finish interview

hono/src/index.ts

@@ -4,27 +4,54 @@ import { Hono } from 'hono'
 const app = new Hono()
 
 const accounts = {
-  '1': {amount: 1000},
-  '2': {amount: 1000},
+  '1' : {amount: 1000},
+  '2' : {amount: 1000},
 }
 
-const transactions = []
+const transactions :ITransferResponse[] = []
+
+interface ITransferResponse {
+  amount: number;
+  sender: '1' | '2';
+  receiver: '1' | '2';
+}
 
 app.post('/transfer', async (c) => {
-  const body = await c.req.json();
+  const body : ITransferResponse = await c.req.json();
   const { amount, sender, receiver } = body;
 
   if (amount <= 0) {
-    return c.json({ error: 'Amount must be greater than 0' }, 1000);
+    return c.json({ error: 'Amount must be greater than 0' });
   }
 
+  if (!Object.keys(accounts).includes(sender) || !Object.keys(accounts).includes(receiver)) {
+    return c.json({ error: 'Account does not exist.' });
+  }
+
+  const senderAccountAmt = accounts[sender].amount;
+  const receiverAccountAmt = accounts[receiver].amount;
+
+  if (amount > senderAccountAmt) {
+    return c.json({ error: 'Sender has insufficient balance' })
+  }
+
+  const newSenderAmount = senderAccountAmt - amount
+  const newReceiverAmount = receiverAccountAmt + amount
+
+  accounts[sender].amount = newSenderAmount;
+  accounts[receiver].amount = newReceiverAmount;
+  
   const transfer = {
     amount,
     sender,
     receiver
   }
 
-  console.log('transfer', transfe);
+  transactions.push(transfer)
+
+  console.log('transfer', transfer);
+  console.log('accounts', accounts);
+  console.log('transactions', transactions);
   return c.json(transfer)
 })