import re


def normalize_phone_number(raw_phone: str) -> str:
    if not raw_phone:
        raise ValueError("Phone number is required")

    phone = re.sub(r"[\s\-\(\)]", "", raw_phone)
    if phone.startswith("00"):
        phone = "+" + phone[2:]

    if phone.startswith("+"):
        digits = phone[1:]
        if not digits.isdigit() or not (8 <= len(digits) <= 15):
            raise ValueError("Invalid phone number format")
        return "+" + digits

    digits = re.sub(r"\D", "", phone)

    if digits.startswith("0") and len(digits) == 10 and digits[1] == "5":
        return "+966" + digits[1:]

    if digits.startswith("5") and len(digits) == 9:
        return "+966" + digits

    raise ValueError("Phone number must be in E.164 format or a valid Saudi mobile")