mev-beta/orig/pkg/tokens/decimals.go

package tokens

import (
	"math"
	"math/big"

	"github.com/ethereum/go-ethereum/common"
)

// Common token addresses on Arbitrum
var (
	WETH  = common.HexToAddress("0x82aF49447D8a07e3bd95BD0d56f35241523fBab1")
	USDC  = common.HexToAddress("0xFF970A61A04b1cA14834A43f5dE4533eBDDB5CC8")
	USDT  = common.HexToAddress("0xFd086bC7CD5C481DCC9C85ebE478A1C0b69FCbb9")
	WBTC  = common.HexToAddress("0x2f2a2543B76A4166549F7aaB2e75Bef0aefC5B0f")
	ARB   = common.HexToAddress("0x912CE59144191C1204E64559FE8253a0e49E6548")
	DAI   = common.HexToAddress("0xDA10009cBd5D07dd0CeCc66161FC93D7c9000da1")
	LINK  = common.HexToAddress("0xf97f4df75117a78c1A5a0DBb814Af92458539FB4")
	UNI   = common.HexToAddress("0xFa7F8980b0f1E64A2062791cc3b0871572f1F7f0")
	GMX   = common.HexToAddress("0xfc5A1A6EB076a2C7aD06eD22C90d7E710E35ad0a")
	MAGIC = common.HexToAddress("0x539bdE0d7Dbd336b79148AA742883198BBF60342")
)

// TokenDecimals maps token addresses to their decimal places
var TokenDecimals = map[common.Address]uint8{
	WETH:  18,
	USDC:  6,
	USDT:  6,
	WBTC:  8,
	ARB:   18,
	DAI:   18,
	LINK:  18,
	UNI:   18,
	GMX:   18,
	MAGIC: 18,
}

// GetTokenDecimals returns the decimal places for a token, defaulting to 18 if unknown
func GetTokenDecimals(tokenAddress common.Address) uint8 {
	if decimals, ok := TokenDecimals[tokenAddress]; ok {
		return decimals
	}
	// Default to 18 decimals for unknown tokens (most ERC20 tokens use 18)
	return 18
}

// ConvertToFloat converts a token amount to a float64 considering its decimals
func ConvertToFloat(amount *big.Int, tokenAddress common.Address) float64 {
	if amount == nil {
		return 0
	}

	decimals := GetTokenDecimals(tokenAddress)
	divisor := math.Pow(10, float64(decimals))

	amountFloat := new(big.Float).SetInt(amount)
	divisorFloat := big.NewFloat(divisor)
	result := new(big.Float).Quo(amountFloat, divisorFloat)

	val, _ := result.Float64()
	return val
}

// ConvertToBigFloat converts a token amount to a *big.Float considering its decimals
func ConvertToBigFloat(amount *big.Int, tokenAddress common.Address) *big.Float {
	if amount == nil {
		return big.NewFloat(0)
	}

	decimals := GetTokenDecimals(tokenAddress)
	divisor := math.Pow(10, float64(decimals))

	amountFloat := new(big.Float).SetInt(amount)
	divisorFloat := big.NewFloat(divisor)
	return new(big.Float).Quo(amountFloat, divisorFloat)
}

// ConvertFromFloat converts a float64 to the token's smallest unit (*big.Int)
func ConvertFromFloat(amount float64, tokenAddress common.Address) *big.Int {
	decimals := GetTokenDecimals(tokenAddress)
	multiplier := math.Pow(10, float64(decimals))

	// Convert to smallest unit
	rawAmount := amount * multiplier

	// Convert to big.Int
	amountBig := new(big.Float).SetFloat64(rawAmount)
	result, _ := amountBig.Int(nil)

	return result
}

// NormalizeAmount converts an amount from one token's decimals to another's
func NormalizeAmount(amount *big.Int, fromToken, toToken common.Address) *big.Int {
	if amount == nil {
		return big.NewInt(0)
	}

	fromDecimals := GetTokenDecimals(fromToken)
	toDecimals := GetTokenDecimals(toToken)

	if fromDecimals == toDecimals {
		return new(big.Int).Set(amount)
	}

	// Convert to float with proper decimals
	amountFloat := ConvertToBigFloat(amount, fromToken)

	// Convert back with target token decimals
	toMultiplier := math.Pow(10, float64(toDecimals))
	multiplierBig := big.NewFloat(toMultiplier)

	result := new(big.Float).Mul(amountFloat, multiplierBig)
	resultInt, _ := result.Int(nil)

	return resultInt
}

// GetMinimumTradeAmount returns the minimum trade amount for a token
// This helps avoid dust trades that aren't economically viable
func GetMinimumTradeAmount(tokenAddress common.Address) *big.Int {
	// Note: decimals are handled in ConvertFromFloat

	// Minimum amounts in token units (not smallest units)
	var minAmount float64
	switch tokenAddress {
	case USDC, USDT:
		minAmount = 10.0 // $10 minimum for stablecoins
	case WBTC:
		minAmount = 0.0001 // 0.0001 BTC minimum
	case WETH, ARB, UNI, LINK, GMX:
		minAmount = 0.01 // 0.01 token minimum
	default:
		minAmount = 0.01 // Default minimum
	}

	return ConvertFromFloat(minAmount, tokenAddress)
}

// FormatTokenAmount formats a token amount for display
func FormatTokenAmount(amount *big.Int, tokenAddress common.Address, precision int) string {
	if amount == nil {
		return "0"
	}

	amountFloat := ConvertToBigFloat(amount, tokenAddress)
	return amountFloat.Text('f', precision)
}