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

class ProductUomChangeWizard(models.TransientModel):
    _name = 'product.uom.change.wizard'
    _description = 'Change Product UOM Wizard'

    product_tmpl_id = fields.Many2one('product.template', string='Product', required=True, readonly=True)
    current_uom_id = fields.Many2one('uom.uom', related='product_tmpl_id.uom_id', string='Current UOM', readonly=True)
    uom_category_id = fields.Many2one('uom.category', related='product_tmpl_id.uom_id.category_id', readonly=True)
    new_uom_id = fields.Many2one('uom.uom', string='New UOM', required=True)
    new_uom_po_id = fields.Many2one('uom.uom', string='New Purchase UOM')

    @api.model
    def default_get(self, fields):
        res = super(ProductUomChangeWizard, self).default_get(fields)
        if self._context.get('active_model') == 'product.template' and self._context.get('active_id'):
            res['product_tmpl_id'] = self._context['active_id']
        elif self._context.get('active_model') == 'product.product' and self._context.get('active_id'):
            product = self.env['product.product'].browse(self._context['active_id'])
            res['product_tmpl_id'] = product.product_tmpl_id.id
        return res

    def action_change_uom(self):
        self.ensure_one()
        if self.new_uom_id.category_id != self.product_tmpl_id.uom_id.category_id:
            raise UserError(_("New UOM must be in the same category as the current UOM."))

        # Update UOM via SQL to bypass the constraint check in product.template write
        self.env.cr.execute("UPDATE product_template SET uom_id = %s WHERE id = %s", (self.new_uom_id.id, self.product_tmpl_id.id))
        
        # Also update Purchase UOM if specified
        if self.new_uom_po_id:
            if self.new_uom_po_id.category_id != self.product_tmpl_id.uom_po_id.category_id:
                 raise UserError(_("New Purchase UOM must be in the same category as the current Purchase UOM."))
            self.env.cr.execute("UPDATE product_template SET uom_po_id = %s WHERE id = %s", (self.new_uom_po_id.id, self.product_tmpl_id.id))

        # Invalidate cache to ensure the new value is read
        self.product_tmpl_id.invalidate_recordset(['uom_id', 'uom_po_id'])
        
        # Log note in chatter
        self.product_tmpl_id.message_post(body=f"UOM forcefully changed from {self.current_uom_id.name} to {self.new_uom_id.name} via Wizard.")

        return {'type': 'ir.actions.act_window_close'}