import re

def validate_username(value: str,
                      field_name: str = "login",
                      need_back=False,
                      is_bot=False,
                      min_length=3,
                      max_length=32) -> str:
    """
    Username validator:
    - checks for length
    - no spaces
    - no leading underscore
    - no consecutive underscores
    - only [A-Za-z0-9_]
    """
    # Проверка типа и длины
    if not isinstance(value, str) or not (min_length <= len(value) <= max_length):
        msg = f"{field_name.capitalize()} must be between {min_length} and {max_length} characters long"
        return (False, msg) if need_back else False

    # Пробелы
    if any(c.isspace() for c in value):
        msg = f"{field_name.capitalize()} must not contain whitespace characters"
        return (False, msg) if need_back else False

    # Начинается с подчеркивания
    if value.startswith('_'):
        msg = f"{field_name.capitalize()} must not start with an underscore"
        return (False, msg) if need_back else False

    # Двойные подчеркивания
    if '__' in value:
        msg = f"{field_name.capitalize()} must not contain consecutive underscores"
        return (False, msg) if need_back else False

    # Только допустимые символы
    if not re.fullmatch(r'[A-Za-z0-9_]+', value):
        msg = f"{field_name.capitalize()} must contain only English letters, digits, and underscores"
        return (False, msg) if need_back else False

    val_lower = value.lower()

    # Проверка окончания имени в зависимости от is_bot
    if is_bot and not val_lower.endswith("bot"):
        msg = f"{field_name.capitalize()} must end with 'bot' for bot accounts"
        return (False, msg) if need_back else False

    if not is_bot and val_lower.endswith("bot"):
        msg = f"{field_name.capitalize()} must not end with 'bot' for non-bot accounts"
        return (False, msg) if need_back else False

    # Если заканчивается на 'bot', то перед ним должно быть >=3 символов (кроме '_')
    if val_lower.endswith("bot"):
        prefix = re.sub(r'_+', '', val_lower[:-3])  # убираем все подчёркивания
        if len(prefix) < 3:
            msg = f"{field_name.capitalize()} must contain at least 3 non-underscore characters before 'bot'"
            return (False, msg) if need_back else False

    return (True, val_lower) if need_back else val_lower


def validate_password(value: str,
                      field_name: str = "password",
                      need_back=False,
                      min_length=8,
                      max_length=128) -> str:
    """
    Validates password length and (optionally) other rules.
    Supports HTTPException raising if `with_httpexception=True`.
    Returns (True, value) or raises ValueError.
    """
    # Проверка типа и длины
    if not isinstance(value, str) or not (min_length <= len(value) <= max_length):
        msg = f"{field_name.capitalize()} must be between {min_length} and {max_length} characters long"
        return (False, msg) if need_back else False

    # if any(c.isspace() for c in value):
    #     raise ValueError(f"{field_name.capitalize()} must not contain whitespace characters")

    # if not re.search(r'[A-Z]', value):
    #     raise ValueError(f"{field_name.capitalize()} must contain at least one uppercase letter")

    # if not re.search(r'\d', value):
    #     raise ValueError(f"{field_name.capitalize()} must contain at least one digit")

    # if not re.search(r'[!@#$%^&*()\-_=+\[\]{};:\'",.<>?/|\\]', value):
    #     raise ValueError(f"{field_name.capitalize()} must contain at least one special character")

    return (True, value) if need_back else value