From 3ac1d71359c958738c97cdf6be6f4ab10125224a Mon Sep 17 00:00:00 2001
From: Brian Levinstein <blevinstein@gmail.com>
Date: Sat, 15 Jan 2022 02:12:06 -0700
Subject: [PATCH] Add CallContract (and helper methods) for calling contracts
 via Metamask (alternative to EVM.Call)

---
 Web3Unity/Scripts/Library/WebGL/Web3GL.cs | 36 ++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/Web3Unity/Scripts/Library/WebGL/Web3GL.cs b/Web3Unity/Scripts/Library/WebGL/Web3GL.cs
index 0cffcc56e..2e40944e4 100644
--- a/Web3Unity/Scripts/Library/WebGL/Web3GL.cs
+++ b/Web3Unity/Scripts/Library/WebGL/Web3GL.cs
@@ -17,6 +17,18 @@ public class Web3GL
     [DllImport("__Internal")]
     private static extern void SetContractResponse(string value);
 
+    [DllImport("__Internal")]
+    private static extern void CallContractJs(string method, string abi, string contract, string args);
+
+    [DllImport("__Internal")]
+    private static extern void ResetCallContractResponse();
+
+    [DllImport("__Internal")]
+    private static extern string CallContractResponse();
+
+    [DllImport("__Internal")]
+    private static extern string CallContractError();
+
     [DllImport("__Internal")]
     private static extern void SendTransactionJs(string to, string value, string gasLimit, string gasPrice);
 
@@ -38,6 +50,28 @@ public class Web3GL
     [DllImport("__Internal")]
     private static extern int GetNetwork();
 
+    async public static Task<string> CallContract(string _method, string _abi, string _contract, string _args, float _waitSeconds = 0.1f)
+    {
+        ResetCallContractResponse();
+        CallContractJs(_method, _abi, _contract, _args);
+        string response = CallContractResponse();
+        string error = CallContractError();
+        while (response == "" && error == "")
+        {
+            await new WaitForSeconds(_waitSeconds);
+            response = CallContractResponse();
+            error = CallContractError();
+        }
+        ResetCallContractResponse();
+        if (error.Length > 0)
+        {
+            throw new Exception(error);
+        } else
+        {
+            return response;
+        }
+    }
+
     // this function will create a metamask tx for user to confirm.
     async public static Task<string> SendContract(string _method, string _abi, string _contract, string _args, string _value, string _gasLimit = "", string _gasPrice = "")
     {
@@ -113,4 +147,4 @@ public static int Network()
     }
 
 }
-#endif
\ No newline at end of file
+#endif