# -*- coding: utf-8 -*-
# Part of Odoo. See LICENSE file for full copyright and licensing details.

from odoo import api, fields, models, _
from odoo.exceptions import UserError
from odoo.tools import float_is_zero, float_repr
from odoo.exceptions import ValidationError
from collections import defaultdict


class ProductTemplate(models.Model):
    _name = 'product.template'
    _inherit = 'product.template'

    cost_method = fields.Selection(related="categ_id.property_cost_method", readonly=True)
    valuation = fields.Selection(related="categ_id.property_valuation", readonly=True)

    def write(self, vals):
        impacted_templates = {}
        move_vals_list = []
        Product = self.env['product.product']
        SVL = self.env['stock.valuation.layer']

        if 'categ_id' in vals:
            # When a change of category implies a change of cost method, we empty out and replenish
            # the stock.
            new_product_category = self.env['product.category'].browse(vals.get('categ_id'))

            for product_template in self:
                product_template = product_template.with_company(product_template.company_id)
                valuation_impacted = False
                if product_template.cost_method != new_product_category.property_cost_method:
                    valuation_impacted = True
                if product_template.valuation != new_product_category.property_valuation:
                    valuation_impacted = True
                if valuation_impacted is False:
                    continue

                # Empty out the stock with the current cost method.
                description = _("Due to a change of product category (from %s to %s), the costing method\
                                has changed for product template %s: from %s to %s.") %\
                    (product_template.categ_id.display_name, new_product_category.display_name,
                     product_template.display_name, product_template.cost_method, new_product_category.property_cost_method)
                out_svl_vals_list, products_orig_quantity_svl, products = Product\
                    ._svl_empty_stock(description, product_template=product_template)
                out_stock_valuation_layers = SVL.create(out_svl_vals_list)
                if product_template.valuation == 'real_time':
                    move_vals_list += Product._svl_empty_stock_am(out_stock_valuation_layers)
                impacted_templates[product_template] = (products, description, products_orig_quantity_svl)

        res = super(ProductTemplate, self).write(vals)

        for product_template, (products, description, products_orig_quantity_svl) in impacted_templates.items():
            # Replenish the stock with the new cost method.
            in_svl_vals_list = products._svl_replenish_stock(description, products_orig_quantity_svl)
            in_stock_valuation_layers = SVL.create(in_svl_vals_list)
            if product_template.valuation == 'real_time':
                move_vals_list += Product._svl_replenish_stock_am(in_stock_valuation_layers)

        # Check access right
        if move_vals_list and not self.env['stock.valuation.layer'].check_access_rights('read', raise_exception=False):
            raise UserError(_("The action leads to the creation of a journal entry, for which you don't have the access rights."))
        # Create the account moves.
        if move_vals_list:
            account_moves = self.env['account.move'].sudo().create(move_vals_list)
            account_moves._post()
        return res

    # -------------------------------------------------------------------------
    # Misc.
    # -------------------------------------------------------------------------
    def _get_product_accounts(self):
        """ Add the stock accounts related to product to the result of super()
        @return: dictionary which contains information regarding stock accounts and super (income+expense accounts)
        """
        accounts = super(ProductTemplate, self)._get_product_accounts()
        res = self._get_asset_accounts()
        accounts.update({
            'stock_input': res['stock_input'] or self.categ_id.property_stock_account_input_categ_id,
            'stock_output': res['stock_output'] or self.categ_id.property_stock_account_output_categ_id,
            'stock_valuation': self.categ_id.property_stock_valuation_account_id or False,
        })
        return accounts

    def get_product_accounts(self, fiscal_pos=None):
        """ Add the stock journal related to product to the result of super()
        @return: dictionary which contains all needed information regarding stock accounts and journal and super (income+expense accounts)
        """
        accounts = super(ProductTemplate, self).get_product_accounts(fiscal_pos=fiscal_pos)
        accounts.update({'stock_journal': self.categ_id.property_stock_journal or False})
        return accounts


class ProductProduct(models.Model):
    _inherit = 'product.product'

    value_svl = fields.Float(compute='_compute_value_svl', compute_sudo=True)
    quantity_svl = fields.Float(compute='_compute_value_svl', compute_sudo=True)
    stock_valuation_layer_ids = fields.One2many('stock.valuation.layer', 'product_id')
    valuation = fields.Selection(related="categ_id.property_valuation", readonly=True)
    cost_method = fields.Selection(related="categ_id.property_cost_method", readonly=True)

    def write(self, vals):
        if 'standard_price' in vals and not self.env.context.get('disable_auto_svl'):
            self.filtered(lambda p: p.cost_method != 'fifo')._change_standard_price(vals['standard_price'])
        return super(ProductProduct, self).write(vals)

