# 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 as dt
from collections import defaultdict
from decimal import Decimal

from sql.aggregate import Sum
from sql.operators import Concat

from trytond.model import fields
from trytond.modules.currency.fields import Monetary
from trytond.modules.product import price_digits, round_price
from trytond.pool import Pool, PoolMeta
from trytond.pyson import Eval
from trytond.tools import grouped_slice, reduce_ids
from trytond.transaction import Transaction


class Work(metaclass=PoolMeta):
    __name__ = 'project.work'
    product = fields.Many2One('product.product', 'Product',
        domain=[
            ('type', '=', 'service'),
            ],
        context={
            'company': Eval('company', -1),
            },
        depends={'company'})
    list_price = Monetary(
        "List Price", currency='currency', digits=price_digits)
    revenue = fields.Function(Monetary(
            "Revenue", currency='currency', digits='currency'),
        'get_total')
    cost = fields.Function(Monetary(
            "Cost", currency='currency', digits='currency'),
        'get_total')
    currency = fields.Function(fields.Many2One('currency.currency',
        'Currency'), 'on_change_with_currency')

    @classmethod
    def __setup__(cls):
        pool = Pool()

        super().__setup__()

        try:
            pool.get('purchase.line')
        except KeyError:
            pass
        else:
            # Add purchase lines if purchase is activated
            cls.purchase_lines = fields.One2Many('purchase.line', 'work',
                'Purchase Lines', domain=[
                    ('purchase.company', '=', Eval('company', -1)),
                    ('type', '=', 'line'),
                    ])

    @classmethod
    def get_total(cls, works, names):
        result = super().get_total(works, names)
        currencies = []
        for name in names:
            field = getattr(cls, name)
            if getattr(field, 'digits', None) == 'currency':
                currencies.append(name)
        if currencies:
            for work in works:
                for name in currencies:
                    result[name][work.id] = work.company.currency.round(
                        result[name][work.id])
        return result

    @classmethod
    def _get_cost(cls, works):
        costs = defaultdict(Decimal)

        for work_id, cost in cls._timesheet_cost(works):
            costs[work_id] += cost

        for work_id, cost in cls._purchase_cost(works):
            costs[work_id] += cost
        return costs

    @classmethod
    def _timesheet_cost(cls, works):
        pool = Pool()
        Line = pool.get('timesheet.line')
        Work = pool.get('timesheet.work')
        transaction = Transaction()
        cursor = transaction.connection.cursor()
        table = cls.__table__()
        work = Work.__table__()
        line = Line.__table__()

        work_ids = [w.id for w in works]
        for sub_ids in grouped_slice(work_ids):
            red_sql = reduce_ids(table.id, sub_ids)
            cursor.execute(*table.join(work,
                    condition=(
                        Concat(cls.__name__ + ',', table.id) == work.origin)
                    ).join(line, condition=line.work == work.id
                    ).select(table.id, Sum(line.cost_price * line.duration),
                    where=red_sql,
                    group_by=[table.id]))
            for work_id, cost in cursor:
                # SQLite stores timedelta as float
                if isinstance(cost, dt.timedelta):
                    cost = cost.total_seconds()
                # Convert from seconds
                cost /= 60 * 60
                yield work_id, Decimal(str(cost))

    @classmethod
    def _purchase_cost(cls, works):
        'Compute direct purchase cost'
        if not hasattr(cls, 'purchase_lines'):
            return

        pool = Pool()
        Currency = pool.get('currency.currency')
        PurchaseLine = pool.get('purchase.line')
        InvoiceLine = pool.get('account.invoice.line')
        Invoice = pool.get('account.invoice')
        Company = pool.get('company.company')

        cursor = Transaction().connection.cursor()
        table = cls.__table__()
        purchase_line = PurchaseLine.__table__()
        invoice_line = InvoiceLine.__table__()
        invoice = Invoice.__table__()
        company = Company.__table__()

        work_ids = [w.id for w in works]
        work2currency = {}
        iline2work = {}
        for sub_ids in grouped_slice(work_ids):
            where = reduce_ids(table.id, sub_ids)
            cursor.execute(*table.join(purchase_line,
                    condition=purchase_line.work == table.id
                    ).join(invoice_line,
                    condition=invoice_line.origin == Concat(
                        'purchase.line,', purchase_line.id)
                    ).join(invoice,
                    condition=invoice_line.invoice == invoice.id
                    ).select(invoice_line.id, table.id,
                    where=where & ~invoice.state.in_(['draft', 'cancelled'])))
            iline2work.update(cursor)

            cursor.execute(*table.join(company,
                    condition=table.company == company.id
                    ).select(table.id, company.currency,
                    where=where))
            work2currency.update(cursor)

        currencies = Currency.browse(set(work2currency.values()))
        id2currency = {c.id: c for c in currencies}

        invoice_lines = InvoiceLine.browse(list(iline2work.keys()))
        for invoice_line in invoice_lines:
            invoice = invoice_line.invoice
            work_id = iline2work[invoice_line.id]
            currency_id = work2currency[work_id]
            currency = id2currency[currency_id]
            if currency != invoice.currency:
                with Transaction().set_context(date=invoice.currency_date):
                    amount = Currency.compute(invoice.currency,
                        invoice_line.amount, currency)
            else:
                amount = invoice_line.amount
            yield work_id, amount

    @classmethod
    def _get_revenue(cls, works):
        revenues = defaultdict(Decimal)
        for work in works:
            if not work.list_price:
                continue
            if work.price_list_hour:
                revenue = work.list_price * Decimal(str(work.effort_hours))
            else:
                revenue = work.list_price
            revenues[work.id] = revenue
        return revenues

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

    @fields.depends('product')
    def on_change_product(self):
        pool = Pool()
        ModelData = pool.get('ir.model.data')
        Uom = pool.get('product.uom')

        if not self.product:
            return

        list_price = self.product.list_price_used
        if list_price is not None:
            if self.price_list_hour:
                hour_uom = Uom(ModelData.get_id('product', 'uom_hour'))
                list_price = Uom.compute_price(
                    self.product.default_uom, list_price, hour_uom)
            list_price = round_price(list_price)
        self.list_price = list_price

    @property
    def price_list_hour(self):
        pool = Pool()
        ModelData = pool.get('ir.model.data')
        Category = pool.get('product.uom.category')
        if not self.product:
            return
        time = Category(ModelData.get_id('product', 'uom_cat_time'))
        return self.product.default_uom_category == time

    @classmethod
    def copy(cls, records, default=None):
        if default is None:
            default = {}
        else:
            default = default.copy()
        if hasattr(cls, 'purchase_lines'):
            # Do not copy purchase lines if purchase is activated
            default.setdefault('purchase_lines', None)
        return super().copy(records, default=default)