import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

import '../../core/constants/app_colors.dart';
import '../../core/constants/app_text_styles.dart';
import '../../data/services/api_service.dart';
import '../widgets/teacher_panel_scaffold.dart';
import 'course_page.dart';
import 'dashboard_page.dart';
import 'license_page.dart';
import 'ticket_page.dart';
import 'transaction_page.dart';

class NewLicensePage extends StatefulWidget {
  final int courseId;
  final String courseTitle;

  const NewLicensePage({
    super.key,
    required this.courseId,
    required this.courseTitle,
  });

  @override
  State<NewLicensePage> createState() => _NewLicensePageState();
}

class _NewLicensePageState extends State<NewLicensePage> {
  final TextEditingController _studentPhoneController = TextEditingController();
  final TextEditingController _studentNameController = TextEditingController();
  final TextEditingController _studentEmailController = TextEditingController();

  final List<_DeviceLimitForm> _deviceLimits = <_DeviceLimitForm>[
    _DeviceLimitForm(),
  ];

  bool _isSubmitting = false;
  String? _errorMessage;

  @override
  void dispose() {
    _studentPhoneController.dispose();
    _studentNameController.dispose();
    _studentEmailController.dispose();
    for (final item in _deviceLimits) {
      item.dispose();
    }
    super.dispose();
  }

  void _addDeviceLimit() {
    setState(() {
      _deviceLimits.add(_DeviceLimitForm());
    });
  }

  void _removeDeviceLimit(int index) {
    if (_deviceLimits.length <= 1) return;
    final removed = _deviceLimits.removeAt(index);
    removed.dispose();
    setState(() {});
  }

  Future<void> _submit() async {
    final studentPhone = _studentPhoneController.text.trim();
    final studentName = _studentNameController.text.trim();
    final studentEmail = _studentEmailController.text.trim();

    if (!RegExp(r'^09\d{9}$').hasMatch(studentPhone)) {
      setState(() {
        _errorMessage = 'شماره موبایل دانشجو باید با 09 شروع شود و 11 رقم باشد.';
      });
      return;
    }

    if (studentName.length > 255) {
      setState(() {
        _errorMessage = 'حداکثر طول نام دانشجو 255 کاراکتر است.';
      });
      return;
    }

    if (studentEmail.isNotEmpty) {
      final emailRegex = RegExp(r'^[^@\s]+@[^@\s]+\.[^@\s]+$');
      if (!emailRegex.hasMatch(studentEmail)) {
        setState(() {
          _errorMessage = 'ایمیل دانشجو معتبر نیست.';
        });
        return;
      }
      if (studentEmail.length > 255) {
        setState(() {
          _errorMessage = 'حداکثر طول ایمیل دانشجو 255 کاراکتر است.';
        });
        return;
      }
    }

    final payloadDeviceLimits = <Map<String, dynamic>>[];
    for (final item in _deviceLimits) {
      final limit = int.tryParse(item.limitController.text.trim());
      if (limit == null || limit < 1 || limit > 10) {
        setState(() {
          _errorMessage = 'مقدار limit هر آیتم باید عدد بین 1 تا 10 باشد.';
        });
        return;
      }
      payloadDeviceLimits.add({
        'os': item.os,
        'limit': limit,
      });
    }

    if (payloadDeviceLimits.isEmpty) {
      setState(() {
        _errorMessage = 'حداقل یک device limit باید وارد شود.';
      });
      return;
    }

    setState(() {
      _isSubmitting = true;
      _errorMessage = null;
    });

    try {
      final apiService = Provider.of<ApiService>(context, listen: false);
      final response = await apiService.createCourseLicense(
        courseId: widget.courseId,
        studentPhone: studentPhone,
        studentName: studentName.isEmpty ? null : studentName,
        studentEmail: studentEmail.isEmpty ? null : studentEmail,
        deviceLimits: payloadDeviceLimits,
      );

      if (!mounted) return;
      final message = (response['message'] ?? 'لایسنس با موفقیت ساخته شد.').toString();
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text(message)),
      );
      Navigator.of(context).pop(true);
    } catch (e) {
      setState(() {
        _errorMessage = e.toString();
      });
    } finally {
      if (mounted) {
        setState(() {
          _isSubmitting = false;
        });
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    final isDesktop = MediaQuery.of(context).size.width > 900;

