Initial commit: add .gitignore and README

src/dex/UniswapV3Service.ts

@@ -0,0 +1,157 @@
+import { ethers } from 'ethers';
+import { formatUnits } from 'ethers';
+import { IDexService } from './DexService.js';
+import { SwapQuote } from '../types/index.js';
+import { ERC20_ABI } from '../aave/contracts.js';
+
+// Uniswap V3 Router ABI (simplified)
+const UNISWAP_V3_ROUTER_ABI = [
+  'function exactInputSingle(tuple(address tokenIn, address tokenOut, uint24 fee, address recipient, uint256 deadline, uint256 amountIn, uint256 amountOutMinimum, uint160 sqrtPriceLimitX96)) external payable returns (uint256 amountOut)',
+  'function multicall(uint256 deadline, bytes[] calldata data) external payable returns (bytes[] memory results)',
+] as const;
+
+// Uniswap V3 Quoter ABI
+const UNISWAP_V3_QUOTER_ABI = [
+  'function quoteExactInputSingle(address tokenIn, address tokenOut, uint24 fee, uint256 amountIn, uint160 sqrtPriceLimitX96) external returns (uint256 amountOut)',
+] as const;
+
+// Common fee tiers for stablecoin pairs
+const STABLECOIN_FEE_TIERS = [100, 500, 3000]; // 0.01%, 0.05%, 0.3%
+
+export class UniswapV3Service implements IDexService {
+  private router: ethers.Contract;
+  private quoter?: ethers.Contract;
+  private signer: ethers.Signer;
+
+  constructor(
+    signer: ethers.Signer,
+    routerAddress: string,
+    quoterAddress?: string
+  ) {
+    this.signer = signer;
+    this.router = new ethers.Contract(routerAddress, UNISWAP_V3_ROUTER_ABI, signer);
+    
+    if (quoterAddress) {
+      this.quoter = new ethers.Contract(quoterAddress, UNISWAP_V3_QUOTER_ABI, signer);
+    }
+  }
+
+  getName(): string {
+    return 'Uniswap V3';
+  }
+
+  /**
+   * Get quote for a swap
+   */
+  async getQuote(
+    tokenIn: string,
+    tokenOut: string,
+    amountIn: bigint
+  ): Promise<SwapQuote> {
+    if (!this.quoter) {
+      // If no quoter, estimate with a simple calculation (not accurate, but better than nothing)
+      return {
+        amountOut: amountIn, // Assume 1:1 for stablecoins
+        priceImpact: 0.001, // 0.1% estimated
+      };
+    }
+
+    let bestQuote: bigint = 0n;
+
+    // Try different fee tiers to find the best quote
+    for (const fee of STABLECOIN_FEE_TIERS) {
+      try {
+        const quote = await this.quoter.quoteExactInputSingle.staticCall(
+          tokenIn,
+          tokenOut,
+          fee,
+          amountIn,
+          0
+        );
+        if (quote > bestQuote) {
+          bestQuote = quote;
+        }
+      } catch (error) {
+        // Pool might not exist for this fee tier, continue
+        continue;
+      }
+    }
+
+    if (bestQuote === 0n) {
+      throw new Error('No valid pool found for token pair');
+    }
+
+    // Calculate price impact (simplified - assumes 1:1 for stablecoins)
+    const amountInNum = Number(formatUnits(amountIn, 18));
+    const amountOutNum = Number(formatUnits(bestQuote, 18));
+    const priceImpact = Math.abs((amountInNum - amountOutNum) / amountInNum);
+
+    return {
+      amountOut: bestQuote,
+      priceImpact,
+    };
+  }
+
+  /**
+   * Execute swap on Uniswap V3
+   */
+  async swap(
+    tokenIn: string,
+    tokenOut: string,
+    amountIn: bigint,
+    amountOutMin: bigint,
+    recipient: string,
+    deadline?: number
+  ): Promise<ethers.ContractTransactionResponse> {
+    // Ensure approval
+    const tokenContract = new ethers.Contract(tokenIn, ERC20_ABI, this.signer);
+    const currentAllowance = await tokenContract.allowance(
+      await this.signer.getAddress(),
+      this.router.target as string
+    );
+
+    if (currentAllowance < amountIn) {
+      const approveTx = await tokenContract.approve(this.router.target as string, ethers.MaxUint256);
+      await approveTx.wait();
+    }
+
+    // Get best fee tier
+    let bestFee = 500; // Default to 0.05%
+    if (this.quoter) {
+      let bestQuote: bigint = 0n;
+      for (const fee of STABLECOIN_FEE_TIERS) {
+        try {
+          const quote = await this.quoter.quoteExactInputSingle.staticCall(
+            tokenIn,
+            tokenOut,
+            fee,
+            amountIn,
+            0
+          );
+          if (quote > bestQuote) {
+            bestQuote = quote;
+            bestFee = fee;
+          }
+        } catch {
+          continue;
+        }
+      }
+    }
+
+    const finalDeadline = deadline || Math.floor(Date.now() / 1000) + 1800; // 30 minutes default
+
+    const tx = await this.router.exactInputSingle({
+      tokenIn,
+      tokenOut,
+      fee: bestFee,
+      recipient,
+      deadline: finalDeadline,
+      amountIn,
+      amountOutMinimum: amountOutMin,
+      sqrtPriceLimitX96: 0,
+    });
+
+    return tx;
+  }
+}
+