import 'package:flutter/material.dart';
import 'package:get/get.dart';
import 'package:flutter_screenutil/flutter_screenutil.dart';
import 'package:intl/intl.dart';
import '../../core/services/chit_group_service.dart';
import '../../core/services/api_service.dart';
import '../../core/models/monthly_draw.dart';
import '../../core/utils/snackbar_util.dart';

class EditDrawDialog extends StatefulWidget {
  final MonthlyDraw draw;

  const EditDrawDialog({
    super.key,
    required this.draw,
  });

  @override
  State<EditDrawDialog> createState() => _EditDrawDialogState();
}

class _EditDrawDialogState extends State<EditDrawDialog> {
  final _formKey = GlobalKey<FormState>();
  final _prizeAmountController = TextEditingController();
  final _notesController = TextEditingController();
  final _apiService = ApiService();
  
  String? _selectedMemberId;
  bool _isLoading = false;
  late int _editMonth;
  late int _editYear;
  late DateTime _drawDate;

  static const _monthNames = <String>[
    '', 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec',
  ];

  DateTime _baselineDrawDate() {
    final d = widget.draw.drawDate;
    if (d.millisecondsSinceEpoch == 0) {
      return DateTime(widget.draw.year, widget.draw.month, 1);
    }
    return d;
  }

  bool _sameCalendarDay(DateTime a, DateTime b) {
    return a.year == b.year && a.month == b.month && a.day == b.day;
  }

  int _clampEditYear(int y) {
    final minY = 2020;
    final maxY = DateTime.now().year + 1;
    if (y < minY) return minY;
    if (y > maxY) return maxY;
    return y;
  }

  @override
  void initState() {
    super.initState();
    _selectedMemberId = widget.draw.winnerId;
    _prizeAmountController.text = widget.draw.prizeAmount.toStringAsFixed(0);
    _notesController.text = widget.draw.notes ?? '';
    _editMonth = widget.draw.month.clamp(1, 12);
    _editYear = _clampEditYear(widget.draw.year);
    _drawDate = _baselineDrawDate();
  }

  @override
  void dispose() {
    _prizeAmountController.dispose();
    _notesController.dispose();
    super.dispose();
  }

  Future<void> _pickDrawDate() async {
    final picked = await showDatePicker(
      context: context,
      initialDate: _drawDate,
      firstDate: DateTime(2020),
      lastDate: DateTime.now().add(const Duration(days: 365 * 3)),
    );
    if (picked != null) {
      setState(() => _drawDate = picked);
    }
  }

  Future<void> _handleSubmit() async {
    if (_formKey.currentState!.validate()) {
      if (_selectedMemberId == null) {
        SnackbarUtil.showError('Please select a winner');
        return;
      }

      setState(() => _isLoading = true);

      try {
        final updates = <String, dynamic>{};
        
        if (_editMonth != widget.draw.month) {
          updates['month'] = _editMonth;
        }
        if (_editYear != widget.draw.year) {
          updates['year'] = _editYear;
        }
        if (!_sameCalendarDay(_drawDate, _baselineDrawDate())) {
          updates['draw_date'] = _drawDate.toUtc().toIso8601String();
        }

        if (_selectedMemberId != widget.draw.winnerId) {
          updates['winner_id'] = _selectedMemberId;
        }
        
        final newPrizeAmount = double.parse(_prizeAmountController.text);
        if (newPrizeAmount != widget.draw.prizeAmount) {
          updates['prize_amount'] = newPrizeAmount;
        }
        
        if (_notesController.text != (widget.draw.notes ?? '')) {
          updates['notes'] = _notesController.text;
        }

        if (updates.isEmpty) {
          SnackbarUtil.showWarning('No changes made');
          Get.back();
          return;
        }

        final response = await _apiService.updateMonthlyDraw(widget.draw.id, updates);

