# -*- coding: utf-8 -*-
# This file is part of the cashbook-planner from m-ds for Tryton.
# The COPYRIGHT file at the top level of this repository contains the
# full copyright notices and license terms.

from datetime import date
from dateutil.rrule import (
    rrule, YEARLY, MONTHLY, WEEKLY, DAILY, MO, TU, WE, TH, FR, SA, SU)
from trytond.model import ModelSQL, ModelView, fields, Index, DeactivableMixin
from trytond.transaction import Transaction
from trytond.pool import Pool
from trytond.report import Report
from trytond.pyson import Eval, Bool, If, And

DEF_NONE = None
SEL_FREQU = [
    ('year', 'Yearly'),
    ('month', 'Monthly'),
    ('week', 'Weekly'),
    ('day', 'Daily')]
SEL_WEEKDAY = [
    ('99', '-'),
    ('0', 'Monday'), ('1', 'Tuesday'), ('2', 'Wednesday'),
    ('3', 'Thursday'), ('4', 'Friday'), ('5', 'Saturday'),
    ('6', 'Sunday')]


class ScheduledBooking(DeactivableMixin, ModelSQL, ModelView):
    'Scheduled Booking'
    __name__ = 'cashbook.planner'

    company = fields.Many2One(
        string='Company', model_name='company.company',
        required=True, ondelete="RESTRICT")
    name = fields.Char(string='Name', required=True)
    description = fields.Text(string='Description')
    cashbook = fields.Many2One(
        string='Cashbook', required=True,
        help='Cash book for which the planned posting is to be executed.',
        model_name='cashbook.book', ondelete='CASCADE',
        domain=[('btype', '!=', None)])
    start_date = fields.Date(string='Start Date', required=True)
    end_date = fields.Date(
        string='End Date', depends=['start_date'],
        states={'readonly': ~Bool(Eval('start_date'))},
        domain=[
            'OR',
            ('end_date', '>', Eval('start_date')),
            ('end_date', '=', DEF_NONE)])
    frequ = fields.Selection(
        string='Frequency', required=True, selection=SEL_FREQU, sort=False)
    weekday = fields.Selection(
        string='Weekday', required=True, selection=SEL_WEEKDAY, sort=False,
        help='Select a day of the week if you want the rule to ' +
        'run on that day.',
        depends=['frequ'],
        states={'invisible': Eval('frequ') != 'month'})
    COND_SETPOS = And(Eval('weekday', '') != '99', Eval('frequ') == 'month')
    setpos = fields.Integer(
        string='Occurrence', depends=['weekday', 'frequ'],
        domain=[
            If(COND_SETPOS,
               [('setpos', '<=', 4), ('setpos', '>=', 1)],
               ('setpos', '=', None))],
        help='For example, if you want to run the rule on the second ' +
        'Wednesday of the month, enter 2 here.',
        states={'required': COND_SETPOS, 'invisible': ~COND_SETPOS})
    COND_MONTHDAY = And(Eval('weekday', '') == '99', Eval('frequ') == 'month')
    monthday = fields.Integer(
        string='Day of month',
        help='If you want the rule to run on a specific day of the month, ' +
        'select the day here.',
        domain=[
            If(COND_MONTHDAY,
                [('monthday', '>=', 1), ('monthday', '<=', 31)],
                ('monthday', '=', None))],
        depends=['weekday', 'frequ'],
        states={'required': COND_MONTHDAY, 'invisible': ~COND_MONTHDAY})
    interval = fields.Integer(
        string='Interval', required=True,
        help='Select an interval to run the rule on every n-th date.',
        domain=[('interval', '>=', 1), ('interval', '<=', 10)])
    nextdates = fields.Function(fields.Char(
        string='Next Dates', readonly=True,
        help='the next 5 appointments based on the configured rule'),
        'on_change_with_nextdates')
    nextrun = fields.One2Many(
        string='Next Execution Date', size=1, field='planner',
        model_name='cashbook.planner.nextrun')

    @classmethod
    def __setup__(cls):
        super(ScheduledBooking, cls).__setup__()
        t = cls.__table__()
        cls._sql_indexes.update({
            Index(
                t,
                (t.company, Index.Equality())),
            Index(
                t,
                (t.start_date, Index.Range(order='ASC'))),
            Index(
                t,
                (t.end_date, Index.Range(order='ASC')),
                where=t.end_date != DEF_NONE),
        })

    def _compute_dates_by_rrule(self, start_date=None, count=5, params={}):
        """ run rrule with values from record or from 'params'

        Args:
            start_date (date, optional): Start date as a filter for
                recurrences. Defaults to None.
            count (int, optional): number of recurrences in result.
                Defaults to 5. max value = 100
            params (dict, optional): Values in the dictionary are
                used instead of the stored values, Defaults to {},
                allowed: frequ, weekday, start_date,
                end_date (preferred over 'count'),
                monthday, interval, setpos

