# This file is part of Tryton.  The COPYRIGHT file at the top level of
# this repository contains the full copyright notices and license terms.
import datetime as dt

from dateutil.rrule import (
    DAILY, FR, MO, MONTHLY, SA, SU, TH, TU, WE, WEEKLY, YEARLY, rrule,
    rruleset)

from trytond.i18n import gettext
from trytond.model import ModelSQL, ModelView, fields
from trytond.pool import Pool
from trytond.transaction import Transaction
from trytond.wizard import Button, StateView, Wizard

from .exceptions import RecurrenceRuleValidationError

WEEKDAYS = {
    'MO': MO,
    'TU': TU,
    'WE': WE,
    'TH': TH,
    'FR': FR,
    'SA': SA,
    'SU': SU,
    }
FREQUENCIES = {
    'yearly': YEARLY,
    'monthly': MONTHLY,
    'weekly': WEEKLY,
    'daily': DAILY,
    }


class RecurrenceRuleSet(ModelSQL, ModelView):
    __name__ = 'sale.subscription.recurrence.rule.set'

    name = fields.Char(
        "Name", required=True, translate=True,
        help="The main identifier of the rule set.")
    rules = fields.One2Many(
        'sale.subscription.recurrence.rule', 'set_', "Rules")

    @classmethod
    def __setup__(cls):
        super().__setup__()
        cls._order.insert(0, ('name', 'ASC'))

    @classmethod
    def default_rules(cls):
        if Transaction().user == 0:
            return []
        return [{}]

    def rruleset(self, dtstart):
        set_ = rruleset(**self._rruleset())
        for rule in self.rules:
            if not rule.exclusive:
                set_.rrule(rule.rrule(dtstart))
            else:
                set_.exrule(rule.rrule(dtstart))
        return set_

    def _rruleset(self):
        return {}


class RecurrenceRule(ModelSQL, ModelView):
    __name__ = 'sale.subscription.recurrence.rule'

    set_ = fields.Many2One(
        'sale.subscription.recurrence.rule.set', "Set",
        required=True, ondelete='CASCADE',
        help="Add the rule below the set.")
    freq = fields.Selection([
            ('yearly', 'Yearly'),
            ('monthly', 'Monthly'),
            ('weekly', 'Weekly'),
            ('daily', 'Daily'),
            ], "Frequency", sort=False, required=True)
    interval = fields.Integer("Interval", required=True)
    byweekday = fields.Char(
        "By Week Day",
        help="A comma separated list of integers or weekday (MO, TU etc).")
    bymonthday = fields.Char(
        "By Month Day",
        help="A comma separated list of integers.")
    byyearday = fields.Char(
        "By Year Day",
        help="A comma separated list of integers.")
    byweekno = fields.Char(
        "By Week Number",
        help="A comma separated list of integers (ISO8601).")
    bymonth = fields.Char(
        "By Month",
        help="A comma separated list of integers.")
    bysetpos = fields.Char(
        "By Position",
        help="A comma separated list of integers.")
    week_start_day = fields.Many2One('ir.calendar.day', "Week Start Day")

    exclusive = fields.Boolean(
        "Exclusive",
        help="If checked, dates which are part of this recurrence rule "
        "will not be generated.")

    @classmethod
    def __setup__(cls):
        super().__setup__()
        cls.__access__.add('set_')

    @classmethod
    def default_interval(cls):
        return 1

    @classmethod
    def default_exclusive(cls):
        return False

    def rrule(self, dtstart):
        return rrule(**self._rrule(dtstart))

    def _rrule(self, dtstart):
        return {
            'dtstart': dtstart,
            'freq': FREQUENCIES[self.freq],
            'interval': self.interval,
            'byweekday': self._byweekday,
            'bymonthday': self._bymonthday,
            'byyearday': self._byyearday,
            'byweekno': self._byweekno,
            'bymonth': self._bymonth,
            'bysetpos': self._bysetpos,
            'wkst': self.week_start_day.index if self.week_start_day else None,
            }