    @api.depends('stock_valuation_layer_ids')
    @api.depends_context('to_date', 'company')
    def _compute_value_svl(self):
        """Compute `value_svl` and `quantity_svl`."""
        company_id = self.env.company.id
        domain = [
            ('product_id', 'in', self.ids),
            ('company_id', '=', company_id),
        ]
        if self.env.context.get('to_date'):
            to_date = fields.Datetime.to_datetime(self.env.context['to_date'])
            domain.append(('create_date', '<=', to_date))
        groups = self.env['stock.valuation.layer'].read_group(domain, ['value:sum', 'quantity:sum'], ['product_id'])
        products = self.browse()
        for group in groups:
            product = self.browse(group['product_id'][0])
            product.value_svl = self.env.company.currency_id.round(group['value'])
            product.quantity_svl = group['quantity']
            products |= product
        remaining = (self - products)
        remaining.value_svl = 0
        remaining.quantity_svl = 0

    # -------------------------------------------------------------------------
    # Actions
    # -------------------------------------------------------------------------
    def action_revaluation(self):
        self.ensure_one()
        ctx = dict(self._context, default_product_id=self.id, default_company_id=self.env.company.id)
        return {
            'name': _("Product Revaluation"),
            'view_mode': 'form',
            'res_model': 'stock.valuation.layer.revaluation',
            'view_id': self.env.ref('stock_account.stock_valuation_layer_revaluation_form_view').id,
            'type': 'ir.actions.act_window',
            'context': ctx,
            'target': 'new'
        }

    # -------------------------------------------------------------------------
    # SVL creation helpers
    # -------------------------------------------------------------------------
    def _prepare_in_svl_vals(self, quantity, unit_cost):
        """Prepare the values for a stock valuation layer created by a receipt.

        :param quantity: the quantity to value, expressed in `self.uom_id`
        :param unit_cost: the unit cost to value `quantity`
        :return: values to use in a call to create
        :rtype: dict
        """
        self.ensure_one()
        vals = {
            'product_id': self.id,
            'value': unit_cost * quantity,
            'unit_cost': unit_cost,
            'quantity': quantity,
        }
        if self.cost_method in ('average', 'fifo'):
            vals['remaining_qty'] = quantity
            vals['remaining_value'] = vals['value']
        return vals

    def _prepare_out_svl_vals(self, quantity, company):
        """Prepare the values for a stock valuation layer created by a delivery.

        :param quantity: the quantity to value, expressed in `self.uom_id`
        :return: values to use in a call to create
        :rtype: dict
        """
        self.ensure_one()
        # Quantity is negative for out valuation layers.
        quantity = -1 * quantity
        vals = {
            'product_id': self.id,
            'value': quantity * self.standard_price,
            'unit_cost': self.standard_price,
            'quantity': quantity,
        }
        if self.cost_method in ('average', 'fifo'):
            fifo_vals = self._run_fifo(abs(quantity), company)
            vals['remaining_qty'] = fifo_vals.get('remaining_qty')
            # In case of AVCO, fix rounding issue of standard price when needed.
            if self.cost_method == 'average':
                currency = self.env.company.currency_id
                rounding_error = currency.round(self.standard_price * self.quantity_svl - self.value_svl)
                if rounding_error:
                    # If it is bigger than the (smallest number of the currency * quantity) / 2,
                    # then it isn't a rounding error but a stock valuation error, we shouldn't fix it under the hood ...
                    if abs(rounding_error) <= (abs(quantity) * currency.rounding) / 2:
                        vals['value'] += rounding_error
                        vals['rounding_adjustment'] = '\nRounding Adjustment: %s%s %s' % (
                            '+' if rounding_error > 0 else '',
                            float_repr(rounding_error, precision_digits=currency.decimal_places),
                            currency.symbol
                        )
            if self.cost_method == 'fifo':
                vals.update(fifo_vals)
        return vals

    def _change_standard_price(self, new_price):
        """Helper to create the stock valuation layers and the account moves
        after an update of standard price.

