pdfGenerator.js

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/**
 * @file services/pdfGenerator.js
 * @module services/pdfGenerator
 * @description Server-side PDF generation service for invoices using PDFKit.
 * Generates professional, template-based PDFs similar to Crystal Reports.
 * 
 * Features:
 * - Professional invoice layout with company branding
 * - GST/tax calculations and breakdown
 * - Line items table with proper formatting
 * - Automatic page breaks
 * - Payment information section
 * - Terms and conditions
 * 
 * @requires pdfkit
 * @requires fs
 * @requires path
 */
 
const PDFDocument = require('pdfkit');
const fs = require('fs');
const path = require('path');
 
// Ensure PDFs directory exists
const PDFS_DIR = path.join(__dirname, '../pdfs');
try {
  if (!fs.existsSync(PDFS_DIR)) {
    console.log('[PDF Generator] Creating pdfs directory:', PDFS_DIR);
    fs.mkdirSync(PDFS_DIR, { recursive: true });
    console.log('[PDF Generator] Directory created successfully');
  } else {
    console.log('[PDF Generator] pdfs directory already exists:', PDFS_DIR);
  }
} catch (err) {
  console.error('[PDF Generator] Failed to create pdfs directory:', err);
  console.error('[PDF Generator] Will attempt to use /tmp instead');
}
 
/**
 * Generate invoice PDF from template
 * @param {Object} invoiceData - Complete invoice data including customer, items, company info
 * @returns {Promise<string>} - Path to generated PDF file
 */
async function generateInvoicePDF(invoiceData) {
  console.log('[PDF Generator] generateInvoicePDF called with:', {
    hasInvoice: !!invoiceData?.invoice,
    hasCustomer: !!invoiceData?.customer,
    hasCompanyInfo: !!invoiceData?.companyInfo,
    itemsCount: invoiceData?.items?.length || 0
  });
  
  return new Promise((resolve, reject) => {
    try {
      const {
        invoice,
        customer,
        companyInfo,
        items = []
      } = invoiceData;
 
      console.log('[PDF Generator] Parsed invoice data:', {
        invoiceId: invoice?.invoice_id,
        customerId: customer?.customer_id,
        companyName: companyInfo?.name
      });
 
      // Generate filename
      const filename = `invoice-${invoice.invoice_id}-${Date.now()}.pdf`;
      const filepath = path.join(PDFS_DIR, filename);
      
      console.log('[PDF Generator] Will write PDF to:', filepath);
 
      // Create PDF document
      console.log('[PDF Generator] Creating PDFDocument...');
      const doc = new PDFDocument({
        size: 'A4',
        margin: 50,
        info: {
          Title: `Invoice #${invoice.invoice_id}`,
          Author: companyInfo.name || 'Independent Business Group',
          Subject: `Tax Invoice for ${customer?.name || 'Customer'}`,
          Keywords: 'invoice, tax invoice, gst',
        }
      });
 
      // Pipe to file
      const stream = fs.createWriteStream(filepath);
      doc.pipe(stream);
 
      // Helper functions
      const formatCurrency = (amount, currency = 'AUD') => {
        return `${currency} $${parseFloat(amount || 0).toFixed(2)}`;
      };
 
      const formatDate = (dateStr) => {
        if (!dateStr) return '-';
        return new Date(dateStr).toLocaleDateString('en-AU', {
          year: 'numeric',
          month: 'long',
          day: 'numeric'
        });
      };
 
      // Define colors
      const primaryColor = '#2563eb';
      const darkGray = '#333333';
      const mediumGray = '#666666';
      const lightGray = '#999999';
      const borderColor = '#dddddd';
 
      // Page dimensions
      const pageWidth = doc.page.width;
      const pageHeight = doc.page.height;
      const contentWidth = pageWidth - 100; // 50px margin on each side
 
      // ===== HEADER SECTION =====
      let yPosition = 50;
 
      // TAX INVOICE title
      doc.fontSize(28)
         .fillColor(darkGray)
         .font('Helvetica-Bold')
         .text('TAX INVOICE', 50, yPosition, { align: 'center' });
      
      yPosition += 40;
 
      // Invoice number
      doc.fontSize(16)
         .fillColor(mediumGray)
         .font('Helvetica')
         .text(`Invoice #${String(invoice.invoice_id).padStart(5, '0')}`, 50, yPosition, { align: 'center' });
      
      yPosition += 30;
 
