/**
 * PDF Generation Utility
 * In a production environment, this would use libraries like jsPDF, PDFKit, or React-PDF
 * For now, we provide a simple text-based PDF generation placeholder
 */

import type { Document, Product } from "@shared/schema";

export interface PDFGenerationOptions {
  format?: 'A4' | 'Letter';
  orientation?: 'portrait' | 'landscape';
  margins?: {
    top: number;
    right: number;
    bottom: number;
    left: number;
  };
}

export class PDFGenerator {
  private static formatDate(date: Date | string | null): string {
    if (!date) return 'Unknown';
    const d = typeof date === 'string' ? new Date(date) : date;
    return d.toLocaleDateString('en-US', {
      year: 'numeric',
      month: 'long',
      day: 'numeric',
    });
  }

  private static formatTime(date: Date | string | null): string {
    if (!date) return 'Unknown';
    const d = typeof date === 'string' ? new Date(date) : date;
    return d.toLocaleTimeString('en-US', {
      hour: '2-digit',
      minute: '2-digit',
    });
  }

  static generateDeliveryNote(document: Document, options?: PDFGenerationOptions): string {
    const content = document.content as any;
    const createdDate = this.formatDate(document.createdAt);
    const createdTime = this.formatTime(document.createdAt);

    return `
==============================================
           WAREHOUSE TRACK PRO
==============================================

DELIVERY NOTE: ${document.documentNumber}
Date: ${createdDate} ${createdTime}
Status: ${document.status.toUpperCase()}

----------------------------------------------
CUSTOMER INFORMATION
----------------------------------------------
Name: ${content.customerName || 'N/A'}
Address: ${content.customerAddress || 'N/A'}

----------------------------------------------
ITEMS
----------------------------------------------
${content.items?.map((item: any, index: number) => `
${index + 1}. ${item.productName} (${item.productSku})
   Quantity: ${item.quantity} ${item.unit}
   ${item.notes ? `Notes: ${item.notes}` : ''}
`).join('') || 'No items listed'}

----------------------------------------------
SUMMARY
----------------------------------------------
Total Items: ${content.totalItems || 0}
Created: ${createdDate} at ${createdTime}

----------------------------------------------
SIGNATURES
----------------------------------------------
Driver: _________________________ Date: _______

Customer: _______________________ Date: _______

==============================================
    Generated by WarehouseTrack Pro
==============================================
    `;
  }

  static generatePackingList(document: Document, options?: PDFGenerationOptions): string {
    const content = document.content as any;
    const createdDate = this.formatDate(document.createdAt);
    const createdTime = this.formatTime(document.createdAt);

    return `
==============================================
           WAREHOUSE TRACK PRO
==============================================

PACKING LIST: ${document.documentNumber}
Date: ${createdDate} ${createdTime}
Status: ${document.status.toUpperCase()}

----------------------------------------------
CUSTOMER INFORMATION
----------------------------------------------
Name: ${content.customerName || 'N/A'}
Address: ${content.customerAddress || 'N/A'}

----------------------------------------------
PACKING DETAILS
----------------------------------------------
${content.items?.map((item: any, index: number) => `
Item ${index + 1}:
  Product: ${item.productName}
  SKU: ${item.productSku}
  Quantity: ${item.quantity} ${item.unit}
  ${item.notes ? `Special Instructions: ${item.notes}` : ''}
  
  Packed: [ ] Checked: [ ] Initial: _____
`).join('') || 'No items to pack'}

----------------------------------------------
PACKING SUMMARY
----------------------------------------------
Total Items: ${content.totalItems || 0}
Total Packages: _______________
Total Weight: _________________

----------------------------------------------
QUALITY CONTROL
----------------------------------------------
Packed By: ________________________ Date: _______
Checked By: _______________________ Date: _______
Approved By: ______________________ Date: _______

==============================================
    Generated by WarehouseTrack Pro
==============================================
    `;
  }

  static generateShippingLabel(document: Document, options?: PDFGenerationOptions): string {
    const content = document.content as any;
    const createdDate = this.formatDate(document.createdAt);

    return `
==============================================
           SHIPPING LABEL
==============================================