    return TeacherPanelScaffold(
      selectedMenu: PanelMenu.license,
      onDashboardTap: () {
        Navigator.of(context).pushReplacement(
          MaterialPageRoute(builder: (context) => const DashboardPage()),
        );
      },
      onCourseTap: () {
        Navigator.of(context).pushReplacement(
          MaterialPageRoute(builder: (context) => const CoursePage()),
        );
      },
      onLicenseTap: () {
        Navigator.of(context).pushReplacement(
          MaterialPageRoute(builder: (context) => const PanelLicensePage()),
        );
      },
      onTransactionTap: () {
        Navigator.of(context).push(
          MaterialPageRoute(builder: (context) => const TransactionPage()),
        );
      },
      onTicketTap: () {
        Navigator.of(context).push(
          MaterialPageRoute(builder: (context) => const TicketPage()),
        );
      },
      child: SingleChildScrollView(
        padding: EdgeInsets.all(isDesktop ? 24 : 12),
        child: Container(
          decoration: BoxDecoration(
            color: Colors.white.withValues(alpha: 0.35),
            borderRadius: BorderRadius.circular(10),
          ),
          padding: EdgeInsets.all(isDesktop ? 18 : 12),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              InkWell(
                onTap: () => Navigator.pop(context),
                child: const Icon(Icons.arrow_back, color: AppColors.sidebarBg),
              ),
              const SizedBox(height: 10),
              Row(
                mainAxisAlignment: MainAxisAlignment.end,
                children: [
                  const Icon(Icons.add_card, size: 18, color: AppColors.sidebarBg),
                  const SizedBox(width: 6),
                  Text(
                    'ساخت لایسنس جدید',
                    style: AppTextStyles.headlineMedium.copyWith(
                      color: AppColors.sidebarBg,
                      fontSize: 20,
                    ),
                  ),
                ],
              ),
              const SizedBox(height: 8),
              Container(
                width: double.infinity,
                padding: const EdgeInsets.all(10),
                decoration: BoxDecoration(
                  color: const Color(0xFFEFF5FF),
                  borderRadius: BorderRadius.circular(8),
                  border: Border.all(color: AppColors.sidebarBg.withValues(alpha: 0.3)),
                ),
                child: Text(
                  'این لایسنس برای دوره: ${widget.courseTitle} (ID: ${widget.courseId})',
                  style: AppTextStyles.bodyLarge.copyWith(color: AppColors.sidebarBg),
                ),
              ),
              const SizedBox(height: 12),
              Container(height: 1, color: Colors.black12),
              const SizedBox(height: 16),

              _buildLabel('شماره موبایل دانشجو *'),
              const SizedBox(height: 6),
              _buildInput(
                _studentPhoneController,
                keyboardType: TextInputType.phone,
                hint: '09xxxxxxxxx',
              ),
              const SizedBox(height: 12),

              _buildLabel('نام دانشجو (اختیاری)'),
              const SizedBox(height: 6),
              _buildInput(_studentNameController),
              const SizedBox(height: 12),

              _buildLabel('ایمیل دانشجو (اختیاری)'),
              const SizedBox(height: 6),
              _buildInput(
                _studentEmailController,
                keyboardType: TextInputType.emailAddress,
              ),

              const SizedBox(height: 22),
              Row(
                mainAxisAlignment: MainAxisAlignment.spaceBetween,
                children: [
                  Text('Device Limits *', style: AppTextStyles.headlineMedium),
                  OutlinedButton.icon(
                    onPressed: _addDeviceLimit,
                    icon: const Icon(Icons.add, size: 16),
                    label: const Text('افزودن آیتم'),
                  ),
                ],
              ),
              const SizedBox(height: 10),
              ..._deviceLimits.asMap().entries.map(
                (entry) {
                  final index = entry.key;
                  final item = entry.value;
                  return Padding(
                    padding: const EdgeInsets.only(bottom: 10),
                    child: _buildDeviceLimitRow(index, item, isDesktop),
                  );
                },
              ),

              if (_errorMessage != null) ...[
                const SizedBox(height: 10),
                Text(
                  _errorMessage!,
                  style: AppTextStyles.bodyMedium.copyWith(color: Colors.red),
                ),
              ],

