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

from odoo import api, fields, tools, models, _
from odoo.exceptions import UserError


class UoMCategory(models.Model):
    _name = 'uom.category'
    _description = 'Product UoM Categories'

    name = fields.Char('Name', required=True, translate=True)


class UoM(models.Model):
    _name = 'uom.uom'
    _description = 'Product Unit of Measure'
    _order = "name"

    name = fields.Char('Unit of Measure', required=True, translate=True)
    category_id = fields.Many2one(
        'uom.category', 'Category', required=True, ondelete='cascade',
        help="Conversion between Units of Measure can only occur if they belong to the same category. The conversion will be made based on the ratios.")
    factor = fields.Float(
        'Ratio', default=1.0, digits=0, required=True,  # force NUMERIC with unlimited precision
        help='How much bigger or smaller this unit is compared to the reference Unit of Measure for this category: 1 * (reference unit) = ratio * (this unit)')
    factor_inv = fields.Float(
        'Bigger Ratio', compute='_compute_factor_inv', digits=0,  # force NUMERIC with unlimited precision
        readonly=True, required=True,
        help='How many times this Unit of Measure is bigger than the reference Unit of Measure in this category: 1 * (this unit) = ratio * (reference unit)')
    rounding = fields.Float(
        'Rounding Precision', default=0.01, digits=0, required=True,
        help="The computed quantity will be a multiple of this value. "
             "Use 1.0 for a Unit of Measure that cannot be further split, such as a piece.")
    active = fields.Boolean('Active', default=True, help="Uncheck the active field to disable a unit of measure without deleting it.")
    uom_type = fields.Selection([
        ('bigger', 'Bigger than the reference Unit of Measure'),
        ('reference', 'Reference Unit of Measure for this category'),
        ('smaller', 'Smaller than the reference Unit of Measure')], 'Type',
        default='reference', required=1)

    _sql_constraints = [
        ('factor_gt_zero', 'CHECK (factor!=0)', 'The conversion ratio for a unit of measure cannot be 0!'),
        ('rounding_gt_zero', 'CHECK (rounding>0)', 'The rounding precision must be greater than 0!')
    ]

    @api.one
    @api.depends('factor')
    def _compute_factor_inv(self):
        self.factor_inv = self.factor and (1.0 / self.factor) or 0.0

    @api.onchange('uom_type')
    def _onchange_uom_type(self):
        if self.uom_type == 'reference':
            self.factor = 1

    @api.model
    def create(self, values):
        if 'factor_inv' in values:
            factor_inv = values.pop('factor_inv')
            values['factor'] = factor_inv and (1.0 / factor_inv) or 0.0
        return super(UoM, self).create(values)

    @api.multi
    def write(self, values):
        if 'factor_inv' in values:
            factor_inv = values.pop('factor_inv')
            values['factor'] = factor_inv and (1.0 / factor_inv) or 0.0
        return super(UoM, self).write(values)

    @api.model
    def name_create(self, name):
        """ The UoM category and factor are required, so we'll have to add temporary values
        for imported UoMs """
        values = {
            self._rec_name: name,
            'factor': 1
        }
        # look for the category based on the english name, i.e. no context on purpose!
        # TODO: should find a way to have it translated but not created until actually used
        if not self._context.get('default_category_id'):
            EnglishUoMCateg = self.env['uom.category'].with_context({})
            misc_category = EnglishUoMCateg.search([('name', '=', 'Unsorted/Imported Units')])
            if misc_category:
                values['category_id'] = misc_category.id
            else:
                values['category_id'] = EnglishUoMCateg.name_create('Unsorted/Imported Units')[0]
        new_uom = self.create(values)
        return new_uom.name_get()[0]

    @api.multi
    def _compute_quantity(self, qty, to_unit, round=True, rounding_method='UP'):
        if not self:
            return qty
        self.ensure_one()
        if self.category_id.id != to_unit.category_id.id:
            if self._context.get('raise-exception', True):
                raise UserError(_('Conversion from Product UoM %s to Default UoM %s is not possible as they both belong to different Category!.') % (self.name, to_unit.name))
            else:
                return qty
        amount = qty / self.factor
        if to_unit:
            amount = amount * to_unit.factor
            if round:
                amount = tools.float_round(amount, precision_rounding=to_unit.rounding, rounding_method=rounding_method)
        return amount

    @api.multi
    def _compute_price(self, price, to_unit):
        self.ensure_one()
        if not self or not price or not to_unit or self == to_unit:
            return price
        if self.category_id.id != to_unit.category_id.id:
            return price
        amount = price * self.factor
        if to_unit:
            amount = amount / to_unit.factor
        return amount
