# This file is part of the sale_payment module for Tryton.
# The COPYRIGHT file at the top level of this repository contains the full
# copyright notices and license terms.
from decimal import Decimal

from trytond.model import ModelView, fields
from trytond.pool import PoolMeta, Pool
from trytond.pyson import Bool, Eval, Not
from trytond.transaction import Transaction
from trytond.wizard import Wizard, StateView, StateTransition, Button


__all__ = ['Sale', 'SalePaymentForm', 'WizardSalePayment',
    'WizardSaleReconcile']

__metaclass__ = PoolMeta


class Sale:
    __name__ = 'sale.sale'
    payments = fields.One2Many('account.statement.line', 'sale', 'Payments')
    paid_amount = fields.Function(fields.Numeric('Paid Amount', readonly=True),
        'get_paid_amount')
    residual_amount = fields.Function(fields.Numeric('Residual Amount',
            readonly=True), 'get_residual_amount')
    sale_device = fields.Many2One('sale.device', 'Sale Device',
            domain=[('shop', '=', Eval('shop'))],
            depends=['shop']
    )

    @classmethod
    def __setup__(cls):
        super(Sale, cls).__setup__()
        cls._buttons.update({
                'wizard_sale_payment': {
                    'invisible': Eval('state') == 'done',
                    'readonly': Not(Bool(Eval('lines'))),
                    },
                })

    @staticmethod
    def default_sale_device():
        User = Pool().get('res.user')
        user = User(Transaction().user)
        return user.sale_device or None

    @classmethod
    def get_paid_amount(cls, sales, names):
        result = {n: {s.id: Decimal(0) for s in sales} for n in names}
        for name in names:
            for sale in sales:
                for payment in sale.payments:
                    result[name][sale.id] += payment.amount
        return result

    @classmethod
    def get_residual_amount(cls, sales, names):
        return {
            n: {s.id: s.total_amount - s.paid_amount for s in sales}
            for n in names
            }

    @classmethod
    @ModelView.button_action('sale_payment.wizard_sale_payment')
    def wizard_sale_payment(cls, sales):
        pass

    @classmethod
    def copy(cls, sales, default=None):
        if default is None:
            default = {}
        default['payments'] = None
        return super(Sale, cls).copy(sales, default)

    def create_moves_without_shipment(self):
        pass


class SalePaymentForm(ModelView):
    'Sale Payment Form'
    __name__ = 'sale.payment.form'
    journal = fields.Many2One('account.statement.journal', 'Statement Journal',
        domain=[
            ('id', 'in', Eval('journals', [])),
            ],
        depends=['journals'], required=True)
    journals = fields.One2Many('account.statement.journal', None,
        'Allowed Statement Journals')
    payment_amount = fields.Numeric('Payment amount', required=True,
        digits=(16, Eval('currency_digits', 2)),
        depends=['currency_digits'])
    currency_digits = fields.Integer('Currency Digits')
    party = fields.Many2One('party.party', 'Party', readonly=True)


class WizardSalePayment(Wizard):
    'Wizard Sale Payment'
    __name__ = 'sale.payment'
    start = StateView('sale.payment.form',
        'sale_payment.sale_payment_view_form', [
            Button('Cancel', 'end', 'tryton-cancel'),
            Button('Pay', 'pay_', 'tryton-ok', default=True),
        ])
    pay_ = StateTransition()

    @classmethod
    def __setup__(cls):
        super(WizardSalePayment, cls).__setup__()
        cls._error_messages.update({
                'not_sale_device': ('You have not defined a sale device for '
                    'your user.'),
                'not_draft_statement': ('A draft statement for "%s" payments '
                    'has not been created.'),
                'not_customer_invoice': ('A customer invoice/refund '
                    'from sale device has not been created.'),
                })

    def default_start(self, fields):
        pool = Pool()
        Sale = pool.get('sale.sale')
        User = pool.get('res.user')
        sale = Sale(Transaction().context['active_id'])
        user = User(Transaction().user)
        sale_device = sale.sale_device or user.sale_device or False
        if user.id != 0 and not sale_device:
            self.raise_user_error('not_sale_device')
        return {
            'journal': sale_device.journal.id
                if sale_device.journal else None,
            'journals': [j.id for j in sale_device.journals],
            'payment_amount': sale.total_amount - sale.paid_amount
                if sale.paid_amount else sale.total_amount,
            'currency_digits': sale.currency_digits,
            'party': sale.party.id,
            }

    def transition_pay_(self):
        pool = Pool()
        Date = pool.get('ir.date')
        Invoice = pool.get('account.invoice')
        Sale = pool.get('sale.sale')
        Statement = pool.get('account.statement')
        StatementLine = pool.get('account.statement.line')

        form = self.start
        statements = Statement.search([
                ('journal', '=', form.journal),
                ('state', '=', 'draft'),
                ], order=[('date', 'DESC')])
        if not statements:
            self.raise_user_error('not_draft_statement', (form.journal.name,))

        active_id = Transaction().context.get('active_id', False)
        sale = Sale(active_id)
        if not sale.reference:
            Sale.set_reference([sale])

        if form.payment_amount:
            payment = StatementLine(
                statement=statements[0].id,
                date=Date.today(),
                amount=form.payment_amount,
                party=sale.party.id,
                account=sale.party.account_receivable.id,
                description=sale.reference,
                sale=active_id
                )
            payment.save()

        if sale.total_amount != sale.paid_amount:
            return 'start'
        if sale.state != 'draft':
            return 'end'

        sale.description = sale.reference
        sale.save()

        Sale.quote([sale])
        Sale.confirm([sale])
        Sale.process([sale])

        if not sale.invoices and sale.invoice_method == 'order':
            self.raise_user_error('not_customer_invoice')

        sale.create_moves_without_shipment()

        grouping = getattr(sale.party, 'sale_invoice_grouping_method', False)
        if sale.invoices and not grouping:
            for invoice in sale.invoices:
                if invoice.state == 'draft':
                    invoice.description = sale.reference
                    invoice.save()
            Invoice.post(sale.invoices)
            for payment in sale.payments:
                payment.invoice = sale.invoices[0].id
                payment.save()

        if sale.is_done():
            sale.state = 'done'
            sale.save()

        return 'end'


class WizardSaleReconcile(Wizard):
    'Reconcile Sales'
    __name__ = 'sale.reconcile'
    start = StateTransition()
    reconcile = StateTransition()

    def transition_start(self):
        pool = Pool()
        Sale = pool.get('sale.sale')
        Line = pool.get('account.move.line')
        for sale in Sale.browse(Transaction().context['active_ids']):
            account = sale.party.account_receivable
            lines = []
            amount = Decimal('0.0')
            for invoice in sale.invoices:
                for line in Line.browse(invoice.get_lines_to_pay(None)):
                    if not line.reconciliation:
                        lines.append(line)
                        amount += line.debit - line.credit
            for payment in sale.payments:
                if not payment.move:
                    continue
                for line in payment.move.lines:
                    if (not line.reconciliation and
                            line.account.id == account.id):
                        lines.append(line)
                        amount += line.debit - line.credit
            if lines and amount == Decimal('0.0'):
                Line.reconcile(lines)
        return 'end'