      // Status badge
      const statusColors = {
        'paid': { bg: '#d4edda', text: '#155724' },
        'sent': { bg: '#fff3cd', text: '#856404' },
        'draft': { bg: '#f8d7da', text: '#721c24' },
        'void': { bg: '#e2e3e5', text: '#383d41' }
      };
      const statusColor = statusColors[invoice.status] || statusColors.draft;
      const statusText = (invoice.payment_status === 'paid' ? 'PAID' : invoice.status?.toUpperCase()) || 'DRAFT';
      
      const statusWidth = doc.widthOfString(statusText) + 30;
      const statusX = (pageWidth - statusWidth) / 2;
      
      doc.roundedRect(statusX, yPosition, statusWidth, 24, 12)
         .fillAndStroke(statusColor.bg, statusColor.bg);
      
      doc.fontSize(11)
         .fillColor(statusColor.text)
         .font('Helvetica-Bold')
         .text(statusText, statusX, yPosition + 7, { width: statusWidth, align: 'center' });
      
      yPosition += 50;
 
      // Horizontal line
      doc.moveTo(50, yPosition)
         .lineTo(pageWidth - 50, yPosition)
         .strokeColor(darkGray)
         .lineWidth(3)
         .stroke();
      
      yPosition += 30;
 
      // ===== FROM/BILL TO SECTION =====
      const columnWidth = (contentWidth - 20) / 2;
 
      // FROM box
      doc.rect(50, yPosition, columnWidth, 140)
         .fillAndStroke('#f9f9f9', borderColor);
      
      doc.fontSize(12)
         .fillColor(darkGray)
         .font('Helvetica-Bold')
         .text('FROM:', 60, yPosition + 10);
      
      doc.fontSize(11)
         .font('Helvetica-Bold')
         .text(companyInfo.name || 'Independent Business Group', 60, yPosition + 30, { width: columnWidth - 20 });
      
      doc.fontSize(9)
         .font('Helvetica')
         .fillColor(mediumGray);
      
      let fromY = yPosition + 50;
      if (companyInfo.abn) {
        doc.text(`ABN: ${companyInfo.abn}`, 60, fromY);
        fromY += 15;
      }
      if (companyInfo.address) {
        doc.text(companyInfo.address, 60, fromY, { width: columnWidth - 20 });
        fromY += 15;
      }
      if (companyInfo.phone) {
        doc.text(`Phone: ${companyInfo.phone}`, 60, fromY);
        fromY += 15;
      }
      if (companyInfo.email) {
        doc.text(`Email: ${companyInfo.email}`, 60, fromY);
      }
 
      // BILL TO box
      const billToX = 50 + columnWidth + 20;
      doc.rect(billToX, yPosition, columnWidth, 140)
         .stroke(borderColor);
      
      doc.fontSize(12)
         .fillColor(darkGray)
         .font('Helvetica-Bold')
         .text('BILL TO:', billToX + 10, yPosition + 10);
      
      if (customer) {
        doc.fontSize(11)
           .font('Helvetica-Bold')
           .text(customer.name, billToX + 10, yPosition + 30, { width: columnWidth - 20 });
        
        doc.fontSize(9)
           .font('Helvetica')
           .fillColor(mediumGray);
        
        let billToY = yPosition + 50;
        if (customer.abn) {
          doc.text(`ABN: ${customer.abn}`, billToX + 10, billToY);
          billToY += 15;
        }
        if (customer.billing_address) {
          doc.text(customer.billing_address, billToX + 10, billToY, { width: columnWidth - 20 });
          billToY += 15;
        }
        if (customer.email) {
          doc.text(`Email: ${customer.email}`, billToX + 10, billToY);
          billToY += 15;
        }
        if (customer.phone) {
          doc.text(`Phone: ${customer.phone}`, billToX + 10, billToY);
        }
      } else {
        doc.fontSize(9)
           .fillColor(mediumGray)
           .text(`Customer ID: ${invoice.customer_id}`, billToX + 10, yPosition + 50);
      }
 
      yPosition += 170;
 
      // ===== INVOICE DETAILS BAR =====
      doc.rect(50, yPosition, contentWidth, 60)
         .fillAndStroke('#f5f5f5', borderColor);
      
      const detailsColumnWidth = contentWidth / 3;
      
