# 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

from sql import As, Join, Null, Select, Table, Union
from sql.conditionals import Greatest

from trytond.i18n import gettext
from trytond.model import ModelSQL, ModelView, ValueMixin, Workflow, fields
from trytond.model.exceptions import AccessError
from trytond.modules.stock.exceptions import PeriodCloseError
from trytond.pool import Pool, PoolMeta
from trytond.pyson import Eval
from trytond.tools import grouped_slice
from trytond.transaction import Transaction

from .exceptions import LotExpiredError, LotExpiredWarning

DATE_STATE = [
    ('none', 'None'),
    ('optional', 'Optional'),
    ('required', 'Required'),
    ]
shelf_life_delay = fields.TimeDelta(
    "Shelf Life Delay",
    help="The delay before removal from the forecast.")


class Configuration(metaclass=PoolMeta):
    __name__ = 'stock.configuration'

    shelf_life_delay = fields.MultiValue(shelf_life_delay)

    @classmethod
    def multivalue_model(cls, field):
        pool = Pool()
        if field == 'shelf_life_delay':
            return pool.get('stock.location.lot.shelf_life')
        return super().multivalue_model(field)


class ConfigurationLotShelfLife(ModelSQL, ValueMixin):
    __name__ = 'stock.location.lot.shelf_life'
    shelf_life_delay = shelf_life_delay


class LotSledMixin:
    __slots__ = ()
    shelf_life_expiration_date = fields.Date('Shelf Life Expiration Date',
        states={
            'required': (
                Eval('shelf_life_expiration_state', 'none') == 'required'),
            'invisible': (
                (Eval('shelf_life_expiration_state', 'none') == 'none')
                & ~Eval('shelf_life_expiration_date')),
            })
    shelf_life_expiration_state = fields.Function(
        fields.Selection(DATE_STATE, 'Shelf Life Expiration State'),
        'on_change_with_shelf_life_expiration_state')
    expiration_date = fields.Date('Expiration Date',
        states={
            'required': Eval('expiration_state', 'none') == 'required',
            'invisible': (
                (Eval('expiration_state', 'none') == 'none')
                & ~Eval('expiration_date')),
            })
    expiration_state = fields.Function(
        fields.Selection(DATE_STATE, 'Expiration State'),
        'on_change_with_expiration_state')

    @fields.depends('product')
    def on_change_with_shelf_life_expiration_state(self, name=None):
        if self.product:
            return self.product.shelf_life_state
        return 'none'

    @fields.depends('product')
    def on_change_with_expiration_state(self, name=None):
        if self.product:
            return self.product.expiration_state
        return 'none'

    @fields.depends('product')
    def on_change_product(self):
        pool = Pool()
        Date = pool.get('ir.date')
        try:
            super().on_change_product()
        except AttributeError:
            pass
        if self.product:
            today = Date.today()
            if (self.product.shelf_life_state != 'none'
                    and self.product.shelf_life_time):
                self.shelf_life_expiration_date = (today
                    + datetime.timedelta(days=self.product.shelf_life_time))
            if (self.product.expiration_state != 'none'
                    and self.product.expiration_time):
                self.expiration_date = (today
                    + datetime.timedelta(days=self.product.expiration_time))


class Lot(LotSledMixin, metaclass=PoolMeta):
    __name__ = 'stock.lot'

    @classmethod
    def check_modification(cls, mode, lots, values=None, external=False):
        super().check_modification(
            mode, lots, values=values, external=external)
        if (mode == 'write'
                and values.keys() & {
                    'shelf_life_expiration_date', 'expiration_date'}):
            cls.check_sled_period_closed(lots)

