// Action #9: Centralized Item Processing & Dynamic Calculations Node
let history = [];
try {
  if (typeof quote_history === 'string' && quote_history.trim() !== '') {
    history = JSON.parse(quote_history);
  } else if (Array.isArray(quote_history)) {
    history = quote_history;
  }
} catch(e) { history = []; }

// Append incoming flow line item
let newDesc = String(desc || '').trim();
let newQty = Number(qty) || 0;
let newRate = Number(rate) || 0;

if (newDesc !== '' && (newQty > 0 || newRate > 0)) {
  history.push({ description: newDesc, quantity: newQty, rate: newRate });
}

// Compute totals across array
let subtotal = 0, summaryText = "", htmlRows = "";
history.forEach((item, index) => {
  let lineTotal = (item.quantity || 0) * (item.rate || 0);
  subtotal += lineTotal;
  summaryText += `${index + 1}. *${item.description}*\n   ${item.quantity} x $${item.rate.toFixed(2)} = *$${lineTotal.toFixed(2)}*\n\n`;
  htmlRows += `<tr><td style='padding:8px;border-bottom:1px solid #ddd;'>${item.description}</td><td style='padding:8px;border-bottom:1px solid #ddd;text-align:center;'>${item.quantity}</td><td style='padding:8px;border-bottom:1px solid #ddd;text-align:right;'>$${item.rate.toFixed(2)}</td><td style='padding:8px;border-bottom:1px solid #ddd;text-align:right;'>$${lineTotal.toFixed(2)}</td></tr>`;
});

let taxRatePercent = Number(tax_rate) || 0;
let taxAmount = (subtotal * taxRatePercent) / 100;
let grandTotal = subtotal + taxAmount;

// Generate read-only preview number without incrementing user database count
let isInvoice = String(document_type || '').toLowerCase() === 'invoice';
let nextCount = isInvoice ? (Number(total_invoices_generated) || 0) + 1 : (Number(total_quotes_generated) || 0) + 1;
let previewDocNumber = isInvoice ? `INV-${String(nextCount).padStart(4, '0')}` : `Q-${String(nextCount).padStart(4, '0')}`;

return {
  subtotal: Number(subtotal.toFixed(2)),
  tax_amount: Number(taxAmount.toFixed(2)),
  quote_grand_total: Number(grandTotal.toFixed(2)),
  quote_items_summary_text: summaryText || "No items added.",
  quote_table_rows_html: htmlRows,
  updated_history: JSON.stringify(history),
  document_number: previewDocNumber
};

// Invoice Count & Revenue Rollup Sequence (Executed Post-PDF Delivery)
let updatedInvoices = currentInvoices + 1;
let updatedIncome = currentIncome + Number(quote_grand_total);
let formattedNumber = `INV-${String(updatedInvoices).padStart(4, '0')}`;

// Strip converted quote ID from zero-storage pending index
let pendingArray = currentPending.split(',').map(s => s.trim()).filter(Boolean);
let updatedPending = pendingArray.filter(q => q !== activeQuoteNum).join(', ');

return {
  total_invoices_generated: updatedInvoices,
  estimated_total_income: Number(updatedIncome.toFixed(2)),
  document_number: formattedNumber,
  pending_quotes_list: updatedPending
};