# -*- coding: utf-8 -*-
from odoo import models, fields, api, _
from odoo.exceptions import UserError

class UoMConversionRule(models.Model):
    _name = 'c2c.uom.conversion.rule'
    _description = 'C2C UoM Conversion Rule'

    name = fields.Char(string='Rule Name', required=True)
    product_category_id = fields.Many2one('product.category', string='Product Category')
    from_uom_id = fields.Many2one('uom.uom', string='From UoM', required=True)
    to_uom_id = fields.Many2one('uom.uom', string='To UoM', required=True)
    ratio = fields.Float(string='Conversion Ratio', default=1.0, required=True, digits=(16, 4))
    description = fields.Text(string='Description')

    @api.model
    def convert(self, product, quantity, from_uom, to_uom):
        """
        Utility method to convert quantities based on local rules if they exist.
        Otherwise falls back to standard Odoo UoM conversion.
        """
        rule = self.search([
            ('product_category_id', '=', product.categ_id.id),
            ('from_uom_id', '=', from_uom.id),
            ('to_uom_id', '=', to_uom.id)
        ], limit=1)
        
        if rule:
            return quantity * rule.ratio
        
        # Fallback to Odoo standard
        return from_uom._compute_quantity(quantity, to_uom)