    @classmethod
    def check_sled_period_closed(cls, lots):
        Period = Pool().get('stock.period')
        Move = Pool().get('stock.move')
        periods = Period.search([
                ('state', '=', 'closed'),
                ], order=[('date', 'DESC')], limit=1)
        if not periods:
            return
        period, = periods
        for lots in grouped_slice(lots):
            lot_ids = [l.id for l in lots]
            moves = Move.search([
                    ('lot', 'in', lot_ids),
                    ['OR', [
                            ('effective_date', '=', None),
                            ('planned_date', '<=', period.date),
                            ],
                        ('effective_date', '<=', period.date),
                        ]], limit=1)
            if moves:
                move, = moves
                raise AccessError(
                    gettext('stock_lot_sled'
                        '.msg_lot_modify_expiration_date_period_close',
                        lot=move.lot.rec_name,
                        move=move.rec_name))


class MoveAddLotsStartLot(LotSledMixin, metaclass=PoolMeta):
    __name__ = 'stock.move.add.lots.start.lot'

    @fields.depends('shelf_life_expiration_date', 'expiration_date')
    def _set_lot_values(self, lot):
        super()._set_lot_values(lot)
        self.shelf_life_expiration_date = lot.shelf_life_expiration_date
        self.expiration_date = lot.expiration_date

    def _get_lot_values(self, move):
        values = super()._get_lot_values(move)
        values['shelf_life_expiration_date'] = self.shelf_life_expiration_date
        values['expiration_date'] = self.expiration_date
        return values


class Move(metaclass=PoolMeta):
    __name__ = 'stock.move'

    @classmethod
    @ModelView.button
    @Workflow.transition('done')
    def do(cls, moves):
        super().do(moves)
        cls.check_expiration_dates(moves)

    @classmethod
    def check_expiration_dates_types(cls):
        "Location types to check for expiration dates"
        return ['supplier', 'customer', 'production']

    @classmethod
    def check_expiration_dates_locations(cls):
        pool = Pool()
        Location = pool.get('stock.location')
        # Prevent pack expired products
        warehouses = Location.search([
                ('type', '=', 'warehouse'),
                ])
        return [w.output_location for w in warehouses]

    @property
    def to_check_expiration(self):
        if (self.lot
                and self.lot.shelf_life_expiration_date
                and self.effective_date > self.lot.shelf_life_expiration_date):
            return True
        return False

    @classmethod
    def check_expiration_dates(cls, moves):
        pool = Pool()
        Group = pool.get('res.group')
        User = pool.get('res.user')
        ModelData = pool.get('ir.model.data')
        Warning = pool.get('res.user.warning')

        types = cls.check_expiration_dates_types()
        locations = cls.check_expiration_dates_locations()

        def in_group():
            group = Group(ModelData.get_id('stock_lot_sled',
                    'group_stock_force_expiration'))
            transition = Transaction()
            user_id = transition.user
            if user_id == 0:
                user_id = transition.context.get('user', user_id)
            if user_id == 0:
                return True
            user = User(user_id)
            return group in user.groups

        for move in moves:
            if not move.to_check_expiration:
                continue
            if (move.from_location.type in types
                    or move.to_location.type in types
                    or move.from_location in locations
                    or move.to_location in locations):
                values = {
                    'move': move.rec_name,
                    'lot': move.lot.rec_name if move.lot else '',
                    }
                if not in_group():
                    raise LotExpiredError(
                        gettext('stock_lot_sled.msg_move_lot_expired',
                            **values))
                else:
                    warning_name = '%s.check_expiration_dates' % move
                    if Warning.check(warning_name):
                        raise LotExpiredWarning(warning_name,
                            gettext('stock_lot_sled.msg_move_lot_expired',
                                **values))

    @classmethod
    def compute_quantities_query(cls, location_ids, with_childs=False,
            grouping=('product',), grouping_filter=None):
        pool = Pool()
        Date = pool.get('ir.date')
        Lot = pool.get('stock.lot')
        Config = pool.get('stock.configuration')

        query = super().compute_quantities_query(
            location_ids, with_childs=with_childs, grouping=grouping,
            grouping_filter=grouping_filter)

        context = Transaction().context
        today = Date.today()

        stock_date_end = context.get('stock_date_end') or datetime.date.max
        if (query and not context.get('skip_lot_sled')
                and ((stock_date_end == today and context.get('forecast'))
                    or stock_date_end > today)):

            config = Config(1)
            shelf_life_delay = config.get_multivalue('shelf_life_delay')
            if shelf_life_delay:
                try:
                    expiration_date = stock_date_end + shelf_life_delay
                except OverflowError:
                    if shelf_life_delay >= datetime.timedelta(0):
                        expiration_date = datetime.date.max
                    else:
                        expiration_date = datetime.date.min
            else:
                expiration_date = stock_date_end

