feat: add SmarDex exact-in swap helper

broadcast/SmardexSwapHelpersDeployer.s.sol/1/run-1782409696286.json

@@ -0,0 +1,52 @@
+{
+  "transactions": [
+    {
+      "hash": "0xddb4fee168bb547dbb51471592fdf67a0c11698b3ea8b02aa506b527e0c340ae",
+      "transactionType": "CREATE2",
+      "contractName": "SmardexSwapHelpers",
+      "contractAddress": "0x701aafa9a3928518aff3c8a041fff5a790669e01",
+      "function": null,
+      "arguments": null,
+      "transaction": {
+        "from": "0x826e0bb2276271efdf2a500597f37b94f6c153ba",
+        "to": "0x4e59b44847b379578588920ca78fbf26c0b4956c",
+        "gas": "0x46082",
+        "value": "0x0",
+        "input": "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",
+        "nonce": "0x15a",
+        "chainId": "0x1"
+      },
+      "additionalContracts": [],
+      "isFixedGasLimit": false
+    }
+  ],
+  "receipts": [
+    {
+      "status": "0x1",
+      "cumulativeGasUsed": "0x19e3778",
+      "logs": [],
+      "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+      "type": "0x2",
+      "transactionHash": "0xddb4fee168bb547dbb51471592fdf67a0c11698b3ea8b02aa506b527e0c340ae",
+      "transactionIndex": "0xcf",
+      "blockHash": "0xcf0d0b0677f03ae6f50fbfe1312d4d00d394ed6c44f01d3ae023d71a9546f5b4",
+      "blockNumber": "0x1838406",
+      "gasUsed": "0x2fe29",
+      "effectiveGasPrice": "0x2826109b",
+      "from": "0x826e0bb2276271efdf2a500597f37b94f6c153ba",
+      "to": "0x4e59b44847b379578588920ca78fbf26c0b4956c",
+      "contractAddress": "0x701aafa9a3928518aff3c8a041fff5a790669e01"
+    }
+  ],
+  "libraries": [],
+  "pending": [],
+  "returns": {
+    "smardexSwapHelpers": {
+      "internal_type": "contract SmardexSwapHelpers",
+      "value": "0x701AaFA9A3928518aff3C8a041FfF5A790669e01"
+    }
+  },
+  "timestamp": 1782409696286,
+  "chain": 1,
+  "commit": "64db0dc"
+}

broadcast/SmardexSwapHelpersDeployer.s.sol/1/run-latest.json

@@ -0,0 +1,52 @@
+{
+  "transactions": [
+    {
+      "hash": "0xddb4fee168bb547dbb51471592fdf67a0c11698b3ea8b02aa506b527e0c340ae",
+      "transactionType": "CREATE2",
+      "contractName": "SmardexSwapHelpers",
+      "contractAddress": "0x701aafa9a3928518aff3c8a041fff5a790669e01",
+      "function": null,
+      "arguments": null,
+      "transaction": {
+        "from": "0x826e0bb2276271efdf2a500597f37b94f6c153ba",
+        "to": "0x4e59b44847b379578588920ca78fbf26c0b4956c",
+        "gas": "0x46082",
+        "value": "0x0",
+        "input": "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",
+        "nonce": "0x15a",
+        "chainId": "0x1"
+      },
+      "additionalContracts": [],
+      "isFixedGasLimit": false
+    }
+  ],
+  "receipts": [
+    {
+      "status": "0x1",
+      "cumulativeGasUsed": "0x19e3778",
+      "logs": [],
+      "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+      "type": "0x2",
+      "transactionHash": "0xddb4fee168bb547dbb51471592fdf67a0c11698b3ea8b02aa506b527e0c340ae",
+      "transactionIndex": "0xcf",
+      "blockHash": "0xcf0d0b0677f03ae6f50fbfe1312d4d00d394ed6c44f01d3ae023d71a9546f5b4",
+      "blockNumber": "0x1838406",
+      "gasUsed": "0x2fe29",
+      "effectiveGasPrice": "0x2826109b",
+      "from": "0x826e0bb2276271efdf2a500597f37b94f6c153ba",
+      "to": "0x4e59b44847b379578588920ca78fbf26c0b4956c",
+      "contractAddress": "0x701aafa9a3928518aff3c8a041fff5a790669e01"
+    }
+  ],
+  "libraries": [],
+  "pending": [],
+  "returns": {
+    "smardexSwapHelpers": {
+      "internal_type": "contract SmardexSwapHelpers",
+      "value": "0x701AaFA9A3928518aff3C8a041FfF5A790669e01"
+    }
+  },
+  "timestamp": 1782409696286,
+  "chain": 1,
+  "commit": "64db0dc"
+}

