from odoo import models, fields, api, _


class StockPicking(models.Model):
    _inherit = 'stock.picking'

    fusion_shipment_count = fields.Integer(
        string='Shipments',
        compute='_compute_fusion_shipment_count',
    )
    fusion_shipping_label_attachment_id = fields.Many2one(
        'ir.attachment',
        string='Shipping Label',
        compute='_compute_fusion_shipping_docs',
        help='Most recent shipping label generated for this delivery '
             '(any carrier).',
    )
    fusion_commercial_invoice_attachment_id = fields.Many2one(
        'ir.attachment',
        string='Commercial Invoice',
        compute='_compute_fusion_shipping_docs',
        help='Most recent commercial (customs) invoice generated for this '
             'delivery (any carrier).',
    )

    def _compute_fusion_shipment_count(self):
        Shipment = self.env['fusion.shipment']
        for picking in self:
            picking.fusion_shipment_count = Shipment.search_count(
                [('picking_id', '=', picking.id)]
            )

    @api.depends('message_ids.attachment_ids')
    def _compute_fusion_shipping_docs(self):
        """Find the latest shipping label + commercial invoice that the
        carrier posted to this delivery's chatter, so they can be opened
        from a smart button.

        Naming is carrier-agnostic (see the carriers' send_shipping):
          - labels contain 'Label' (Label-, LabelUPS, LabelShipping-...)
          - invoices contain 'CommercialInvoice' (UPS/Canada Post) or start
            with 'ShippingDoc-' (FedEx/DHL, via _get_delivery_doc_prefix).
        """
        Attachment = self.env['ir.attachment']
        for picking in self:
            invoice = label = Attachment
            if isinstance(picking.id, int):
                atts = Attachment.search(
                    [('res_model', '=', 'stock.picking'),
                     ('res_id', '=', picking.id)],
                    order='id desc')
                for att in atts:
                    name = att.name or ''
                    norm = name.lower().replace(' ', '').replace('-', '')
                    if 'commercialinvoice' in norm or name.startswith('ShippingDoc'):
                        invoice = invoice or att
                    elif 'label' in name.lower() and 'return' not in name.lower():
                        label = label or att
                    if invoice and label:
                        break
            picking.fusion_commercial_invoice_attachment_id = invoice.id
            picking.fusion_shipping_label_attachment_id = label.id

    def _fusion_open_attachment(self, attachment):
        """Open a shipping document for the operator.

        Routes PDFs through ir.attachment.action_fusion_preview (preview
        dialog) when fusion_pdf_preview is installed, else opens the file
        in a new tab. Mirrors fusion.shipment._action_open_attachment.
        See CLAUDE.md "PDF Preview".
        """
        self.ensure_one()
        if not attachment:
            return False
        if hasattr(attachment, 'action_fusion_preview'):
            return attachment.action_fusion_preview(
                title=attachment.name or _('Shipping Document'),
                model_name=self._name,
                record_ids=self.id,
            )
        return {
            'type': 'ir.actions.act_url',
            'url': '/web/content/%s?download=false' % attachment.id,
            'target': 'new',
        }

    def action_view_fusion_shipping_label(self):
        return self._fusion_open_attachment(
            self.fusion_shipping_label_attachment_id)

    def action_view_fusion_commercial_invoice(self):
        return self._fusion_open_attachment(
            self.fusion_commercial_invoice_attachment_id)

    def action_view_fusion_shipments(self):
        self.ensure_one()
        shipments = self.env['fusion.shipment'].search(
            [('picking_id', '=', self.id)]
        )
        action = {
            'type': 'ir.actions.act_window',
            'name': 'Shipments',
            'res_model': 'fusion.shipment',
            'view_mode': 'list,form',
            'domain': [('picking_id', '=', self.id)],
        }
        if len(shipments) == 1:
            action['view_mode'] = 'form'
            action['res_id'] = shipments.id
        return action