From 4fdd973e0f0d25a3305bb17436e6fb7ae0e1b6a9 Mon Sep 17 00:00:00 2001
From: Giovanni Sanchez <108043524+sisyphusSmiling@users.noreply.github.com>
Date: Tue, 23 Apr 2024 17:42:22 -0500
Subject: [PATCH] add totalSupply util method & script

---
 .../contracts/bridge/FlowEVMBridgeUtils.cdc   | 21 +++++++++++++++++++
 cadence/scripts/utils/total_supply.cdc        | 16 ++++++++++++++
 2 files changed, 37 insertions(+)
 create mode 100644 cadence/scripts/utils/total_supply.cdc

diff --git a/cadence/contracts/bridge/FlowEVMBridgeUtils.cdc b/cadence/contracts/bridge/FlowEVMBridgeUtils.cdc
index c7bd9e4d..99e0386e 100644
--- a/cadence/contracts/bridge/FlowEVMBridgeUtils.cdc
+++ b/cadence/contracts/bridge/FlowEVMBridgeUtils.cdc
@@ -445,6 +445,27 @@ contract FlowEVMBridgeUtils {
         return self.balanceOf(owner: owner, evmContractAddress: evmContractAddress) >= amount
     }
 
+    /// Retrieves the total supply of the ERC20 contract at the given EVM contract address. Reverts on EVM call failure.
+    ///
+    /// @param evmContractAddress: The EVM contract address to retrieve the total supply from
+    ///
+    /// @return the total supply of the ERC20
+    ///
+    access(all)
+    fun totalSupply(evmContractAddress: EVM.EVMAddress): UInt256 {
+        let callResult = self.call(
+            signature: "totalSupply()",
+            targetEVMAddress: evmContractAddress,
+            args: [],
+            gasLimit: 60000,
+            value: 0.0
+        )
+        assert(callResult.status == EVM.Status.successful, message: "Call to ERC20.totalSupply() failed")
+        let decodedResult = EVM.decodeABI(types: [Type<UInt256>()], data: callResult.data) as! [AnyStruct]
+        assert(decodedResult.length == 1, message: "Invalid response length")
+        return decodedResult[0] as! UInt256
+    }
+
     /************************
         Derivation Utils
      ************************/
diff --git a/cadence/scripts/utils/total_supply.cdc b/cadence/scripts/utils/total_supply.cdc
new file mode 100644
index 00000000..d6991ed5
--- /dev/null
+++ b/cadence/scripts/utils/total_supply.cdc
@@ -0,0 +1,16 @@
+import "EVM"
+
+import "EVMUtils"
+import "FlowEVMBridgeUtils"
+
+/// Retrieves the total supply of the ERC20 contract at the given EVM contract address. Reverts on EVM call failure.
+///
+/// @param evmContractAddress: The EVM contract address to retrieve the total supply from
+///
+/// @return the total supply of the ERC20
+///
+access(all) fun main(evmContractAddressHex: String): UInt256 {
+    let evmContractAddress = EVMUtils.getEVMAddressFromHexString(address: evmContractAddressHex)
+        ?? panic("Invalid EVM contract address hex: ".concat(evmContractAddressHex))
+    return FlowEVMBridgeUtils.totalSupply(evmContractAddress: evmContractAddress)
+}