# -*- encoding: utf-8 -*-
from openerp import models, fields, api
import datetime as dt


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

    consumption_calculation_method = fields.Selection(
        selection=[("sales_history", "Sales History")],
        string="Consumption Calculation Method",
        default="sales_history",
    )
    calculation_range = fields.Integer("Calculation range (days)", default=14)

    average_consumption = fields.Float(
        string="Average Consumption",
        compute="_compute_average_daily_consumption",
        readonly=True,
        digits=(100, 2),
    )

    total_consumption = fields.Float(
        string="Total Consumption",
        default=0,
        compute="_compute_total_consumption",
        store=True,
        readonly=True,
        digits=(100, 2),
    )

    estimated_stock_coverage = fields.Float(
        string="Estimated Stock Coverage (days)",
        compute="_compute_estimated_stock_coverage",
        default=0,
        digits=(100, 2),
        readonly=True,
    )

    @api.multi
    @api.depends("total_consumption")
    def _compute_average_daily_consumption(self):
        for template in self:
            if template.calculation_range > 0:
                avg = template.total_consumption / template.calculation_range
            else:
                avg = 0
            template.average_consumption = avg

        return True

    @api.multi
    @api.depends("calculation_range")
    def _compute_total_consumption(self):
        for template in self:
            products = self.env["product.product"].search(
                [("product_tmpl_id", "=", template.id)]
            )

            today = dt.date.today()
            pol_date_limit = today - dt.timedelta(
                days=template.calculation_range
            )

            order_lines = self.env["pos.order.line"].search(
                [
                    ("product_id", "in", products.ids),
                    (
                        "create_date",
                        ">",
                        fields.Datetime.to_string(pol_date_limit),
                    ),  # noqa
                ]
            )

            if order_lines:
                order_lines = order_lines.filtered(
                    lambda ol: ol.order_id.state
                    in ["done", "invoiced", "paid"]
                )  # noqa
                template.total_consumption = sum(order_lines.mapped("qty"))
            else:
                template.total_consumption = 0
        return True

    @api.multi
    @api.depends("total_consumption")
    def _compute_estimated_stock_coverage(self):
        for product_template in self:
            qty = product_template.qty_available
            avg = product_template.average_consumption
            if avg > 0:
                product_template.estimated_stock_coverage = qty / avg
            else:
                # todo what would be a good default value? (not float(inf))
                product_template.estimated_stock_coverage = 9999

        return True

    @api.model
    def _batch_compute_total_consumption(self):
        products = self.env["product.template"].search([("active", "=", True)])

        query = """
            select
              template.id as product_template_id,
              sum(pol.qty) as total_consumption
            from pos_order_line pol
              join pos_order po ON pol.order_id = po.id
              join product_product product ON pol.product_id = product.id
              join product_template template ON product.product_tmpl_id = template.id
              where po.state in ('done', 'invoiced', 'paid')
                and template.active
                and pol.create_date
                    BETWEEN date_trunc('day', now()) - calculation_range * interval '1 days'
                        and date_trunc('day', now())
            group by product_template_id
        """  # noqa

        self.env.cr.execute(query)
        results = {pid: qty for pid, qty in self.env.cr.fetchall()}

        for product in products:
            product.total_consumption = results.get(
                product.id, product.total_consumption
            )