feat: better Kyber quotes (#2683)

* feat: Kyber rework

* Get additional reserves per token

contracts/asset-proxy/CHANGELOG.json

@@ -21,6 +21,10 @@
             {
                 "note": "Added `MooniswapBridge`",
                 "pr": 2675
+            },
+            {
+                "note": "Reworked `KyberBridge`",
+                "pr": 2683
             }
         ]
     },

contracts/asset-proxy/contracts/src/bridges/KyberBridge.sol

@@ -1,6 +1,6 @@
 /*
 
-  Copyright 2019 ZeroEx Intl.
+  Copyright 2020 ZeroEx Intl.
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -45,6 +45,7 @@ contract KyberBridge is
         uint256 fromTokenBalance;
         uint256 payableAmount;
         uint256 conversionRate;
+        bytes hint;
     }
 
     /// @dev Kyber ETH pseudo-address.
@@ -85,47 +86,35 @@ contract KyberBridge is
         state.kyber = IKyberNetworkProxy(_getKyberNetworkProxyAddress());
         state.weth = IEtherToken(_getWethAddress());
         // Decode the bridge data to get the `fromTokenAddress`.
-        (state.fromTokenAddress) = abi.decode(bridgeData, (address));
+        (state.fromTokenAddress, state.hint) = abi.decode(bridgeData, (address, bytes));
         // Query the balance of "from" tokens.
         state.fromTokenBalance = IERC20Token(state.fromTokenAddress).balanceOf(address(this));
         if (state.fromTokenBalance == 0) {
             // Return failure if no input tokens.
             return BRIDGE_FAILED;
         }
-        // Compute the conversion rate, expressed in 18 decimals.
-        // The sequential notation is to get around stack limits.
-        state.conversionRate = KYBER_RATE_BASE;
-        state.conversionRate = state.conversionRate.safeMul(amount);
-        state.conversionRate = state.conversionRate.safeMul(
-            10 ** uint256(LibERC20Token.decimals(state.fromTokenAddress))
-        );
-        state.conversionRate = state.conversionRate.safeDiv(state.fromTokenBalance);
-        state.conversionRate = state.conversionRate.safeDiv(
-            10 ** uint256(LibERC20Token.decimals(toTokenAddress))
-        );
         if (state.fromTokenAddress == toTokenAddress) {
             // Just transfer the tokens if they're the same.
             LibERC20Token.transfer(state.fromTokenAddress, to, state.fromTokenBalance);
             return BRIDGE_SUCCESS;
-        } else if (state.fromTokenAddress != address(state.weth)) {
-            // If the input token is not WETH, grant an allowance to the exchange
-            // to spend them.
+        }
+        if (state.fromTokenAddress == address(state.weth)) {
+            // From WETH
+            state.fromTokenAddress = KYBER_ETH_ADDRESS;
+            state.payableAmount = state.fromTokenBalance;
+            state.weth.withdraw(state.fromTokenBalance);
+        } else {
             LibERC20Token.approveIfBelow(
                 state.fromTokenAddress,
                 address(state.kyber),
                 state.fromTokenBalance
             );
-        } else {
-            // If the input token is WETH, unwrap it and attach it to the call.
-            state.fromTokenAddress = KYBER_ETH_ADDRESS;
-            state.payableAmount = state.fromTokenBalance;
-            state.weth.withdraw(state.fromTokenBalance);
         }
         bool isToTokenWeth = toTokenAddress == address(state.weth);
 
         // Try to sell all of this contract's input token balance through
         // `KyberNetworkProxy.trade()`.
-        uint256 boughtAmount = state.kyber.trade.value(state.payableAmount)(
+        uint256 boughtAmount = state.kyber.tradeWithHint.value(state.payableAmount)(
             // Input token.
             state.fromTokenAddress,
             // Sell amount.
@@ -137,11 +126,11 @@ contract KyberBridge is
             isToTokenWeth ? address(uint160(address(this))) : address(uint160(to)),
             // Buy as much as possible.
             uint256(-1),
-            // Compute the minimum conversion rate, which is expressed in units with
-            // 18 decimal places.
-            state.conversionRate,
+            // The minimum conversion rate
+            1,
             // No affiliate address.
-            address(0)
+            address(0),
+            state.hint
         );
         // Wrap ETH output and transfer to recipient.
         if (isToTokenWeth) {
@@ -173,4 +162,5 @@ contract KyberBridge is
     {
         return LEGACY_WALLET_MAGIC_VALUE;
     }
+
 }

contracts/asset-proxy/contracts/src/interfaces/IKyberNetworkProxy.sol

@@ -42,5 +42,31 @@ interface IKyberNetworkProxy {
     )
         external
         payable
-        returns(uint256 boughtAmount);
+        returns (uint256 boughtAmount);
+
+    /// @dev Sells `sellTokenAddress` tokens for `buyTokenAddress` tokens
+    /// using a hint for the reserve.
+    /// @param sellTokenAddress Token to sell.
+    /// @param sellAmount Amount of tokens to sell.
+    /// @param buyTokenAddress Token to buy.
+    /// @param recipientAddress Address to send bought tokens to.
+    /// @param maxBuyTokenAmount A limit on the amount of tokens to buy.
+    /// @param minConversionRate The minimal conversion rate. If actual rate
+    ///        is lower, trade is canceled.
+    /// @param walletId The wallet ID to send part of the fees
+    /// @param hint The hint for the selective inclusion (or exclusion) of reserves
+    /// @return boughtAmount Amount of tokens bought.
+    function tradeWithHint(
+        address sellTokenAddress,
+        uint256 sellAmount,
+        address buyTokenAddress,
+        address payable recipientAddress,
+        uint256 maxBuyTokenAmount,
+        uint256 minConversionRate,
+        address payable walletId,
+        bytes calldata hint
+    )
+        external
+        payable
+        returns (uint256 boughtAmount);
 }

contracts/utils/contracts/src/DeploymentConstants.sol

@@ -1,6 +1,6 @@
 /*
 
-  Copyright 2019 ZeroEx Intl.
+  Copyright 2020 ZeroEx Intl.
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -28,6 +28,8 @@ contract DeploymentConstants {
     address constant private WETH_ADDRESS = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
     /// @dev Mainnet address of the KyberNetworkProxy contract.
     address constant private KYBER_NETWORK_PROXY_ADDRESS = 0x9AAb3f75489902f3a48495025729a0AF77d4b11e;
+    /// @dev Mainnet address of the KyberHintHandler contract.
+    address constant private KYBER_HINT_HANDLER_ADDRESS = 0xa1C0Fa73c39CFBcC11ec9Eb1Afc665aba9996E2C;
     /// @dev Mainnet address of the `UniswapExchangeFactory` contract.
     address constant private UNISWAP_EXCHANGE_FACTORY_ADDRESS = 0xc0a47dFe034B400B47bDaD5FecDa2621de6c4d95;
     /// @dev Mainnet address of the `UniswapV2Router01` contract.
@@ -155,6 +157,16 @@ contract DeploymentConstants {
         return KYBER_NETWORK_PROXY_ADDRESS;
     }
 
+    /// @dev Overridable way to get the `KyberHintHandler` address.
+    /// @return kyberAddress The `IKyberHintHandler` address.
+    function _getKyberHintHandlerAddress()
+        internal
+        view
+        returns (address hintHandlerAddress)
+    {
+        return KYBER_HINT_HANDLER_ADDRESS;
+    }
+
     /// @dev Overridable way to get the WETH address.
     /// @return wethAddress The WETH address.
     function _getWethAddress()