default functionality

masker.go

@@ -1 +1,187 @@
 package masker
+
+import (
+	"strings"
+)
+
+type Masker struct{}
+
+func (m *Masker) overlay(str string, overlay string, start int, end int) string {
+	r := []rune(str)
+	l := len(r)
+
+	if l == 0 {
+		return ""
+	}
+
+	if start < 0 {
+		start = 0
+	}
+	if start > l {
+		start = l
+	}
+	if end < 0 {
+		end = 0
+	}
+	if end > l {
+		end = l
+	}
+	if start > end {
+		start, end = end, start
+	}
+
+	return string(r[:start]) + overlay + string(r[end:])
+}
+
+func (m *Masker) Name(i string) string {
+	l := len([]rune(i))
+	if l == 0 {
+		return ""
+	}
+
+	// если есть пробел
+	i = strings.Trim(i, " ")
+	if chunks := strings.Split(i, " "); len(chunks) > 1 {
+		tmp := make([]string, 0, l)
+		for _, v := range chunks {
+			if v != "" {
+				tmp = append(tmp, m.Name(v))
+			}
+		}
+		return strings.Join(tmp, " ")
+	}
+
+	if l == 2 || l == 3 {
+		return m.overlay(i, "*", 1, 2)
+	}
+
+	if l > 3 {
+		return m.overlay(i, "**", 1, 3)
+	}
+
+	return "*"
+}
+
+func (m *Masker) CreditCard(i string) string {
+	l := len([]rune(i))
+	if l == 0 {
+		return ""
+	}
+	return m.overlay(i, "******", 6, 12)
+}
+
+func (m *Masker) Email(i string) string {
+	l := len([]rune(i))
+	if l == 0 {
+		return ""
+	}
+
+	chunks := strings.Split(i, "@")
+
+	return m.overlay(chunks[0], "****", 3, 7) + "@" + chunks[1]
+}
+
+func (m *Masker) Mobile(i string) string {
+	if len(i) == 0 {
+		return ""
+	}
+	return m.overlay(i, "***", 4, 7)
+}
+
+func (m *Masker) Password(i string) string {
+	l := len([]rune(i))
+	if l == 0 {
+		return ""
+	}
+	return "************"
+}
+
+func (m *Masker) PassportSeries(i string) string {
+	l := len([]rune(i))
+	if l == 0 {
+		return ""
+	}
+	return m.overlay(i, "**", 1, 3)
+}
+
+func (m *Masker) PassportNumber(i string) string {
+	l := len([]rune(i))
+	if l == 0 {
+		return ""
+	}
+	return m.overlay(i, "****", 1, 5)
+}
+
+func (m *Masker) Code(i string) string {
+	l := len([]rune(i))
+	if l == 0 {
+		return ""
+	}
+	if l == 1 {
+		return "*"
+	}
+	if l == 2 || l == 3 {
+		return m.overlay(i, strings.Repeat("*", l-1), 1, l)
+	}
+	return m.overlay(i, strings.Repeat("*", l-2), 1, l-1)
+}
+
+func (m *Masker) LastFourDigits(i string) string {
+	l := len([]rune(i))
+	if l == 0 {
+		return ""
+	}
+
+	if l < 5 {
+		return "****"
+	}
+
+	return m.overlay(i, strings.Repeat("*", l-4), 0, l-4)
+}
+
+// New create Masker
+func New() *Masker {
+	return &Masker{}
+}
+
+var instance *Masker
+
+func init() {
+	instance = New()
+}
+
+func Name(i string) string {
+	return instance.Name(i)
+}
+
+func CreditCard(i string) string {
+	return instance.CreditCard(i)
+}
+
+func Email(i string) string {
+	return instance.Email(i)
+}
+
+func Mobile(i string) string {
+	return instance.Mobile(i)
+}
+
+func Password(i string) string {
+	return instance.Password(i)
+}
+
+func PassportSeries(i string) string {
+	return instance.PassportSeries(i)
+}
+
+func PassportNumber(i string) string {
+	return instance.PassportNumber(i)
+}
+
+func Code(i string) string {
+	return instance.Code(i)
+}
+
+func LastFourDigits(i string) string {
+	return instance.LastFourDigits(i)
+}