push(tx);
+        } 
+          
         
         if(results.items.length > MAX_TX_QUERY_LIMIT_HISTORY) { //remove items from array when overflown
           results.items.sort((a, b) => (b.__height || 0xffffffff) - (a.__height || 0xffffffff) || b.txid().localeCompare(a.txid()));
           let del_count = results.items.length - MAX_TX_QUERY_LIMIT_HISTORY;
-          let start_index = old_support ? MAX_TX_QUERY_LIMIT_HISTORY : 0;
+          let start_index = (old_support || options.reverse) ? MAX_TX_QUERY_LIMIT_HISTORY : 0;
           results.items.splice(start_index, del_count);
 
           results.incomplete = true;
@@ -884,7 +893,9 @@ AddressService.prototype._getTxidStream = function(address, options) {
     //reverse: true // txids stream from low confirmations to high confirmations
   };
   //NOTE: commentted reverse to keep the order in asc when reading to preserve continuity when using `after` option
-
+  //reverse option can be used explictly when latest tx are required
+  if(options.reverse)
+    criteria.reverse = true;
   // txid stream
   var txidStream = this._db.createKeyStream(criteria);
 
@@ -1020,6 +1031,10 @@ AddressService.prototype._streamAddressSummary = function(address, options, stre
     options.mempoolOnly = false;
   }
 
+  if (_.isUndefined(options.reverse)) {
+    options.reverse = false;
+  }
+
   //declare the queue to process tx data
   var tmpTxList = {}; //store processed txid temporarily to ignore duplication
 
@@ -1081,10 +1096,11 @@ AddressService.prototype._streamAddressSummary = function(address, options, stre
 
   }
 
-  async.waterfall([
+    const waterfall_array = [];
 
+    waterfall_array.push(
     //Find start height if `after` option is passed
-    function(next){
+      function start_fall(next){
 
       if(_.isUndefined(options.after)) {
         return next();
@@ -1106,10 +1122,10 @@ AddressService.prototype._streamAddressSummary = function(address, options, stre
         
       });
 
-    },
+    });
 
-    // stream the rest of the confirmed txids out of the address index
-    function(next) {
+    // stream the confirmed txids out of the address index
+    function query_confirmed_txids(next) {
 
       if (options.mempoolOnly) {  //Option to query from mempool only (ie, unconfirmed txs only)
         return next();
@@ -1145,31 +1161,38 @@ AddressService.prototype._streamAddressSummary = function(address, options, stre
       var txidStream = self._getTxidStream(address, options);
       txidStream.pipe(txIdTransformStream);
       
-    },
+    }
 
     // query the mempool for relevant txs for this address
-    function(next) {
+    function query_mempool_txids(next) {
 
       if (!options.queryMempool) {
         return next(null, []);
       }
 
-      self._mempool.getTxidsByAddress(address, 'both', next);
-    },
+      self._mempool.getTxidsByAddress(address, 'both', function(mempoolTxids) {
 
-    // add the meta data such as input values, etc.
-    function(mempoolTxids, next) {
+        if (mempoolTxids.length <= 0) {
+          return next();
+        }
+  
+        mempoolTxids.map(id => q.push(id, chunkCallback));
+        next();
+      });
 
-      if (mempoolTxids.length <= 0) {
-        return next();
-      }
+    }
 
-      mempoolTxids.map(id => q.push(id, chunkCallback));
-      next();
-    },
+    if(options.reverse){ //when queried txs in reverse key order, mempool first then confirmed
+      waterfall_array.push(query_mempool_txids);
+      waterfall_array.push(query_confirmed_txids);
+    } else {  //when queried tx in key order, confirmed tx 1st, then mempool
+      waterfall_array.push(query_confirmed_txids);
+      waterfall_array.push(query_mempool_txids);
+    }
 
+    waterfall_array.push(
     //wait for queue to complete
-    function(next) {
+    function end_fall(next) {
 
       if(!q.started || q.idle()) //No tx in query (or) already finished querying
         return next();
@@ -1177,9 +1200,9 @@ AddressService.prototype._streamAddressSummary = function(address, options, stre
       else
         q.drain = () => next();
 
-    }
+    });
 
-  ], callback);
+  async.waterfall(waterfall_array, callback);
 
 }