"""
Script description: This script provides string validations for various user inputs.

Libraries Imported:
-------------------
- re: Implements regular expressions for pattern matching.
"""

import re


class Validator:
    """
    This class provides validation methods for usernames, names, emails, and passwords.
    """
    def __init__(self):
        pass
    def diagnose_password(self, password: str) -> str:
        """
        Diagnoses the validity of the entered password and returns an error message if invalid.

        Parameters
        ----------
        password : str
            The password to be diagnosed.

        Returns
        -------
        str
            Error message listing password requirements that were not met.
        """
        min_length = 8
        max_length = 20
        errors = []
        if not min_length <= len(password) <= max_length:
            errors.append(f'Between {min_length} and {max_length} characters long \n\n')
        if not re.search(r'[a-z]', password):
            errors.append('Contain at least one lowercase letter \n\n')
        if not re.search(r'[A-Z]', password):
            errors.append('Contain at least one uppercase letter \n\n')
        if not re.search(r'\d', password):
            errors.append('Contain at least one digit \n\n')
        if not re.search(r'[!@#$%^&*()_+\-=\[\]{};:\'\"\\|,.<>\/?`~]', password):
            errors.append('Contain at least one special character (@$!%*?&) \n\n')
        return '**Password must:** \n\n' + ''.join(errors)
    def validate_email(self, email: str) -> bool:
        """
        Checks the validity of the entered email.

        Parameters
        ----------
        email : str
            The email to be validated.

        Returns
        -------
        bool
            True if the email is valid, False otherwise.
        """
        pattern = r"^[a-zA-Z0-9._%+-]{1,254}@[a-zA-Z0-9.-]{1,253}\.[a-zA-Z]{2,63}$"
        return bool(re.match(pattern, email))
    def validate_length(self, variable: str, min_length: int=0, max_length: int=254) -> bool:
        """
        Checks if a given string is within the specified length range.

        Parameters
        ----------
        variable : str
            The string to be validated.
        min_length : int, default=0
            The minimum required length for the string.
        max_length : int, default=254
            The maximum allowed length for the string.

        Returns
        -------
        bool
            True if the string length is within range, False otherwise.
        """
        pattern = rf"^.{{{min_length},{max_length}}}$"
        return bool(re.match(pattern, variable))
    def validate_name(self, name: str) -> bool:
        """
        Checks the validity of the entered name.

        Parameters
        ----------
        name : str
            The name to be validated.

        Returns
        -------
        bool
            True if the name is valid, False otherwise.
        """
        pattern = r"^[A-Za-z\u00C0-\u024F\u0370-\u1FFF\u2C00-\uD7FF\u4E00-\u9FFF' .-]{2,100}$"
        return bool(re.match(pattern, name, re.UNICODE))
    def validate_password(self, password: str) -> bool:
        """
        Checks the validity of the entered password.

        Parameters
        ----------
        password : str
            The password to be validated.

        Returns
        -------
        bool
            True if the password is valid, False otherwise.
        """
        pattern = r"^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[!@#$%^&*()_+\-=\[\]{};':\"\\|,.<>\/?`~])[A-Za-z\d!@#$%^&*()_+\-=\[\]{};':\"\\|,.<>\/?`~]{8,20}$"
        return bool(re.match(pattern, password))
    def validate_username(self, username: str) -> bool:
        """
        Checks the validity of the entered username.

        Parameters
        ----------
        username : str
            The username to be validated.

        Returns
        -------
        bool
            True if the username is valid, False otherwise.
        """
        pattern = r"^([a-zA-Z0-9_-]{1,20}|[a-zA-Z0-9._%+-]{1,254}@[a-zA-Z0-9.-]{1,253}\.[a-zA-Z]{2,63})$"
        return bool(re.match(pattern, username))