first commit of restructured project
This commit is contained in:
KS Jannette
74
trahn-trade-backend/internal/ethereum/abi.go
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74
trahn-trade-backend/internal/ethereum/abi.go
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@@ -0,0 +1,74 @@
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package ethereum
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import (
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"io"
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"strings"
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)
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// Minimal ABIs for Uniswap V2 Router02 and ERC20 — only the methods we call.
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func mustRouterABI() io.Reader {
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return strings.NewReader(`[
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{
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"name": "swapExactTokensForETH",
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"type": "function",
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"stateMutability": "nonpayable",
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"inputs": [
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{"name": "amountIn", "type": "uint256"},
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{"name": "amountOutMin", "type": "uint256"},
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{"name": "path", "type": "address[]"},
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{"name": "to", "type": "address"},
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{"name": "deadline", "type": "uint256"}
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],
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"outputs": [
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{"name": "amounts", "type": "uint256[]"}
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]
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},
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{
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"name": "swapExactETHForTokens",
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"type": "function",
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"stateMutability": "payable",
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"inputs": [
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{"name": "amountOutMin", "type": "uint256"},
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{"name": "path", "type": "address[]"},
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{"name": "to", "type": "address"},
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{"name": "deadline", "type": "uint256"}
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],
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"outputs": [
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{"name": "amounts", "type": "uint256[]"}
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]
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}
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]`)
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}
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func mustERC20ABI() io.Reader {
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return strings.NewReader(`[
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{
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"name": "balanceOf",
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"type": "function",
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"stateMutability": "view",
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"inputs": [{"name": "_owner", "type": "address"}],
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"outputs": [{"name": "balance", "type": "uint256"}]
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},
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{
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"name": "allowance",
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"type": "function",
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"stateMutability": "view",
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"inputs": [
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{"name": "_owner", "type": "address"},
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{"name": "_spender", "type": "address"}
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],
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"outputs": [{"name": "", "type": "uint256"}]
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},
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{
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"name": "approve",
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"type": "function",
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"stateMutability": "nonpayable",
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"inputs": [
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{"name": "_spender", "type": "address"},
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{"name": "_value", "type": "uint256"}
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],
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"outputs": [{"name": "", "type": "bool"}]
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}
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]`)
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}
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118
trahn-trade-backend/internal/ethereum/client.go
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118
trahn-trade-backend/internal/ethereum/client.go
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@@ -0,0 +1,118 @@
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package ethereum
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import (
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"context"
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"crypto/ecdsa"
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"fmt"
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"math/big"
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"strings"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/core/types"
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"github.com/ethereum/go-ethereum/crypto"
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"github.com/ethereum/go-ethereum/ethclient"
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)
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type Client struct {
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rpc *ethclient.Client
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privateKey *ecdsa.PrivateKey
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wallet common.Address
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chainID *big.Int
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gasLimit uint64
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gasMul float64
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}
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func NewClient(rpcURL, privateKeyHex string, chainID int64, gasLimit int, gasMultiplier float64) (*Client, error) {
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rpc, err := ethclient.Dial(rpcURL)
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if err != nil {
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return nil, fmt.Errorf("dial RPC: %w", err)
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}
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pkHex := strings.TrimPrefix(privateKeyHex, "0x")
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pk, err := crypto.HexToECDSA(pkHex)
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if err != nil {
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return nil, fmt.Errorf("parse private key: %w", err)
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}
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addr := crypto.PubkeyToAddress(pk.PublicKey)
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return &Client{
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rpc: rpc,
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privateKey: pk,
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wallet: addr,
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chainID: big.NewInt(chainID),
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gasLimit: uint64(gasLimit),
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gasMul: gasMultiplier,
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}, nil
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}
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func (c *Client) WalletAddress() common.Address { return c.wallet }
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func (c *Client) GasLimit() uint64 { return c.gasLimit }
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func (c *Client) Close() { c.rpc.Close() }
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func (c *Client) ETHBalance(ctx context.Context) (*big.Int, error) {
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return c.rpc.BalanceAt(ctx, c.wallet, nil)
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}
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func (c *Client) GasPrice(ctx context.Context) (*big.Int, error) {
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price, err := c.rpc.SuggestGasPrice(ctx)
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if err != nil {
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return nil, err
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}
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// Apply multiplier
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mul := new(big.Float).SetFloat64(c.gasMul)
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adjusted := new(big.Float).Mul(new(big.Float).SetInt(price), mul)
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result, _ := adjusted.Int(nil)
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return result, nil
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}
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func (c *Client) Nonce(ctx context.Context) (uint64, error) {
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return c.rpc.PendingNonceAt(ctx, c.wallet)
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}
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// SignAndSend signs a legacy transaction and broadcasts it, returning the tx hash.