        :param new_price: new standard price
        """
        # Handle stock valuation layers.

        if self.filtered(lambda p: p.valuation == 'real_time') and not self.env['stock.valuation.layer'].check_access_rights('read', raise_exception=False):
            raise UserError(_("You cannot update the cost of a product in automated valuation as it leads to the creation of a journal entry, for which you don't have the access rights."))

        svl_vals_list = []
        company_id = self.env.company
        for product in self:
            if product.cost_method not in ('standard', 'average'):
                continue
            quantity_svl = product.sudo().quantity_svl
            if float_is_zero(quantity_svl, precision_rounding=product.uom_id.rounding):
                continue
            diff = new_price - product.standard_price
            value = company_id.currency_id.round(quantity_svl * diff)
            if company_id.currency_id.is_zero(value):
                continue

            svl_vals = {
                'company_id': company_id.id,
                'product_id': product.id,
                'description': _('Product value manually modified (from %s to %s)') % (product.standard_price, new_price),
                'value': value,
                'quantity': 0,
            }
            svl_vals_list.append(svl_vals)
        stock_valuation_layers = self.env['stock.valuation.layer'].sudo().create(svl_vals_list)

        # Handle account moves.
        product_accounts = {product.id: product.product_tmpl_id.get_product_accounts() for product in self}
        am_vals_list = []
        for stock_valuation_layer in stock_valuation_layers:
            product = stock_valuation_layer.product_id
            value = stock_valuation_layer.value

            if product.type != 'product' or product.valuation != 'real_time':
                continue

            # Sanity check.
            if not product_accounts[product.id].get('expense'):
                raise UserError(_('You must set a counterpart account on your product category.'))
            if not product_accounts[product.id].get('stock_valuation'):
                raise UserError(_('You don\'t have any stock valuation account defined on your product category. You must define one before processing this operation.'))

            if value < 0:
                debit_account_id = product_accounts[product.id]['expense'].id
                credit_account_id = product_accounts[product.id]['stock_valuation'].id
            else:
                debit_account_id = product_accounts[product.id]['stock_valuation'].id
                credit_account_id = product_accounts[product.id]['expense'].id

            move_vals = {
                'journal_id': product_accounts[product.id]['stock_journal'].id,
                'company_id': company_id.id,
                'ref': product.default_code,
                'stock_valuation_layer_ids': [(6, None, [stock_valuation_layer.id])],
                'move_type': 'entry',
                'line_ids': [(0, 0, {
                    'name': _(
                        '%(user)s changed cost from %(previous)s to %(new_price)s - %(product)s',
                        user=self.env.user.name,
                        previous=product.standard_price,
                        new_price=new_price,
                        product=product.display_name
                    ),
                    'account_id': debit_account_id,
                    'debit': abs(value),
                    'credit': 0,
                    'product_id': product.id,
                }), (0, 0, {
                    'name': _(
                        '%(user)s changed cost from %(previous)s to %(new_price)s - %(product)s',
                        user=self.env.user.name,
                        previous=product.standard_price,
                        new_price=new_price,
                        product=product.display_name
                    ),
                    'account_id': credit_account_id,
                    'debit': 0,
                    'credit': abs(value),
                    'product_id': product.id,
                })],
            }
            am_vals_list.append(move_vals)

        account_moves = self.env['account.move'].sudo().create(am_vals_list)
        if account_moves:
            account_moves._post()

    def _run_fifo(self, quantity, company):
        self.ensure_one()

        # Find back incoming stock valuation layers (called candidates here) to value `quantity`.
        qty_to_take_on_candidates = quantity
        candidates = self.env['stock.valuation.layer'].sudo().search([
            ('product_id', '=', self.id),
            ('remaining_qty', '>', 0),
            ('company_id', '=', company.id),
        ])
        new_standard_price = 0
        tmp_value = 0  # to accumulate the value taken on the candidates
        for candidate in candidates:
            qty_taken_on_candidate = min(qty_to_take_on_candidates, candidate.remaining_qty)

            candidate_unit_cost = candidate.remaining_value / candidate.remaining_qty
            new_standard_price = candidate_unit_cost
            value_taken_on_candidate = qty_taken_on_candidate * candidate_unit_cost
            value_taken_on_candidate = candidate.currency_id.round(value_taken_on_candidate)
            new_remaining_value = candidate.remaining_value - value_taken_on_candidate

            candidate_vals = {
                'remaining_qty': candidate.remaining_qty - qty_taken_on_candidate,
                'remaining_value': new_remaining_value,
            }

            candidate.write(candidate_vals)

            qty_to_take_on_candidates -= qty_taken_on_candidate
            tmp_value += value_taken_on_candidate

            if float_is_zero(qty_to_take_on_candidates, precision_rounding=self.uom_id.rounding):
                if float_is_zero(candidate.remaining_qty, precision_rounding=self.uom_id.rounding):
                    next_candidates = candidates.filtered(lambda svl: svl.remaining_qty > 0)
                    new_standard_price = next_candidates and next_candidates[0].unit_cost or new_standard_price
                break

