From a441bde2c89e654e028469cb066b9e59760c30ac Mon Sep 17 00:00:00 2001
From: Noah Citron <noah@jeff.org>
Date: Sat, 20 Aug 2022 13:18:40 -0400
Subject: [PATCH] add execution module

---
 src/execution.rs     | 33 +++++++++++++++++++++++++++++++++
 src/execution_rpc.rs |  5 +++--
 src/main.rs          | 24 ++++++++++--------------
 3 files changed, 46 insertions(+), 16 deletions(-)
 create mode 100644 src/execution.rs

diff --git a/src/execution.rs b/src/execution.rs
new file mode 100644
index 0000000..fdf7f42
--- /dev/null
+++ b/src/execution.rs
@@ -0,0 +1,33 @@
+use ethers::utils::keccak256;
+use eyre::Result;
+use ethers::prelude::{U256, Address};
+
+use crate::proof::{encode_account, verify_proof};
+use crate::consensus_rpc::ExecutionPayload;
+use crate::execution_rpc::ExecutionRpc;
+
+pub struct ExecutionClient {
+    execution_rpc: ExecutionRpc
+}
+
+impl ExecutionClient {
+    pub fn new(rpc: &str) -> Self {
+        let execution_rpc = ExecutionRpc::new(rpc);
+        ExecutionClient { execution_rpc }
+    }
+
+    pub async fn get_balance(&self, account: &Address, payload: &ExecutionPayload) -> Result<U256> {
+        let proof = self.execution_rpc.get_proof(&account, payload.block_number).await?;
+
+        let account_path = keccak256(account.as_bytes()).to_vec();
+        let account_encoded = encode_account(&proof);
+
+        let is_valid = verify_proof(&proof.account_proof, &payload.state_root, &account_path, &account_encoded);
+
+        if !is_valid {
+            eyre::bail!("Invalid Proof");
+        }
+
+        Ok(proof.balance)
+    }
+}
diff --git a/src/execution_rpc.rs b/src/execution_rpc.rs
index 1f9d30a..2f07e3b 100644
--- a/src/execution_rpc.rs
+++ b/src/execution_rpc.rs
@@ -14,10 +14,11 @@ impl ExecutionRpc {
         ExecutionRpc { rpc: rpc.to_string() }
     }
 
-    pub async fn get_proof(&self, address: &str, block: u64) -> Result<Proof> {
+    pub async fn get_proof(&self, address: &Address, block: u64) -> Result<Proof> {
         let client = HttpClientBuilder::default().build(&self.rpc)?;
         let block_hex = format!("0x{:x}", block);
-        let params = rpc_params!(address, [""], block_hex);
+        let addr_hex = format!("0x{}", hex::encode(address.as_bytes()));
+        let params = rpc_params!(addr_hex, [""], block_hex);
         Ok(client.request("eth_getProof", params).await?)
     }
 }
diff --git a/src/main.rs b/src/main.rs
index 7bd443f..ab465c8 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,12 +1,14 @@
+use std::str::FromStr;
+
+use ethers::prelude::Address;
 use eyre::Result;
 
 use consensus::*;
-use execution_rpc::*;
-use proof::*;
-use utils::hex_str_to_bytes;
+use execution::*;
 
 pub mod consensus;
 pub mod consensus_rpc;
+pub mod execution;
 pub mod execution_rpc;
 pub mod utils;
 pub mod proof;
@@ -19,22 +21,16 @@ async fn main() -> Result<()> {
     let mut client = ConsensusClient::new(rpc, checkpoint).await?;    
     
     let rpc = "https://eth-goerli.g.alchemy.com:443/v2/o_8Qa9kgwDPf9G8sroyQ-uQtyhyWa3ao";
-    let execution = ExecutionRpc::new(rpc);
+    let execution = ExecutionClient::new(rpc);
     
     client.sync().await?;
 
     let payload = client.get_execution_payload().await?;
-    println!("verified execution block hash: {}", hex::encode(payload.block_hash));
+    println!("verified execution block hash: {}", hex::encode(&payload.block_hash));
 
-    let addr = "0x25c4a76E7d118705e7Ea2e9b7d8C59930d8aCD3b";
-    let proof = execution.get_proof(addr, payload.block_number).await?;
-
-    let account_path = get_account_path(&hex_str_to_bytes(addr)?);
-    let account_encoded = encode_account(&proof);
-
-    let is_valid = verify_proof(&proof.account_proof, &payload.state_root, &account_path, &account_encoded);
-
-    println!("is account proof valid: {}", is_valid);
+    let addr = Address::from_str("0x25c4a76E7d118705e7Ea2e9b7d8C59930d8aCD3b")?;
+    let balance = execution.get_balance(&addr, &payload).await?;
+    println!("verified account balance: {}", balance);
 
     Ok(())
 }