# 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 sql import Null
from sql.functions import CharLength
from sql.operators import Equal

import trytond.config as config
from trytond.i18n import gettext
from trytond.model import Exclude, ModelSQL, ModelView, Workflow, fields
from trytond.modules.company.model import CompanyValueMixin
from trytond.modules.currency.fields import Monetary
from trytond.pool import Pool, PoolMeta
from trytond.pyson import Bool, Eval, Id
from trytond.report import Report, get_email
from trytond.sendmail import send_message_transactional
from trytond.tools.email_ import (
    EmailNotValidError, set_from_header, validate_email)
from trytond.transaction import Transaction
from trytond.wizard import Button, StateTransition, StateView

from .exceptions import GiftCardLineValidationError


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

    gift_card_sequence = fields.MultiValue(fields.Many2One(
            'ir.sequence', "Gift Card Sequence",
            domain=[
                ('company', 'in', [
                        Eval('context', {}).get('company', -1), None]),
                ('sequence_type', '=', Id(
                        'sale_gift_card', 'sequence_type_gift_card')),
                ]))

    @classmethod
    def multivalue_model(cls, field):
        pool = Pool()
        if field == 'gift_card_sequence':
            return pool.get('sale.configuration.gift_card.sequence')
        return super().multivalue_model(field)


class ConfigurationGiftCardSequence(ModelSQL, CompanyValueMixin):
    __name__ = 'sale.configuration.gift_card.sequence'
    gift_card_sequence = fields.Many2One(
        'ir.sequence', "Gift Card Sequence",
        domain=[
            ('company', 'in', [Eval('company', -1), None]),
            ('sequence_type', '=', Id(
                    'sale_gift_card', 'sequence_type_gift_card')),
            ])


class GiftCard(ModelSQL, ModelView):
    __name__ = 'sale.gift_card'
    _rec_name = 'number'

    _states = {
        'readonly': Bool(Eval('origin')) | Bool(Eval('spent_on')),
        }

    number = fields.Char(
        "Number", required=True, states=_states)
    company = fields.Many2One(
        'company.company', "Company", required=True, states=_states)
    product = fields.Many2One(
        'product.product', "Product", required=True,
        domain=[
            ('gift_card', '=', True),
            ],
        context={
            'company': Eval('company', -1),
            },
        states=_states, depends={'company'})
    value = Monetary(
        "Value", currency='currency', digits='currency', required=True,
        states=_states)
    currency = fields.Many2One(
        'currency.currency', "Currency", required=True, states=_states)

    origin = fields.Reference("Origin", selection='get_origin', readonly=True)
    spent_on = fields.Reference(
        "Spent On", selection='get_spent_on', readonly=True)

    del _states

    @classmethod
    def __setup__(cls):
        super().__setup__()
        t = cls.__table__()
        cls._sql_constraints = [
            ('number_exclude',
                Exclude(t, (t.number, Equal), (t.company, Equal),
                    where=(t.spent_on == Null)),
                'sale_gift_card.msg_gift_card_number_unique'),
            ]
        cls._order.insert(0, ('number', 'ASC'))

    @classmethod
    def order_number(cls, tables):
        table, _ = tables[None]
        return [CharLength(table.number), table.number]

    @classmethod
    def default_company(cls):
        return Transaction().context.get('company')

    @classmethod
    def _get_origin(cls):
        return ['sale.line', 'stock.move']

    @classmethod
    def get_origin(cls):
        pool = Pool()
        Model = pool.get('ir.model')
        return [(None, '')] + [
            (m, Model.get_name(m)) for m in cls._get_origin()]

    @fields.depends('origin', 'value', 'currency')
    def on_change_origin(self):
        pool = Pool()
        SaleLine = pool.get('sale.line')
        StockMove = pool.get('stock.move')
        UoM = pool.get('product.uom')
        if isinstance(self.origin, SaleLine):
            line = self.origin
            self.company = line.sale.company
            self.product = line.product
            if line.unit and line.unit_price and line.product:
                self.value = UoM.compute_price(
                    line.unit, line.unit_price, line.product.default_uom)
                self.currency = line.sale.currency
        elif isinstance(self.origin, StockMove):
            move = self.origin
            self.company = move.company
            self.product = move.product
            if move.unit and move.unit_price:
                self.value = UoM.compute_price(
                    move.unit, move.unit_price, move.product.default_uom)
                self.currency = move.currency
        if self.value and self.currency:
            self.value = self.currency.round(self.value)

