import { requireAuth } from '@/server/utils/auth';
import { getExpenseById } from '@/server/utils/nocodb';
import { processExpenseWithCurrency } from '@/server/utils/currency';

interface PDFOptions {
  documentName: string;
  subheader?: string;
  groupBy: 'none' | 'payer' | 'category' | 'date';
  includeReceipts: boolean;
  includeSummary: boolean;
  includeDetails: boolean;
  pageFormat: 'A4' | 'Letter' | 'Legal';
  includeProcessingFee?: boolean;
}

interface Expense {
  Id: number;
  'Establishment Name': string;
  Price: string;
  PriceNumber: number;
  DisplayPrice: string;
  PriceUSD?: number;
  ConversionRate?: number;
  Payer: string;
  Category: string;
  'Payment Method': string;
  Time: string;
  Contents?: string;
  Receipt?: any[];
}

export default defineEventHandler(async (event) => {
  await requireAuth(event);
  
  const body = await readBody(event);
  const { expenseIds, options } = body;
  
  if (!expenseIds || !Array.isArray(expenseIds) || expenseIds.length === 0) {
    throw createError({
      statusCode: 400,
      statusMessage: 'Expense IDs are required'
    });
  }
  
  if (!options || !options.documentName) {
    throw createError({
      statusCode: 400,
      statusMessage: 'PDF options with document name are required'
    });
  }
  
  console.log('[expenses/generate-pdf] PDF generation requested for expenses:', expenseIds);
  
  try {
    // Fetch expense data
    const expenses: Expense[] = [];
    for (const expenseId of expenseIds) {
      const expense = await getExpenseById(expenseId);
      if (expense) {
        const processedExpense = await processExpenseWithCurrency(expense);
        expenses.push(processedExpense);
      }
    }
    
    if (expenses.length === 0) {
      throw createError({
        statusCode: 404,
        statusMessage: 'No valid expenses found'
      });
    }
    
    // Calculate totals to show the preview is working correctly
    const totals = calculateTotals(expenses, options.includeProcessingFee);
    
    console.log('[expenses/generate-pdf] Successfully calculated totals:', totals);
    console.log('[expenses/generate-pdf] Options received:', options);
    
    // For now, return a helpful error with the calculated information
    throw createError({
      statusCode: 501,
      statusMessage: 'PDF generation is being upgraded',
      message: `PDF generation is being upgraded! ✅ Your selection is ready:
      
📊 Summary:
• ${totals.count} expenses selected
• Total: €${totals.originalTotal.toFixed(2)}
• USD equivalent: $${totals.usdTotal.toFixed(2)}
${options.includeProcessingFee ? `• With 5% fee: €${totals.finalTotal.toFixed(2)}` : ''}

📋 Document: "${options.documentName}"
${options.subheader ? `📝 Subtitle: "${options.subheader}"` : ''}
🔗 Grouping: ${getGroupingLabel(options.groupBy)}

💡 Use CSV export for now, or contact support for manual PDF generation with these exact settings.`
    });
    
  } catch (error: any) {
    // If it's our intentional error, re-throw it
    if (error.statusCode === 501) {
      throw error;
    }
    
    console.error('[expenses/generate-pdf] Error generating PDF:', error);
    throw createError({
      statusCode: 500,
      statusMessage: error.message || 'Failed to generate PDF'
    });
  }
});

function calculateTotals(expenses: Expense[], includeProcessingFee: boolean) {
  const originalTotal = expenses.reduce((sum, exp) => sum + (exp.PriceNumber || 0), 0);
  const usdTotal = expenses.reduce((sum, exp) => sum + (exp.PriceUSD || exp.PriceNumber || 0), 0);
  
  const processingFee = includeProcessingFee ? originalTotal * 0.05 : 0;
  const finalTotal = originalTotal + processingFee;
  
  return {
    originalTotal,
    usdTotal,
    processingFee,
    finalTotal,
    count: expenses.length
  };
}

function getGroupingLabel(groupBy: string): string {
  switch (groupBy) {
    case 'payer': return 'By Person';
    case 'category': return 'By Category';
    case 'date': return 'By Date';
    default: return 'No Grouping';
  }
}