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

from trytond.model import ModelView, ModelSQL, Workflow, fields
from trytond.pyson import Eval
from trytond.pool import Pool, PoolMeta
from trytond.transaction import Transaction
from trytond.modules.stock import StockMixin

__all__ = ['Lot', 'LotType', 'Move', 'ShipmentIn', 'ShipmentOut',
    'ShipmentOutReturn',
    'Period', 'PeriodCacheLot',
    'Inventory', 'InventoryLine']
__metaclass__ = PoolMeta


class Lot(ModelSQL, ModelView, StockMixin):
    "Stock Lot"
    __name__ = 'stock.lot'
    _rec_name = 'number'
    number = fields.Char('Number', required=True, select=True)
    product = fields.Many2One('product.product', 'Product', required=True)
    quantity = fields.Function(fields.Float('Quantity'), 'get_quantity',
        searcher='search_quantity')
    forecast_quantity = fields.Function(fields.Float('Forecast Quantity'),
        'get_quantity', searcher='search_quantity')

    @classmethod
    def get_quantity(cls, lots, name):
        location_ids = Transaction().context.get('locations')
        products = list(set(l.product for l in lots))
        return cls._get_quantity(lots, name, location_ids, products,
            grouping=('product', 'lot'))

    @classmethod
    def search_quantity(cls, name, domain=None):
        location_ids = Transaction().context.get('locations')
        return cls._search_quantity(name, location_ids, domain,
            grouping=('product', 'lot'))


class LotType(ModelSQL, ModelView):
    "Stock Lot Type"
    __name__ = 'stock.lot.type'
    name = fields.Char('Name', required=True, translate=True)
    code = fields.Char('Code', required=True)


class Move:
    __name__ = 'stock.move'
    lot = fields.Many2One('stock.lot', 'Lot',
        domain=[
            ('product', '=', Eval('product')),
            ],
        states={
            'readonly': Eval('state').in_(['cancel', 'done']),
            },
        depends=['state', 'product'])

    @classmethod
    def __setup__(cls):
        super(Move, cls).__setup__()
        cls._error_messages.update({
                'lot_required': 'Lot is required for move of product "%s".',
                })

    def check_lot(self):
        "Check if lot is required"
        if (self.state == 'done'
                and self.internal_quantity
                and not self.lot
                and self.product.lot_is_required(
                    self.from_location, self.to_location)):
            self.raise_user_error('lot_required', self.product.rec_name)

    @classmethod
    def validate(cls, moves):
        super(Move, cls).validate(moves)
        for move in moves:
            move.check_lot()


class ShipmentIn:
    __name__ = 'stock.shipment.in'

    @classmethod
    def _get_inventory_moves(cls, incoming_move):
        move = super(ShipmentIn, cls)._get_inventory_moves(incoming_move)
        if move and incoming_move.lot:
            move.lot = incoming_move.lot
        return move


class ShipmentOut:
    __name__ = 'stock.shipment.out'

    @classmethod
    @ModelView.button
    @Workflow.transition('packed')
    def pack(cls, shipments):
        pool = Pool()
        Uom = pool.get('product.uom')
        Move = pool.get('stock.move')

        super(ShipmentOut, cls).pack(shipments)

        # Unassign move to allow update
        Move.draft([m for s in shipments for m in s.outgoing_moves])

        for shipment in shipments:
            outgoing_by_product = {}
            for move in shipment.outgoing_moves:
                outgoing_by_product.setdefault(move.product.id,
                    []).append(move)
            for move in shipment.inventory_moves:
                if not move.lot:
                    continue
                quantity = Uom.compute_qty(move.uom, move.quantity,
                    move.product.default_uom, round=False)
                outgoing_moves = outgoing_by_product[move.product.id]
                while outgoing_moves and quantity > 0:
                    out_move = outgoing_moves.pop()
                    out_quantity = Uom.compute_qty(out_move.uom,
                        out_move.quantity, out_move.product.default_uom,
                        round=False)
                    if quantity < out_quantity:
                        outgoing_moves.extend(Move.copy([out_move], default={
                                    'quantity': out_quantity - quantity,
                                    }))
                        Move.write([out_move], {
                                'quantity': quantity,
                                })
                    Move.write([out_move], {
                            'lot': move.lot.id,
                            })
                    quantity -= out_quantity
                assert quantity <= 0

        Move.assign([m for s in shipments for m in s.outgoing_moves])


class ShipmentOutReturn:
    __name__ = 'stock.shipment.out.return'

