from datetime import datetime, timedelta
from flask_babelex import lazy_gettext as _

from . import CalendarSystem


class GregorianCalendar(CalendarSystem):
    __name__ = _('Gregorian')

    __has_months__ = True

    START_DAY = 0
    END_DAY = 7

    day_names = (
        _('Monday'),
        _('Tuesday'),
        _('Wednesday'),
        _('Thursday'),
        _('Friday'),
        _('Saturday'),
        _('Sunday'),
    )

    def __init__(self, timestamp):
        self.timestamp = datetime.utcfromtimestamp(timestamp)

    @property
    def month(self):
        return self.timestamp.strftime("%B, %Y")

    @property
    def days(self):
        day_list = []

        start_day = self.timestamp.replace(day=1)

        while start_day.weekday() > self.START_DAY:
            start_day -= timedelta(days=1)

        day_list.append(start_day)
        current_day = start_day

        while current_day.weekday() < self.END_DAY and current_day.month <= self.timestamp.month:
            current_day += timedelta(days=1)
            day_list.append(current_day)

        return day_list

    def day_events(self, date, user=None):
        from ..models import Event

        events = Event.query

        if user:
            events = events.filter(Event.user == user)

        start_timestamp = date.replace(hour=0, minute=0, second=0, microsecond=0)
        end_timestamp = start_timestamp + timedelta(days=1)

        events = events.filter(((Event.start_time >= start_timestamp) & (Event.start_time < end_timestamp)) |
                               ((Event.end_time >= start_timestamp) & (Event.end_time < end_timestamp)))

        return events