import { NextRequest, NextResponse } from 'next/server';
import { nocodbClient } from '@/api/nocodbClient';
import type { OrderFilters } from '@/api/nocodbClient';
import * as XLSX from 'xlsx';
import Papa from 'papaparse';

/**
 * GET /api/admin/orders/export
 * Export orders to CSV or Excel
 * Query params:
 *   - format: 'csv' | 'xlsx' (default: csv)
 *   - status: Filter by status
 *   - dateFrom, dateTo: Date range filter
 */
export async function GET(request: NextRequest) {
  try {
    const searchParams = request.nextUrl.searchParams;
    const format = searchParams.get('format') || 'csv';

    // Build filters (same as orders list)
    const filters: OrderFilters = {};
    if (searchParams.get('status')) filters.status = searchParams.get('status')!;
    if (searchParams.get('dateFrom')) filters.dateFrom = searchParams.get('dateFrom')!;
    if (searchParams.get('dateTo')) filters.dateTo = searchParams.get('dateTo')!;

    // Get all matching orders (no pagination for export)
    const response = await nocodbClient.getOrders(filters, { limit: 10000 });
    const orders = response.list;

    // Transform data for export
    const exportData = orders.map((order) => ({
      'Order ID': order.orderId,
      'Status': order.status,
      'Created Date': order.CreatedAt ? new Date(order.CreatedAt).toLocaleDateString() : '',
      'Vessel Name': order.vesselName,
      'IMO Number': order.imoNumber || '',
      'Distance (NM)': order.distance || '',
      'Avg Speed (kn)': order.avgSpeed || '',
      'CO2 Tons': order.co2Tons || '',
      'Total Amount': order.totalAmount || '',
      'Currency': order.currency || '',
      'Customer Name': order.customerName || '',
      'Customer Email': order.customerEmail || '',
      'Customer Company': order.customerCompany || '',
      'Departure Port': order.departurePort || '',
      'Arrival Port': order.arrivalPort || '',
      'Payment Method': order.paymentMethod || '',
      'Payment Reference': order.paymentReference || '',
      'Wren Order ID': order.wrenOrderId || '',
      'Certificate URL': order.certificateUrl || '',
      'Fulfilled At': order.fulfilledAt ? new Date(order.fulfilledAt).toLocaleDateString() : '',
      'Notes': order.notes || '',
    }));

    if (format === 'xlsx') {
      // Generate Excel file
      const worksheet = XLSX.utils.json_to_sheet(exportData);
      const workbook = XLSX.utils.book_new();
      XLSX.utils.book_append_sheet(workbook, worksheet, 'Orders');

      // Style headers (make them bold)
      const range = XLSX.utils.decode_range(worksheet['!ref'] || 'A1');
      for (let col = range.s.c; col <= range.e.c; col++) {
        const cellAddress = XLSX.utils.encode_cell({ r: 0, c: col });
        if (!worksheet[cellAddress]) continue;
        worksheet[cellAddress].s = {
          font: { bold: true },
          fill: { fgColor: { rgb: 'D3D3D3' } },
        };
      }

      // Set column widths
      worksheet['!cols'] = [
        { wch: 20 }, // Order ID
        { wch: 12 }, // Status
        { wch: 15 }, // Created Date
        { wch: 25 }, // Vessel Name
        { wch: 12 }, // IMO Number
        { wch: 12 }, // Distance
        { wch: 12 }, // Avg Speed
        { wch: 10 }, // CO2 Tons
        { wch: 12 }, // Total Amount
        { wch: 10 }, // Currency
        { wch: 20 }, // Customer Name
        { wch: 25 }, // Customer Email
        { wch: 25 }, // Customer Company
        { wch: 20 }, // Departure Port
        { wch: 20 }, // Arrival Port
        { wch: 15 }, // Payment Method
        { wch: 20 }, // Payment Reference
        { wch: 20 }, // Wren Order ID
        { wch: 30 }, // Certificate URL
        { wch: 15 }, // Fulfilled At
        { wch: 40 }, // Notes
      ];

      // Generate buffer
      const buffer = XLSX.write(workbook, { type: 'buffer', bookType: 'xlsx' });

      // Return Excel file
      return new NextResponse(buffer, {
        status: 200,
        headers: {
          'Content-Type': 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
          'Content-Disposition': `attachment; filename="puffin-orders-${Date.now()}.xlsx"`,
        },
      });
    } else {
      // Generate CSV
      const csv = Papa.unparse(exportData);

      // Return CSV file
      return new NextResponse(csv, {
        status: 200,
        headers: {
          'Content-Type': 'text/csv',
          'Content-Disposition': `attachment; filename="puffin-orders-${Date.now()}.csv"`,
        },
      });
    }
  } catch (error) {
    console.error('Error exporting orders:', error);
    return NextResponse.json(
      {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to export orders',
      },
      { status: 500 }
    );
  }
}