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func (c *Client) SignAndSend(ctx context.Context, to common.Address, value *big.Int, data []byte) (string, error) {
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nonce, err := c.Nonce(ctx)
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if err != nil {
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return "", fmt.Errorf("get nonce: %w", err)
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}
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gasPrice, err := c.GasPrice(ctx)
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if err != nil {
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return "", fmt.Errorf("get gas price: %w", err)
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}
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tx := types.NewTx(&types.LegacyTx{
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Nonce: nonce,
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To: &to,
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Value: value,
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Gas: c.gasLimit,
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GasPrice: gasPrice,
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Data: data,
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})
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signer := types.NewEIP155Signer(c.chainID)
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signed, err := types.SignTx(tx, signer, c.privateKey)
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if err != nil {
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return "", fmt.Errorf("sign tx: %w", err)
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}
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if err := c.rpc.SendTransaction(ctx, signed); err != nil {
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return "", fmt.Errorf("send tx: %w", err)
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}
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return signed.Hash().Hex(), nil
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}
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// CallContract performs a read-only eth_call and returns the raw result.
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func (c *Client) CallContract(ctx context.Context, to common.Address, data []byte) ([]byte, error) {
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msg := map[string]interface{}{
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"to": to.Hex(),
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"data": fmt.Sprintf("0x%x", data),
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}
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var result string
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err := c.rpc.Client().CallContext(ctx, &result, "eth_call", msg, "latest")
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if err != nil {
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return nil, err
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}
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return common.FromHex(result), nil
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}
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184
trahn-trade-backend/internal/ethereum/uniswap.go
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184
trahn-trade-backend/internal/ethereum/uniswap.go
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@@ -0,0 +1,184 @@
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package ethereum
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import (
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"context"
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"fmt"
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"math"
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"math/big"
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"time"
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"github.com/ethereum/go-ethereum/accounts/abi"
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"github.com/ethereum/go-ethereum/common"
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)
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const explorerTxPrefix = "https://etherscan.io/tx/"
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// UniswapV2 wraps an Ethereum Client and provides Uniswap V2 Router swap methods.
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type UniswapV2 struct {
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client *Client
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routerAddr common.Address
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wethAddr common.Address
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quoteAddr common.Address
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quoteSymbol string
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quoteDec int
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slippagePct float64
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routerABI abi.ABI
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erc20ABI abi.ABI
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}
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func NewUniswapV2(
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client *Client,
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routerAddr, wethAddr, quoteAddr string,
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quoteSymbol string,
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quoteDecimals int,
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slippagePct float64,
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) (*UniswapV2, error) {
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rABI, err := abi.JSON(mustRouterABI())
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if err != nil {
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return nil, fmt.Errorf("parse router ABI: %w", err)
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}
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eABI, err := abi.JSON(mustERC20ABI())
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if err != nil {
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return nil, fmt.Errorf("parse ERC20 ABI: %w", err)
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}
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return &UniswapV2{
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client: client,
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routerAddr: common.HexToAddress(routerAddr),
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wethAddr: common.HexToAddress(wethAddr),
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quoteAddr: common.HexToAddress(quoteAddr),
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quoteSymbol: quoteSymbol,
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quoteDec: quoteDecimals,
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slippagePct: slippagePct,
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routerABI: rABI,
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erc20ABI: eABI,
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}, nil
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}
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func (u *UniswapV2) ExplorerURL(txHash string) string {
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return explorerTxPrefix + txHash
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}
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// TokenBalance returns the ERC20 token balance as a human-readable float.
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func (u *UniswapV2) TokenBalance(ctx context.Context) (float64, error) {
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data, err := u.erc20ABI.Pack("balanceOf", u.client.wallet)
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if err != nil {
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return 0, err
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}
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result, err := u.client.CallContract(ctx, u.quoteAddr, data)
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if err != nil {
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return 0, fmt.Errorf("balanceOf call: %w", err)
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}
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bal := new(big.Int).SetBytes(result)
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divisor := math.Pow10(u.quoteDec)
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f, _ := new(big.Float).Quo(new(big.Float).SetInt(bal), new(big.Float).SetFloat64(divisor)).Float64()
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return f, nil
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}
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// ETHBalance returns wallet ETH balance as a human-readable float.