            def join(move, lot):
                return move.join(lot, 'LEFT',
                    condition=move.lot == lot.id)

            def find_table(join):
                if not isinstance(join, Join):
                    return
                for pos in ['left', 'right']:
                    item = getattr(join, pos)
                    if isinstance(item, Table):
                        if item._name == cls._table:
                            return join, pos, item
                    else:
                        found = find_table(item)
                        if found:
                            return found

            def find_queries(query):
                if isinstance(query, Union):
                    for sub_query in query.queries:
                        for q in find_queries(sub_query):
                            yield q
                elif isinstance(query, Select):
                    yield query
                    for table in query.from_:
                        for q in find_queries(table):
                            yield q
                elif isinstance(query, Join):
                    for pos in ['left', 'right']:
                        item = getattr(query, pos)
                        for q in find_queries(item):
                            yield q

            def add_join(from_, lot):
                # Find move table
                for i, table in enumerate(from_):
                    if isinstance(table, Table) and table._name == cls._table:
                        sub_query.from_[i] = join(table, lot)
                        break
                    found = find_table(table)
                    if found:
                        join_, pos, table = found
                        setattr(join_, pos, join(table, lot))
                        break
                else:
                    # Not query on move table
                    return False
                return True

            union, = query.from_
            for sub_query in find_queries(union):
                lot = Lot.__table__()
                if add_join(sub_query.from_, lot):
                    clause = (
                        (lot.shelf_life_expiration_date == Null)
                        | (lot.shelf_life_expiration_date >= expiration_date))
                    if sub_query.where:
                        sub_query.where &= clause
                    else:
                        sub_query.where = clause

            stock_date_start = context.get('stock_date_start')
            if stock_date_start:
                with Transaction().set_context(
                        stock_date_start=None,
                        skip_lot_sled=True):
                    query_expired = cls.compute_quantities_query(
                        location_ids, with_childs=with_childs,
                        grouping=grouping, grouping_filter=grouping_filter)
                    union_expired, = query_expired.from_
                    for sub_query in find_queries(union_expired):
                        lot = Lot.__table__()
                        if add_join(sub_query.from_, lot):
                            # only lot expiring during the period
                            clause = (
                                (lot.shelf_life_expiration_date
                                    >= stock_date_start)
                                & (lot.shelf_life_expiration_date
                                    < stock_date_end))
                            if sub_query.where:
                                sub_query.where &= clause
                            else:
                                sub_query.where = clause
                        # Inverse quantity
                        for column in sub_query._columns:
                            if (isinstance(column, As)
                                    and column.output_name == 'quantity'):
                                column.expression = -column.expression
                    union.queries += union_expired.queries
        return query


class Period(metaclass=PoolMeta):
    __name__ = 'stock.period'

    @classmethod
    @ModelView.button
    def close(cls, periods):
        pool = Pool()
        Move = pool.get('stock.move')
        Lot = pool.get('stock.lot')
        Date = pool.get('ir.date')
        Lang = pool.get('ir.lang')
        cursor = Transaction().connection.cursor()
        move = Move.__table__()
        lot = Lot.__table__()

        super().close(periods)

        # Don't allow to close a period if all products at this date
        # are not yet expired
        recent_date = max(
            (period.date for period in periods),
            default=datetime.date.min)
        today = Date.today()

        query = move.join(lot, 'INNER',
            condition=move.lot == lot.id).select(lot.id,
                where=(Greatest(move.effective_date, move.planned_date)
                    <= recent_date)
                & (lot.shelf_life_expiration_date >= today)
                )
        cursor.execute(*query)
        lot_id = cursor.fetchone()
        if lot_id:
            lot_id, = lot_id
            lot = Lot(lot_id)
            lang = Lang.get()
            raise PeriodCloseError(
                gettext('stock_lot_sled.msg_period_close_sled',
                    lot=lot.rec_name,
                    date=lang.strftime(lot.shelf_life_expiration_date)))