        # Update the standard price with the price of the last used candidate, if any.
        if new_standard_price and self.cost_method == 'fifo':
            self.sudo().with_company(company.id).with_context(disable_auto_svl=True).standard_price = new_standard_price

        # If there's still quantity to value but we're out of candidates, we fall in the
        # negative stock use case. We chose to value the out move at the price of the
        # last out and a correction entry will be made once `_fifo_vacuum` is called.
        vals = {}
        if float_is_zero(qty_to_take_on_candidates, precision_rounding=self.uom_id.rounding):
            vals = {
                'value': -tmp_value,
                'unit_cost': tmp_value / quantity,
            }
        else:
            assert qty_to_take_on_candidates > 0
            last_fifo_price = new_standard_price or self.standard_price
            negative_stock_value = last_fifo_price * -qty_to_take_on_candidates
            tmp_value += abs(negative_stock_value)
            vals = {
                'remaining_qty': -qty_to_take_on_candidates,
                'value': -tmp_value,
                'unit_cost': last_fifo_price,
            }
        return vals

    def _run_fifo_vacuum(self, company=None):
        """Compensate layer valued at an estimated price with the price of future receipts
        if any. If the estimated price is equals to the real price, no layer is created but
        the original layer is marked as compensated.

        :param company: recordset of `res.company` to limit the execution of the vacuum
        """
        self.ensure_one()
        if company is None:
            company = self.env.company
        svls_to_vacuum = self.env['stock.valuation.layer'].sudo().search([
            ('product_id', '=', self.id),
            ('remaining_qty', '<', 0),
            ('stock_move_id', '!=', False),
            ('company_id', '=', company.id),
        ], order='create_date, id')
        if not svls_to_vacuum:
            return

        domain = [
            ('company_id', '=', company.id),
            ('product_id', '=', self.id),
            ('remaining_qty', '>', 0),
            ('create_date', '>=', svls_to_vacuum[0].create_date),
        ]
        all_candidates = self.env['stock.valuation.layer'].sudo().search(domain)

        for svl_to_vacuum in svls_to_vacuum:
            # We don't use search to avoid executing _flush_search and to decrease interaction with DB
            candidates = all_candidates.filtered(
                lambda r: r.create_date > svl_to_vacuum.create_date
                or r.create_date == svl_to_vacuum.create_date
                and r.id > svl_to_vacuum.id
            )
            if not candidates:
                break
            qty_to_take_on_candidates = abs(svl_to_vacuum.remaining_qty)
            qty_taken_on_candidates = 0
            tmp_value = 0
            for candidate in candidates:
                qty_taken_on_candidate = min(candidate.remaining_qty, qty_to_take_on_candidates)
                qty_taken_on_candidates += qty_taken_on_candidate

                candidate_unit_cost = candidate.remaining_value / candidate.remaining_qty
                value_taken_on_candidate = qty_taken_on_candidate * candidate_unit_cost
                value_taken_on_candidate = candidate.currency_id.round(value_taken_on_candidate)
                new_remaining_value = candidate.remaining_value - value_taken_on_candidate

                candidate_vals = {
                    'remaining_qty': candidate.remaining_qty - qty_taken_on_candidate,
                    'remaining_value': new_remaining_value
                }
                candidate.write(candidate_vals)
                if not (candidate.remaining_qty > 0):
                    all_candidates -= candidate

                qty_to_take_on_candidates -= qty_taken_on_candidate
                tmp_value += value_taken_on_candidate
                if float_is_zero(qty_to_take_on_candidates, precision_rounding=self.uom_id.rounding):
                    break

            # Get the estimated value we will correct.
            remaining_value_before_vacuum = svl_to_vacuum.unit_cost * qty_taken_on_candidates
            new_remaining_qty = svl_to_vacuum.remaining_qty + qty_taken_on_candidates
            corrected_value = remaining_value_before_vacuum - tmp_value
            svl_to_vacuum.write({
                'remaining_qty': new_remaining_qty,
            })

            # Don't create a layer or an accounting entry if the corrected value is zero.
            if svl_to_vacuum.currency_id.is_zero(corrected_value):
                continue

            corrected_value = svl_to_vacuum.currency_id.round(corrected_value)
            move = svl_to_vacuum.stock_move_id
            vals = {
                'product_id': self.id,
                'value': corrected_value,
                'unit_cost': 0,
                'quantity': 0,
                'remaining_qty': 0,
                'stock_move_id': move.id,
                'company_id': move.company_id.id,
                'description': 'Revaluation of %s (negative inventory)' % move.picking_id.name or move.name,
                'stock_valuation_layer_id': svl_to_vacuum.id,
            }
            vacuum_svl = self.env['stock.valuation.layer'].sudo().create(vals)

