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


class SubcontractLotGenerator(models.TransientModel):
    _name = 'subcontract.lot.generator'
    _description = 'Subcontract Lot Generator Wizard'

    picking_id = fields.Many2one('stock.picking', string='Picking', required=True)
    move_id = fields.Many2one('stock.move', string='Move', required=True)
    product_id = fields.Many2one('product.product', string='Product', required=True)
    quantity = fields.Float('Quantity', required=True, default=1.0)
    lot_count = fields.Integer('Number of Lots', default=1, help='Number of lots to generate')
    tracking = fields.Selection(related='product_id.tracking')
    use_sequence = fields.Boolean('Use Product Sequence', default=True)
    
    @api.onchange('product_id')
    def _onchange_product_id(self):
        if self.product_id:
            if self.product_id.tracking == 'serial':
                self.lot_count = int(self.quantity)
            else:
                self.lot_count = 1

    @api.onchange('quantity', 'tracking')
    def _onchange_quantity(self):
        if self.tracking == 'serial':
            self.lot_count = int(self.quantity)

    def action_generate_lots(self):
        """Generate lots based on wizard configuration."""
        self.ensure_one()
        
        if not self.product_id.tracking in ['lot', 'serial']:
            raise UserError(_('Product must have lot or serial tracking enabled.'))
        
        if self.lot_count <= 0:
            raise UserError(_('Number of lots must be greater than 0.'))
        
        # Get the sequence
        tmpl = self.product_id.product_tmpl_id
        lot_sequence = getattr(tmpl, 'lot_sequence_id', False)
        
        if not lot_sequence and self.use_sequence:
            raise UserError(_('No lot sequence configured for product %s') % self.product_id.display_name)
        
        # Generate lot names
        if self.use_sequence and lot_sequence:
            # Use standard Odoo sequence generation
            # Removed custom batch allocation and unsafe prefix overrides
            lot_names = [lot_sequence.next_by_id() for _ in range(self.lot_count)]
        else:
            # Generate simple sequential names fallback
            lot_names = [f"LOT-{i+1:04d}" for i in range(self.lot_count)]
        
        # Create the lots
        Lot = self.env['stock.lot']
        lot_vals_list = []
        for lot_name in lot_names:
            lot_vals = {
                'name': lot_name,
                'product_id': self.product_id.id,
                'company_id': self.picking_id.company_id.id,
            }
            lot_vals_list.append(lot_vals)
        
        lots = Lot.create(lot_vals_list)
        
        # Calculate quantity in Product's Base UOM
        # self.quantity is in self.move_id.product_uom (or whatever was passed)
        base_uom = self.product_id.uom_id
        move_uom = self.move_id.product_uom
        
        total_base_qty = self.quantity
        if move_uom and base_uom and move_uom != base_uom:
            total_base_qty = move_uom._compute_quantity(self.quantity, base_uom)
            
        if self.tracking == 'serial':
            # One move line per lot for serial tracking, usually 1 unit of base UOM per serial
            qty_per_lot = 1.0
        else:
            # Distribute quantity across lots for lot tracking
            qty_per_lot = total_base_qty / self.lot_count
            
        for lot in lots:
            vals = {
                'move_id': self.move_id.id,
                'product_id': self.product_id.id,
                'lot_id': lot.id,
                'quantity': qty_per_lot, # Odoo 19 uses 'quantity' instead of product_uom_qty/qty_done in stock.move.line for initial demand? 
                # Let's check standard stock.move.line fields. Usually it's quantity (done) or reserved_uom_qty.
                # In Odoo 19 stock.move.line has 'quantity'.
                'product_uom_id': base_uom.id,
                'location_id': self.move_id.location_id.id,
                'location_dest_id': self.move_id.location_dest_id.id,
                'picking_id': self.picking_id.id,
            }
            self.env['stock.move.line'].create(vals)
        
        return {
            'type': 'ir.actions.client',
            'tag': 'display_notification',
            'params': {
                'title': _('Success'),
                'message': _('Generated %d lots for %s') % (len(lots), self.product_id.display_name),
                'type': 'success',
                'sticky': False,
            }
        }