        if (response['success']) {
          SnackbarUtil.showSuccess(
            'Draw updated successfully',
            title: 'Success',
          );
          Get.back(result: true);
        } else {
          final isAlreadyWon = response['alreadyWon'] ?? false;
          final winnerName = response['winnerName'] ?? '';
          if (isAlreadyWon && winnerName.isNotEmpty) {
            SnackbarUtil.showError(
              '$winnerName has already won in another draw.\nEach member can only win once.',
              title: 'Duplicate winner',
              duration: const Duration(seconds: 4),
            );
          } else {
            SnackbarUtil.showError(
              response['message'] ?? 'Failed to update draw',
              title: 'Error',
            );
          }
        }
      } catch (e) {
        SnackbarUtil.showError('Error: ${e.toString()}');
      } finally {
        setState(() => _isLoading = false);
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    return Dialog(
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(20.r)),
      child: Container(
        width: 500.w,
        constraints: BoxConstraints(
          maxHeight: MediaQuery.of(context).size.height * 0.85,
        ),
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            // Fixed Header
            Container(
              padding: EdgeInsets.all(24.w),
              decoration: BoxDecoration(
                color: Colors.white,
                borderRadius: BorderRadius.only(
                  topLeft: Radius.circular(20.r),
                  topRight: Radius.circular(20.r),
                ),
                border: Border(
                  bottom: BorderSide(color: Colors.grey.shade200),
                ),
              ),
              child: Row(
                children: [
                  Icon(Icons.edit, color: Colors.orange.shade600, size: 28.w),
                  SizedBox(width: 12.w),
                  Expanded(
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        Text(
                          'Edit Draw Result',
                          style: TextStyle(
                            fontSize: 20.sp,
                            fontWeight: FontWeight.bold,
                          ),
                        ),
                        Text(
                          'Originally ${widget.draw.month}/${widget.draw.year}',
                          style: TextStyle(
                            fontSize: 14.sp,
                            color: Colors.grey.shade600,
                          ),
                        ),
                      ],
                    ),
                  ),
                  IconButton(
                    icon: const Icon(Icons.close),
                    onPressed: () => Get.back(),
                  ),
                ],
              ),
            ),

            // Scrollable Content
            Flexible(
              child: SingleChildScrollView(
                padding: EdgeInsets.all(24.w),
                child: Form(
                  key: _formKey,
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      // Warning Message
                      Container(
                        padding: EdgeInsets.all(16.w),
                        decoration: BoxDecoration(
                          color: Colors.orange.shade50,
                          borderRadius: BorderRadius.circular(12.r),
                          border: Border.all(color: Colors.orange.shade200),
                        ),
                        child: Row(
                          children: [
                            Icon(Icons.warning_amber_rounded, 
                              color: Colors.orange.shade700, size: 24.w),
                            SizedBox(width: 12.w),
                            Expanded(
                              child: Text(
                                'Carefully verify changes before saving. This will update the official draw record.',
                                style: TextStyle(
                                  color: Colors.orange.shade900,
                                  fontSize: 14.sp,
                                  fontWeight: FontWeight.w500,
                                ),
                              ),
                            ),
                          ],
                        ),
                      ),
                      SizedBox(height: 24.h),

                      Text(
                        'Draw month & year',
                        style: TextStyle(
                          fontSize: 16.sp,
                          fontWeight: FontWeight.w600,
                        ),
                      ),
                      SizedBox(height: 8.h),
                      Row(
                        children: [
                          Expanded(
                            child: DropdownButtonFormField<int>(
                              value: _editMonth,
                              decoration: InputDecoration(
                                labelText: 'Month',
                                border: OutlineInputBorder(
                                  borderRadius: BorderRadius.circular(12.r),
                                ),
                                filled: true,
                                fillColor: Colors.grey.shade50,
                              ),
                              items: List.generate(12, (i) {
                                final m = i + 1;
                                return DropdownMenuItem(
                                  value: m,
                                  child: Text('${_monthNames[m]} ($m)'),
                                );
                              }),
                              onChanged: (v) {
                                if (v != null) setState(() => _editMonth = v);
                              },
                            ),
                          ),
                          SizedBox(width: 12.w),
                          Expanded(
                            child: DropdownButtonFormField<int>(
                              value: _editYear,
                              decoration: InputDecoration(
                                labelText: 'Year',
                                border: OutlineInputBorder(
                                  borderRadius: BorderRadius.circular(12.r),
                                ),
                                filled: true,
                                fillColor: Colors.grey.shade50,
                              ),
                              items: List.generate(
                                DateTime.now().year - 2019 + 2,
                                (i) {
                                  final y = 2020 + i;
                                  return DropdownMenuItem(
                                    value: y,
                                    child: Text('$y'),
                                  );
                                },
                              ),
                              onChanged: (v) {
                                if (v != null) setState(() => _editYear = v);
                              },
                            ),
                          ),
                        ],
                      ),
                      SizedBox(height: 8.h),
                      Text(
                        'This is the calendar month this draw belongs to. It must not clash with another draw in this group.',
                        style: TextStyle(fontSize: 12.sp, color: Colors.grey.shade600),
                      ),
                      SizedBox(height: 20.h),