    @property
    def _byweekday(self):
        if not self.byweekday:
            return None
        byweekday = []
        for weekday in self.byweekday.split(','):
            try:
                weekday = int(weekday)
            except ValueError:
                pass
            else:
                if 0 <= weekday <= len(WEEKDAYS):
                    byweekday.append(weekday)
                    continue
                else:
                    raise ValueError('Invalid weekday')
            try:
                cls = WEEKDAYS[weekday[:2]]
            except KeyError:
                raise ValueError('Invalid weekday')
            if not weekday[2:]:
                byweekday.append(cls)
            else:
                byweekday.append(cls(int(weekday[3:-1])))
        return byweekday

    @property
    def _bymonthday(self):
        if not self.bymonthday:
            return None
        return [int(md) for md in self.bymonthday.split(',')]

    @property
    def _byyearday(self):
        if not self.byyearday:
            return None
        return [int(yd) for yd in self.byyearday.split(',')]

    @property
    def _byweekno(self):
        if not self.byweekno:
            return None
        return [int(wn) for wn in self.byweekno.split(',')]

    @property
    def _bymonth(self):
        if not self.bymonth:
            return None
        return [int(m) for m in self.bymonth.split(',')]

    @property
    def _bysetpos(self):
        if not self.bysetpos:
            return None
        positions = []
        for setpos in self.bysetpos.split(','):
            setpos = int(setpos)
            if -366 <= setpos <= 366:
                positions.append(setpos)
            else:
                raise ValueError('Invalid setpos')
        return positions

    def pre_validate(self):
        for name in ['byweekday', 'bymonthday', 'byyearday', 'byweekno',
                'bymonth', 'bysetpos']:
            self.check_by(name)

    def check_by(self, name):
        try:
            getattr(self, '_%s' % name)
        except ValueError as exception:
            raise RecurrenceRuleValidationError(
                gettext('sale_subscription.msg_recurrence_rule_invalid_by',
                    value=getattr(self, name),
                    recurrence_rule=self.rec_name,
                    exception=exception,
                    **self.__names__(name))) from exception


class TestRecurrenceRuleSet(Wizard):
    __name__ = 'sale.subscription.recurrence.rule.set.test'
    start_state = 'test'
    test = StateView(
        'sale.subscription.recurrence.rule.set.test',
        'sale_subscription.recurrence_rule_set_test_view_form',
        [Button("Close", 'end', 'tryton-close', default=True)])

    def default_test(self, fields):
        default = {}
        if (self.model and self.model.__name__
                == 'sale.subscription.recurrence.rule.set'):
            if self.record:
                default['recurrence'] = self.record.id
        return default


class TestRecurrenceRuleSetView(ModelView):
    __name__ = 'sale.subscription.recurrence.rule.set.test'
    recurrence = fields.Many2One(
        'sale.subscription.recurrence.rule.set',
        "Subscription Recurrence", required=True)
    start_date = fields.Date("Start Date", required=True)
    count = fields.Integer("Count", required=True,
        help="Used to determine how many occurences to compute.")
    result = fields.One2Many(
        'sale.subscription.recurrence.rule.set.test.result',
        None, "Result", readonly=True)

    @classmethod
    def default_start_date(cls):
        return Pool().get('ir.date').today()

    @fields.depends('recurrence', 'start_date', 'count', 'result')
    def on_change_with_result(self):
        pool = Pool()
        Result = pool.get('sale.subscription.recurrence.rule.set.test.result')
        result = []
        if self.recurrence and self.start_date and self.count:
            rruleset = self.recurrence.rruleset(self.start_date)
            datetime = dt.datetime.combine(self.start_date, dt.time())
            for date in rruleset.xafter(datetime, self.count, inc=True):
                result.append(Result(date=date.date()))
        return result


class TestRecurrenceRuleSetViewResult(ModelView):
    __name__ = 'sale.subscription.recurrence.rule.set.test.result'
    date = fields.Date("Date", readonly=True)