            # Create the account move.
            if self.valuation != 'real_time':
                continue
            vacuum_svl.stock_move_id._account_entry_move(
                vacuum_svl.quantity, vacuum_svl.description, vacuum_svl.id, vacuum_svl.value
            )
            # Create the related expense entry
            self._create_fifo_vacuum_anglo_saxon_expense_entry(vacuum_svl, svl_to_vacuum)

        # If some negative stock were fixed, we need to recompute the standard price.
        product = self.with_company(company.id)
        if product.cost_method == 'average' and not float_is_zero(product.quantity_svl, precision_rounding=self.uom_id.rounding):
            product.sudo().with_context(disable_auto_svl=True).write({'standard_price': product.value_svl / product.quantity_svl})


    def _create_fifo_vacuum_anglo_saxon_expense_entry(self, vacuum_svl, svl_to_vacuum):
        """ When product is delivered and invoiced while you don't have units in stock anymore, there are chances of that
            product getting undervalued/overvalued. So, we should nevertheless take into account the fact that the product has
            already been delivered and invoiced to the customer by posting the value difference in the expense account also.
            Consider the below case where product is getting undervalued:

            You bought 8 units @ 10$ -> You have a stock valuation of 8 units, unit cost 10.
            Then you deliver 10 units of the product.
            You assumed the missing 2 should go out at a value of 10$ but you are not sure yet as it hasn't been bought in Odoo yet.
            Afterwards, you buy missing 2 units of the same product at 12$ instead of expected 10$.
            In case the product has been undervalued when delivered without stock, the vacuum entry is the following one (this entry already takes place):

            Account                         | Debit   | Credit
            ===================================================
            Stock Valuation                 | 0.00     | 4.00
            Stock Interim (Delivered)       | 4.00     | 0.00

            So, on delivering product with different price, We should create additional journal items like:
            Account                         | Debit    | Credit
            ===================================================
            Stock Interim (Delivered)       | 0.00     | 4.00
            Expenses Revaluation            | 4.00     | 0.00
        """
        if not vacuum_svl.company_id.anglo_saxon_accounting or not svl_to_vacuum.stock_move_id._is_out():
            return False
        AccountMove = self.env['account.move'].sudo()
        account_move_lines = svl_to_vacuum.account_move_id.line_ids
        # Find related customer invoice where product is delivered while you don't have units in stock anymore
        reconciled_line_ids = list(set(account_move_lines._reconciled_lines()) - set(account_move_lines.ids))
        account_move = AccountMove.search([('line_ids','in', reconciled_line_ids)], limit=1)
        # If delivered quantity is not invoiced then no need to create this entry
        if not account_move:
            return False
        accounts = svl_to_vacuum.product_id.product_tmpl_id.get_product_accounts(fiscal_pos=account_move.fiscal_position_id)
        if not accounts.get('stock_output') or not accounts.get('expense'):
            return False
        description = "Expenses %s" % (vacuum_svl.description)
        move_lines = vacuum_svl.stock_move_id._prepare_account_move_line(
            vacuum_svl.quantity, vacuum_svl.value * -1,
            accounts['stock_output'].id, accounts['expense'].id,
            description)
        new_account_move = AccountMove.sudo().create({
            'journal_id': accounts['stock_journal'].id,
            'line_ids': move_lines,
            'date': self._context.get('force_period_date', fields.Date.context_today(self)),
            'ref': description,
            'stock_move_id': vacuum_svl.stock_move_id.id,
            'move_type': 'entry',
        })
        new_account_move._post()
        to_reconcile_account_move_lines = vacuum_svl.account_move_id.line_ids.filtered(lambda l: not l.reconciled and l.account_id == accounts['stock_output'] and l.account_id.reconcile)
        to_reconcile_account_move_lines += new_account_move.line_ids.filtered(lambda l: not l.reconciled and l.account_id == accounts['stock_output'] and l.account_id.reconcile)
        return to_reconcile_account_move_lines.reconcile()

    @api.model
    def _svl_empty_stock(self, description, product_category=None, product_template=None):
        impacted_product_ids = []
        impacted_products = self.env['product.product']
        products_orig_quantity_svl = {}