    @classmethod
    def _get_spent_on(cls):
        return ['sale.sale']

    @classmethod
    def get_spent_on(cls):
        pool = Pool()
        Model = pool.get('ir.model')
        return [(None, '')] + [
            (m, Model.get_name(m)) for m in cls._get_spent_on()]

    @property
    def _email(self):
        pool = Pool()
        SaleLine = pool.get('sale.line')
        if isinstance(self.origin, SaleLine):
            return self.origin.gift_card_email or self.origin.sale.party.email

    @property
    def _languages(self):
        pool = Pool()
        SaleLine = pool.get('sale.line')
        languages = []
        if isinstance(self.origin, SaleLine):
            lang = self.origin.sale.party.lang
            if lang:
                languages.append(lang)
        return languages

    @classmethod
    def send(cls, gift_cards, from_=None):
        pool = Pool()
        Lang = pool.get('ir.lang')
        from_cfg = config.get('email', 'from')
        for gift_card in gift_cards:
            email = gift_card._email
            if not email:
                continue
            languages = gift_card._languages
            if not languages:
                languages.append(Lang.get())
            msg, title = get_email(
                'sale.gift_card.email', gift_card, languages)
            set_from_header(msg, from_cfg, from_ or from_cfg)
            msg['To'] = email
            msg['Subject'] = title
            send_message_transactional(msg, strict=True)


class GiftCardReport(Report):
    __name__ = 'sale.gift_card'

    @classmethod
    def _get_records(cls, ids, model, data):
        pool = Pool()
        if model in {'sale.sale', 'sale.point.sale'}:
            Sale = pool.get(model)
            sales = Sale.browse(ids)
            ids = [
                g.id for s in sales
                for line in s.lines
                for g in line.gift_cards]
            model = 'sale.gift_card'
        return super()._get_records(ids, model, data)


class GiftCardEmail(Report):
    __name__ = 'sale.gift_card.email'


class GiftCard_POS(metaclass=PoolMeta):
    __name__ = 'sale.gift_card'

    @classmethod
    def _get_origin(cls):
        return super()._get_origin() + ['sale.point.sale.line']

    @fields.depends('origin')
    def on_change_origin(self):
        pool = Pool()
        POSLine = pool.get('sale.point.sale.line')
        UOM = pool.get('product.uom')
        if isinstance(self.origin, POSLine):
            line = self.origin
            self.company = line.sale.company
            self.product = line.product
            if line.unit and line.unit_price and line.product:
                self.value = UOM.compute_price(
                    line.unit, line.unit_price, line.product.default_uom)
                self.currency = line.sale.currency
        super().on_change_origin()

    @classmethod
    def _get_spent_on(cls):
        return super()._get_spent_on() + ['sale.point.sale']

    @property
    def _email(self):
        pool = Pool()
        POSLine = pool.get('sale.point.sale.line')
        email = super()._email
        if isinstance(self.origin, POSLine):
            email = self.origin.gift_card_email
        return email


class Sale(metaclass=PoolMeta):
    __name__ = 'sale.sale'

    gift_cards = fields.One2Many(
        'sale.gift_card', 'spent_on', "Gift Cards",
        domain=[
            ('company', '=', Eval('company', -1)),
            ('currency', '=', Eval('currency', -1)),
            ],
        add_remove=[
            ('spent_on', '=', None),
            ],
        states={
            'readonly': Eval('state') != 'draft',
            })

    @classmethod
    @ModelView.button
    @Workflow.transition('quotation')
    def quote(cls, sales):
        for sale in sales:
            sale.add_return_gift_cards()
        cls.save(sales)
        super().quote(sales)

    def add_return_gift_cards(self):
        lines = list(self.lines)
        for line in self.lines:
            if line.is_gift_card and line.quantity < 0:
                lines.remove(line)
        for gift_card in self.gift_cards:
            lines.append(self.get_return_gift_card_line(gift_card))
        self.lines = lines

    def get_return_gift_card_line(self, gift_card):
        pool = Pool()
        Line = pool.get('sale.line')
        sequence = None
        if self.lines:
            last_line = self.lines[-1]
            if last_line.sequence is not None:
                sequence = last_line.sequence + 1
        return Line(
            sale=self,
            sequence=sequence,
            type='line',
            product=gift_card.product,
            quantity=-1,
            unit=gift_card.product.default_uom,
            unit_price=gift_card.value,
            )

