import 'dart:typed_data';

import 'package:file_picker/file_picker.dart';
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 'dashboard_page.dart';
import 'license_page.dart';
import 'ticket_page.dart';
import 'transaction_page.dart';

class NewCoursePage extends StatefulWidget {
  const NewCoursePage({super.key});

  @override
  State<NewCoursePage> createState() => _NewCoursePageState();
}

class _NewCoursePageState extends State<NewCoursePage> {
  final TextEditingController _titleController = TextEditingController();
  final TextEditingController _descriptionController = TextEditingController();
  final TextEditingController _priceController = TextEditingController(
    text: '0',
  );
  final TextEditingController _teacherPhoneController = TextEditingController();
  final TextEditingController _altController = TextEditingController();

  // Not in current API contract. Keep for future backend support.
  // final TextEditingController _supportLinkController = TextEditingController();
  // final TextEditingController _accessLimitController = TextEditingController(text: '-1');
  // final TextEditingController _noteController = TextEditingController();

  _PickedLocalFile? _coverFile;
  _PickedLocalFile? _previewVideoFile;

  bool _isSubmitting = false;
  String? _errorMessage;

  @override
  void dispose() {
    _titleController.dispose();
    _descriptionController.dispose();
    _priceController.dispose();
    _teacherPhoneController.dispose();
    _altController.dispose();
    super.dispose();
  }

  Future<void> _pickCover() async {
    final result = await FilePicker.platform.pickFiles(
      type: FileType.custom,
      allowedExtensions: ['jpg', 'jpeg', 'png', 'webp'],
      withData: true,
    );

    if (result == null || result.files.isEmpty) {
      return;
    }

    final picked = result.files.first;
    if (picked.bytes == null) {
      setState(() {
        _errorMessage = 'خواندن فایل تصویر ناموفق بود.';
      });
      return;
    }

    setState(() {
      _coverFile = _PickedLocalFile(
        name: picked.name,
        bytes: picked.bytes!,
        sizeBytes: picked.size,
      );
      _errorMessage = null;
    });
  }

  Future<void> _pickPreviewVideo() async {
    final result = await FilePicker.platform.pickFiles(
      type: FileType.custom,
      allowedExtensions: ['mp4', 'mov', 'mkv', 'avi', 'webm'],
      withData: true,
    );

    if (result == null || result.files.isEmpty) {
      return;
    }

    final picked = result.files.first;
    if (picked.bytes == null) {
      setState(() {
        _errorMessage = 'خواندن فایل ویدیو ناموفق بود.';
      });
      return;
    }

    const maxVideoBytes = 50 * 1024 * 1024;
    if (picked.size > maxVideoBytes) {
      setState(() {
        _errorMessage = 'حجم ویدیوی پیش‌نمایش باید حداکثر 50 مگابایت باشد.';
      });
      return;
    }

    setState(() {
      _previewVideoFile = _PickedLocalFile(
        name: picked.name,
        bytes: picked.bytes!,
        sizeBytes: picked.size,
      );
      _errorMessage = null;
    });
  }

  Future<void> _submit() async {
    final title = _titleController.text.trim();
    final description = _descriptionController.text.trim();
    final priceRaw = _priceController.text.trim();
    final teacherPhone = _teacherPhoneController.text.trim();
    final alt = _altController.text.trim();

    if (title.isEmpty) {
      setState(() => _errorMessage = 'عنوان دوره الزامی است.');
      return;
    }
    if (title.length > 255) {
      setState(() => _errorMessage = 'حداکثر طول عنوان 255 کاراکتر است.');
      return;
    }
    if (description.isEmpty) {
      setState(() => _errorMessage = 'توضیحات دوره الزامی است.');
      return;
    }
    if (alt.isEmpty) {
      setState(() => _errorMessage = 'Alt الزامی است.');
      return;
    }
    if (alt.length > 225) {
      setState(() => _errorMessage = 'حداکثر طول alt 225 کاراکتر است.');
      return;
    }

    final price = num.tryParse(priceRaw);
    if (price == null || price < 0) {
      setState(
        () => _errorMessage = 'قیمت باید عدد معتبر بزرگ‌تر یا مساوی صفر باشد.',
      );
      return;
    }

    if (_coverFile == null) {
      setState(() => _errorMessage = 'تصویر دوره الزامی است.');
      return;
    }

    if (_previewVideoFile == null) {
      setState(() => _errorMessage = 'ویدیوی پیش‌نمایش الزامی است.');
      return;
    }

    if (teacherPhone.isEmpty) {
      setState(() => _errorMessage = 'شماره موبایل مدرس الزامی است.');
      return;
    }

    if (!RegExp(r'^09\d{9}$').hasMatch(teacherPhone)) {
      setState(() => _errorMessage = 'فرمت شماره مدرس صحیح نیست.');
      return;
    }

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

    try {
      final apiService = Provider.of<ApiService>(context, listen: false);
      final response = await apiService.createCourse(
        title: title,
        description: description,
        price: price,
        coverBytes: _coverFile!.bytes,
        coverFileName: _coverFile!.name,
        previewVideoBytes: _previewVideoFile!.bytes,
        previewVideoFileName: _previewVideoFile!.name,
        teacherPhone: teacherPhone,
        alt: alt,
      );