Tracking Number: ${document.documentNumber}
Date: ${createdDate}

----------------------------------------------
FROM:
WarehouseTrack Pro
[Your Warehouse Address]
[City, State ZIP]

----------------------------------------------
TO:
${content.customerName || '[Customer Name]'}
${content.customerAddress || '[Customer Address]'}

----------------------------------------------
PACKAGE DETAILS:
----------------------------------------------
Contents: ${content.totalItems || 0} items
Weight: ________________
Dimensions: ____________

Service Type: [ ] Standard [ ] Express [ ] Overnight

----------------------------------------------
BARCODE AREA
----------------------------------------------
||||| ${document.documentNumber} |||||

==============================================
    Handle with Care
==============================================
    `;
  }

  static generateGoodsReceipt(document: Document, options?: PDFGenerationOptions): string {
    const content = document.content as any;
    const createdDate = this.formatDate(document.createdAt);
    const createdTime = this.formatTime(document.createdAt);

    return `
==============================================
           WAREHOUSE TRACK PRO
==============================================

GOODS RECEIPT: ${document.documentNumber}
Date: ${createdDate} ${createdTime}
Status: ${document.status.toUpperCase()}

----------------------------------------------
SUPPLIER INFORMATION
----------------------------------------------
Name: ${content.customerName || 'N/A'}
Address: ${content.customerAddress || 'N/A'}

----------------------------------------------
RECEIVED ITEMS
----------------------------------------------
${content.items?.map((item: any, index: number) => `
${index + 1}. ${item.productName} (${item.productSku})
   Expected: ${item.quantity} ${item.unit}
   Received: _______ ${item.unit}
   Condition: [ ] Good [ ] Damaged [ ] Defective
   ${item.notes ? `Notes: ${item.notes}` : ''}
`).join('') || 'No items listed'}

----------------------------------------------
RECEIVING SUMMARY
----------------------------------------------
Total Items Expected: ${content.totalItems || 0}
Total Items Received: ________________
Discrepancies: _______________________

----------------------------------------------
AUTHORIZATION
----------------------------------------------
Received By: ______________________ Date: _______
Signature: ________________________

Checked By: _______________________ Date: _______
Signature: ________________________

==============================================
    Generated by WarehouseTrack Pro
==============================================
    `;
  }

  static generateStockReport(document: Document, products?: Product[], options?: PDFGenerationOptions): string {
    const createdDate = this.formatDate(document.createdAt);
    const createdTime = this.formatTime(document.createdAt);

    const totalValue = products?.reduce((sum, product) => {
      const price = parseFloat(product.price || "0");
      return sum + (price * product.currentStock);
    }, 0) || 0;

    const inStockCount = products?.filter(p => p.currentStock > p.minThreshold).length || 0;
    const lowStockCount = products?.filter(p => p.currentStock > 0 && p.currentStock <= p.minThreshold).length || 0;
    const outOfStockCount = products?.filter(p => p.currentStock === 0).length || 0;

    return `
==============================================
           WAREHOUSE TRACK PRO
==============================================

STOCK REPORT: ${document.documentNumber}
Generated: ${createdDate} ${createdTime}
Report Period: Current Inventory Status

----------------------------------------------
INVENTORY SUMMARY
----------------------------------------------
Total Products: ${products?.length || 0}
Total Value: $${totalValue.toFixed(2)}

Stock Status:
  In Stock: ${inStockCount}
  Low Stock: ${lowStockCount}
  Out of Stock: ${outOfStockCount}

----------------------------------------------
DETAILED INVENTORY
----------------------------------------------
${products?.map((product, index) => {
  const status = product.currentStock === 0 ? 'OUT OF STOCK' : 
                product.currentStock <= product.minThreshold ? 'LOW STOCK' : 'IN STOCK';
  const value = (parseFloat(product.price || "0") * product.currentStock).toFixed(2);
  
  return `
${index + 1}. ${product.name}
   SKU: ${product.sku}
   Current Stock: ${product.currentStock} ${product.unit}
   Min Threshold: ${product.minThreshold} ${product.unit}
   Unit Price: $${product.price || '0.00'}
   Total Value: $${value}
   Status: ${status}
`;
}).join('') || 'No products in inventory'}

