import re
from abc import ABC, abstractmethod

from notifications_utils.field import Field
from notifications_utils.formatters import formatted_list
from notifications_utils.recipients import (
    InvalidEmailError,
    validate_email_address,
)
from notifications_utils.sanitise_text import SanitiseSMS
from notifications_utils.template import BroadcastMessageTemplate
from wtforms import ValidationError

from app.main._commonly_used_passwords import commonly_used_passwords
from app.models.spreadsheet import Spreadsheet
from app.utils.user import is_gov_user


class CommonlyUsedPassword:
    def __init__(self, message=None):
        if not message:
            message = 'Password is in list of commonly used passwords.'
        self.message = message

    def __call__(self, form, field):
        if field.data in commonly_used_passwords:
            raise ValidationError(self.message)


class CsvFileValidator:

    def __init__(self, message='Not a csv file'):
        self.message = message

    def __call__(self, form, field):
        if not Spreadsheet.can_handle(field.data.filename):
            raise ValidationError("{} is not a spreadsheet that Notify can read".format(field.data.filename))


class ValidGovEmail:

    def __call__(self, form, field):

        if field.data == '':
            return

        from flask import url_for
        message = '''
            Enter a public sector email address or
            <a class="govuk-link govuk-link--no-visited-state" href="{}">find out who can use Notify</a>
        '''.format(url_for('main.who_can_use_notify'))
        if not is_gov_user(field.data.lower()):
            raise ValidationError(message)


class ValidEmail:

    message = 'Enter a valid email address'

    def __call__(self, form, field):

        if not field.data:
            return

        try:
            validate_email_address(field.data)
        except InvalidEmailError:
            raise ValidationError(self.message)


class NoCommasInPlaceHolders:

    def __init__(self, message='You cannot put commas between double brackets'):
        self.message = message

    def __call__(self, form, field):
        if ',' in ''.join(Field(field.data).placeholders):
            raise ValidationError(self.message)


class NoElementInSVG(ABC):

    @property
    @abstractmethod
    def element(self):
        pass

    @property
    @abstractmethod
    def message(self):
        pass

    def __call__(self, form, field):
        svg_contents = field.data.stream.read().decode("utf-8")
        field.data.stream.seek(0)
        if f'<{self.element}' in svg_contents.lower():
            raise ValidationError(self.message)


class NoEmbeddedImagesInSVG(NoElementInSVG):
    element = 'image'
    message = 'This SVG has an embedded raster image in it and will not render well'


class NoTextInSVG(NoElementInSVG):
    element = 'text'
    message = 'This SVG has text which has not been converted to paths and may not render well'


class OnlySMSCharacters:

    def __init__(self, *args, template_type, **kwargs):
        self._template_type = template_type
        super().__init__(*args, **kwargs)

    def __call__(self, form, field):
        non_sms_characters = sorted(list(SanitiseSMS.get_non_compatible_characters(field.data)))
        if non_sms_characters:
            raise ValidationError(
                'You cannot use {} in {}. {} will not show up properly on everyone’s phones.'.format(
                    formatted_list(non_sms_characters, conjunction='or', before_each='', after_each=''),
                    {
                        'broadcast': 'broadcasts',
                        'sms': 'text messages',
                    }.get(self._template_type),
                    ('It' if len(non_sms_characters) == 1 else 'They')
                )
            )


class NoPlaceholders:

    def __init__(self, message=None):
        self.message = message or (
            'You can’t use ((double brackets)) to personalise this message'
        )

    def __call__(self, form, field):
        if Field(field.data).placeholders:
            raise ValidationError(self.message)


class BroadcastLength:

    def __call__(self, form, field):
        template = BroadcastMessageTemplate({
            'template_type': 'broadcast',
            'content': field.data,
        })

        if template.content_too_long:
            non_gsm_characters = list(sorted(template.non_gsm_characters))
            if non_gsm_characters:
                raise ValidationError(
                    f'Content must be {template.max_content_count:,.0f} '
                    f'characters or fewer because it contains '
                    f'{formatted_list(non_gsm_characters, conjunction="and", before_each="", after_each="")}'
                )
            raise ValidationError(
                f'Content must be {template.max_content_count:,.0f} '
                f'characters or fewer'
            )


class LettersNumbersSingleQuotesFullStopsAndUnderscoresOnly:

    regex = re.compile(r"^[a-zA-Z0-9\s\._']+$")

    def __init__(self, message='Use letters and numbers only'):
        self.message = message

    def __call__(self, form, field):
        if field.data and not re.match(self.regex, field.data):
            raise ValidationError(self.message)


class DoesNotStartWithDoubleZero:

    def __init__(self, message="Cannot start with 00"):
        self.message = message

    def __call__(self, form, field):
        if field.data and field.data.startswith("00"):
            raise ValidationError(self.message)


class MustContainAlphanumericCharacters:

    regex = re.compile(r".*[a-zA-Z0-9].*[a-zA-Z0-9].*")

    def __init__(
        self,
        message="Must include at least two alphanumeric characters"
    ):
        self.message = message

    def __call__(self, form, field):
        if field.data and not re.match(self.regex, field.data):
            raise ValidationError(self.message)