// server/api/members/overdue-count.get.ts

export default defineEventHandler(async (event) => {
  try {
    const { getMembers } = await import('~/server/utils/nocodb');
    const { calculateDuesStatus } = await import('~/server/utils/dues-calculator');

    // Get all members
    const allMembers = await getMembers();
    
    if (!allMembers?.list) {
      return {
        success: true,
        data: { 
          count: 0,
          overdueMembers: [],
          dataSource: 'unavailable'
        }
      };
    }

    const today = new Date();
    const overdueMembers: any[] = [];

    for (const member of allMembers.list) {
      // Use dues-calculator for proper dues status calculation
      const duesStatus = await calculateDuesStatus(member);
      
      // Only include members who are overdue
      if (duesStatus.isOverdue && duesStatus.daysOverdue !== null) {
        // Format overdue duration
        const totalMonths = Math.floor(duesStatus.daysOverdue / 30.44);
        const years = Math.floor(totalMonths / 12);
        const months = totalMonths % 12;
        
        let formattedDuration = '';
        if (years > 0) {
          formattedDuration = `${years} year${years !== 1 ? 's' : ''}`;
          if (months > 0) {
            formattedDuration += ` ${months} month${months !== 1 ? 's' : ''}`;
          }
        } else if (totalMonths > 0) {
          formattedDuration = `${totalMonths} month${totalMonths !== 1 ? 's' : ''}`;
        } else {
          const days = duesStatus.daysOverdue;
          formattedDuration = `${days} day${days !== 1 ? 's' : ''}`;
        }
        formattedDuration += ' overdue';
        
        overdueMembers.push({
          id: member.Id,
          name: member.FullName || `${member.first_name} ${member.last_name}`,
          email: member.email,
          status: member.membership_status,
          overdueDuration: formattedDuration,
          daysOverdue: duesStatus.daysOverdue,
          totalMonthsOverdue: totalMonths,
          dueDate: duesStatus.dueDate,
          amount: duesStatus.amount,
          currency: duesStatus.currency,
          dataSource: duesStatus.source,
          confidence: duesStatus.confidence,
          isInactive: member.membership_status === 'Inactive'
        });
      }
    }

    // Sort by most overdue first (by days)
    overdueMembers.sort((a, b) => b.daysOverdue - a.daysOverdue);
    
    // Log data quality metrics
    const highConfidenceCount = overdueMembers.filter(m => m.confidence === 'high').length;
    const mediumConfidenceCount = overdueMembers.filter(m => m.confidence === 'medium').length;
    const lowConfidenceCount = overdueMembers.filter(m => m.confidence === 'low').length;
    
    console.log(`[overdue-count] Found ${overdueMembers.length} overdue members:`, {
      highConfidence: highConfidenceCount,
      mediumConfidence: mediumConfidenceCount,
      lowConfidence: lowConfidenceCount
    });
    
    // Alert if many low confidence results
    if (lowConfidenceCount > overdueMembers.length * 0.3) {
      console.warn(`[overdue-count] High percentage of low confidence dues data (${lowConfidenceCount}/${overdueMembers.length}). Data quality review recommended.`);
    }

    return {
      success: true,
      data: { 
        count: overdueMembers.length,
        overdueMembers: overdueMembers,
        dataQuality: {
          highConfidence: highConfidenceCount,
          mediumConfidence: mediumConfidenceCount,
          lowConfidence: lowConfidenceCount
        }
      }
    };

  } catch (error: any) {
    console.error('[API] Error fetching overdue count:', error);
    
    throw createError({
      statusCode: error.statusCode || 500,
      statusMessage: error.message || 'Failed to fetch overdue count'
    });
  }
});