From f1e965800710787f7749409d43d732ac709326da Mon Sep 17 00:00:00 2001
From: sairajzero <sairaj0630@gmail.com>
Date: Mon, 6 Dec 2021 22:13:37 +0530
Subject: [PATCH] Audit Transaction

Store the following values upon successful transaction
- Timestamp
- Quanity, unit value, total cost
- Old/New Balance of Rupee and FLO for both seller and buyer
---
 args/schema.sql | 19 +++++++++++++++++
 src/coupling.js | 56 ++++++++++++++++++++++++++++++++++++++++++-------
 2 files changed, 68 insertions(+), 7 deletions(-)

diff --git a/args/schema.sql b/args/schema.sql
index c970b8b..f394531 100644
--- a/args/schema.sql
+++ b/args/schema.sql
@@ -137,6 +137,25 @@ CREATE TABLE priceHistory (
     rec_time DATETIME DEFAULT CURRENT_TIMESTAMP
 );
 
+CREATE TABLE auditTransaction(
+    rec_time DATETIME DEFAULT CURRENT_TIMESTAMP,
+    unit_price FLOAT NOT NULL,
+    quantity FLOAT NOT NULL,
+    total_cost FLOAT NOT NULL,
+    sellerID CHAR(34) NOT NULL,
+    FLO_seller_old FLOAT NOT NULL,
+    FLO_seller_new FLOAT NOT NULL,
+    Rupee_seller_old FLOAT NOT NULL,
+    Rupee_seller_new FLOAT NOT NULL,
+    buyerID CHAR(34) NOT NULL,
+    FLO_buyer_old FLOAT NOT NULL,
+    FLO_buyer_new FLOAT NOT NULL,
+    Rupee_buyer_old FLOAT NOT NULL,
+    Rupee_buyer_new FLOAT NOT NULL,
+    FOREIGN KEY (sellerID) REFERENCES Users(floID),
+    FOREIGN KEY (buyerID) REFERENCES Users(floID)
+);
+
 /* Backup feature (Table and Triggers) */
 
 CREATE TABLE _backup (
diff --git a/src/coupling.js b/src/coupling.js
index 6fc9f4e..72099bd 100644
--- a/src/coupling.js
+++ b/src/coupling.js
@@ -25,13 +25,17 @@ function processCoupling(bestPairQueue) {
                 clear_sell = spend_result.incomplete && !spend_result.flag_baseNull; //clear_sell can be true only if an order is placed without enough FLO
             processOrders(seller_best, buyer_best, txQueries, tx_quantity, clear_sell);
             updateBalance(seller_best, buyer_best, txQueries, bestPairQueue.cur_rate, tx_quantity);
-            //process txn query in SQL
-            DB.transaction(txQueries).then(_ => {
-                bestPairQueue.next(tx_quantity, spend_result.incomplete, spend_result.flag_baseNull);
-                console.log(`Transaction was successful! BuyOrder:${buyer_best.id}| SellOrder:${seller_best.id}`);
-                price.updateLastTime();
-                //Since a tx was successful, match again
-                processCoupling(bestPairQueue);
+            //begin audit
+            beginAudit(seller_best.floID, buyer_best.floID, bestPairQueue.cur_rate, tx_quantity).then(audit => {
+                //process txn query in SQL
+                DB.transaction(txQueries).then(_ => {
+                    bestPairQueue.next(tx_quantity, spend_result.incomplete, spend_result.flag_baseNull);
+                    console.log(`Transaction was successful! BuyOrder:${buyer_best.id}| SellOrder:${seller_best.id}`);
+                    audit.end();
+                    price.updateLastTime();
+                    //Since a tx was successful, match again
+                    processCoupling(bestPairQueue);
+                }).catch(error => console.error(error));
             }).catch(error => console.error(error));
         }).catch(error => console.error(error));
     }).catch(error => {
@@ -111,6 +115,44 @@ function updateBalance(seller_best, buyer_best, txQueries, cur_price, quantity)
     txQueries.push(["INSERT INTO Transactions (seller, buyer, quantity, unitValue) VALUES (?, ?, ?, ?)", [seller_best.floID, buyer_best.floID, quantity, cur_price]]);
 }
 
+function beginAudit(sellerID, buyerID, unit_price, quantity) {
+    return new Promise((resolve, reject) => {
+        auditBalance(sellerID, buyerID).then(old_bal => resolve({
+            end: () => endAudit(sellerID, buyerID, old_bal, unit_price, quantity)
+        })).catch(error => reject(error))
+    })
+}
+
+function endAudit(sellerID, buyerID, old_bal, unit_price, quantity) {
+    auditBalance(sellerID, buyerID).then(new_bal => {
+        DB.query("INSERT INTO auditTransaction (sellerID, buyerID, quantity, unit_price, total_cost, " +
+            " Rupee_seller_old, Rupee_seller_new, Rupee_buyer_old, Rupee_buyer_new," +
+            " FLO_seller_old, FLO_seller_new, FLO_buyer_old, FLO_buyer_new) " +
+            " Value (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)", [sellerID, buyerID, quantity, unit_price, quantity * unit_price,
+                old_bal[sellerID].Rupee, new_bal[sellerID].Rupee, old_bal[buyerID].Rupee, new_bal[buyerID].Rupee,
+                old_bal[sellerID].FLO, new_bal[sellerID].FLO, old_bal[buyerID].FLO, new_bal[buyerID].FLO,
+            ]).then(_ => null).catch(error => console.error(error))
+    }).catch(error => console.error(error));
+}
+
+function auditBalance(sellerID, buyerID) {
+    return new Promise((resolve, reject) => {
+        let balance = {
+            [sellerID]: {},
+            [buyerID]: {}
+        };
+        DB.query("SELECT floID, rupeeBalance FROM Cash WHERE floID IN (?, ?)", [sellerID, buyerID]).then(result => {
+            for (let i in result)
+                balance[result[i].floID].Rupee = result[i].rupeeBalance;
+            DB.query("SELECT floID, SUM(quantity) as floBal FROM Vault WHERE floID IN (?, ?) GROUP BY floID", [sellerID, buyerID]).then(result => {
+                for (let i in result)
+                    balance[result[i].floID].FLO = result[i].floBal;
+                resolve(balance);
+            }).catch(error => reject(error))
+        }).catch(error => reject(error))
+    })
+}
+
 module.exports = {
     initiate,
     group,