      if (!mounted) return;
      final serverMessage = (response['message'] ?? 'دوره با موفقیت ساخته شد.')
          .toString();
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(SnackBar(content: Text(serverMessage)));
      Navigator.of(context).pop();
    } 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.course,
      onDashboardTap: () {
        Navigator.of(context).pushReplacement(
          MaterialPageRoute(builder: (context) => const DashboardPage()),
        );
      },
      onCourseTap: () {
        if (Navigator.of(context).canPop()) {
          Navigator.of(context).pop();
        }
      },
      onLicenseTap: () {
        Navigator.of(context).push(
          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: 8),
              Row(
                mainAxisAlignment: MainAxisAlignment.end,
                children: [
                  const Icon(
                    Icons.school,
                    color: AppColors.sidebarBg,
                    size: 18,
                  ),
                  const SizedBox(width: 6),
                  Text(
                    'دوره جدید',
                    style: AppTextStyles.headlineMedium.copyWith(
                      color: AppColors.sidebarBg,
                      fontSize: 20,
                    ),
                  ),
                ],
              ),
              const SizedBox(height: 14),
              Container(height: 1, color: Colors.black12),
              const SizedBox(height: 16),
              Text('اطلاعات دوره', style: AppTextStyles.headlineMedium),
              const SizedBox(height: 14),

              _buildLabel('نام دوره *'),
              const SizedBox(height: 6),
              _buildInput(_titleController),
              const SizedBox(height: 12),

              _buildLabel('توضیحات *'),
              const SizedBox(height: 6),
              _buildInput(_descriptionController, minLines: 3, maxLines: 5),
              const SizedBox(height: 12),

              _buildLabel('Alt *'),
              const SizedBox(height: 6),
              _buildInput(_altController),
              const SizedBox(height: 12),

              _buildLabel('قیمت *'),
              const SizedBox(height: 6),
              _buildInput(
                _priceController,
                keyboardType: const TextInputType.numberWithOptions(
                  decimal: true,
                ),
              ),
              const SizedBox(height: 12),

              _buildLabel('شماره موبایل مدرس *'),
              const SizedBox(height: 6),
              _buildInput(
                _teacherPhoneController,
                keyboardType: TextInputType.phone,
              ),
              const SizedBox(height: 12),

              _buildLabel('تصویر دوره (cover) *'),
              const SizedBox(height: 6),
              _buildFilePickerRow(
                fileName: _coverFile?.name ?? 'فایلی انتخاب نشده',
                sizeBytes: _coverFile?.sizeBytes,
                onPick: _pickCover,
                buttonLabel: 'انتخاب تصویر',
              ),
              const SizedBox(height: 12),

              _buildLabel('ویدیوی پیش‌نمایش (preview_video) *'),
              const SizedBox(height: 6),
              _buildFilePickerRow(
                fileName: _previewVideoFile?.name ?? 'فایلی انتخاب نشده',
                sizeBytes: _previewVideoFile?.sizeBytes,
                onPick: _pickPreviewVideo,
                buttonLabel: 'انتخاب ویدیو',
              ),
              const SizedBox(height: 6),
              Text(
                'حداکثر حجم ویدیوی پیش‌نمایش: 50 مگابایت',
                style: AppTextStyles.bodyMedium,
              ),

              // Not in current API contract. Keep for future backend support.
              // const SizedBox(height: 22),
              // Text('تنظیمات پیش‌فرض لایسنس جدید', style: AppTextStyles.headlineMedium),
              // const SizedBox(height: 14),
              // _buildLabel('حد دسترسی'),
              // const SizedBox(height: 6),
              // _buildInput(_accessLimitController),
              // const SizedBox(height: 12),
              // _buildLabel('لینک پشتیبانی'),
              // const SizedBox(height: 6),
              // _buildInput(_supportLinkController),
              // const SizedBox(height: 22),
              // _buildLabel('یادداشت'),
              // const SizedBox(height: 8),
              // _buildInput(_noteController, minLines: 4, maxLines: 6),
              if (_errorMessage != null) ...[
                const SizedBox(height: 16),
                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 _buildLabel(String text) {
    return Text(text, style: AppTextStyles.bodyLarge);
  }

  Widget _buildInput(
    TextEditingController controller, {
    TextInputType? keyboardType,
    int minLines = 1,
    int maxLines = 1,
  }) {
    return TextField(
      controller: controller,
      keyboardType: keyboardType,
      minLines: minLines,
      maxLines: maxLines,
      decoration: InputDecoration(
        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,
        ),
      ),
    );
  }

  Widget _buildFilePickerRow({
    required String fileName,
    required int? sizeBytes,
    required VoidCallback onPick,
    required String buttonLabel,
  }) {
    return Row(
      children: [
        Expanded(
          child: Container(
            height: 44,
            padding: const EdgeInsets.symmetric(horizontal: 12),
            decoration: BoxDecoration(
              color: Colors.white,
              borderRadius: BorderRadius.circular(10),
              border: Border.all(
                color: AppColors.sidebarBg.withValues(alpha: 0.7),
              ),
            ),
            alignment: Alignment.centerRight,
            child: Text(
              sizeBytes == null
                  ? fileName
                  : '$fileName (${(sizeBytes / (1024 * 1024)).toStringAsFixed(2)} MB)',
              maxLines: 1,
              overflow: TextOverflow.ellipsis,
              style: AppTextStyles.bodyLarge.copyWith(
                color: AppColors.sidebarBg,
              ),
            ),
          ),
        ),
        const SizedBox(width: 8),
        SizedBox(
          height: 44,
          child: OutlinedButton(
            onPressed: onPick,
            style: OutlinedButton.styleFrom(
              side: BorderSide(
                color: AppColors.sidebarBg.withValues(alpha: 0.7),
              ),
            ),
            child: Text(buttonLabel),
          ),
        ),
      ],
    );
  }
}

class _PickedLocalFile {
  final String name;
  final Uint8List bytes;
  final int sizeBytes;

  _PickedLocalFile({
    required this.name,
    required this.bytes,
    required this.sizeBytes,
  });
}