# SPDX-License-Identifier: AGPL-3.0-or-later
"""
Forms for the email app.
"""
import re

from django import forms
from django.core.exceptions import ValidationError
from django.utils.translation import gettext_lazy as _

from plinth.modules.names.components import DomainName

from . import aliases as aliases_module


def _get_domain_choices():
    """Double domain entries for inclusion in the choice field."""
    return ((domain.name, domain.name) for domain in DomainName.list())


class DomainForm(forms.Form):
    primary_domain = forms.ChoiceField(
        choices=_get_domain_choices,
        label=_('Primary domain'),
        help_text=_(
            'Mails are received for all domains configured in the system. '
            'Among these, select the most important one.'),
        required=True,
    )


class AliasCreateForm(forms.Form):
    """Form to create a new alias."""
    alias = forms.CharField(label=_('New alias (without @domain)'),
                            min_length=2, max_length=50)

    def clean_alias(self):
        """Return the checked value for alias."""
        value = self.data['alias'].strip().lower()
        if not re.match('^[a-z0-9-_\\.]+$', value):
            raise ValidationError(_('Contains illegal characters'))

        if not re.match('^[a-z0-9].*[a-z0-9]$', value):
            raise ValidationError(_('Must start and end with a-z or 0-9'))

        if re.match('^[0-9]+$', value):
            raise ValidationError(_('Cannot be a number'))

        if aliases_module.exists(value):
            raise ValidationError('Alias is already taken')

        return value


class AliasListForm(forms.Form):
    """Form to list/enable/disable/delete current aliases."""
    aliases = forms.MultipleChoiceField(label=_('Aliases'),
                                        widget=forms.CheckboxSelectMultiple)

    def __init__(self, aliases, *args, **kwargs):
        """Populate the choices for aliases."""
        super().__init__(*args, **kwargs)
        enabled_aliases = [(alias.name, alias.name) for alias in aliases
                           if alias.enabled]
        disabled_aliases = [(alias.name, alias.name) for alias in aliases
                            if not alias.enabled]
        choices = []
        if enabled_aliases:
            choices.append((_('Enabled'), enabled_aliases))

        if disabled_aliases:
            choices.append((_('Disabled'), disabled_aliases))

        self.fields['aliases'].choices = choices

    def clean(self):
        """Add the pressed button to cleaned data."""
        cleaned_data = super().clean()
        buttons = [key[4:] for key in self.data if key.startswith('btn_')]
        if len(buttons) != 1 or buttons[0] not in ('enable', 'disable',
                                                   'delete'):
            raise ValidationError('Invalid button pressed')

        cleaned_data['action'] = buttons[0]
        return cleaned_data