validators.py

from PyQt5.QtGui import QRegExpValidator, QIntValidator, QDoubleValidator, QRegularExpressionValidator
from PyQt5.QtCore import QRegExp, QRegularExpression


def get_name_validator():
    """
    Returns a QRegExpValidator that allows letters (both uppercase and lowercase),
    spaces, hyphens, and apostrophes. Suitable for validating names.
    """
    name_regex = QRegExp("^[A-Za-zÀ-ÿ ,.'-]+$")
    return QRegExpValidator(name_regex)


def get_id_validator():
    """
    Returns a QIntValidator that only allows integer values between 0000 and 9999.
    Ensures that the ID is a four-digit number.
    """
    id_validator = QIntValidator(0, 9999)
    return id_validator


def get_dob_validator():
    """
    Returns a QRegExpValidator that enforces the YYYY-MM-DD date format.
    Validates Date of Birth entries.
    """
    dob_regex = QRegExp("^\\d{4}-(0[1-9]|1[0-2])-(0[1-9]|[12]\\d|3[01])$")
    return QRegExpValidator(dob_regex)



def get_grade_validator():
    """
    Returns a QRegularExpressionValidator that allows numbers between 0 and 100,
    with up to two decimal places.
    """
    # Regular expression explanation:
    # ^ - start of string
    # (100(\.00?)?) - matches 100 or 100.0 or 100.00
    # | - OR
    # ([0-9]{1,2}(\.[0-9]{1,2})?) - matches 0-99 with optional .0 or .00 etc.
    # $ - end of string
    regex = QRegularExpression(r"^(100(\.00?)?|[0-9]{1,2}(\.[0-9]{1,2})?)$")
    grade_validator = QRegularExpressionValidator(regex)
    return grade_validator


def get_positive_int_validator():
    """
    Returns a QIntValidator that only allows positive integer values.
    Useful for fields that require positive integers beyond a specific range.
    """
    positive_int_validator = QIntValidator(1, 2147483647)  # 32-bit integer max
    return positive_int_validator


def pad_with_zeros(value, total_length=4):
    """
    Pads the given number with leading zeros to ensure it has a specified total length.

    Parameters:
        value (int or str): The input number to pad.
        total_length (int): The desired total length of the output string. Default is 4.

    Returns:
        str: The padded string with leading zeros.

    Raises:
        ValueError: If the input is not a valid integer or if it's negative.
    """
    try:
        # Convert the input to an integer
        num = int(value)

        if num < 0:
            raise ValueError("Value cannot be negative.")

        # Convert back to string with leading zeros
        padded = f"{num:0{total_length}d}"

        # If the number exceeds the total_length, truncate from the left
        if len(padded) > total_length:
            padded = padded[-total_length:]

        return padded
    except ValueError as e:
        raise ValueError(f"Invalid input for padding: {value}. {e}")