    @classmethod
    def _get_inventory_moves(cls, incoming_move):
        move = super(ShipmentOutReturn,
            cls)._get_inventory_moves(incoming_move)
        if move and incoming_move.lot:
            move.lot = incoming_move.lot
        return move


class Period:
    __name__ = 'stock.period'
    lot_caches = fields.One2Many('stock.period.cache.lot', 'period',
        'Lot Caches', readonly=True)

    @classmethod
    def groupings(cls):
        return super(Period, cls).groupings() + [('product', 'lot')]

    @classmethod
    def get_cache(cls, grouping):
        pool = Pool()
        Cache = super(Period, cls).get_cache(grouping)
        if grouping == ('product', 'lot'):
            return pool.get('stock.period.cache.lot')
        return Cache


class PeriodCacheLot(ModelSQL, ModelView):
    '''
    Stock Period Cache per Lot

    It is used to store cached computation of stock quantities per lot.
    '''
    __name__ = 'stock.period.cache.lot'
    period = fields.Many2One('stock.period', 'Period', required=True,
        readonly=True, select=True, ondelete='CASCADE')
    location = fields.Many2One('stock.location', 'Location', required=True,
        readonly=True, select=True, ondelete='CASCADE')
    product = fields.Many2One('product.product', 'Product', required=True,
        readonly=True, ondelete='CASCADE')
    lot = fields.Many2One('stock.lot', 'Lot', readonly=True,
        ondelete='CASCADE')
    internal_quantity = fields.Float('Internal Quantity', readonly=True)


class Inventory:
    __name__ = 'stock.inventory'

    @classmethod
    def complete_lines(cls, inventories):
        pool = Pool()
        Product = pool.get('product.product')
        Line = pool.get('stock.inventory.line')

        super(Inventory, cls).complete_lines(inventories)

        # Create and/or update lines with product that will require lot for
        # their moves.
        to_create = []
        for inventory in inventories:
            product2lines = defaultdict(list)
            for line in inventory.lines:
                if (line.product.lot_is_required(inventory.location,
                            inventory.lost_found)
                        or line.product.lot_is_required(inventory.lost_found,
                            inventory.location)):
                    product2lines[line.product.id].append(line)
            if product2lines:
                with Transaction().set_context(stock_date_end=inventory.date):
                    pbl = Product.products_by_location([inventory.location.id],
                        product_ids=product2lines.keys(),
                        grouping=('product', 'lot'))
                product_qty = defaultdict(dict)
                for (location_id, product_id, lot_id), quantity \
                        in pbl.iteritems():
                    product_qty[product_id][lot_id] = quantity

                products = Product.browse(product_qty.keys())
                product2uom = dict((p.id, p.default_uom.id) for p in products)

                for product_id, lines in product2lines.iteritems():
                    quantities = product_qty[product_id]
                    uom_id = product2uom[product_id]
                    for line in lines:
                        lot_id = line.lot.id if line.lot else None
                        if lot_id in quantities:
                            quantity = quantities.pop(lot_id)
                        elif lot_id is None and quantities:
                            lot_id = quantities.keys()[0]
                            quantity = quantities.pop(lot_id)
                        else:
                            lot_id = None
                            quantity = 0.0

                        values = line.update_values4complete(quantity, uom_id)
                        if (values or lot_id != (line.lot.id
                                    if line.lot else None)):
                            values['lot'] = lot_id
                            Line.write([line], values)
                    if quantities:
                        for lot_id, quantity in quantities.iteritems():
                            values = Line.create_values4complete(product_id,
                                inventory, quantity, uom_id)
                            values['lot'] = lot_id
                            to_create.append(values)
        if to_create:
            Line.create(to_create)


class InventoryLine:
    __name__ = 'stock.inventory.line'
    lot = fields.Many2One('stock.lot', 'Lot',
        domain=[
            ('product', '=', Eval('product')),
            ],
        depends=['product'])

    @classmethod
    def __setup__(cls):
        super(InventoryLine, cls).__setup__()
        cls._order.insert(1, ('lot', 'ASC'))

    def get_rec_name(self, name):
        rec_name = super(InventoryLine, self).get_rec_name(name)
        if self.lot:
            rec_name += ' - %s' % self.lot.rec_name
        return rec_name

    @property
    def unique_key(self):
        return super(InventoryLine, self).unique_key + (self.lot,)

    def get_move(self):
        move = super(InventoryLine, self).get_move()
        if move:
            move.lot = self.lot
        return move