feat: support interacting with smart contracts on EVM-based blockchains

examples/hero_vault/contract_example.rhai

@@ -0,0 +1,101 @@
+// Example Rhai script for interacting with smart contracts using Hero Vault
+// This script demonstrates loading a contract ABI and interacting with a contract
+
+// Step 1: Set up wallet and network
+let space_name = "contract_demo_space";
+let password = "secure_password123";
+
+print("Creating key space: " + space_name);
+if create_key_space(space_name, password) {
+    print("✓ Key space created successfully");
+
+    // Create a keypair
+    print("\nCreating keypair...");
+    if create_keypair("contract_key", password) {
+        print("✓ Created contract keypair");
+    }
+
+    // Step 2: Create an Ethereum wallet for Gnosis Chain
+    print("\nCreating Ethereum wallet...");
+    if create_ethereum_wallet() {
+        print("✓ Ethereum wallet created");
+
+        let address = get_ethereum_address();
+        print("Ethereum address: " + address);
+
+        // Step 3: Define a simple ERC-20 ABI (partial)
+        let erc20_abi = `[
+            {
+                "constant": true,
+                "inputs": [],
+                "name": "name",
+                "outputs": [{"name": "", "type": "string"}],
+                "payable": false,
+                "stateMutability": "view",
+                "type": "function"
+            },
+            {
+                "constant": true,
+                "inputs": [],
+                "name": "symbol",
+                "outputs": [{"name": "", "type": "string"}],
+                "payable": false,
+                "stateMutability": "view",
+                "type": "function"
+            },
+            {
+                "constant": true,
+                "inputs": [],
+                "name": "decimals",
+                "outputs": [{"name": "", "type": "uint8"}],
+                "payable": false,
+                "stateMutability": "view",
+                "type": "function"
+            },
+            {
+                "constant": true,
+                "inputs": [{"name": "owner", "type": "address"}],
+                "name": "balanceOf",
+                "outputs": [{"name": "", "type": "uint256"}],
+                "payable": false,
+                "stateMutability": "view",
+                "type": "function"
+            }
+        ]`;
+
+        // Step 4: Load the contract ABI
+        print("\nLoading contract ABI...");
+        let contract = load_contract_abi("Gnosis", "0x4ECaBa5870353805a9F068101A40E0f32ed605C6", erc20_abi);
+        if contract != "" {
+            print("✓ Contract loaded successfully");
+
+            // Step 5: Call read-only functions
+            print("\nCalling read-only functions...");
+
+            // Get token name
+            let token_name = call_contract_read(contract, "name");
+            print("Token name: " + token_name);
+
+            // Get token symbol
+            let token_symbol = call_contract_read(contract, "symbol");
+            print("Token symbol: " + token_symbol);
+
+            // Get token decimals
+            let token_decimals = call_contract_read(contract, "decimals");
+            print("Token decimals: " + token_decimals);
+
+            // Note: In a full implementation, we would handle function arguments
+            // For now, we're just demonstrating the basic structure
+            print("Note: balanceOf function requires an address argument, which is not implemented in this example");
+            print("In a full implementation, we would pass the address and get the balance");
+        } else {
+            print("✗ Failed to load contract");
+        }
+    } else {
+        print("✗ Failed to create Ethereum wallet");
+    }
+} else {
+    print("✗ Failed to create key space");
+}
+
+print("\nContract example completed");

src/hero_vault/error.rs

@@ -40,6 +40,14 @@ pub enum CryptoError {
     /// Serialization error
     #[error("Serialization error: {0}")]
     SerializationError(String),
+
+    /// Invalid address format
+    #[error("Invalid address format: {0}")]
+    InvalidAddress(String),
+
+    /// Smart contract error
+    #[error("Smart contract error: {0}")]
+    ContractError(String),
 }
 
