format the number to a standard version

cmd/africastalking/main.go

@@ -20,6 +20,7 @@ import (
 	"git.defalsify.org/vise.git/logging"
 	"git.defalsify.org/vise.git/resource"
 
+	"git.grassecon.net/urdt/ussd/common"
 	"git.grassecon.net/urdt/ussd/config"
 	"git.grassecon.net/urdt/ussd/initializers"
 	"git.grassecon.net/urdt/ussd/internal/handlers"
@@ -76,7 +77,13 @@ func (arp *atRequestParser) GetSessionId(rq any) (string, error) {
 		return "", fmt.Errorf("no phone number found")
 	}
 
-	return phoneNumber, nil
+	formattedNumber, err := common.FormatPhoneNumber(phoneNumber)
+	if err != nil {
+		fmt.Printf("Error: %v\n", err)
+		return "", fmt.Errorf("failed to format number")
+	}
+
+	return formattedNumber, nil
 }
 
 func (arp *atRequestParser) GetInput(rq any) ([]byte, error) {

common/recipient.go

@@ -3,6 +3,7 @@ package common
 import (
 	"fmt"
 	"regexp"
+	"strings"
 )
 
 // Define the regex patterns as constants
@@ -46,3 +47,17 @@ func CheckRecipient(recipient string) (string, error) {
 
 	return "", fmt.Errorf("invalid recipient: must be a phone number, address or alias")
 }
+
+// FormatPhoneNumber formats a Kenyan phone number to "254xxxxxxxx".
+func FormatPhoneNumber(phone string) (string, error) {
+	// 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:]
+	}
+
+	return phone, nil
+}