import 'package:file_picker/file_picker.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.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 CourseDetailsPage extends StatefulWidget {
  final int courseId;

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

  @override
  State<CourseDetailsPage> createState() => _CourseDetailsPageState();
}

class _CourseDetailsPageState extends State<CourseDetailsPage> {
  bool _isLoading = true;
  String? _errorMessage;
  Map<String, dynamic>? _course;

  final TextEditingController _videoTitleController = TextEditingController();

  List<Map<String, dynamic>> _courseVideos = <Map<String, dynamic>>[];
  Uint8List? _pickedVideoBytes;
  String? _pickedVideoName;
  int? _pickedVideoSize;

  bool _isUploadingVideo = false;
  int _uploadPercent = 0;
  String? _uploadErrorMessage;

  @override
  void initState() {
    super.initState();
    _loadCourse();
  }

  @override
  void dispose() {
    _videoTitleController.dispose();
    super.dispose();
  }

  Future<void> _loadCourse() async {
    setState(() {
      _isLoading = true;
      _errorMessage = null;
    });

    try {
      final apiService = Provider.of<ApiService>(context, listen: false);
      final response = await apiService.getCourseById(widget.courseId);
      final data = response['data'];
      final course = data is Map<String, dynamic> ? data : <String, dynamic>{};

      setState(() {
        _course = course;
        _isLoading = false;
      });

      _initVideosFromCourse(course);
    } catch (e) {
      setState(() {
        _errorMessage = e.toString();
        _isLoading = false;
      });
    }
  }

  void _initVideosFromCourse(Map<String, dynamic> course) {
    final previewUrl = course['preview_video_url']?.toString();
    if (previewUrl == null || previewUrl.isEmpty) {
      setState(() {
        _courseVideos = <Map<String, dynamic>>[];
      });
      return;
    }

    setState(() {
      _courseVideos = <Map<String, dynamic>>[
        <String, dynamic>{
          'title': 'ویدیوی پیش‌نمایش',
          'preview_video_url': previewUrl,
          'created_at': '-',
          'updated_at': '-',
        },
      ];
    });
  }

  Future<void> _pickVideoFile() async {
    final result = await FilePicker.platform.pickFiles(
      type: FileType.video,
      withData: true,
    );

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

    final file = result.files.first;
    if (file.bytes == null) {
      setState(() {
        _uploadErrorMessage = 'خواندن فایل انتخاب‌شده ناموفق بود.';
      });
      return;
    }

    setState(() {
      _pickedVideoBytes = file.bytes;
      _pickedVideoName = file.name;
      _pickedVideoSize = file.size;
      _uploadErrorMessage = null;
    });
  }

  Future<void> _uploadVideo() async {
    final title = _videoTitleController.text.trim();
    if (title.isEmpty) {
      setState(() {
        _uploadErrorMessage = 'عنوان ویدیو الزامی است.';
      });
      return;
    }

    if (title.length > 255) {
      setState(() {
        _uploadErrorMessage = 'حداکثر طول عنوان ویدیو 255 کاراکتر است.';
      });
      return;
    }

    if (_pickedVideoBytes == null) {
      setState(() {
        _uploadErrorMessage = 'فایل ویدیو را انتخاب کنید.';
      });
      return;
    }

    setState(() {
      _isUploadingVideo = true;
      _uploadPercent = 0;
      _uploadErrorMessage = null;
    });

    try {
      final apiService = Provider.of<ApiService>(context, listen: false);
      final response = await apiService.uploadEncryptedCourseVideo(
        courseId: widget.courseId,
        title: title,
        sourceVideoBytes: _pickedVideoBytes!,
        onSendProgress: (sent, total) {
          if (!mounted || total <= 0) return;
          setState(() {
            _uploadPercent = ((sent / total) * 100).round();
          });
        },
      );

      final data = response['data'];
      final created = data is Map<String, dynamic>
          ? Map<String, dynamic>.from(data)
          : <String, dynamic>{'title': title};

      setState(() {
        _courseVideos = <Map<String, dynamic>>[created, ..._courseVideos];
        _isUploadingVideo = false;
        _uploadPercent = 100;
        _videoTitleController.clear();
        _pickedVideoBytes = null;
        _pickedVideoName = null;
        _pickedVideoSize = null;
      });

      if (!mounted) return;
      final message =
          (response['message'] ?? 'ویدیوی رمزنگاری شده با موفقیت دریافت و ثبت شد.')
              .toString();
      ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text(message)));
    } catch (e) {
      setState(() {
        _isUploadingVideo = false;
        _uploadErrorMessage = e.toString();
      });
    }
  }

  @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: () {
        Navigator.of(context).pushReplacement(
          MaterialPageRoute(builder: (context) => const CoursePage()),
        );
      },
      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: Padding(
        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: _buildContent(isDesktop),
        ),
      ),
    );
  }

