frappe.ui.form.on('Customer', {
    refresh: function(frm) {
        // Wait for the form and its custom HTML fields to render
        frappe.after_ajax(() => {
            // Look for a button with the data attribute
            const $btn = frm.$wrapper.find('[data-generate-customer-assets-csv]');

            if ($btn.length) {
                // Prevent double-binding
                $btn.off('click').on('click', function () {
                    const assets = frm.doc.customer_assets || [];

                    if (!assets.length) {
                        frappe.msgprint('No customer assets found.');
                        return;
                    }

                    const excludedFields = [
                        'owner', 'creation', 'modified', 'modified_by', 'docstatus', 'idx'
                    ];

                    const fields = Object.keys(assets[0]).filter(
                        field => !excludedFields.includes(field)
                    );

                    const csvRows = [];
                    csvRows.push(fields.join(','));

                    assets.forEach(row => {
                        const csvRow = fields.map(field => {
                            let val = row[field] || '';
                            return `"${String(val).replace(/"/g, '""')}"`;
                        });
                        csvRows.push(csvRow.join(','));
                    });

                    const csvContent = csvRows.join('\n');
                    const blob = new Blob([csvContent], { type: 'text/csv;charset=utf-8;' });
                    const url = URL.createObjectURL(blob);

                    const a = document.createElement('a');
                    a.href = url;
                    a.download = `CustomerAssets-${frm.doc.name}.csv`;
                    document.body.appendChild(a);
                    a.click();
                    document.body.removeChild(a);
                });
            }
        });
    }
});