From d7fbf2a40761c617b656e687d8d122b7d2ee63e4 Mon Sep 17 00:00:00 2001
From: David Katz <15Dkatz@shcp.edu>
Date: Wed, 28 Sep 2022 12:47:00 -0700
Subject: [PATCH] Clear Blockchain Transactions

---
 wallet/transaction-pool.js      | 16 ++++++++++++++++
 wallet/transaction-pool.test.js | 34 +++++++++++++++++++++++++++++++++
 2 files changed, 50 insertions(+)

diff --git a/wallet/transaction-pool.js b/wallet/transaction-pool.js
index 4e546fb..73a3c48 100644
--- a/wallet/transaction-pool.js
+++ b/wallet/transaction-pool.js
@@ -5,6 +5,10 @@ class TransactionPool {
     this.transactionMap = {};
   }
 
+  clear() {
+    this.transactionMap = {};
+  }
+
   setTransaction(transaction) {
     this.transactionMap[transaction.id] = transaction;
   }
@@ -24,6 +28,18 @@ class TransactionPool {
       transaction => Transaction.validTransaction(transaction)
     );
   }
+
+  clearBlockchainTransactions({ chain }) {
+    for (let i=1; i<chain.length; i++) {
+      const block = chain[i];
+
+      for (let transaction of block.data) {
+        if (this.transactionMap[transaction.id]) {
+          delete this.transactionMap[transaction.id];
+        }
+      }
+    }
+  }
 }
 
 module.exports = TransactionPool;
diff --git a/wallet/transaction-pool.test.js b/wallet/transaction-pool.test.js
index e8a9ce0..d864d73 100644
--- a/wallet/transaction-pool.test.js
+++ b/wallet/transaction-pool.test.js
@@ -1,6 +1,7 @@
 const TransactionPool = require('./transaction-pool');
 const Transaction = require('./transaction');
 const Wallet = require('./index');
+const Blockchain = require('../blockchain');
 
 describe('TransactionPool', () => {
   let transactionPool, transaction, senderWallet;
@@ -70,4 +71,37 @@ describe('TransactionPool', () => {
       expect(errorMock).toHaveBeenCalled();
     });
   });
+
+  describe('clear()', () => {
+    it('clears the transactions', () => {
+      transactionPool.clear();
+
+      expect(transactionPool.transactionMap).toEqual({});
+    });
+  });
+
+  describe('clearBlockchainTransactions()', () => {
+    it('clears the pool of any existing blockchain transactions', () => {
+      const blockchain = new Blockchain();
+      const expectedTransactionMap = {};
+
+      for (let i=0; i<6; i++) {
+        const transaction = new Wallet().createTransaction({
+          recipient: 'foo', amount: 20
+        });
+
+        transactionPool.setTransaction(transaction);
+
+        if (i%2===0) {
+          blockchain.addBlock({ data: [transaction] });
+        } else {
+          expectedTransactionMap[transaction.id] = transaction;
+        }
+      }
+
+      transactionPool.clearBlockchainTransactions({ chain: blockchain.chain });
+
+      expect(transactionPool.transactionMap).toEqual(expectedTransactionMap);
+    });
+  });
 });