    @classmethod
    @ModelView.button
    def process(cls, sales):
        pool = Pool()
        GiftCard = pool.get('sale.gift_card')
        cls.lock(sales)
        gift_cards = []
        for sale in sales:
            for line in sale.lines:
                cards = line.get_gift_cards()
                if cards:
                    gift_cards.extend(cards)
        GiftCard.save(gift_cards)
        GiftCard.send(gift_cards)
        super().process(sales)


class POSSale(metaclass=PoolMeta):
    __name__ = 'sale.point.sale'

    gift_cards = fields.One2Many(
        'sale.gift_card', 'spent_on', "Gift Cards",
        domain=[
            ('company', '=', Eval('company', -1)),
            ('currency', '=', Eval('currency', -1)),
            ],
        add_remove=[
            ('spent_on', '=', None),
            ],
        states={
            'readonly': Eval('state') != 'draft',
            })

    @fields.depends('state', 'gift_cards')
    def on_change_with_total(self, name=None):
        total = super().on_change_with_total(name=name)
        if self.state == 'open':
            total -= sum(c.value for c in self.gift_cards)
        return total

    @classmethod
    @Workflow.transition('done')
    def do(cls, sales):
        for sale in sales:
            sale.add_return_gift_cards()
        cls.save(sales)
        super().do(sales)
        pool = Pool()
        GiftCard = pool.get('sale.gift_card')
        cls.lock(sales)
        gift_cards = []
        for sale in sales:
            for line in sale.lines:
                cards = line.get_gift_cards()
                if cards:
                    gift_cards.extend(cards)
        GiftCard.save(gift_cards)
        GiftCard.send(gift_cards)

    # TODO: print gift cards

    def add_return_gift_cards(self):
        lines = list(self.lines)
        for line in self.lines:
            if line.is_gift_card and line.quantity < 0:
                lines.remove(line)
        for gift_card in self.gift_cards:
            lines.append(self.get_return_gift_card_line(gift_card))
        self.lines = lines

    def get_return_gift_card_line(self, gift_card):
        pool = Pool()
        Line = pool.get('sale.point.sale.line')
        return Line(
            sale=self,
            product=gift_card.product,
            quantity=-1,
            unit=gift_card.product.default_uom,
            unit_list_price=gift_card.value,
            unit_gross_price=gift_card.value,
            )


class _LineMixin:
    __slots__ = ()

    gift_cards = fields.One2Many(
        'sale.gift_card', 'origin', "Gift Cards", readonly=True,
        states={
            'invisible': ~Eval('gift_cards', []),
            })
    is_gift_card = fields.Function(
        fields.Boolean("Is Gift Card"), 'on_change_with_is_gift_card')
    is_gift_card_service = fields.Function(
        fields.Boolean("Is Gift Card Service"),
        'on_change_with_is_gift_card_service')
    gift_card_email = fields.Char(
        "Gift Card Email",
        states={
            'invisible': ~Eval('is_gift_card_service', False),
            },
        help="Leave empty for the customer email.")

    @fields.depends('product')
    def on_change_with_is_gift_card(self, name=None):
        return self.product and self.product.gift_card

    @fields.depends('product', methods=['on_change_with_is_gift_card'])
    def on_change_with_is_gift_card_service(self, name=None):
        return (self.on_change_with_is_gift_card()
            and self.product.type == 'service')