      // Invoice Date
      doc.fontSize(8)
         .fillColor(lightGray)
         .font('Helvetica')
         .text('INVOICE DATE:', 60, yPosition + 12);
      doc.fontSize(10)
         .fillColor(darkGray)
         .font('Helvetica-Bold')
         .text(formatDate(invoice.issued_date), 60, yPosition + 26);
      
      // Due Date
      doc.fontSize(8)
         .fillColor(lightGray)
         .font('Helvetica')
         .text('DUE DATE:', 60 + detailsColumnWidth, yPosition + 12);
      doc.fontSize(10)
         .fillColor(darkGray)
         .font('Helvetica-Bold')
         .text(formatDate(invoice.due_date), 60 + detailsColumnWidth, yPosition + 26);
      
      // Payment Status
      doc.fontSize(8)
         .fillColor(lightGray)
         .font('Helvetica')
         .text('PAYMENT STATUS:', 60 + detailsColumnWidth * 2, yPosition + 12);
      doc.fontSize(10)
         .fillColor(invoice.payment_status === 'paid' ? '#155724' : '#856404')
         .font('Helvetica-Bold')
         .text((invoice.payment_status || 'unpaid').toUpperCase(), 60 + detailsColumnWidth * 2, yPosition + 26);
      
      yPosition += 80;
 
      // ===== LINE ITEMS TABLE =====
      if (invoice.description) {
        doc.fontSize(10)
           .fillColor(mediumGray)
           .font('Helvetica-Oblique')
           .text(`Description: ${invoice.description}`, 50, yPosition, { width: contentWidth });
        yPosition += 30;
      }
 
      // Table header
      const tableTop = yPosition;
      
      // Column positions - properly spaced to avoid overlap
      const colDescription = 50;
      const colQty = 280;
      const colPrice = 325;
      const colSubtotal = 390;
      const colGST = 455;
      const colTotal = 505;
 
      doc.rect(50, tableTop, contentWidth, 30)
         .fillAndStroke(darkGray, darkGray);
      
      doc.fontSize(9)
         .fillColor('white')
         .font('Helvetica-Bold')
         .text('DESCRIPTION', colDescription + 5, tableTop + 10, { width: 215 })
         .text('QTY', colQty, tableTop + 10, { width: 35, align: 'center' })
         .text('PRICE', colPrice, tableTop + 10, { width: 60, align: 'right' })
         .text('SUBTOTAL', colSubtotal, tableTop + 10, { width: 60, align: 'right' })
         .text('GST', colGST, tableTop + 10, { width: 45, align: 'right' })
         .text('TOTAL', colTotal, tableTop + 10, { width: 40, align: 'right' });
      
      yPosition = tableTop + 35;
 
      // Table rows
      items.forEach((item, index) => {
        const rowHeight = 25; 
        const bgColor = index % 2 === 0 ? '#ffffff' : '#f9f9f9';
        
        doc.rect(50, yPosition, contentWidth, rowHeight)
           .fill(bgColor);
        
        const subtotal = parseFloat(item.total || (item.quantity * item.unit_price) || 0);
        const gstAmount = subtotal * 0.10;
        const lineTotal = subtotal + gstAmount;
        
        doc.fontSize(9)
           .fillColor(darkGray)
           .font('Helvetica')
           .text(item.description || '', colDescription + 5, yPosition + 8, { width: 215, ellipsis: true })
           .text(item.quantity.toString(), colQty, yPosition + 8, { width: 35, align: 'center' })
           .text(`$${parseFloat(item.unit_price).toFixed(2)}`, colPrice, yPosition + 8, { width: 60, align: 'right' })
           .text(`$${subtotal.toFixed(2)}`, colSubtotal, yPosition + 8, { width: 60, align: 'right' })
           .text(`$${gstAmount.toFixed(2)}`, colGST, yPosition + 8, { width: 45, align: 'right' })
           .text(`$${lineTotal.toFixed(2)}`, colTotal, yPosition + 8, { width: 40, align: 'right' });
        
        yPosition += rowHeight;
        
        // Check if we need a new page - only if we have more than 250px of content remaining
        if (yPosition > pageHeight - 250) {
          doc.addPage();
          yPosition = 50;
        }
      });
 
      // Table bottom border
      doc.moveTo(50, yPosition)
         .lineTo(pageWidth - 50, yPosition)
         .strokeColor(borderColor)
         .stroke();
      
      yPosition += 30;
 
