Moved mobile validation to utils module for use in csv upload as well.

This could be moved to shared utils code base at some point.

app/main/utils.py

@@ -24,3 +24,50 @@ class BrowsableItem(object):
     @property
     def destructive(self):
         pass
+
+
+class InvalidPhoneError(Exception):
+    def __init__(self, message):
+        self.message = message
+
+
+def validate_phone_number(number):
+
+    sanitised_number = number.replace('(', '')
+    sanitised_number = sanitised_number.replace(')', '')
+    sanitised_number = sanitised_number.replace(' ', '')
+    sanitised_number = sanitised_number.replace('-', '')
+
+    if sanitised_number.startswith('+'):
+        sanitised_number = sanitised_number[1:]
+
+    valid_prefixes = ['07', '447', '4407', '00447']
+    if not sum(sanitised_number.startswith(prefix) for prefix in valid_prefixes):
+        raise InvalidPhoneError('Must be a UK mobile number (eg 07700 900460)')
+
+    for digit in sanitised_number:
+        try:
+            int(digit)
+        except(ValueError):
+            raise InvalidPhoneError('Must not contain letters or symbols')
+
+    # Split number on first 7
+    sanitised_number = sanitised_number.split('7', 1)[1]
+
+    if len(sanitised_number) > 9:
+        raise InvalidPhoneError('Too many digits')
+
+    if len(sanitised_number) < 9:
+        raise InvalidPhoneError('Not enough digits')
+
+    return sanitised_number
+
+
+def format_phone_number(number):
+    import re
+    if len(number) > 9:
+        raise InvalidPhoneError('Too many digits')
+
+    if len(number) < 9:
+        raise InvalidPhoneError('Not enough digits')
+    return '+447{}{}{}'.format(*re.findall('...', number))