 /// Convert CryptoError to SAL's Error type

src/hero_vault/ethereum/contract.rs

@@ -0,0 +1,159 @@
+//! Smart contract interaction functionality.
+//!
+//! This module provides functionality for interacting with smart contracts on EVM-based blockchains.
+
+use ethers::prelude::*;
+use ethers::abi::{Abi, Token};
+use std::sync::Arc;
+use std::str::FromStr;
+use serde::{Serialize, Deserialize};
+
+use crate::hero_vault::error::CryptoError;
+use super::wallet::EthereumWallet;
+use super::networks::NetworkConfig;
+
+/// A smart contract instance.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct Contract {
+    /// The contract address
+    pub address: Address,
+    /// The contract ABI
+    pub abi: Abi,
+    /// The network the contract is deployed on
+    pub network: NetworkConfig,
+}
+
+impl Contract {
+    /// Creates a new contract instance.
+    pub fn new(address: Address, abi: Abi, network: NetworkConfig) -> Self {
+        Contract {
+            address,
+            abi,
+            network,
+        }
+    }
+
+    /// Creates a new contract instance from an address string and ABI.
+    pub fn from_address_string(address_str: &str, abi: Abi, network: NetworkConfig) -> Result<Self, CryptoError> {
+        let address = Address::from_str(address_str)
+            .map_err(|e| CryptoError::InvalidAddress(format!("Invalid address format: {}", e)))?;
+
+        Ok(Contract::new(address, abi, network))
+    }
+
+    /// Creates an ethers Contract instance for interaction.
+    pub fn create_ethers_contract(&self, provider: Provider<Http>, _wallet: Option<&EthereumWallet>) -> Result<ethers::contract::Contract<ethers::providers::Provider<Http>>, CryptoError> {
+        let contract = ethers::contract::Contract::new(
+            self.address,
+            self.abi.clone(),
+            Arc::new(provider),
+        );
+
+        Ok(contract)
+    }
+}
+
+/// Loads a contract ABI from a JSON string.
+pub fn load_abi_from_json(json_str: &str) -> Result<Abi, CryptoError> {
+    serde_json::from_str(json_str)
+        .map_err(|e| CryptoError::SerializationError(format!("Failed to parse ABI JSON: {}", e)))
+}
+
+/// Calls a read-only function on a contract.
+pub async fn call_read_function(
+    contract: &Contract,
+    provider: &Provider<Http>,
+    function_name: &str,
+    args: Vec<Token>,
+) -> Result<Vec<Token>, CryptoError> {
+    // Create the ethers contract (not used directly but kept for future extensions)
+    let _ethers_contract = contract.create_ethers_contract(provider.clone(), None)?;
+
+    // Get the function from the ABI
+    let function = contract.abi.function(function_name)
+        .map_err(|e| CryptoError::ContractError(format!("Function not found in ABI: {}", e)))?;
+
+    // Encode the function call
+    let call_data = function.encode_input(&args)
+        .map_err(|e| CryptoError::ContractError(format!("Failed to encode function call: {}", e)))?;
+
+    // Make the call
+    let tx = TransactionRequest::new()
+        .to(contract.address)
+        .data(call_data);
+
+    let result = provider.call(&tx.into(), None).await
+        .map_err(|e| CryptoError::ContractError(format!("Contract call failed: {}", e)))?;
+
+    // Decode the result
+    let decoded = function.decode_output(&result)
+        .map_err(|e| CryptoError::ContractError(format!("Failed to decode function output: {}", e)))?;
+
+    Ok(decoded)
+}
+
+/// Executes a state-changing function on a contract.
+pub async fn call_write_function(
+    contract: &Contract,
+    wallet: &EthereumWallet,
+    provider: &Provider<Http>,
+    function_name: &str,
+    args: Vec<Token>,
+) -> Result<H256, CryptoError> {
+    // Create a client with the wallet
+    let client = SignerMiddleware::new(
+        provider.clone(),
+        wallet.wallet.clone(),
+    );
+
+    // Get the function from the ABI
+    let function = contract.abi.function(function_name)
+        .map_err(|e| CryptoError::ContractError(format!("Function not found in ABI: {}", e)))?;
+
+    // Encode the function call
+    let call_data = function.encode_input(&args)
+        .map_err(|e| CryptoError::ContractError(format!("Failed to encode function call: {}", e)))?;
+
+    // Create the transaction request
+    let tx = TransactionRequest::new()
+        .to(contract.address)
+        .data(call_data);
+
+    // Send the transaction using the client directly
+    let pending_tx = client.send_transaction(tx, None)
+        .await
+        .map_err(|e| CryptoError::ContractError(format!("Failed to send transaction: {}", e)))?;
+
+    // Return the transaction hash
+    Ok(pending_tx.tx_hash())
+}
+
+/// Estimates gas for a contract function call.
+pub async fn estimate_gas(
+    contract: &Contract,
+    wallet: &EthereumWallet,
+    provider: &Provider<Http>,
+    function_name: &str,
+    args: Vec<Token>,
+) -> Result<U256, CryptoError> {
+    // Get the function from the ABI
+    let function = contract.abi.function(function_name)
+        .map_err(|e| CryptoError::ContractError(format!("Function not found in ABI: {}", e)))?;
+
+    // Encode the function call
+    let call_data = function.encode_input(&args)
+        .map_err(|e| CryptoError::ContractError(format!("Failed to encode function call: {}", e)))?;
+
+    // Create the transaction request
+    let tx = TransactionRequest::new()
+        .from(wallet.address)
+        .to(contract.address)
+        .data(call_data);
+
+    // Estimate gas
+    let gas = provider.estimate_gas(&tx.into(), None)
+        .await
+        .map_err(|e| CryptoError::ContractError(format!("Failed to estimate gas: {}", e)))?;
+
+    Ok(gas)
+}