              const SizedBox(height: 22),
              Wrap(
                spacing: 10,
                runSpacing: 10,
                children: [
                  SizedBox(
                    width: isDesktop ? 140 : double.infinity,
                    height: 44,
                    child: ElevatedButton(
                      onPressed: _isSubmitting ? null : _submit,
                      style: ElevatedButton.styleFrom(
                        backgroundColor: const Color(0xFF43C61C),
                        foregroundColor: Colors.white,
                      ),
                      child: _isSubmitting
                          ? const SizedBox(
                              width: 20,
                              height: 20,
                              child: CircularProgressIndicator(
                                strokeWidth: 2,
                                color: Colors.white,
                              ),
                            )
                          : const Text('تایید'),
                    ),
                  ),
                  SizedBox(
                    width: isDesktop ? 140 : double.infinity,
                    height: 44,
                    child: ElevatedButton(
                      onPressed: _isSubmitting ? null : () => Navigator.pop(context),
                      style: ElevatedButton.styleFrom(
                        backgroundColor: const Color(0xFFC95757),
                        foregroundColor: Colors.white,
                      ),
                      child: const Text('انصراف'),
                    ),
                  ),
                ],
              ),
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildDeviceLimitRow(int index, _DeviceLimitForm item, bool isDesktop) {
    final osItems = const [
      DropdownMenuItem(value: 'android', child: Text('android')),
      DropdownMenuItem(value: 'windows', child: Text('windows')),
      DropdownMenuItem(value: 'linux', child: Text('linux')),
      DropdownMenuItem(value: 'ios', child: Text('ios')),
    ];

    if (!isDesktop) {
      return Container(
        padding: const EdgeInsets.all(10),
        decoration: BoxDecoration(
          color: Colors.white,
          borderRadius: BorderRadius.circular(10),
          border: Border.all(color: Colors.black12),
        ),
        child: Column(
          children: [
            DropdownButtonFormField<String>(
              initialValue: item.os,
              decoration: _inputDecoration('os'),
              items: osItems,
              onChanged: (v) {
                if (v == null) return;
                setState(() {
                  item.os = v;
                });
              },
            ),
            const SizedBox(height: 8),
            TextField(
              controller: item.limitController,
              keyboardType: TextInputType.number,
              decoration: _inputDecoration('limit (1..10)'),
            ),
            const SizedBox(height: 8),
            Align(
              alignment: Alignment.centerLeft,
              child: IconButton(
                onPressed: _deviceLimits.length > 1 ? () => _removeDeviceLimit(index) : null,
                icon: const Icon(Icons.delete_outline),
              ),
            ),
          ],
        ),
      );
    }

    return Row(
      children: [
        Expanded(
          flex: 3,
          child: DropdownButtonFormField<String>(
            initialValue: item.os,
            decoration: _inputDecoration('os'),
            items: osItems,
            onChanged: (v) {
              if (v == null) return;
              setState(() {
                item.os = v;
              });
            },
          ),
        ),
        const SizedBox(width: 8),
        Expanded(
          flex: 2,
          child: TextField(
            controller: item.limitController,
            keyboardType: TextInputType.number,
            decoration: _inputDecoration('limit (1..10)'),
          ),
        ),
        const SizedBox(width: 8),
        IconButton(
          onPressed: _deviceLimits.length > 1 ? () => _removeDeviceLimit(index) : null,
          icon: const Icon(Icons.delete_outline),
        ),
      ],
    );
  }

  Widget _buildLabel(String text) {
    return Text(text, style: AppTextStyles.bodyLarge);
  }

  Widget _buildInput(
    TextEditingController controller, {
    TextInputType? keyboardType,
    String? hint,
  }) {
    return TextField(
      controller: controller,
      keyboardType: keyboardType,
      decoration: _inputDecoration(hint),
    );
  }

  InputDecoration _inputDecoration(String? hint) {
    return InputDecoration(
      hintText: hint,
      isDense: true,
      filled: true,
      fillColor: Colors.white,
      border: OutlineInputBorder(
        borderRadius: BorderRadius.circular(10),
        borderSide: BorderSide(color: AppColors.sidebarBg.withValues(alpha: 0.7)),
      ),
      enabledBorder: OutlineInputBorder(
        borderRadius: BorderRadius.circular(10),
        borderSide: BorderSide(color: AppColors.sidebarBg.withValues(alpha: 0.7)),
      ),
      contentPadding: const EdgeInsets.symmetric(horizontal: 12, vertical: 10),
    );
  }
}

class _DeviceLimitForm {
  String os = 'android';
  final TextEditingController limitController;

  _DeviceLimitForm({
    String limit = '1',
  }) : limitController = TextEditingController(text: limit);

  void dispose() {
    limitController.dispose();
  }
}