common/phone/phone.go

75 lines
2.1 KiB
Go

package phone
import (
"errors"
"regexp"
"strings"
)
// Define the regex patterns as constants
const (
// TODO: This should rather use a phone package to determine whether valid phone number for any region.
// Kenyan phone numbers: must be exactly 10 digits (07XXXXXXXX or 01XXXXXXXX) when starting with 0
// Or start with 254 / +254 and still follow the same pattern
phoneRegex = `^(?:\+254|254|0)(7\d{8}|1[01]\d{7})$`
)
// IsValidPhoneNumber checks if the given number is a valid phone number
func IsValidPhoneNumber(phonenumber string) bool {
match, _ := regexp.MatchString(phoneRegex, phonenumber)
return match
}
// FormatPhoneNumber formats a Kenyan phone number to "+254xxxxxxxx".
func FormatPhoneNumber(phone string) (string, error) {
if !IsValidPhoneNumber(phone) {
return "", errors.New("invalid phone number")
}
// Remove any leading "+" and spaces
phone = strings.TrimPrefix(phone, "+")
phone = strings.ReplaceAll(phone, " ", "")
// Replace leading "0" with "254" if present
if strings.HasPrefix(phone, "0") {
phone = "254" + phone[1:]
}
// Add "+" if not already present
if !strings.HasPrefix(phone, "254") {
return "", errors.New("unexpected format")
}
return "+" + phone, nil
}
// FormatToLocalPhoneNumber converts a phone number like "+2547XXXXXXXX"
// or "2547XXXXXXXX" into the local format "07XXXXXXXX" / "01XXXXXXXX".
func FormatToLocalPhoneNumber(phone string) (string, error) {
// Remove leading "+" and spaces
phone = strings.TrimPrefix(phone, "+")
phone = strings.ReplaceAll(phone, " ", "")
// Must start with 254
if !strings.HasPrefix(phone, "254") {
return "", errors.New("invalid international phone format")
}
// Remove "254" prefix → get 7XXXXXXXX or 1XXXXXXXX
rest := phone[3:]
// Validate: must be 9 digits
if len(rest) != 9 {
return "", errors.New("invalid phone number length")
}
// Kenyan mobile numbers start with 7 or 1 (Safaricom/Airtel/Telkom prefixes)
if !(strings.HasPrefix(rest, "7") || strings.HasPrefix(rest, "1")) {
return "", errors.New("invalid Kenyan mobile prefix")
}
// Convert to local: prepend "0"
local := "0" + rest
return local, nil
}