forms.py

"""
This is the forms.py module, primarily responsible for defining and validating forms in the Flask
application using Flask-WTF.

This module includes four form classes:

RegisterForm: This class defines the registration form with fields for 'name', 'username'
and 'password', and validates the inputs.

LoginForm: This class defines the login form with fields for 'username' and 'password', and a
'submit' button.

NewUserForm: This class defines the form for adding a new user with fields for 'name',
'username', 'password', 'admin' status and 'blocked' status. This form includes a unique
username validation method to prevent duplications.

UpdateUserForm: This class defines the form for updating user details. The fields are the same as
in the NewUserForm class excluding the 'admin' and 'blocked' status fields.

Each form field is defined with validators to handle required data constraints and length
limitations.
"""

from flask_wtf import FlaskForm
from wtforms import StringField, PasswordField, BooleanField
from wtforms import SubmitField
from wtforms.validators import DataRequired, Length
from wtforms.validators import InputRequired, ValidationError, Optional

from features.models import User


class RegisterForm(FlaskForm):
    """
    A form for user registration with input fields: 'name', 'username', and 'password'.
    All fields have built-in validators to ensure data is provided and meets length criteria.
    """

    name = StringField('Name', validators=[DataRequired(), Length(min=2, max=50)])
    username = StringField('Username', validators=[DataRequired(), Length(min=4, max=25)])
    password = PasswordField('Password', validators=[DataRequired()])


class LoginForm(FlaskForm):
    """
    A form used to log into the system. Contains 'username' and 'password' fields.
    DataRequired validator ensures that fields are not submitted empty.
    """

    username = StringField('Username', validators=[DataRequired(), Length(min=4, max=25)])
    password = PasswordField('Password', validators=[DataRequired()])
    submit = SubmitField('Login')


class NewUserForm(FlaskForm):
    """
    This form is used to create a new user account. It includes fields for 'name',
    'username', 'password', 'admin' status, and 'blocked' status. Also, it provides a custom
    validation method for username to ensure it is unique across the user database.
    """

    name = StringField(validators=[
        Length(max=40)], render_kw={"placeholder": "Name"})

    username = StringField(validators=[
        InputRequired(), Length(min=4, max=20)], render_kw={"placeholder": "Username"})

    password = PasswordField(validators=[
        InputRequired(), Length(min=8, max=20)], render_kw={"placeholder": "Password"})

    admin = BooleanField(validators=[Optional()])

    blocked = BooleanField(validators=[Optional()])

    submit = SubmitField('Add User')
    

    @staticmethod
    def validate_username(form, field):
        """
        This static method validates the username field of the given form.

        Parameters:
        form (FlaskForm): The form containing the 'username' field.
        field (Field): The 'username' field to be validated.

        The function checks if a user already exists with the provided username in the database.
        If a user is found, a ValidationError is raised with a message to choose a different
        username.

        It's designed to be used as a custom validator in Flask-WTF forms.
        """
        print(form.username)
        if User.query.filter_by(username=field.data).first():
            raise ValidationError('This username is already taken. Please choose another.')


class UpdateUserForm(FlaskForm):
    """
    This form is used for updating existing user's information. It includes fields
    for 'name', 'username', and 'password'. All fields have built-in validators to
    ensure data is provided and meets the defined length criteria.
    """

    name = StringField(validators=[
        Length(min=3, max=40)], render_kw={"placeholder": "Name"})

    username = StringField(validators=[
        InputRequired(), Length(min=4, max=20)], render_kw={"placeholder": "Username"})

    password = PasswordField(validators=[
        InputRequired(), Length(min=8, max=20)], render_kw={"placeholder": "Password"})

    submit = SubmitField('Update User')