script/SmardexSwapHelpersDeployer.s.sol

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.28;
+
+import { SmardexSwapHelpers } from "../src/helpers/SmardexSwapHelpers.sol";
+import { Script } from "forge-std/Script.sol";
+
+contract SmardexSwapHelpersDeployer is Script {
+    function run() public returns (SmardexSwapHelpers smardexSwapHelpers) {
+        uint256 deployerPrivateKey = vm.envUint("PRIVATE_KEY");
+
+        vm.startBroadcast(deployerPrivateKey);
+
+        // Stateless pure encoder: router-agnostic, same address (CREATE2) on every chain.
+        smardexSwapHelpers = new SmardexSwapHelpers{ salt: "SmardexSwapHelpers" }();
+
+        vm.stopBroadcast();
+    }
+}

src/helpers/SmardexSwapHelpers.sol

@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.28;
+
+import { SafeCast } from "@openzeppelin/contracts/utils/math/SafeCast.sol";
+
+contract SmardexSwapHelpers {
+    using SafeCast for uint256;
+
+    uint8 private constant PAYMENT_TRANSFER_FROM = 2;
+
+    function encodeSwapInputs(
+        address tokenIn,
+        address tokenOut,
+        uint256 amountIn,
+        uint256 minAmountOut,
+        address to
+    )
+        external
+        pure
+        returns (bytes[] memory inputs)
+    {
+        address[] memory path = new address[](2);
+        path[0] = tokenIn;
+        path[1] = tokenOut;
+
+        inputs = new bytes[](1);
+        inputs[0] = abi.encode(amountIn.toUint128(), minAmountOut.toUint128(), path, to, PAYMENT_TRANSFER_FROM);
+    }
+}

test/unit/concrete/helpers/SmardexSwapHelpers.t.sol

@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.28;
+
+import { SmardexSwapHelpers } from "../../../../src/helpers/SmardexSwapHelpers.sol";
+import { Test } from "forge-std/Test.sol";
+
+contract SmardexSwapHelpersTest is Test {
+    SmardexSwapHelpers public helpers;
+
+    uint8 internal constant PAYMENT_TRANSFER_FROM = 2;
+
+    address internal constant TOKEN_IN = 0x7f39C581F595B53c5cb19bD0b3f8dA6c935E2Ca0; // wstETH
+    address internal constant TOKEN_OUT = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2; // WETH
+    address internal constant TO = 0x00000000000000000000000000000000DeaDBeef;
+
+    function setUp() public {
+        helpers = new SmardexSwapHelpers();
+    }
+
+    function test_encodeSwapInputs_matchesRouterEncoding() public view {
+        uint256 amountIn = 1 ether;
+        uint256 minAmountOut = 0.9 ether;
+
+        bytes[] memory inputs = helpers.encodeSwapInputs(TOKEN_IN, TOKEN_OUT, amountIn, minAmountOut, TO);
+
+        assertEq(inputs.length, 1, "single input");
+
+        address[] memory path = new address[](2);
+        path[0] = TOKEN_IN;
+        path[1] = TOKEN_OUT;
+        bytes memory expected = abi.encode(uint128(amountIn), uint128(minAmountOut), path, TO, PAYMENT_TRANSFER_FROM);
+        assertEq(inputs[0], expected, "encoding must match the SmarDex swapInput layout");
+    }
+
+    function test_encodeSwapInputs_decodesRoundTrip() public view {
+        uint256 amountIn = 12_345;
+        uint256 minAmountOut = 678;
+
+        bytes[] memory inputs = helpers.encodeSwapInputs(TOKEN_IN, TOKEN_OUT, amountIn, minAmountOut, TO);
+
+        (uint128 dAmountIn, uint128 dMinAmountOut, address[] memory dPath, address dTo, uint8 dPayment) =
+            abi.decode(inputs[0], (uint128, uint128, address[], address, uint8));
+
+        assertEq(dAmountIn, uint128(amountIn), "amountIn");
+        assertEq(dMinAmountOut, uint128(minAmountOut), "minAmountOut");
+        assertEq(dPath.length, 2, "path length");
+        assertEq(dPath[0], TOKEN_IN, "path[0]");
+        assertEq(dPath[1], TOKEN_OUT, "path[1]");
+        assertEq(dTo, TO, "to");
+        assertEq(dPayment, PAYMENT_TRANSFER_FROM, "payment");
+    }
+
+    function test_encodeSwapInputs_revertsOnAmountInOverflow() public {
+        uint256 tooBig = uint256(type(uint128).max) + 1;
+        vm.expectRevert();
+        helpers.encodeSwapInputs(TOKEN_IN, TOKEN_OUT, tooBig, 0, TO);
+    }
+
+    function test_encodeSwapInputs_revertsOnMinAmountOutOverflow() public {
+        uint256 tooBig = uint256(type(uint128).max) + 1;
+        vm.expectRevert();
+        helpers.encodeSwapInputs(TOKEN_IN, TOKEN_OUT, 1 ether, tooBig, TO);
+    }
+}