    @classmethod
    def view_attributes(cls):
        return super().view_attributes() + [
            ('//page[@id="gift_cards"]', 'states', {
                    'invisible': ~Eval('is_gift_card_service', False),
                    }, ['is_gift_card_service']),
            ]

    def get_gift_cards(self):
        if (not self.is_gift_card_service
                or self.quantity < 0
                or self.gift_cards):
            return
        pool = Pool()
        GiftCard = pool.get('sale.gift_card')
        UoM = pool.get('product.uom')
        Config = pool.get('sale.configuration')
        config = Config(1)
        cards = []
        quantity = UoM.compute_qty(
            self.unit, self.quantity, self.product.default_uom)
        quantity -= len(self.gift_cards)
        quantity = max(quantity, 0)
        unit_price = UoM.compute_price(
            self.unit, self.unit_price, self.product.default_uom)
        unit_price = self.sale.currency.round(unit_price)
        sequence = config.get_multivalue(
            'gift_card_sequence', company=self.sale.company.id)
        if sequence:
            numbers = sequence.get_many(int(quantity))
        else:
            numbers = range(int(quantity))
        for number in numbers:
            card = GiftCard()
            card.company = self.sale.company
            if sequence:
                card.number = number
            card.product = self.product
            card.value = unit_price
            card.currency = self.sale.currency
            card.origin = self
            cards.append(card)
        return cards

    @classmethod
    def validate_fields(cls, cards, fields_names):
        super().validate_fields(cards, fields_names)
        cls.check_valid_email(cards, fields_names)

    @classmethod
    def check_valid_email(cls, cards, fields_names=None):
        if fields_names and 'email' not in fields_names:
            return
        for card in cards:
            if card.gift_card_email:
                try:
                    validate_email(card.gift_card_email)
                except EmailNotValidError as e:
                    raise GiftCardLineValidationError(gettext(
                            'sale_gift_card.msg_gift_card_email_invalid',
                            card=card.rec_name,
                            email=card.gift_card_email),
                        str(e)) from e


class Line(_LineMixin, metaclass=PoolMeta):
    __name__ = 'sale.line'


class POSSaleLine(_LineMixin, metaclass=PoolMeta):
    __name__ = 'sale.point.sale.line'

    @classmethod
    def __setup__(cls):
        super().__setup__()
        # Prevent selling goods gift card as POS does not manage shipment
        cls.product.domain = [
            cls.product.domain,
            ['OR',
                ('gift_card', '!=', True),
                ('type', '=', 'service'),
                ],
            ]


class POSPay(metaclass=PoolMeta):
    __name__ = 'sale.point.sale.pay'

    gift_card = StateView(
        'sale.point.sale.pay.gift_card',
        'sale_gift_card.sale_point_sale_pay_gift_card_view_form', [
            Button("Cancel", 'end', 'tryton-cancel'),
            Button("Add", 'add_gift_card', 'tryton-ok', default=True),
            ])
    add_gift_card = StateTransition()

    @classmethod
    def __setup__(cls):
        super().__setup__()
        cls.payment.buttons.insert(-1, Button(
                "Gift Card", 'gift_card',
                states={
                    'invisible': Eval('amount', 0) >= 0,
                    },
                validate=False))

    def default_gift_card(self, fields):
        return {
            'sale': self.record.id,
            'amount': -self.record.amount_to_pay,
            }

    def transition_add_gift_card(self):
        self._add_gift_card().save()
        if self.record.amount_to_pay:
            return 'payment'
        else:
            self.model.process([self.record])
            return 'end'

    def _add_gift_card(self):
        pool = Pool()
        Line = pool.get('sale.point.sale.line')
        return Line(
            sale=self.record,
            product=self.gift_card.product,
            quantity=1,
            unit=self.gift_card.product.default_uom,
            unit_list_price=self.gift_card.amount,
            unit_gross_price=self.gift_card.amount,
            gift_card_email=self.gift_card.email,
            )


class POSPayGiftCard(ModelView):
    __name__ = 'sale.point.sale.pay.gift_card'

    sale = fields.Many2One('sale.point.sale', "Sale")
    product = fields.Many2One(
        'product.product', "Product", required=True,
        domain=[
            ('salable', '=', True),
            ('gift_card', '=', True),
            ])
    amount = Monetary(
        "Amount", currency='currency', digits='currency', required=True)
    email = fields.Char("Email")

    currency = fields.Function(
        fields.Many2One('currency.currency', "Currency"),
        'on_change_with_currency')

    @fields.depends('sale')
    def on_change_with_currency(self, name=None):
        if self.sale and self.sale.company:
            return self.sale.company.currency