import datetime

from django.utils.safestring import mark_safe
from django.urls.converters import StringConverter

from .utils import str_to_date


class PagePathConverter(StringConverter):
    """ Match path for pages, including surrounding slashes. """
    regex = r'/?|([-_a-zA-Z0-9]+/)*?'

    def to_python(self, value):
        if not value or value[0] != '/':
            value = '/' + value
        if len(value) > 1 and value[-1] != '/':
            value = value + '/'
        return value

    def to_url(self, value):
        if value[0] == '/':
            value = value[1:]
        if value[-1] != '/':
            value = value + '/'
        return mark_safe(value)


class WeekConverter:
    """ Converter for date as YYYYY/WW """
    regex = r'[0-9]{4}/[0-9]{2}'

    def to_python(self, value):
        return datetime.datetime.strptime(value + '/1', '%G/%V/%u').date()

    def to_url(self, value):
        return '{:04d}/{:02d}'.format(*value.isocalendar())


class DateConverter:
    """ Converter for date as YYYY/MM/DD """
    regex = r'[0-9]{4}/[0-9]{2}/[0-9]{2}'

    def to_python(self, value):
        return str_to_date(value)

    def to_url(self, value):
        return '{:04d}/{:02d}/{:02d}'.format(value.year, value.month,
                                             value.day)