        # get the impacted products
        domain = [('type', '=', 'product')]
        if product_category is not None:
            domain += [('categ_id', '=', product_category.id)]
        elif product_template is not None:
            domain += [('product_tmpl_id', '=', product_template.id)]
        else:
            raise ValueError()
        products = self.env['product.product'].search_read(domain, ['quantity_svl'])
        for product in products:
            impacted_product_ids.append(product['id'])
            products_orig_quantity_svl[product['id']] = product['quantity_svl']
        impacted_products |= self.env['product.product'].browse(impacted_product_ids)

        # empty out the stock for the impacted products
        empty_stock_svl_list = []
        for product in impacted_products:
            # FIXME sle: why not use products_orig_quantity_svl here?
            if float_is_zero(product.quantity_svl, precision_rounding=product.uom_id.rounding):
                # FIXME: create an empty layer to track the change?
                continue
            svsl_vals = product._prepare_out_svl_vals(product.quantity_svl, self.env.company)
            svsl_vals['description'] = description + svsl_vals.pop('rounding_adjustment', '')
            svsl_vals['company_id'] = self.env.company.id
            empty_stock_svl_list.append(svsl_vals)
        return empty_stock_svl_list, products_orig_quantity_svl, impacted_products

    def _svl_replenish_stock(self, description, products_orig_quantity_svl):
        refill_stock_svl_list = []
        for product in self:
            quantity_svl = products_orig_quantity_svl[product.id]
            if quantity_svl:
                svl_vals = product._prepare_in_svl_vals(quantity_svl, product.standard_price)
                svl_vals['description'] = description
                svl_vals['company_id'] = self.env.company.id
                refill_stock_svl_list.append(svl_vals)
        return refill_stock_svl_list

    @api.model
    def _svl_empty_stock_am(self, stock_valuation_layers):
        move_vals_list = []
        product_accounts = {product.id: product.product_tmpl_id.get_product_accounts() for product in stock_valuation_layers.mapped('product_id')}
        for out_stock_valuation_layer in stock_valuation_layers:
            product = out_stock_valuation_layer.product_id
            expense_account = product._get_product_accounts()['expense']
            if not expense_account:
                raise UserError(_('Please define an expense account for this product: "%s" (id:%d) - or for its category: "%s".') % (product.name, product.id, self.name))
            if not product_accounts[product.id].get('stock_valuation'):
                raise UserError(_('You don\'t have any stock valuation account defined on your product category. You must define one before processing this operation.'))

            debit_account_id = expense_account.id
            credit_account_id = product_accounts[product.id]['stock_valuation'].id
            value = out_stock_valuation_layer.value
            move_vals = {
                'journal_id': product_accounts[product.id]['stock_journal'].id,
                'company_id': self.env.company.id,
                'ref': product.default_code,
                'stock_valuation_layer_ids': [(6, None, [out_stock_valuation_layer.id])],
                'line_ids': [(0, 0, {
                    'name': out_stock_valuation_layer.description,
                    'account_id': debit_account_id,
                    'debit': abs(value),
                    'credit': 0,
                    'product_id': product.id,
                }), (0, 0, {
                    'name': out_stock_valuation_layer.description,
                    'account_id': credit_account_id,
                    'debit': 0,
                    'credit': abs(value),
                    'product_id': product.id,
                })],
                'move_type': 'entry',
            }
            move_vals_list.append(move_vals)
        return move_vals_list

    def _svl_replenish_stock_am(self, stock_valuation_layers):
        move_vals_list = []
        product_accounts = {product.id: product.product_tmpl_id.get_product_accounts() for product in stock_valuation_layers.mapped('product_id')}
        for out_stock_valuation_layer in stock_valuation_layers:
            product = out_stock_valuation_layer.product_id
            if not product_accounts[product.id].get('stock_input'):
                raise UserError(_('You don\'t have any input valuation account defined on your product category. You must define one before processing this operation.'))
            if not product_accounts[product.id].get('stock_valuation'):
                raise UserError(_('You don\'t have any stock valuation account defined on your product category. You must define one before processing this operation.'))

            debit_account_id = product_accounts[product.id]['stock_valuation'].id
            credit_account_id = product_accounts[product.id]['stock_input'].id
            value = out_stock_valuation_layer.value
            move_vals = {
                'journal_id': product_accounts[product.id]['stock_journal'].id,
                'company_id': self.env.company.id,
                'ref': product.default_code,
                'stock_valuation_layer_ids': [(6, None, [out_stock_valuation_layer.id])],
                'line_ids': [(0, 0, {
                    'name': out_stock_valuation_layer.description,
                    'account_id': debit_account_id,
                    'debit': abs(value),
                    'credit': 0,
                    'product_id': product.id,
                }), (0, 0, {
                    'name': out_stock_valuation_layer.description,
                    'account_id': credit_account_id,
                    'debit': 0,
                    'credit': abs(value),
                    'product_id': product.id,
                })],
                'move_type': 'entry',
            }
            move_vals_list.append(move_vals)
        return move_vals_list