                      Text(
                        'Draw date',
                        style: TextStyle(
                          fontSize: 16.sp,
                          fontWeight: FontWeight.w600,
                        ),
                      ),
                      SizedBox(height: 8.h),
                      InkWell(
                        onTap: _pickDrawDate,
                        borderRadius: BorderRadius.circular(12.r),
                        child: InputDecorator(
                          decoration: InputDecoration(
                            prefixIcon: const Icon(Icons.calendar_today_outlined),
                            border: OutlineInputBorder(
                              borderRadius: BorderRadius.circular(12.r),
                            ),
                            filled: true,
                            fillColor: Colors.grey.shade50,
                          ),
                          child: Text(
                            DateFormat('d MMM yyyy').format(_drawDate),
                            style: TextStyle(fontSize: 16.sp),
                          ),
                        ),
                      ),
                      SizedBox(height: 8.h),
                      Text(
                        'When the draw actually happened (shown in history).',
                        style: TextStyle(fontSize: 12.sp, color: Colors.grey.shade600),
                      ),
                      SizedBox(height: 20.h),

                      // Select Winner
                      Text(
                        'Winner',
                        style: TextStyle(
                          fontSize: 16.sp,
                          fontWeight: FontWeight.w600,
                        ),
                      ),
                      SizedBox(height: 12.h),
                      Obx(() {
                        final members = Get.find<ChitGroupService>().groupMembers;
                        
                        if (members.isEmpty) {
                          return Container(
                            padding: EdgeInsets.all(16.w),
                            decoration: BoxDecoration(
                              color: Colors.grey.shade100,
                              borderRadius: BorderRadius.circular(12.r),
                            ),
                            child: Text(
                              'Loading members...',
                              style: TextStyle(
                                color: Colors.grey.shade600,
                                fontSize: 14.sp,
                              ),
                            ),
                          );
                        }

                        return Container(
                          constraints: BoxConstraints(
                            maxHeight: 250.h,
                          ),
                          decoration: BoxDecoration(
                            border: Border.all(color: Colors.grey.shade300),
                            borderRadius: BorderRadius.circular(12.r),
                          ),
                          child: ListView.builder(
                            shrinkWrap: true,
                            itemCount: members.length,
                            itemBuilder: (context, index) {
                              final member = members[index];
                              final isSelected = member.userId == _selectedMemberId;
                              final isCurrentWinner = member.userId == widget.draw.winnerId;
                              final isLast = index == members.length - 1;
                              
                              return InkWell(
                                onTap: () {
                                  setState(() {
                                    _selectedMemberId = member.userId;
                                  });
                                },
                                borderRadius: BorderRadius.vertical(
                                  top: index == 0 ? Radius.circular(12.r) : Radius.zero,
                                  bottom: isLast ? Radius.circular(12.r) : Radius.zero,
                                ),
                                child: Container(
                                  padding: EdgeInsets.symmetric(
                                    horizontal: 12.w,
                                    vertical: 14.h,
                                  ),
                                  decoration: BoxDecoration(
                                    color: isSelected ? Colors.green.shade50 : null,
                                    border: !isLast ? Border(
                                      bottom: BorderSide(color: Colors.grey.shade200),
                                    ) : null,
                                  ),
                                  child: Row(
                                    children: [
                                      Icon(
                                        isSelected ? Icons.radio_button_checked : Icons.radio_button_unchecked,
                                        color: isSelected ? Colors.green.shade600 : Colors.grey.shade400,
                                        size: 24.w,
                                      ),
                                      SizedBox(width: 12.w),
                                      Expanded(
                                        child: Column(
                                          crossAxisAlignment: CrossAxisAlignment.start,
                                          children: [
                                            Row(
                                              children: [
                                                Expanded(
                                                  child: Text(
                                                    member.user?.fullName ?? 'Unknown',
                                                    style: TextStyle(
                                                      fontSize: 16.sp,
                                                      fontWeight: isSelected ? FontWeight.w600 : FontWeight.normal,
                                                    ),
                                                  ),
                                                ),
                                                if (isCurrentWinner) ...[
                                                  Container(
                                                    padding: EdgeInsets.symmetric(
                                                      horizontal: 6.w,
                                                      vertical: 2.h,
                                                    ),
                                                    decoration: BoxDecoration(
                                                      color: Colors.blue.shade100,
                                                      borderRadius: BorderRadius.circular(4.r),
                                                    ),
                                                    child: Text(
                                                      'Current',
                                                      style: TextStyle(
                                                        fontSize: 10.sp,
                                                        color: Colors.blue.shade800,
                                                        fontWeight: FontWeight.w600,
                                                      ),
                                                    ),
                                                  ),
                                                ],
                                              ],
                                            ),
                                            if (member.user?.mobileNumber != null) ...[
                                              SizedBox(height: 2.h),
                                              Text(
                                                member.user!.mobileNumber,
                                                style: TextStyle(
                                                  fontSize: 13.sp,
                                                  color: Colors.grey.shade600,
                                                ),
                                              ),
                                            ],
                                          ],
                                        ),
                                      ),
                                      if (isSelected)
                                        Icon(Icons.check_circle, 
                                          color: Colors.green.shade600, size: 20.w),
                                    ],
                                  ),
                                ),
                              );
                            },
                          ),
                        );
                      }),
                      SizedBox(height: 20.h),

