package arbitrage

import (
	"fmt"
	"math/big"

	"github.com/fraktal/mev-beta/pkg/math"
)

var sharedDecimalConverter = math.NewDecimalConverter()

// universalFromWei converts a wei-denominated big.Int into a UniversalDecimal with 18 decimals.
// It gracefully handles nil values by returning a zero amount.
func universalFromWei(dec *math.DecimalConverter, value *big.Int, symbol string) *math.UniversalDecimal {
	if dec == nil {
		dec = sharedDecimalConverter
	}

	if value == nil {
		zero, _ := math.NewUniversalDecimal(big.NewInt(0), 18, symbol)
		return zero
	}

	return dec.FromWei(value, 18, symbol)
}

func universalOrFromWei(dec *math.DecimalConverter, decimal *math.UniversalDecimal, fallback *big.Int, decimals uint8, symbol string) *math.UniversalDecimal {
	if decimal != nil {
		return decimal
	}

	if fallback == nil {
		zero, _ := math.NewUniversalDecimal(big.NewInt(0), decimals, symbol)
		return zero
	}

	if dec == nil {
		dc := sharedDecimalConverter
		return dc.FromWei(fallback, decimals, symbol)
	}

	return dec.FromWei(fallback, decimals, symbol)
}

func floatStringFromDecimal(ud *math.UniversalDecimal, precision int) string {
	if precision < 0 {
		precision = int(ud.Decimals)
	}

	if ud == nil {
		if precision <= 0 {
			return "0"
		}
		return fmt.Sprintf("0.%0*d", precision, 0)
	}

	if ud.Decimals == 0 {
		return ud.Value.String()
	}

	numerator := new(big.Int).Set(ud.Value)
	denominator := new(big.Int).Exp(big.NewInt(10), big.NewInt(int64(ud.Decimals)), nil)
	rat := new(big.Rat).SetFrac(numerator, denominator)
	return rat.FloatString(precision)
}

func ethAmountString(dec *math.DecimalConverter, decimal *math.UniversalDecimal, wei *big.Int) string {
	if dec == nil {
		dec = sharedDecimalConverter
	}
	ud := universalOrFromWei(dec, decimal, wei, 18, "ETH")
	return floatStringFromDecimal(ud, 6)
}

func gweiAmountString(dec *math.DecimalConverter, decimal *math.UniversalDecimal, wei *big.Int) string {
	if dec == nil {
		dec = sharedDecimalConverter
	}
	if decimal != nil {
		return floatStringFromDecimal(decimal, 2)
	}
	if wei == nil {
		return "0.00"
	}
	numerator := new(big.Rat).SetInt(wei)
	denominator := new(big.Rat).SetInt(big.NewInt(1_000_000_000))
	return new(big.Rat).Quo(numerator, denominator).FloatString(2)
}

// Removed unused format functions - moved to examples/profitability_demo.go if needed