----------------------------------------------
LOW STOCK ALERTS
----------------------------------------------
${products?.filter(p => p.currentStock > 0 && p.currentStock <= p.minThreshold).map(product => `
⚠️  ${product.name} (${product.sku})
    Current: ${product.currentStock} ${product.unit}
    Minimum: ${product.minThreshold} ${product.unit}
`).join('') || 'No low stock items'}

----------------------------------------------
OUT OF STOCK ITEMS
----------------------------------------------
${products?.filter(p => p.currentStock === 0).map(product => `
❌ ${product.name} (${product.sku})
   Minimum Required: ${product.minThreshold} ${product.unit}
`).join('') || 'No out of stock items'}

==============================================
    Generated by WarehouseTrack Pro
==============================================
    `;
  }

  static generateDispatchNote(document: Document, options?: PDFGenerationOptions): string {
    const content = document.content as any;
    const createdDate = this.formatDate(document.createdAt);
    const createdTime = this.formatTime(document.createdAt);

    return `
==============================================
           WAREHOUSE TRACK PRO
==============================================

DISPATCH NOTE: ${document.documentNumber}
Date: ${createdDate} ${createdTime}
Status: ${document.status.toUpperCase()}

----------------------------------------------
DISPATCH INFORMATION
----------------------------------------------
Customer: ${content.customerName || 'N/A'}
Delivery Address: ${content.customerAddress || 'N/A'}

----------------------------------------------
DISPATCHED ITEMS
----------------------------------------------
${content.items?.map((item: any, index: number) => `
${index + 1}. ${item.productName} (${item.productSku})
   Quantity Dispatched: ${item.quantity} ${item.unit}
   ${item.notes ? `Instructions: ${item.notes}` : ''}
   Condition: [ ] Good [ ] Fragile [ ] Hazardous
`).join('') || 'No items dispatched'}

----------------------------------------------
DISPATCH SUMMARY
----------------------------------------------
Total Items: ${content.totalItems || 0}
Dispatch Time: ${createdTime}
Expected Delivery: ____________________

----------------------------------------------
TRANSPORTATION DETAILS
----------------------------------------------
Vehicle: _____________________________
Driver: ______________________________
Contact: _____________________________

----------------------------------------------
AUTHORIZATION
----------------------------------------------
Dispatched By: ____________________ Date: _______
Signature: ________________________

Authorized By: ____________________ Date: _______
Signature: ________________________

==============================================
    Generated by WarehouseTrack Pro
==============================================
    `;
  }

  static generateDocument(document: Document, products?: Product[], options?: PDFGenerationOptions): string {
    switch (document.type) {
      case 'delivery_note':
        return this.generateDeliveryNote(document, options);
      case 'packing_list':
        return this.generatePackingList(document, options);
      case 'shipping_label':
        return this.generateShippingLabel(document, options);
      case 'goods_receipt':
        return this.generateGoodsReceipt(document, options);
      case 'stock_report':
        return this.generateStockReport(document, products, options);
      case 'dispatch_note':
        return this.generateDispatchNote(document, options);
      default:
        return `
==============================================
           WAREHOUSE TRACK PRO
==============================================

DOCUMENT: ${document.documentNumber}
Type: ${document.type}
Title: ${document.title}
Date: ${this.formatDate(document.createdAt)}
Status: ${document.status.toUpperCase()}

Content:
${JSON.stringify(document.content, null, 2)}

==============================================
    Generated by WarehouseTrack Pro
==============================================
        `;
    }
  }

  static async downloadPDF(doc: Document, products?: Product[], options?: PDFGenerationOptions): Promise<void> {
    const pdfContent = this.generateDocument(doc, products, options);
    
    const blob = new Blob([pdfContent], { type: 'text/plain' });
    const url = window.URL.createObjectURL(blob);
    const a = window.document.createElement('a');
    a.href = url;
    a.download = `${doc.documentNumber}.pdf`;
    window.document.body.appendChild(a);
    a.click();
    window.URL.revokeObjectURL(url);
    window.document.body.removeChild(a);
  }
}

export default PDFGenerator;