                      // Prize Amount
                      Text(
                        'Prize Amount',
                        style: TextStyle(
                          fontSize: 16.sp,
                          fontWeight: FontWeight.w600,
                        ),
                      ),
                      SizedBox(height: 8.h),
                      TextFormField(
                        controller: _prizeAmountController,
                        keyboardType: TextInputType.number,
                        decoration: InputDecoration(
                          hintText: 'Prize amount',
                          prefixText: '₹ ',
                          prefixIcon: const Icon(Icons.currency_rupee),
                          border: OutlineInputBorder(
                            borderRadius: BorderRadius.circular(12.r),
                          ),
                          filled: true,
                          fillColor: Colors.grey.shade50,
                        ),
                        validator: (value) {
                          if (value?.isEmpty ?? true) return 'Required';
                          if (double.tryParse(value!) == null) return 'Invalid amount';
                          return null;
                        },
                      ),
                      SizedBox(height: 20.h),

                      // Notes (Optional)
                      Text(
                        'Notes (Optional)',
                        style: TextStyle(
                          fontSize: 16.sp,
                          fontWeight: FontWeight.w600,
                        ),
                      ),
                      SizedBox(height: 8.h),
                      TextFormField(
                        controller: _notesController,
                        maxLines: 3,
                        decoration: InputDecoration(
                          hintText: 'Reason for editing (optional)',
                          border: OutlineInputBorder(
                            borderRadius: BorderRadius.circular(12.r),
                          ),
                          filled: true,
                          fillColor: Colors.grey.shade50,
                        ),
                      ),
                    ],
                  ),
                ),
              ),
            ),

            // Fixed Footer with Actions
            Container(
              padding: EdgeInsets.all(24.w),
              decoration: BoxDecoration(
                color: Colors.white,
                borderRadius: BorderRadius.only(
                  bottomLeft: Radius.circular(20.r),
                  bottomRight: Radius.circular(20.r),
                ),
                border: Border(
                  top: BorderSide(color: Colors.grey.shade200),
                ),
              ),
              child: Row(
                children: [
                  Expanded(
                    child: OutlinedButton(
                      onPressed: _isLoading ? null : () => Get.back(),
                      style: OutlinedButton.styleFrom(
                        padding: EdgeInsets.symmetric(vertical: 14.h),
                        shape: RoundedRectangleBorder(
                          borderRadius: BorderRadius.circular(12.r),
                        ),
                      ),
                      child: Text(
                        'Cancel',
                        style: TextStyle(fontSize: 16.sp),
                      ),
                    ),
                  ),
                  SizedBox(width: 16.w),
                  Expanded(
                    child: ElevatedButton(
                      onPressed: _isLoading ? null : _handleSubmit,
                      style: ElevatedButton.styleFrom(
                        backgroundColor: Colors.orange.shade600,
                        foregroundColor: Colors.white,
                        padding: EdgeInsets.symmetric(vertical: 14.h),
                        shape: RoundedRectangleBorder(
                          borderRadius: BorderRadius.circular(12.r),
                        ),
                        elevation: 2,
                      ),
                      child: _isLoading
                          ? SizedBox(
                              height: 20.h,
                              width: 20.w,
                              child: const CircularProgressIndicator(
                                strokeWidth: 2,
                                valueColor: AlwaysStoppedAnimation<Color>(Colors.white),
                              ),
                            )
                          : Text(
                              'Update Draw',
                              style: TextStyle(fontSize: 16.sp, fontWeight: FontWeight.w600),
                            ),
                    ),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }
}