    # -------------------------------------------------------------------------
    # Anglo saxon helpers
    # -------------------------------------------------------------------------
    def _stock_account_get_anglo_saxon_price_unit(self, uom=False):
        price = self.standard_price
        if not self or not uom or self.uom_id.id == uom.id:
            return price or 0.0
        return self.uom_id._compute_price(price, uom)

    def _compute_average_price(self, qty_invoiced, qty_to_invoice, stock_moves):
        """Go over the valuation layers of `stock_moves` to value `qty_to_invoice` while taking
        care of ignoring `qty_invoiced`. If `qty_to_invoice` is greater than what's possible to
        value with the valuation layers, use the product's standard price.

        :param qty_invoiced: quantity already invoiced
        :param qty_to_invoice: quantity to invoice
        :param stock_moves: recordset of `stock.move`
        :returns: the anglo saxon price unit
        :rtype: float
        """
        self.ensure_one()
        if not qty_to_invoice:
            return 0.0

        returned_quantities = defaultdict(float)
        for move in stock_moves:
            if move.origin_returned_move_id:
                returned_quantities[move.origin_returned_move_id.id] += abs(sum(move.stock_valuation_layer_ids.mapped('quantity')))
        candidates = stock_moves\
            .sudo()\
            .filtered(lambda m: not (m.origin_returned_move_id and sum(m.stock_valuation_layer_ids.mapped('quantity')) >= 0))\
            .mapped('stock_valuation_layer_ids')\
            .sorted()
        qty_to_take_on_candidates = qty_to_invoice
        tmp_value = 0  # to accumulate the value taken on the candidates
        for candidate in candidates:
            candidate_quantity = abs(candidate.quantity)
            if candidate.stock_move_id.id in returned_quantities:
                candidate_quantity -= returned_quantities[candidate.stock_move_id.id]
            if float_is_zero(candidate_quantity, precision_rounding=candidate.uom_id.rounding):
                continue  # correction entries
            if not float_is_zero(qty_invoiced, precision_rounding=candidate.uom_id.rounding):
                qty_ignored = min(qty_invoiced, candidate_quantity)
                qty_invoiced -= qty_ignored
                candidate_quantity -= qty_ignored
                if float_is_zero(candidate_quantity, precision_rounding=candidate.uom_id.rounding):
                    continue
            qty_taken_on_candidate = min(qty_to_take_on_candidates, candidate_quantity)

            qty_to_take_on_candidates -= qty_taken_on_candidate
            tmp_value += qty_taken_on_candidate * \
                ((candidate.value + sum(candidate.stock_valuation_layer_ids.mapped('value'))) / candidate.quantity)
            if float_is_zero(qty_to_take_on_candidates, precision_rounding=candidate.uom_id.rounding):
                break

        # If there's still quantity to invoice but we're out of candidates, we chose the standard
        # price to estimate the anglo saxon price unit.
        if not float_is_zero(qty_to_take_on_candidates, precision_rounding=self.uom_id.rounding):
            negative_stock_value = self.standard_price * qty_to_take_on_candidates
            tmp_value += negative_stock_value

        return tmp_value / qty_to_invoice


class ProductCategory(models.Model):
    _inherit = 'product.category'

    property_valuation = fields.Selection([
        ('manual_periodic', 'Manual'),
        ('real_time', 'Automated')], string='Inventory Valuation',
        company_dependent=True, copy=True, required=True,
        help="""Manual: The accounting entries to value the inventory are not posted automatically.
        Automated: An accounting entry is automatically created to value the inventory when a product enters or leaves the company.
        """)

