aergoio/aergo

package jsonrpc

import (
    "fmt"
    "math/big"
    "strconv"
    "strings"
)

// var unit map[string]*big.Int
var units map[string]int
var unitlist []string

func init() {
    units = map[string]int{}
    units["aergo"] = 18
    units["gaer"] = 9
    units["aer"] = 0
    unitlist = []string{"aergo", "gaer", "aer"}
}

func ParseUnit(s string) (*big.Int, error) {
    result, ok := new(big.Int).SetString(strings.TrimSpace(s), 10)
    if !ok {
        lower := strings.ToLower(s)
        for _, v := range unitlist {
            if strings.Contains(lower, v) {
                number := strings.TrimSpace(strings.TrimSuffix(lower, v))
                numbers := strings.Split(number, ".")
                var nstr string
                var pos int
                switch len(numbers) {
                case 1:
                    nstr = numbers[0]
                    pos = 0
                case 2:
                    if len(numbers[1]) > units[v] {
                        return big.NewInt(0), fmt.Errorf("too small unit %s", s)
                    }
                    nstr = numbers[0] + numbers[1]
                    pos = len(numbers[1])
                default:
                    continue
                }
                for i := pos; i < units[v]; i++ {
                    nstr += "0"
                }
                n, ok := new(big.Int).SetString(nstr, 10)
                if !ok {
                    continue
                } else {
                    return n, nil
                }
            }
        }
        return big.NewInt(0), fmt.Errorf("could not parse %s", s)
    }
    return result, nil
}

func ConvertUnit(n *big.Int, unit string) (string, error) {
    unit = strings.ToLower(unit)
    nstr := n.String()

    if len(nstr) > units[unit] {
        dotpos := len(nstr) - units[unit]
        nstr = nstr[0:dotpos] + "." + nstr[dotpos:]
        return strings.TrimRight(strings.TrimRight(nstr, "0"), ".") + " " + unit, nil
    }
    result := strings.TrimRight(fmt.Sprintf(".%0"+strconv.Itoa(units[unit])+"d", n), ".0")
    result = "0" + result + " " + unit
    return result, nil
}