src/hero_vault/ethereum/mod.rs

@@ -1,6 +1,7 @@
 //! Ethereum wallet functionality
 //!
-//! This module provides functionality for creating and managing Ethereum wallets.
+//! This module provides functionality for creating and managing Ethereum wallets
+//! and interacting with smart contracts on EVM-based blockchains.
 //!
 //! The module is organized into several components:
 //! - `wallet.rs`: Core Ethereum wallet implementation
@@ -8,11 +9,13 @@
 //! - `provider.rs`: Provider creation and management
 //! - `transaction.rs`: Transaction-related functionality
 //! - `storage.rs`: Wallet storage functionality
+//! - `contract.rs`: Smart contract interaction functionality
 
 mod wallet;
 mod provider;
 mod transaction;
 mod storage;
+mod contract;
 pub mod networks;
 #[cfg(test)]
 pub mod tests;
@@ -64,3 +67,12 @@ pub use networks::{
     get_all_networks,
     names,
 };
+
+// Re-export contract functions
+pub use contract::{
+    Contract,
+    load_abi_from_json,
+    call_read_function,
+    call_write_function,
+    estimate_gas,
+};

src/hero_vault/ethereum/networks.rs

@@ -5,9 +5,10 @@
 
 use std::collections::HashMap;
 use std::sync::OnceLock;
+use serde::{Serialize, Deserialize};
 
 /// Configuration for an EVM-compatible network
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct NetworkConfig {
     pub name: String,
     pub chain_id: u64,

src/hero_vault/ethereum/tests/contract_tests.rs

@@ -0,0 +1,83 @@
+//! Tests for smart contract functionality.
+
+use ethers::types::Address;
+use std::str::FromStr;
+
+use crate::hero_vault::ethereum::*;
+
+#[test]
+fn test_contract_creation() {
+    // Create a simple ABI
+    let abi_json = r#"[
+        {
+            "inputs": [],
+            "name": "getValue",
+            "outputs": [{"type": "uint256", "name": ""}],
+            "stateMutability": "view",
+            "type": "function"
+        },
+        {
+            "inputs": [{"type": "uint256", "name": "newValue"}],
+            "name": "setValue",
+            "outputs": [],
+            "stateMutability": "nonpayable",
+            "type": "function"
+        }
+    ]"#;
+
+    // Parse the ABI
+    let abi = load_abi_from_json(abi_json).unwrap();
+
+    // Create a contract address
+    let address = Address::from_str("0x1234567890123456789012345678901234567890").unwrap();
+
+    // Create a network config
+    let network = networks::gnosis();
+
+    // Create a contract
+    let contract = Contract::new(address, abi, network);
+
+    // Verify the contract was created correctly
+    assert_eq!(contract.address, address);
+    assert_eq!(contract.network.name, "Gnosis");
+
+    // Verify the ABI contains the expected functions
+    assert!(contract.abi.function("getValue").is_ok());
+    assert!(contract.abi.function("setValue").is_ok());
+}
+
+#[test]
+fn test_contract_from_address_string() {
+    // Create a simple ABI
+    let abi_json = r#"[
+        {
+            "inputs": [],
+            "name": "getValue",
+            "outputs": [{"type": "uint256", "name": ""}],
+            "stateMutability": "view",
+            "type": "function"
+        }
+    ]"#;
+
+    // Parse the ABI
+    let abi = load_abi_from_json(abi_json).unwrap();
+
+    // Create a network config
+    let network = networks::gnosis();
+
+    // Create a contract from an address string
+    let address_str = "0x1234567890123456789012345678901234567890";
+    let contract = Contract::from_address_string(address_str, abi, network).unwrap();
+
+    // Verify the contract was created correctly
+    assert_eq!(contract.address, Address::from_str(address_str).unwrap());
+
+    // Test with an invalid address
+    let invalid_address = "0xinvalid";
+    let result = Contract::from_address_string(invalid_address, contract.abi.clone(), contract.network.clone());
+    assert!(result.is_err());
+}
+
+// Note: We can't easily test the actual contract calls in unit tests without mocking
+// the provider, which would be complex. These would be better tested in integration tests
+// with a local blockchain or testnet.