  Widget _buildContent(bool isDesktop) {
    if (_isLoading) {
      return const Center(child: CircularProgressIndicator());
    }

    if (_errorMessage != null) {
      return Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Text(
              _errorMessage!,
              style: AppTextStyles.bodyMedium.copyWith(color: Colors.red),
              textAlign: TextAlign.center,
            ),
            const SizedBox(height: 12),
            OutlinedButton(
              onPressed: _loadCourse,
              child: const Text('تلاش مجدد'),
            ),
          ],
        ),
      );
    }

    if (_course == null || _course!.isEmpty) {
      return const Center(child: Text('اطلاعات دوره یافت نشد.'));
    }

    final title = (_course!['title'] ?? '-').toString();
    final description = (_course!['description'] ?? '-').toString();
    final price = (_course!['price'] ?? 0).toString();
    final coverUrl = _course!['cover_url']?.toString();
    final previewVideoUrl = _course!['preview_video_url']?.toString();
    final teacher = _extractTeacherName(_course!['teacher_name']);

    return SingleChildScrollView(
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Row(
            children: [
              InkWell(
                onTap: () => Navigator.of(context).pop(),
                child: const Icon(Icons.arrow_back, color: AppColors.sidebarBg),
              ),
              const SizedBox(width: 10),
              Text(
                'نمایش دوره',
                style: AppTextStyles.headlineMedium.copyWith(
                  color: AppColors.sidebarBg,
                ),
              ),
            ],
          ),
          const SizedBox(height: 14),
          Container(height: 1, color: Colors.black12),
          const SizedBox(height: 20),
          if (isDesktop)
            Row(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Expanded(flex: 3, child: _buildCover(coverUrl)),
                const SizedBox(width: 16),
                Expanded(
                  flex: 5,
                  child: _buildInfoBox(
                    title: title,
                    teacher: teacher,
                    price: price,
                    description: description,
                    previewVideoUrl: previewVideoUrl,
                  ),
                ),
              ],
            )
          else ...[
            _buildCover(coverUrl),
            const SizedBox(height: 12),
            _buildInfoBox(
              title: title,
              teacher: teacher,
              price: price,
              description: description,
              previewVideoUrl: previewVideoUrl,
            ),
          ],
          const SizedBox(height: 20),
          _buildVideoUploadSection(),
          const SizedBox(height: 12),
          _buildVideoListSection(),
        ],
      ),
    );
  }

  Widget _buildCover(String? coverUrl) {
    return Container(
      height: 280,
      width: double.infinity,
      decoration: BoxDecoration(
        borderRadius: BorderRadius.circular(12),
        border: Border.all(color: Colors.black12),
        color: Colors.white,
      ),
      child: ClipRRect(
        borderRadius: BorderRadius.circular(12),
        child: coverUrl == null || coverUrl.isEmpty
            ? const Center(
                child: Icon(Icons.image_not_supported_outlined, size: 56),
              )
            : Image.network(
                coverUrl,
                fit: BoxFit.cover,
                errorBuilder: (_, _, _) => const Center(
                  child: Icon(Icons.broken_image_outlined, size: 56),
                ),
              ),
      ),
    );
  }

  Widget _buildInfoBox({
    required String title,
    required String teacher,
    required String price,
    required String description,
    required String? previewVideoUrl,
  }) {
    return Container(
      width: double.infinity,
      padding: const EdgeInsets.all(14),
      decoration: BoxDecoration(
        color: Colors.white,
        borderRadius: BorderRadius.circular(12),
        border: Border.all(color: Colors.black12),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          _InfoRow(label: 'عنوان دوره', value: title),
          const SizedBox(height: 10),
          _InfoRow(label: 'مدرس', value: teacher),
          const SizedBox(height: 10),
          _InfoRow(label: 'قیمت', value: '$price تومان'),
          const SizedBox(height: 10),
          _InfoRow(label: 'توضیحات', value: description, multiLine: true),
          const SizedBox(height: 10),
          _buildPreviewVideoSection(previewVideoUrl),
        ],
      ),
    );
  }

  Widget _buildPreviewVideoSection(String? previewVideoUrl) {
    final hasUrl = previewVideoUrl != null && previewVideoUrl.isNotEmpty;

    return Container(
      width: double.infinity,
      padding: const EdgeInsets.all(10),
      decoration: BoxDecoration(
        color: Colors.grey.shade50,
        borderRadius: BorderRadius.circular(10),
        border: Border.all(color: Colors.grey.shade300),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text('لینک ویدیوی پیش‌نمایش', style: AppTextStyles.bodyLarge),
          const SizedBox(height: 8),
          SelectableText(
            hasUrl ? previewVideoUrl : '-',
            style: AppTextStyles.bodyMedium,
          ),
          if (hasUrl) ...[
            const SizedBox(height: 8),
            TextButton.icon(
              onPressed: () async {
                await Clipboard.setData(ClipboardData(text: previewVideoUrl));
                if (!mounted) return;
                ScaffoldMessenger.of(
                  context,
                ).showSnackBar(const SnackBar(content: Text('لینک کپی شد.')));
              },
              icon: const Icon(Icons.copy, size: 16),
              label: const Text('کپی لینک'),
            ),
          ],
        ],
      ),
    );
  }

