uniswap v3 pair

contracts/interfaces/uniswap/Quoter.sol

@@ -74,10 +74,10 @@ library Quoter {
         Slot0 memory slot0Start;
         (
             slot0Start.sqrtPriceX96,
-            slot0Start.tick, // uint16 observationIndex, // uint16 observationCardinality, // uint16 observationCardinalityNext,
-            ,
-            ,
-            ,
+            slot0Start.tick,
+            , // uint16 observationIndex
+            , // uint16 observationCardinality
+            , // uint16 observationCardinalityNext
             slot0Start.feeProtocol,
             // bool unlocked
 
@@ -186,14 +186,14 @@ library Quoter {
                     (
                         ,
                         // uint128 liquidityGross,
-                        int128 liquidityNet, // uint256 feeGrowthOutside0X128, // uint256 feeGrowthOutside1X128, // int56 tickCumulativeOutside, // uint160 secondsPerLiquidityOutsideX128, // uint32 secondsOutside,
-                        ,
-                        ,
-                        ,
-                        ,
-                        ,
-
-                    ) = // bool initialized
+                        int128 liquidityNet,
+                        , // uint256 feeGrowthOutside0X128
+                        , // uint256 feeGrowthOutside1X128
+                        , // int56 tickCumulativeOutside
+                        , // uint160 secondsPerLiquidityOutsideX128
+                        , // uint32 secondsOutside
+                        // bool initialized
+                    ) =
                         pool.ticks(step.tickNext);
 
                     // if we're moving leftward, we interpret liquidityNet as the opposite sign

contracts/swappa/PairUniswapV3.sol

@@ -1,63 +1,61 @@
 // SPDX-License-Identifier: MIT
-pragma solidity ~0.6.8;
+pragma solidity >=0.4.0 <0.8.0;
 
 import "@openzeppelin/contracts/math/SafeMath.sol";
 import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
-import "../interfaces/uniswap/IUniswapV2Pair.sol";
 import "../interfaces/uniswap/IUniswapV3Pool.sol";
 import "../interfaces/uniswap/Quoter.sol";
+import "../interfaces/uniswap/SafeCast.sol";
+import "../interfaces/uniswap/TickMath.sol";
 import "./ISwappaPairV1.sol";
 
 contract PairUniswapV3 is ISwappaPairV1 {
     using SafeMath for uint;
+    using SafeCast for uint;
 
-	function swap(
-		address input,
-		address output,
-		address to,
-		bytes calldata data
-	) external override {
-		(address pairAddr, uint feeK) = parseData(data);
-		uint inputAmount = ERC20(input).balanceOf(address(this));
-		require(
-			ERC20(input).transfer(pairAddr, inputAmount),
-			"PairUniswapV2: transfer failed!");
-		IUniswapV2Pair pair = IUniswapV2Pair(pairAddr);
-		(uint reserve0, uint reserve1,) = pair.getReserves();
-		if (pair.token0() == input) {
-			uint outputAmount = getAmountOut(inputAmount, reserve0, reserve1, feeK);
-			pair.swap(0, outputAmount, to, new bytes(0));
-		} else {
-			uint outputAmount = getAmountOut(inputAmount, reserve1, reserve0, feeK);
-			pair.swap(outputAmount, 0, to, new bytes(0));
-		}
-	}
-
-	function parseData(bytes memory data) private pure returns (address pairAddr, uint fee) {
-		require(data.length == 21, "PairUniswapV2: invalid data!");
-		fee = uint(1000).sub(uint8(data[20]));
-    assembly {
-      pairAddr := mload(add(data, 20))
+    function swap(
+        address input,
+        address output,
+        address to,
+        bytes calldata data
+    ) external override {
+        address pairAddr = parseData(data);
+        uint inputAmount = ERC20(input).balanceOf(address(this));
+        require(
+            ERC20(input).transfer(pairAddr, inputAmount),
+            "PairUniswapV3: transfer failed!");
+        IUniswapV3Pool pair = IUniswapV3Pool(pairAddr);
+        bool zeroForOne = pair.token0() == input;
+        pair.swap(
+            to,
+            zeroForOne,
+            inputAmount.toInt256(),
+            zeroForOne ? TickMath.MIN_SQRT_RATIO + 1 : TickMath.MAX_SQRT_RATIO - 1,
+            new bytes(0));
     }
-	}
 
-	function getOutputAmount(
-		address input,
-		address output,
-		uint amountIn,
-		bytes calldata data
-	) external view override returns (uint amountOut) {
-		(address pairAddr, uint feeK) = parseData(data);
-		IUniswapV2Pair pair = IUniswapV2Pair(pairAddr);
-		(uint reserve0, uint reserve1,) = pair.getReserves();
-		(uint reserveIn, uint reserveOut) = pair.token0() == input ? (reserve0, reserve1) : (reserve1, reserve0);
-		return getAmountOut(amountIn, reserveIn, reserveOut, feeK);
-	}
+    function parseData(bytes memory data) private pure returns (address pairAddr) {
+        require(data.length == 20, "PairUniswapV3: invalid data!");
+        assembly {
+        pairAddr := mload(add(data, 20))
+        }
+    }
 
-	function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut, uint feeK) internal pure returns (uint amountOut) {
-		uint amountInWithFee = amountIn.mul(feeK);
-		uint numerator = amountInWithFee.mul(reserveOut);
-		uint denominator = reserveIn.mul(1000).add(amountInWithFee);
-		amountOut = numerator / denominator;
-  	}
+    function getOutputAmount(
+        address input,
+        address output,
+        uint amountIn,
+        bytes calldata data
+    ) external view override returns (uint amountOut) {
+        address pairAddr = parseData(data);
+        IUniswapV3Pool pair = IUniswapV3Pool(pairAddr);
+        bool zeroForOne = pair.token0() == input;
+        // amount0, amount1 are delta of the pair reserves
+        (int256 amount0, int256 amount1) = Quoter.quote(
+            pair,
+            zeroForOne,
+            amountIn.toInt256(),
+            zeroForOne ? TickMath.MIN_SQRT_RATIO + 1 : TickMath.MAX_SQRT_RATIO - 1);
+        return zeroForOne ? uint256(-amount1) : uint256(-amount0);
+    }
 }