feat: transfer tokens (#200)

Signed-off-by: Mariusz Jasuwienas <[email protected]>

contracts/HtsSystemContract.sol

@@ -125,42 +125,17 @@ contract HtsSystemContract is IHederaTokenService, IERC20Events, IERC721Events {
         return dissociateTokens(account, tokens);
     }
 
-
-
     function transferTokens(
         address token,
         address[] memory accountId,
         int64[] memory amount
-    ) htsCall public returns (int64 responseCode) {
+    ) htsCall external returns (int64 responseCode) {
         require(token != address(0), "transferTokens: invalid token");
         require(accountId.length > 0, "transferTokens: missing recipients");
         require(amount.length == accountId.length, "transferTokens: inconsistent input");
-
-        int64 total = 0;
         for (uint256 i = 0; i < accountId.length; i++) {
-            total += amount[i];
-        }
-        require(total == 0, "transferTokens: total amount must balance");
-
-        for (uint256 from = 0; from < amount.length; from++) {
-            if (amount[from] >= 0) {
-                continue;
-            }
-            for (uint256 to = 0; to < amount.length; to++) {
-                if (amount[to] <= 0) {
-                    continue;
-                }
-                int64 transferAmount = amount[to] < -amount[from] ? amount[to] : -amount[from];
-                transferToken(token, accountId[from], accountId[to], transferAmount);
-                amount[from] += transferAmount;
-                amount[to] -= transferAmount;
-                if (amount[from] == 0) {
-                    break;
-                }
-            }
-        }
-        for (uint256 i = 0; i < amount.length; i++) { // Ensure all amounts are fully balanced after processing
-            require(amount[i] == 0, "transferTokens: unmatched transfers");
+            responseCode = transferToken(token, msg.sender, accountId[i], amount[i]);
+            require(responseCode == HederaResponseCodes.SUCCESS, "transferTokens: transfer failed");
         }
         responseCode = HederaResponseCodes.SUCCESS;
     }