      // ===== TOTALS SECTION =====
      const totalsX = pageWidth - 230;
      const totalsWidth = 180;
 
      // Subtotal
      doc.rect(totalsX, yPosition, totalsWidth, 25)
         .fillAndStroke('#f9f9f9', borderColor);
      doc.fontSize(10)
         .fillColor(darkGray)
         .font('Helvetica-Bold')
         .text('Subtotal (ex GST):', totalsX + 10, yPosition + 8)
         .text(formatCurrency(invoice.subtotal, invoice.currency), totalsX + 10, yPosition + 8, { width: totalsWidth - 20, align: 'right' });
      
      yPosition += 25;
 
      // GST
      doc.rect(totalsX, yPosition, totalsWidth, 25)
         .fillAndStroke('#f9f9f9', borderColor);
      doc.text(`GST (${parseFloat(invoice.tax_rate || 10).toFixed(0)}%):`, totalsX + 10, yPosition + 8)
         .text(formatCurrency(invoice.tax_amount, invoice.currency), totalsX + 10, yPosition + 8, { width: totalsWidth - 20, align: 'right' });
      
      yPosition += 25;
 
      // Total
      doc.rect(totalsX, yPosition, totalsWidth, 35)
         .fillAndStroke(darkGray, darkGray);
      doc.fontSize(12)
         .fillColor('white')
         .font('Helvetica-Bold')
         .text('TOTAL (inc GST):', totalsX + 10, yPosition + 11)
         .text(formatCurrency(invoice.total, invoice.currency), totalsX + 10, yPosition + 11, { width: totalsWidth - 20, align: 'right' });
      
      yPosition += 60;
 
      // ===== PAYMENT INFORMATION =====
      if (invoice.payment_status === 'paid' && invoice.payment_date) {
        doc.rect(50, yPosition, contentWidth, 60)
           .fillAndStroke('#d4edda', '#28a745');
        
        doc.fontSize(11)
           .fillColor('#155724')
           .font('Helvetica-Bold')
           .text('PAYMENT RECEIVED', 60, yPosition + 10);
        
        doc.fontSize(9)
           .font('Helvetica')
           .text(`Paid on: ${formatDate(invoice.payment_date)}`, 60, yPosition + 28);
        
        if (invoice.payment_method) {
          doc.text(`Method: ${invoice.payment_method}`, 60, yPosition + 42);
        }
        
        yPosition += 80;
      }
 
      // ===== FOOTER / TERMS =====
      if (yPosition > pageHeight - 150) {
        doc.addPage();
        yPosition = 50;
      }
 
      doc.fontSize(8)
         .fillColor(lightGray)
         .font('Helvetica-Oblique')
         .text('Terms & Conditions: Payment is due within 30 days. Please include invoice number with payment.', 50, yPosition, {
           width: contentWidth,
           align: 'center'
         });
      
      yPosition += 30;
 
      // Page numbers
      const pageCount = doc.bufferedPageRange().count;
      for (let i = 0; i < pageCount; i++) {
        doc.switchToPage(i);
        doc.fontSize(8)
           .fillColor(lightGray)
           .text(
             `Page ${i + 1} of ${pageCount}`,
             50,
             doc.page.height - 50,
             { align: 'center', width: doc.page.width - 100 }
           );
      }
 
      // Finalize PDF
      doc.end();
 
      stream.on('finish', () => {
        console.log(`[PDF Generator] Generated invoice PDF: ${filename}`);
        resolve(filepath);
      });
 
      stream.on('error', (err) => {
        console.error('[PDF Generator] Error writing PDF:', err);
        reject(err);
      });
 
    } catch (error) {
      console.error('[PDF Generator] Error generating PDF:', error);
      reject(error);
    }
  });
}
 
/**
 * Delete old invoice PDFs (cleanup)
 * @param {number} invoiceId - Invoice ID to clean up PDFs for
 */
async function deleteInvoicePDFs(invoiceId) {
  const pattern = `invoice-${invoiceId}-`;
  const files = fs.readdirSync(PDFS_DIR);
  
  files.forEach(file => {
    if (file.startsWith(pattern)) {
      const filepath = path.join(PDFS_DIR, file);
      fs.unlinkSync(filepath);
      console.log(`[PDF Generator] Deleted old PDF: ${file}`);
    }
  });
}
 
module.exports = {
  generateInvoicePDF,
  deleteInvoicePDFs,
  PDFS_DIR
};