    ###### cost method is added for Cost per Lot/Serial Number ####
    property_cost_method = fields.Selection([
        ('standard', 'Standard Price'),
        ('fifo', 'First In First Out (FIFO)'),
        ('average', 'Average Cost (AVCO)')], string="Costing Method",
        company_dependent=True, copy=True, required=True,
        help="""Standard Price: The products are valued at their standard cost defined on the product.
        Average Cost (AVCO): The products are valued at weighted average cost.
        First In First Out (FIFO): The products are valued supposing those that enter the company first will also leave it first.
        """)
    property_stock_journal = fields.Many2one(
        'account.journal', 'Stock Journal', company_dependent=True,
        domain="[('company_id', '=', allowed_company_ids[0])]", check_company=True,
        help="When doing automated inventory valuation, this is the Accounting Journal in which entries will be automatically posted when stock moves are processed.")
    property_stock_account_input_categ_id = fields.Many2one(
        'account.account', 'Stock Input Account', company_dependent=True,
        domain="[('company_id', '=', allowed_company_ids[0]), ('deprecated', '=', False)]", check_company=True,
        help="""Counterpart journal items for all incoming stock moves will be posted in this account, unless there is a specific valuation account
                set on the source location. This is the default value for all products in this category. It can also directly be set on each product.""")
    property_stock_account_output_categ_id = fields.Many2one(
        'account.account', 'Stock Output Account', company_dependent=True,
        domain="[('company_id', '=', allowed_company_ids[0]), ('deprecated', '=', False)]", check_company=True,
        help="""When doing automated inventory valuation, counterpart journal items for all outgoing stock moves will be posted in this account,
                unless there is a specific valuation account set on the destination location. This is the default value for all products in this category.
                It can also directly be set on each product.""")
    property_stock_valuation_account_id = fields.Many2one(
        'account.account', 'Stock Valuation Account', company_dependent=True,
        domain="[('company_id', '=', allowed_company_ids[0]), ('deprecated', '=', False)]", check_company=True,
        help="""When automated inventory valuation is enabled on a product, this account will hold the current value of the products.""",)

    @api.constrains('property_stock_valuation_account_id', 'property_stock_account_output_categ_id', 'property_stock_account_input_categ_id')
    def _check_valuation_accouts(self):
        # Prevent to set the valuation account as the input or output account.
        for category in self:
            valuation_account = category.property_stock_valuation_account_id
            input_and_output_accounts = category.property_stock_account_input_categ_id | category.property_stock_account_output_categ_id
            if valuation_account and valuation_account in input_and_output_accounts:
                raise ValidationError(_('The Stock Input and/or Output accounts cannot be the same as the Stock Valuation account.'))

    @api.onchange('property_cost_method')
    def onchange_property_valuation(self):
        if not self._origin:
            # don't display the warning when creating a product category
            return
        return {
            'warning': {
                'title': _("Warning"),
                'message': _("Changing your cost method is an important change that will impact your inventory valuation. Are you sure you want to make that change?"),
            }
        }

    def write(self, vals):
        impacted_categories = {}
        move_vals_list = []
        Product = self.env['product.product']
        SVL = self.env['stock.valuation.layer']

        if 'property_cost_method' in vals or 'property_valuation' in vals:
            # When the cost method or the valuation are changed on a product category, we empty
            # out and replenish the stock for each impacted products.
            new_cost_method = vals.get('property_cost_method')
            new_valuation = vals.get('property_valuation')


            for product_category in self:
                valuation_impacted = False
                if new_cost_method and new_cost_method != product_category.property_cost_method:
                    valuation_impacted = True
                if new_valuation and new_valuation != product_category.property_valuation:
                    valuation_impacted = True
                if valuation_impacted is False:
                    continue

                # Empty out the stock with the current cost method.
                if new_cost_method:
                    description = _("Costing method change for product category %s: from %s to %s.") \
                        % (product_category.display_name, product_category.property_cost_method, new_cost_method)
                else:
                    description = _("Valuation method change for product category %s: from %s to %s.") \
                        % (product_category.display_name, product_category.property_valuation, new_valuation)
                out_svl_vals_list, products_orig_quantity_svl, products = Product\
                    ._svl_empty_stock(description, product_category=product_category)
                out_stock_valuation_layers = SVL.sudo().create(out_svl_vals_list)
                if product_category.property_valuation == 'real_time':
                    move_vals_list += Product._svl_empty_stock_am(out_stock_valuation_layers)
                impacted_categories[product_category] = (products, description, products_orig_quantity_svl)

        res = super(ProductCategory, self).write(vals)

        for product_category, (products, description, products_orig_quantity_svl) in impacted_categories.items():
            # Replenish the stock with the new cost method.
            in_svl_vals_list = products._svl_replenish_stock(description, products_orig_quantity_svl)
            in_stock_valuation_layers = SVL.sudo().create(in_svl_vals_list)
            if product_category.property_valuation == 'real_time':
                move_vals_list += Product._svl_replenish_stock_am(in_stock_valuation_layers)

        # Check access right
        if move_vals_list and not self.env['stock.valuation.layer'].check_access_rights('read', raise_exception=False):
            raise UserError(_("The action leads to the creation of a journal entry, for which you don't have the access rights."))
        # Create the account moves.
        if move_vals_list:
            account_moves = self.env['account.move'].sudo().create(move_vals_list)
            account_moves._post()
        return res
