from odoo import api, models, _
import logging

_logger = logging.getLogger(__name__)


class StockMove(models.Model):
    _inherit = 'stock.move'

    def _auto_generate_lots_for_subcontract(self):
        """
        Auto-generate lot numbers for subcontracting moves.
        This method handles the automatic lot generation for subcontracted products.
        """
        self.ensure_one()
        
        if not self.product_id.tracking in ['lot', 'serial']:
            return []
        
        product = self.product_id
        tmpl = product.product_tmpl_id
        # Use standard Odoo 19 lot_sequence_id field
        lot_sequence = getattr(tmpl, 'lot_sequence_id', False)
        
        if not lot_sequence:
            _logger.warning(f"No lot sequence configured for product {product.display_name}")
            return []
        
        # Check if we already have move lines with lots
        existing_lots = self.move_line_ids.filtered(lambda ml: ml.lot_id)
        if existing_lots:
            _logger.info(f"Move already has lots assigned: {[lot.lot_id.name for lot in existing_lots]}")
            return existing_lots.mapped('lot_id')
        
        # Calculate how many lots we need to generate
        remaining_qty = self.product_uom_qty
        
        # For serial tracking, create one lot per unit
        if product.tracking == 'serial':
            lots_needed = int(remaining_qty)
        else:
            # For lot tracking, create one lot for the entire quantity
            lots_needed = 1
        
        if lots_needed <= 0:
            return []
        
        # Generate lot names using standard sequence
        lot_names = [lot_sequence.next_by_id() for _ in range(lots_needed)]
        
        # Create the lots
        Lot = self.env['stock.lot']
        lot_vals_list = []
        for lot_name in lot_names:
            lot_vals = {
                'name': lot_name,
                'product_id': product.id,
                'company_id': self.company_id.id,
            }
            lot_vals_list.append(lot_vals)
        
        lots = Lot.create(lot_vals_list)
        
        # Assign lots to existing move lines or create new ones
        existing_move_lines = self.move_line_ids.filtered(lambda ml: not ml.lot_id)
        
        if existing_move_lines and product.tracking == 'lot':
            # For lot tracking, assign the first lot to the first available move line
            if lots:
                existing_move_lines[0].lot_id = lots[0].id
                _logger.info(f"Assigned lot {lots[0].name} to existing move line")
        elif product.tracking == 'serial':
            # For serial tracking, we need one move line per lot
            # If we don't have enough move lines, let Odoo handle the creation
            # by using the standard lot assignment mechanism
            for i, lot in enumerate(lots):
                if i < len(existing_move_lines):
                    existing_move_lines[i].lot_id = lot.id
                else:
                    # Let Odoo create additional move lines as needed
                    break
        
        _logger.info(f"Auto-generated {len(lots)} lots for subcontract move of product {product.display_name}")
        return lots

    def action_generate_lots_for_move(self):
        """Open the lot generator wizard for this specific move."""
        self.ensure_one()
        
        if not getattr(self, 'is_subcontract', False):
            return {
                'type': 'ir.actions.client',
                'tag': 'display_notification',
                'params': {
                    'title': 'Not a Subcontract Move',
                    'message': 'This action is only available for subcontract moves.',
                    'type': 'warning',
                    'sticky': False,
                }
            }
        
        if self.product_id.tracking == 'none':
            return {
                'type': 'ir.actions.client',
                'tag': 'display_notification',
                'params': {
                    'title': 'No Tracking Required',
                    'message': 'This product does not require lot/serial tracking.',
                    'type': 'info',
                    'sticky': False,
                }
            }
        
        return {
            'name': 'Generate Lots for Move',
            'type': 'ir.actions.act_window',
            'res_model': 'subcontract.lot.generator',
            'view_mode': 'form',
            'target': 'new',
            'context': {
                'default_move_id': self.id,
                'default_picking_id': self.picking_id.id,
                'default_product_id': self.product_id.id,
                'default_quantity': self.product_uom_qty,
            },
        }