        Returns:
            list: date values, result of rrlue
        """
        pfrequ = {
            'year': YEARLY, 'month': MONTHLY, 'week': WEEKLY, 'day': DAILY}
        pweekday = {
            '0': MO, '1': TU, '2': WE, '3': TH, '4': FR, '5': SA, '6': SU,
            '99': None}.get(params.get('weekday', self.weekday), None)

        if count is None:
            count = 5
        count = 1 if count < 1 else 100 if count > 100 else count

        end_date = params.get('end_date', self.end_date)
        frequ = pfrequ[params.get('frequ', self.frequ)]

        setpos = params.get('setpos', self.setpos)
        if setpos is not None:
            setpos = 1 if setpos < 1 else 4 if setpos > 4 else setpos

        monthday = params.get('monthday', self.monthday)
        if monthday is not None:
            monthday = 1 if monthday < 1 else 31 if monthday > 31 else monthday

        interval = params.get('interval', self.interval)
        if interval is None:
            interval = 1
        interval = 1 if interval < 1 else 10 if interval > 10 else interval

        assert (monthday is None) or (pweekday is None), \
            "weekday and monthday cannot be used together"

        dtrule = rrule(
            freq=frequ, byweekday=pweekday,
            dtstart=params.get('start_date', self.start_date),
            until=end_date,
            bysetpos=setpos if frequ == MONTHLY else None,
            bymonthday=monthday, interval=interval)

        result = []
        for x in dtrule:
            if (start_date and (x.date() >= start_date)) or \
                    (start_date is None):
                result.append(x.date())
            if len(result) >= count:
                break
        return result

    @fields.depends(
            'start_date', 'end_date', 'frequ', 'weekday', 'monthday',
            'interval', 'setpos')
    def on_change_with_nextdates(self, name=None):
        """ Calculates the next 5 appointments based on the configured rule,
            returns a formatted date list

        Args:
            name (string, optional): name of field. Defaults to None.

        context:
            start_date (date, optional): start date for dates in result,
                defaults to today if not set or None

        Returns:
            string: formatted list of dates
        """
        IrDate = Pool().get('ir.date')
        context = Transaction().context

        start_date = context.get('start_date', None)
        if not isinstance(start_date, date):
            start_date = IrDate.today()

        return ' | '.join([
            Report.format_date(x)
            for x in self._compute_dates_by_rrule(
                start_date=start_date,
                params={
                    'start_date': self.start_date,
                    'end_date': self.end_date,
                    'frequ': self.frequ,
                    'weekday': self.weekday,
                    'monthday': self.monthday,
                    'interval': self.interval,
                    'setpos': self.setpos}
            )])

    @fields.depends('frequ', 'setpos', 'weekday', 'monthday')
    def on_change_frequ(self):
        """ update fields
        """
        if self.frequ and self.frequ == 'month':
            if self.weekday:
                if self.weekday == '99':
                    if self.monthday is None:
                        self.monthday = 1
                    self.setpos = None
                else:
                    if self.setpos is None:
                        self.setpos = 1
                    self.monthday = None
        else:
            self.setpos = None
            self.monthday = None
            self.weekday = '99'

    @fields.depends('frequ', 'setpos', 'weekday', 'monthday')
    def on_change_weekday(self):
        """ clear day-of-month if weekday is used
        """
        self.on_change_frequ()

    @classmethod
    def default_interval(cls):
        """ get default for interval

        Returns:
            int: 1 = each occurence
        """
        return 1

    @classmethod
    def default_weekday(cls):
        """ get default for weekday-rule

        Returns:
            string: '99' = not set
        """
        return '99'

    @classmethod
    def default_monthday(cls):
        """ get default for day-of-month

        Returns:
            int: 1
        """
        return 1

    @classmethod
    def default_frequ(cls):
        """ get default for frequency

        Returns:
            string: 'month'
        """
        return 'month'

    @staticmethod
    def default_company():
        return Transaction().context.get('company') or None

    @classmethod
    def default_start_date(cls):
        """ get today as start-date

        Returns:
            date: date of today
        """
        IrDate = Pool().get('ir.date')
        return IrDate.today()

    @classmethod
    def update_next_occurence(cls, records):
        """ compute date of next execution, create/update nextrun-record,
            delete nextrun-record if scheduled booking is disabled

        Args:
            records (list): scheduled-booking records
        """
        pool = Pool()
        IrDate = pool.get('ir.date')
        NextRun = pool.get('cashbook.planner.nextrun')

        to_create = []
        to_write = []
        to_delete = []
        for record in records:
            if not record.active:
                # delete nextrun-record if disabled
                if record.nextrun:
                    to_delete.extend(record.nextrun)
            elif record.active:
                # get next-run date
                next_date = record._compute_dates_by_rrule(
                    start_date=IrDate.today(), count=1)
                if next_date:
                    next_date = next_date[0]
                else:
                    continue

                if not record.nextrun:
                    # add record if not exist
                    to_create.append({'planner': record.id, 'date': next_date})
                else:
                    # update existing records
                    for nxrun in record.nextrun:
                        if nxrun.date != next_date:
                            to_write.extend([[nxrun], {'date': next_date}])
        if to_create:
            NextRun.create(to_create)
        if to_delete:
            NextRun.delete(to_delete)
        if to_write:
            NextRun.write(*to_write)

    @classmethod
    def cronjob(cls):
        pass

# ens ScheduledBooking