niki/vendor/github.com/brianvoe/gofakeit/v6/finance.go

package gofakeit

import (
	"math/rand"
	"strconv"
	"unicode"
)

const cusipStr = upperStr + numericStr

// CUSIP

func Cusip() string {

	return cusip(globalFaker.Rand)

}

func (f *Faker) Cusip() string {

	return cusip(f.Rand)

}

func cusip(r *rand.Rand) string {

	cusipBytes := make([]byte, 8)

	for i := 0; i < len(cusipBytes); i++ {

		cusipBytes[i] = byte(cusipStr[r.Intn(len(cusipStr))])

	}

	baseCusip := string(cusipBytes)

	chkDigit := cusipChecksumDigit(baseCusip)

	return baseCusip + chkDigit

}

// ISIN

func Isin() string {

	return isin(globalFaker.Rand)

}

func (f *Faker) Isin() string {

	return isin(f.Rand)

}

func isin(r *rand.Rand) string {

	countryCode := CountryAbr()

	nsin := cusip(r)

	isinChkDig := isinChecksumDigit(countryCode + nsin)

	return countryCode + nsin + isinChkDig

}

// cusipChecksumDigit returns the checksum digit for a CUSIP

func cusipChecksumDigit(cusip string) string {

	sum := 0

	for i, c := range cusip {

		v := 0

		if unicode.IsDigit(c) {

			v = int(c - '0')

		}

		if unicode.IsLetter(c) {

			//0-indexed ordinal position of Letter + 10

			v = int(c-'A') + 10

		}

		if i%2 != 0 {

			// Multiply odd digits by two

			v = v * 2

		}

		sum = sum + int(v/10) + v%10

	}

	return strconv.Itoa((10 - (sum % 10)) % 10)

}

// isinChecksumDigit returns the checksum digit for an ISIN

func isinChecksumDigit(isin string) string {

	isinDigits := make([]int, 0)

	for _, c := range isin {

		if unicode.IsLetter(c) {

			letterVal := int(c) - 55

			// Each digit is added as a separate value

			isinDigits = append(isinDigits, letterVal/10)

			isinDigits = append(isinDigits, letterVal%10)

		}

		if unicode.IsDigit(c) {

			isinDigits = append(isinDigits, int(c-'0'))

		}

	}

	oddSum := 0

	evenSum := 0

	// Take the per digit sum of the digitized ISIN, doubling even indexed digits

	for i, d := range isinDigits {

		if i%2 == 0 {

			elem := 2 * d

			if elem > 9 {

				// If the element now has two digits, sum those digits

				elem = (elem % 10) + (elem / 10)

			}

			evenSum += elem

		} else {

			oddSum += d

		}

	}

	return strconv.Itoa((10 - (oddSum+evenSum)%10) % 10)

}

// Lookup Adds

func addFinanceLookup() {

	AddFuncLookup("cusip", Info{

		Display: "CUSIP",

		Category: "finance",

		Description: "Unique identifier for securities, especially bonds, in the United States and Canada",

		Example: "38259P508",

		Output: "string",

		Generate: func(r *rand.Rand, m *MapParams, info *Info) (any, error) {

			return cusip(r), nil

		},
	})

	AddFuncLookup("isin", Info{

		Display: "ISIN",

		Category: "finance",

		Description: "International standard code for uniquely identifying securities worldwide",

		Example: "CVLRQCZBXQ97",

		Output: "string",

		Generate: func(r *rand.Rand, m *MapParams, info *Info) (any, error) {

			return isin(r), nil

		},
	})

}