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func (u *UniswapV2) ETHBalance(ctx context.Context) (float64, error) {
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bal, err := u.client.ETHBalance(ctx)
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if err != nil {
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return 0, err
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}
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f, _ := new(big.Float).Quo(new(big.Float).SetInt(bal), new(big.Float).SetFloat64(1e18)).Float64()
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return f, nil
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}
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// EnsureAllowance checks the router's allowance for the quote token and approves max if needed.
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func (u *UniswapV2) EnsureAllowance(ctx context.Context, requiredAmount float64) error {
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data, err := u.erc20ABI.Pack("allowance", u.client.wallet, u.routerAddr)
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if err != nil {
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return err
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}
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result, err := u.client.CallContract(ctx, u.quoteAddr, data)
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if err != nil {
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return fmt.Errorf("allowance call: %w", err)
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}
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current := new(big.Int).SetBytes(result)
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requiredWei := toTokenWei(requiredAmount*2, u.quoteDec)
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if current.Cmp(requiredWei) >= 0 {
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return nil
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}
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fmt.Printf("Setting %s allowance for Uniswap Router...\n", u.quoteSymbol)
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maxUint256 := new(big.Int).Sub(new(big.Int).Lsh(big.NewInt(1), 256), big.NewInt(1))
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approveData, err := u.erc20ABI.Pack("approve", u.routerAddr, maxUint256)
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if err != nil {
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return err
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}
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txHash, err := u.client.SignAndSend(ctx, u.quoteAddr, big.NewInt(0), approveData)
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if err != nil {
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return fmt.Errorf("approve tx: %w", err)
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}
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fmt.Printf("Allowance TX confirmed: %s\n", u.ExplorerURL(txHash))
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return nil
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}
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// SwapUSDCForETH executes swapExactTokensForETH on the Uniswap V2 Router.
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// Returns the transaction hash.
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func (u *UniswapV2) SwapUSDCForETH(ctx context.Context, usdcAmount, minETHOut float64) (string, error) {
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if err := u.EnsureAllowance(ctx, usdcAmount); err != nil {
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return "", err
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}
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path := []common.Address{u.quoteAddr, u.wethAddr}
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deadline := big.NewInt(time.Now().Unix() + 20*60)
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amountIn := toTokenWei(usdcAmount, u.quoteDec)
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// Apply slippage to minETHOut
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minOutWei := toEthWei(minETHOut * (1 - u.slippagePct/100))
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data, err := u.routerABI.Pack("swapExactTokensForETH",
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amountIn, minOutWei, path, u.client.wallet, deadline)
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if err != nil {
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return "", fmt.Errorf("pack swapExactTokensForETH: %w", err)
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}
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return u.client.SignAndSend(ctx, u.routerAddr, big.NewInt(0), data)
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}
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// SwapETHForUSDC executes swapExactETHForTokens on the Uniswap V2 Router.
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// Returns the transaction hash.
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func (u *UniswapV2) SwapETHForUSDC(ctx context.Context, ethAmount float64) (string, error) {
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path := []common.Address{u.wethAddr, u.quoteAddr}
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deadline := big.NewInt(time.Now().Unix() + 20*60)
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value := toEthWei(ethAmount)
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data, err := u.routerABI.Pack("swapExactETHForTokens",
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big.NewInt(0), path, u.client.wallet, deadline)
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if err != nil {
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return "", fmt.Errorf("pack swapExactETHForTokens: %w", err)
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}
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return u.client.SignAndSend(ctx, u.routerAddr, value, data)
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}
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// GasCostETH estimates the gas cost for a transaction in ETH.
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func (u *UniswapV2) GasCostETH(ctx context.Context) (float64, error) {
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gasPrice, err := u.client.GasPrice(ctx)
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if err != nil {
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return 0, err
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}
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cost := new(big.Int).Mul(gasPrice, new(big.Int).SetUint64(u.client.GasLimit()))
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f, _ := new(big.Float).Quo(new(big.Float).SetInt(cost), new(big.Float).SetFloat64(1e18)).Float64()
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return f, nil
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}
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// --- helpers ---
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func toEthWei(eth float64) *big.Int {
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// eth * 1e18
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f := new(big.Float).Mul(new(big.Float).SetFloat64(eth), new(big.Float).SetFloat64(1e18))
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i, _ := f.Int(nil)
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return i
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}
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func toTokenWei(amount float64, decimals int) *big.Int {
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f := new(big.Float).Mul(
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new(big.Float).SetFloat64(amount),
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new(big.Float).SetFloat64(math.Pow10(decimals)),
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)
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i, _ := f.Int(nil)
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return i
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}
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Block a user