70 lines
1.5 KiB
Go
70 lines
1.5 KiB
Go
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package fake
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import (
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"strings"
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"strconv"
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)
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type creditCard struct {
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vendor string
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length int
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prefixes []int
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}
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var creditCards = map[string]creditCard{
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"visa": {"VISA", 16, []int{4539, 4556, 4916, 4532, 4929, 40240071, 4485, 4716, 4}},
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"mastercard": {"MasterCard", 16, []int{51, 52, 53, 54, 55}},
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"amex": {"American Express", 15, []int{34, 37}},
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"discover": {"Discover", 16, []int{6011}},
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}
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// CreditCardType returns one of the following credit values:
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// VISA, MasterCard, American Express and Discover
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func CreditCardType() string {
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n := len(creditCards)
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var vendors []string
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for _, cc := range creditCards {
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vendors = append(vendors, cc.vendor)
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}
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return vendors[r.Intn(n)]
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}
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// CreditCardNum generated credit card number according to the card number rules
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func CreditCardNum(vendor string) string {
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if vendor != "" {
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vendor = strings.ToLower(vendor)
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} else {
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var vendors []string
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for v := range creditCards {
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vendors = append(vendors, v)
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}
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vendor = vendors[r.Intn(len(vendors))]
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}
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card := creditCards[vendor]
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prefix := strconv.Itoa(card.prefixes[r.Intn(len(card.prefixes))])
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num := []rune(prefix)
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for i := 0; i < card.length-len(prefix); i++ {
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num = append(num, genCCDigit(num))
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}
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return string(num)
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}
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func genCCDigit(num []rune) rune {
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sum := 0
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for i := len(num) - 1; i >= 0; i-- {
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n := int(num[i])
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if i%2 != 0 {
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sum += n
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} else {
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if n*2 > 9 {
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sum += n*2 - 9
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} else {
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sum += n * 2
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}
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}
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}
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return rune(((sum/10+1)*10 - sum) % 10)
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}
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