import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:lucide_icons/lucide_icons.dart';
import 'package:intl/intl.dart';
import '../../../transactions/providers/providers.dart';
import '../../../transactions/data/models.dart';
import '../../../../core/theme/nature_colors.dart';

class UpcomingDuesWidget extends ConsumerWidget {
  const UpcomingDuesWidget({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final walletsState = ref.watch(walletProvider);
    
    if (!walletsState.hasValue || walletsState.value == null) {
      return const SizedBox.shrink();
    }
    
    final wallets = walletsState.value!;
    
    // Filter for payables that have a due date/amount
    final payables = wallets.where((w) => w.nature == 'PAYABLES').toList();
    
    if (payables.isEmpty) {
      return const SizedBox.shrink();
    }
    
    final now = DateTime.now();
    
    // Calculate dues
    final List<Map<String, dynamic>> dues = [];
    
    for (var w in payables) {
      double dueAmount = 0;
      DateTime? dueDate;
      String dueLabel = 'Upcoming Due';
      
      if (w.subNature == 'CREDIT_CARD' || w.subNature == 'OD_LIMIT') {
        // Balance is negative if we owe money
        if (w.balance < 0) {
          dueAmount = w.balance.abs();
        }
      } else if (w.subNature == 'LOAN_EMI' || w.subNature == 'POLICY_PREMIUM') {
        dueAmount = w.fixedAmount ?? 0;
      }
      
      if (dueAmount > 0 && w.cycleDate != null) {
        int year = now.year;
        int month = now.month;
        
        // Find next due date based on cycle
        if (w.paymentCycle == 'MONTHLY' || w.paymentCycle == null) {
          if (now.day > w.cycleDate!) {
            // Due date has passed for this month, next is next month
            month++;
            if (month > 12) {
              month = 1;
              year++;
            }
          }
        } else if (w.paymentCycle == 'YEARLY') {
          // Assume cycleDate is day of current month, this is simplistic
          if (now.day > w.cycleDate!) {
             year++;
          }
        }
        
        // Handle end of month issues (e.g. Feb 30th)
        int maxDays = DateTime(year, month + 1, 0).day;
        int day = w.cycleDate! > maxDays ? maxDays : w.cycleDate!;
        
        dueDate = DateTime(year, month, day);
        
        int daysLeft = dueDate.difference(DateTime(now.year, now.month, now.day)).inDays;
        
        if (daysLeft == 0) {
          dueLabel = 'Due Today';
        } else if (daysLeft == 1) {
          dueLabel = 'Due Tomorrow';
        } else {
          dueLabel = 'Due in $daysLeft days';
        }
        
        dues.add({
          'wallet': w,
          'amount': dueAmount,
          'dueDate': dueDate,
          'label': dueLabel,
          'daysLeft': daysLeft,
        });
      }
    }
    
    if (dues.isEmpty) {
      return const SizedBox.shrink();
    }
    
    // Sort by nearest due date
    dues.sort((a, b) => (a['daysLeft'] as int).compareTo(b['daysLeft'] as int));
    
    // Only show top 3 dues
    final displayDues = dues.take(3).toList();
    
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Row(
          children: [
            const Icon(LucideIcons.calendarClock, color: Color(0xFF6C63FF), size: 20),
            const SizedBox(width: 8),
            Text('Upcoming Dues', style: Theme.of(context).textTheme.bodyLarge?.copyWith(fontWeight: FontWeight.bold)),
          ],
        ),
        const SizedBox(height: 12),
        ...displayDues.map((due) {
          final w = due['wallet'] as Wallet;
          final amount = due['amount'] as double;
          final dueDate = due['dueDate'] as DateTime;
          final label = due['label'] as String;
          final daysLeft = due['daysLeft'] as int;
          
          final isUrgent = daysLeft <= 3;
          
          return Container(
            margin: const EdgeInsets.only(bottom: 12),
            padding: const EdgeInsets.all(16),
            decoration: BoxDecoration(
              color: isUrgent ? Colors.red.shade50 : Colors.white,
              borderRadius: BorderRadius.circular(16),
              border: Border.all(color: isUrgent ? Colors.red.shade200 : Colors.grey.shade200),
              boxShadow: [
                if (!isUrgent) BoxShadow(color: Colors.black.withOpacity(0.02), blurRadius: 8, offset: const Offset(0, 2))
              ],
            ),
            child: Row(
              children: [
                Container(
                  padding: const EdgeInsets.all(10),
                  decoration: BoxDecoration(
                    color: (isUrgent ? Colors.red : NatureColors.getColor('PAYABLES')).withOpacity(0.1),
                    shape: BoxShape.circle,
                  ),
                  child: Icon(
                    w.subNature == 'CREDIT_CARD' ? LucideIcons.creditCard : 
                    (w.subNature == 'LOAN_EMI' ? LucideIcons.home : LucideIcons.fileText),
                    color: isUrgent ? Colors.red : NatureColors.getColor('PAYABLES'),
                    size: 20,
                  ),
                ),
                const SizedBox(width: 16),
                Expanded(
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Text(w.name, style: const TextStyle(fontWeight: FontWeight.bold, fontSize: 15)),
                      const SizedBox(height: 4),
                      Text(
                        '$label • ${DateFormat('MMM dd').format(dueDate)}',
                        style: TextStyle(
                          color: isUrgent ? Colors.red.shade700 : Colors.grey.shade600, 
                          fontSize: 12,
                          fontWeight: isUrgent ? FontWeight.bold : FontWeight.normal
                        ),
                      ),
                    ],
                  ),
                ),
                Text(
                  'Rs. ${amount.toStringAsFixed(0)}',
                  style: TextStyle(
                    fontWeight: FontWeight.bold, 
                    fontSize: 16,
                    color: isUrgent ? Colors.red.shade700 : Colors.black87
                  ),
                ),
              ],
            ),
          );
        }),
        const SizedBox(height: 12),
      ],
    );
  }
}