package topology

import (
	"fmt"
	"regexp"
	"strconv"
	"strings"
)

var (
	kbitRate         uint64 = 1e+3 // bits per kbit
	mbitRate         uint64 = 1e+6 // bits per mbit
	kbit                    = regexp.MustCompile(`^[1-9][0-9]*([kK]bit$)`)
	mbit                    = regexp.MustCompile(`^[1-9][0-9]*([mM]bit$)`)
	defaultRateLimit        = 100 * mbitRate
)

// converts bits to mbits
func convertBitsToMbits(bits uint64) string {
	mbits := bits / mbitRate
	return fmt.Sprintf("%dmbit", int(mbits)) /* #nosec G115 */
}

// convert the rate limiting mbit/kbit to bytes
func convertRateLimitToBits(rateLimit string) uint64 {
	var conversionRate uint64
	var rateString string

	switch {
	case kbit.Match([]byte(rateLimit)):
		rateString = strings.TrimSuffix(rateLimit, "kbit")
		conversionRate = kbitRate
	case mbit.Match([]byte(rateLimit)):
		rateString = strings.TrimSuffix(rateLimit, "mbit")
		conversionRate = mbitRate
	default:
		return defaultRateLimit
	}

	rate, err := strconv.ParseUint(rateString, 10, 64)
	if err != nil {
		return defaultRateLimit
	}
	return rate * conversionRate
}