# 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 decimal import Decimal

from trytond.pool import PoolMeta, Pool
from trytond.model import ModelView, Workflow, fields
from trytond.pyson import Eval, If, Bool
from trytond.transaction import Transaction
from trytond.tools import grouped_slice

__all__ = ['Invoice', 'InvoiceLine']


class Invoice(metaclass=PoolMeta):
    __name__ = 'account.invoice'
    agent = fields.Many2One('commission.agent', 'Commission Agent',
        domain=[
            ('type_', '=', 'agent'),
            ('company', '=', Eval('company', -1)),
            ],
        states={
            'invisible': Eval('type') == 'in',
            'readonly': Eval('state', '') != 'draft',
            },
        depends=['type', 'company', 'state'])

    @classmethod
    @ModelView.button
    @Workflow.transition('posted')
    def post(cls, invoices):
        # Create commission only the first time the invoice is posted
        to_commission = [i for i in invoices
            if i.state not in ['posted', 'paid']]
        super(Invoice, cls).post(invoices)
        cls.create_commissions(to_commission)

    @classmethod
    def create_commissions(cls, invoices):
        pool = Pool()
        Commission = pool.get('commission')
        all_commissions = []
        for invoice in invoices:
            for line in invoice.lines:
                commissions = line.get_commissions()
                if commissions:
                    all_commissions.extend(commissions)

        Commission.save(all_commissions)
        return all_commissions

    @classmethod
    @Workflow.transition('paid')
    def paid(cls, invoices):
        pool = Pool()
        Date = pool.get('ir.date')
        Commission = pool.get('commission')

        today = Date.today()

        super(Invoice, cls).paid(invoices)

        for sub_invoices in grouped_slice(invoices):
            ids = [i.id for i in sub_invoices]
            commissions = Commission.search([
                    ('date', '=', None),
                    ('origin.invoice', 'in', ids, 'account.invoice.line'),
                    ])
            Commission.write(commissions, {
                    'date': today,
                    })

    @classmethod
    @ModelView.button
    @Workflow.transition('cancel')
    def cancel(cls, invoices):
        pool = Pool()
        Commission = pool.get('commission')

        super(Invoice, cls).cancel(invoices)

        to_delete = []
        to_save = []
        for sub_invoices in grouped_slice(invoices):
            ids = [i.id for i in sub_invoices]
            to_delete += Commission.search([
                    ('invoice_line', '=', None),
                    ('origin.invoice', 'in', ids, 'account.invoice.line'),
                    ])
            to_cancel = Commission.search([
                    ('invoice_line', '!=', None),
                    ('origin.invoice', 'in', ids, 'account.invoice.line'),
                    ])
            for commission in Commission.copy(to_cancel):
                commission.amount *= -1
                to_save.append(commission)

        Commission.delete(to_delete)
        Commission.save(to_save)

    def _credit(self):
        credit = super(Invoice, self)._credit()
        credit.agent = self.agent
        return credit


class InvoiceLine(metaclass=PoolMeta):
    __name__ = 'account.invoice.line'
    principal = fields.Many2One('commission.agent', 'Commission Principal',
        domain=[
            ('type_', '=', 'principal'),
            ('company', '=', Eval('_parent_invoice', {}).get('company',
                    Eval('company', -1))),
            ],
        states={
            'invisible': If(Bool(Eval('_parent_invoice')),
                Eval('_parent_invoice', {}).get('type') == 'in',
                Eval('invoice_type') == 'in'),
            }, depends=['invoice_type', 'company'])
    commissions = fields.One2Many('commission', 'origin', 'Commissions',
        readonly=True,
        states={
            'invisible': ~Eval('commissions'),
            })
    from_commissions = fields.One2Many('commission', 'invoice_line',
        'From Commissions', readonly=True,
        states={
            'invisible': ~Eval('from_commissions'),
            })

    @property
    def agent_plans_used(self):
        "List of agent, plan tuple"
        used = []
        if self.invoice.agent:
            used.append((self.invoice.agent, self.invoice.agent.plan))
        if self.principal:
            used.append((self.principal, self.principal.plan))
        return used

    def get_commissions(self):
        pool = Pool()
        Commission = pool.get('commission')
        Currency = pool.get('currency.currency')
        Date = pool.get('ir.date')

        if self.type != 'line':
            return []

        today = Date.today()
        commissions = []
        for agent, plan in self.agent_plans_used:
            if not plan:
                continue
            with Transaction().set_context(date=self.invoice.currency_date):
                amount = Currency.compute(self.invoice.currency,
                    self.amount, agent.currency, round=False)
            amount = self._get_commission_amount(amount, plan)
            if amount:
                digits = Commission.amount.digits
                amount = amount.quantize(Decimal(str(10.0 ** -digits[1])))
            if not amount:
                continue

            commission = Commission()
            commission.origin = self
            if plan.commission_method == 'posting':
                commission.date = today
            commission.agent = agent
            commission.product = plan.commission_product
            commission.amount = amount
            commissions.append(commission)
        return commissions

    def _get_commission_amount(self, amount, plan, pattern=None):
        return plan.compute(amount, self.product, pattern=pattern)

    @fields.depends('product', 'principal')
    def on_change_product(self):
        super(InvoiceLine, self).on_change_product()
        if self.product:
            if self.product.principals:
                if self.principal not in self.product.principals:
                    self.principal = self.product.principal
            elif self.principal:
                self.principal = None

    @classmethod
    def view_attributes(cls):
        return super(InvoiceLine, cls).view_attributes() + [
            ('//page[@id="commissions"]', 'states', {
                    'invisible': Eval('type') != 'line',
                    })]

    @classmethod
    def copy(cls, lines, default=None):
        if default is None:
            default = {}
        else:
            default = default.copy()
        default.setdefault('commissions', None)
        default.setdefault('from_commissions', None)
        return super(InvoiceLine, cls).copy(lines, default=default)