src/hero_vault/ethereum/tests/mod.rs

@@ -3,3 +3,4 @@
 mod wallet_tests;
 mod network_tests;
 mod transaction_tests;
+mod contract_tests;

src/rhai/hero_vault.rs

@@ -1,6 +1,6 @@
 //! Rhai bindings for SAL crypto functionality
 
-use rhai::{Engine, Dynamic, FnPtr, EvalAltResult};
+use rhai::{Engine, Dynamic, EvalAltResult};
 use base64::{Engine as _, engine::general_purpose::STANDARD as BASE64};
 use std::fs;
 use std::path::PathBuf;
@@ -9,11 +9,10 @@ use std::sync::Mutex;
 use once_cell::sync::Lazy;
 use tokio::runtime::Runtime;
 use ethers::types::{Address, U256};
+use ethers::abi::Token;
 use std::str::FromStr;
 
 use crate::hero_vault::{keypair, symmetric, ethereum};
-use crate::hero_vault::error::CryptoError;
-use crate::hero_vault::kvs;
 
 // Global Tokio runtime for blocking async operations
 static RUNTIME: Lazy<Mutex<Runtime>> = Lazy::new(|| {
@@ -698,6 +697,175 @@ fn send_eth(wallet_network: &str, to_address: &str, amount_str: &str) -> String
     }
 }
 
