# Program Breakdown

Here's a breakdown of the program's functionality:

1. **State Initialization**:

   ```jsx
   const [fee, setFee] = useState<number | null>(null);
   const [error, setError] = useState<string>('');
   const [senderAddress, setSenderAddress] = useState<string>('');
   const [receiverAddress, setReceiverAddress] = useState<string>('');
   const [rpcUrl, setRpcUrl] = useState<string>('');
   ```

   Here, React's `useState` hook initializes five pieces of state: `fee` for storing the estimated fee, `error` for any errors that occur during the estimation process, `senderAddress` and `receiverAddress` for the respective blockchain addresses involved in the transaction, and `rpcUrl` for the URL of the connected RPC.
2. **Effect Hook for Fee Estimation**:

   ```jsx
   useEffect(() => {
     // Async function to estimate transaction fee
     const estimateTransactionFee = async () => {
       // ... Code to estimate fee
     };
     estimateTransactionFee();
   }, []);
   ```

   This `useEffect` hook runs once when the component mounts, thanks to the empty dependency array (`[]`). It defines and invokes the `estimateTransactionFee` async function to estimate the transaction fee.
3. **Setting Up Connection and Transaction Details**:

   ```jsx
   const customRpcUrl = "https://testnet.dev2.eclipsenetwork.xyz";
   const connection = new web3.Connection(customRpcUrl);
   setRpcUrl(customRpcUrl);
   ```

   The program establishes a connection to the Eclipse testnet using a custom RPC URL and updates the `customRpcUrl` const with this URL.

   ```jsx
   const senderPublicKey = new web3.PublicKey('...');
   const recipientPublicKey = new web3.PublicKey('...');
   const amountInLamports = 1_000_000_000;
   setSenderAddress(senderPublicKey.toString());
   setReceiverAddress(recipientPublicKey.toString());
   ```

   It sets up the sender and receiver public keys and the amount to transfer (in lamports/wei), updating the corresponding states with these details.
4. **Transaction Preparation and Fee Estimation**:

   ```jsx
   const transferInstruction = web3.SystemProgram.transfer({
     fromPubkey: senderPublicKey,
     toPubkey: recipientPublicKey,
     lamports: amountInLamports
   });
   transaction.add(transferInstruction);
   ```

   A transfer instruction is created and added to the transaction. This instruction specifies the sender, receiver, and amount to transfer.

   ```jsx
   const { blockhash } = await connection.getLatestBlockhash();
   transaction.recentBlockhash = blockhash;
   transaction.feePayer = senderPublicKey;
   ```

   The transaction is prepared with the latest blockhash and the fee payer's public key.

   ```jsx
   const message = transaction.compileMessage();
   const estimatedFee = await connection.getFeeForMessage(message, 'recent');
   ```

   The transaction's message is compiled, and the fee is estimated by querying the blockchain with this message.
5. **Updating State with the Estimated Fee or Error**:

   ```jsx
   if (estimatedFee.value === null) {
     throw new Error('Failed to estimate fee');
   }
   setFee(estimatedFee.value);
   ```

   If the fee estimation is successful, the `fee` state is updated with the estimated value. If the estimation fails or an error occurs, the `error` state is updated accordingly.
6. **Rendering UI Components**: The UI displays the connected RPC URL, sender and receiver addresses, and either the estimated fee, an error message, or a loading indicator, based on the current state:

   ```jsx
   <p>Connected RPC URL: {rpcUrl}</p>
   <p>Sender Address: {senderAddress}</p>
   <p>Receiver Address: {receiverAddress}</p>
   ```

   This straightforward approach allows users to see the fee estimation results or the error encountered during the process, providing transparency and insight into the transaction fee estimation on the Eclipse blockchain.


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