/**
 * Invoice PDF Generation Service
 * Generates PDF invoices from invoice data
 */

import { Invoice, InvoiceLineItem } from '../types/billing.js'
import { logger } from '../lib/logger.js'

/**
 * Generate PDF for an invoice
 * Note: This is a placeholder implementation. In production, use a library like:
 * - pdfkit
 * - puppeteer (for HTML to PDF)
 * - @react-pdf/renderer (for React-based PDFs)
 */
export async function generateInvoicePDF(invoice: Invoice): Promise<Buffer> {
  // TODO: Implement actual PDF generation
  // For now, return a placeholder
  logger.warn('PDF generation not yet implemented - returning placeholder')
  
  // In production, this would:
  // 1. Create PDF document with invoice header
  // 2. Add billing period, invoice number, dates
  // 3. Add line items table
  // 4. Add subtotal, tax, total
  // 5. Add payment terms and instructions
  // 6. Return PDF buffer
  
  const placeholder = Buffer.from('PDF placeholder - implement with pdfkit or similar')
  return placeholder
}

/**
 * Generate invoice PDF and save to storage
 */
export async function generateAndSaveInvoicePDF(
  invoice: Invoice,
  storagePath?: string
): Promise<string> {
  const pdfBuffer = await generateInvoicePDF(invoice)
  
  // TODO: Save PDF to storage (S3, local filesystem, etc.)
  // For now, just log
  logger.info('Invoice PDF generated', {
    invoiceId: invoice.id,
    invoiceNumber: invoice.invoiceNumber,
    size: pdfBuffer.length,
  })
  
  // Return path where PDF is stored
  return storagePath || `/invoices/${invoice.id}.pdf`
}