+// Smart contract operations
+
+// Load a contract ABI from a JSON string and create a contract instance
+fn load_contract_abi(network_name: &str, address: &str, abi_json: &str) -> String {
+    // Get the network
+    let network = match ethereum::networks::get_network_by_name(network_name) {
+        Some(network) => network,
+        None => {
+            log::error!("Unknown network: {}", network_name);
+            return String::new();
+        }
+    };
+
+    // Parse the ABI
+    let abi = match ethereum::load_abi_from_json(abi_json) {
+        Ok(abi) => abi,
+        Err(e) => {
+            log::error!("Error parsing ABI: {}", e);
+            return String::new();
+        }
+    };
+
+    // Create the contract
+    match ethereum::Contract::from_address_string(address, abi, network) {
+        Ok(contract) => {
+            // Serialize the contract to JSON for storage
+            match serde_json::to_string(&contract) {
+                Ok(json) => json,
+                Err(e) => {
+                    log::error!("Error serializing contract: {}", e);
+                    String::new()
+                }
+            }
+        },
+        Err(e) => {
+            log::error!("Error creating contract: {}", e);
+            String::new()
+        }
+    }
+}
+
+// Load a contract ABI from a file
+fn load_contract_abi_from_file(network_name: &str, address: &str, file_path: &str) -> String {
+    // Read the ABI file
+    match fs::read_to_string(file_path) {
+        Ok(abi_json) => load_contract_abi(network_name, address, &abi_json),
+        Err(e) => {
+            log::error!("Error reading ABI file: {}", e);
+            String::new()
+        }
+    }
+}
+
+// Call a read-only function on a contract
+fn call_contract_read(contract_json: &str, function_name: &str) -> Dynamic {
+    // Deserialize the contract
+    let contract: ethereum::Contract = match serde_json::from_str(contract_json) {
+        Ok(contract) => contract,
+        Err(e) => {
+            log::error!("Error deserializing contract: {}", e);
+            return Dynamic::UNIT;
+        }
+    };
+
+    // Get the runtime
+    let rt = match RUNTIME.lock() {
+        Ok(rt) => rt,
+        Err(e) => {
+            log::error!("Failed to acquire runtime lock: {}", e);
+            return Dynamic::UNIT;
+        }
+    };
+
+    // Create a provider
+    let provider = match ethereum::create_provider(&contract.network) {
+        Ok(p) => p,
+        Err(e) => {
+            log::error!("Failed to create provider: {}", e);
+            return Dynamic::UNIT;
+        }
+    };
+
+    // For simplicity, we're not handling arguments in this implementation
+    let tokens: Vec<Token> = Vec::new();
+
+    // Execute the call in a blocking manner
+    match rt.block_on(async {
+        ethereum::call_read_function(&contract, &provider, function_name, tokens).await
+    }) {
+        Ok(result) => {
+            // Convert the result to a Rhai value
+            if result.is_empty() {
+                Dynamic::UNIT
+            } else {
+                // For simplicity, we'll just return the first value as a string
+                match &result[0] {
+                    Token::String(s) => Dynamic::from(s.clone()),
+                    Token::Uint(u) => Dynamic::from(u.to_string()),
+                    Token::Int(i) => Dynamic::from(i.to_string()),
+                    Token::Bool(b) => Dynamic::from(*b),
+                    Token::Address(a) => Dynamic::from(format!("{:?}", a)),
+                    _ => {
+                        log::error!("Unsupported return type");
+                        Dynamic::UNIT
+                    }
+                }
+            }
+        },
+        Err(e) => {
+            log::error!("Failed to call contract function: {}", e);
+            Dynamic::UNIT
+        }
+    }
+}
+
+// Call a state-changing function on a contract
+fn call_contract_write(contract_json: &str, function_name: &str) -> String {
+    // Deserialize the contract
+    let contract: ethereum::Contract = match serde_json::from_str(contract_json) {
+        Ok(contract) => contract,
+        Err(e) => {
+            log::error!("Error deserializing contract: {}", e);
+            return String::new();
+        }
+    };
+
+    // Get the runtime
+    let rt = match RUNTIME.lock() {
+        Ok(rt) => rt,
+        Err(e) => {
+            log::error!("Failed to acquire runtime lock: {}", e);
+            return String::new();
+        }
+    };
+
+    // Get the wallet
+    let network_name_proper = contract.network.name.as_str();
+    let wallet = match ethereum::get_current_ethereum_wallet_for_network(network_name_proper) {
+        Ok(w) => w,
+        Err(e) => {
+            log::error!("Failed to get wallet: {}", e);
+            return String::new();
+        }
+    };
+
+    // Create a provider
+    let provider = match ethereum::create_provider(&contract.network) {
+        Ok(p) => p,
+        Err(e) => {
+            log::error!("Failed to create provider: {}", e);
+            return String::new();
+        }
+    };
+
+    // For simplicity, we're not handling arguments in this implementation
+    let tokens: Vec<Token> = Vec::new();
+
+    // Execute the transaction in a blocking manner
+    match rt.block_on(async {
+        ethereum::call_write_function(&contract, &wallet, &provider, function_name, tokens).await
+    }) {
+        Ok(tx_hash) => format!("{:?}", tx_hash),
+        Err(e) => {
+            log::error!("Transaction failed: {}", e);
+            String::new()
+        }
+    }
+}
+
 /// Register crypto functions with the Rhai engine
 pub fn register_crypto_module(engine: &mut Engine) -> Result<(), Box<EvalAltResult>> {
     // Register key space functions
@@ -746,5 +914,11 @@ pub fn register_crypto_module(engine: &mut Engine) -> Result<(), Box<EvalAltResu
     engine.register_fn("send_eth", send_eth);
     engine.register_fn("get_balance", get_balance);
 
+    // Register smart contract functions
+    engine.register_fn("load_contract_abi", load_contract_abi);
+    engine.register_fn("load_contract_abi_from_file", load_contract_abi_from_file);
+    engine.register_fn("call_contract_read", call_contract_read);
+    engine.register_fn("call_contract_write", call_contract_write);
+
     Ok(())
 }