  Widget _buildVideoUploadSection() {
    return Container(
      width: double.infinity,
      padding: const EdgeInsets.all(14),
      decoration: BoxDecoration(
        color: Colors.white,
        borderRadius: BorderRadius.circular(12),
        border: Border.all(color: Colors.black12),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text('آپلود ویدیوی جدید', style: AppTextStyles.headlineMedium),
          const SizedBox(height: 10),
          TextField(
            controller: _videoTitleController,
            decoration: InputDecoration(
              labelText: 'عنوان ویدیو *',
              border: OutlineInputBorder(
                borderRadius: BorderRadius.circular(8),
              ),
            ),
          ),
          const SizedBox(height: 10),
          Row(
            children: [
              Expanded(
                child: Text(
                  _pickedVideoName == null
                      ? 'فایلی انتخاب نشده'
                      : '$_pickedVideoName (${((_pickedVideoSize ?? 0) / (1024 * 1024)).toStringAsFixed(2)} MB)',
                  maxLines: 1,
                  overflow: TextOverflow.ellipsis,
                  style: AppTextStyles.bodyMedium,
                ),
              ),
              const SizedBox(width: 8),
              OutlinedButton.icon(
                onPressed: _isUploadingVideo ? null : _pickVideoFile,
                icon: const Icon(Icons.upload_file),
                label: const Text('انتخاب فایل'),
              ),
            ],
          ),
          const SizedBox(height: 10),
          if (_isUploadingVideo) ...[
            LinearProgressIndicator(value: _uploadPercent / 100),
            const SizedBox(height: 6),
            Text('پیشرفت آپلود: $_uploadPercent%', style: AppTextStyles.bodyMedium),
          ],
          if (_uploadErrorMessage != null) ...[
            const SizedBox(height: 8),
            Text(
              _uploadErrorMessage!,
              style: AppTextStyles.bodyMedium.copyWith(color: Colors.red),
            ),
          ],
          const SizedBox(height: 10),
          ElevatedButton.icon(
            onPressed: _isUploadingVideo ? null : _uploadVideo,
            icon: const Icon(Icons.cloud_upload_outlined),
            label: const Text('رمزنگاری و آپلود ویدیو'),
            style: ElevatedButton.styleFrom(
              backgroundColor: AppColors.sidebarBg,
              foregroundColor: Colors.white,
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildVideoListSection() {
    return Container(
      width: double.infinity,
      padding: const EdgeInsets.all(14),
      decoration: BoxDecoration(
        color: Colors.white,
        borderRadius: BorderRadius.circular(12),
        border: Border.all(color: Colors.black12),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text('لیست ویدیوهای آپلودشده', style: AppTextStyles.headlineMedium),
          const SizedBox(height: 10),
          if (_courseVideos.isEmpty)
            Text(
              'فعلاً ویدیویی برای این دوره ثبت نشده است.',
              style: AppTextStyles.bodyMedium,
            )
          else
            ListView.separated(
              itemCount: _courseVideos.length,
              shrinkWrap: true,
              physics: const NeverScrollableScrollPhysics(),
              separatorBuilder: (_, _) => const Divider(height: 16),
              itemBuilder: (context, index) {
                final item = _courseVideos[index];
                final title = (item['title'] ?? 'بدون عنوان').toString();
                final createdAt = (item['created_at'] ?? '-').toString();
                final previewUrl = item['preview_video_url']?.toString();

                return Row(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Container(
                      width: 34,
                      height: 34,
                      decoration: BoxDecoration(
                        color: AppColors.sidebarBg.withValues(alpha: 0.1),
                        borderRadius: BorderRadius.circular(8),
                      ),
                      child: const Icon(Icons.ondemand_video, size: 18),
                    ),
                    const SizedBox(width: 10),
                    Expanded(
                      child: Column(
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: [
                          Text(
                            title,
                            style: AppTextStyles.bodyLarge.copyWith(
                              fontWeight: FontWeight.w700,
                            ),
                          ),
                          const SizedBox(height: 4),
                          Text('تاریخ ثبت: $createdAt', style: AppTextStyles.bodyMedium),
                          if (previewUrl != null && previewUrl.isNotEmpty) ...[
                            const SizedBox(height: 4),
                            SelectableText(
                              previewUrl,
                              style: AppTextStyles.bodyMedium,
                            ),
                          ],
                        ],
                      ),
                    ),
                  ],
                );
              },
            ),
        ],
      ),
    );
  }

  String _extractTeacherName(dynamic teacherObj) {
    if (teacherObj is Map<String, dynamic>) {
      final value = teacherObj['user_name'];
      if (value is String && value.trim().isNotEmpty) {
        return value;
      }
    }
    return '-';
  }
}

class _InfoRow extends StatelessWidget {
  final String label;
  final String value;
  final bool multiLine;

  const _InfoRow({
    required this.label,
    required this.value,
    this.multiLine = false,
  });

  @override
  Widget build(BuildContext context) {
    return Row(
      crossAxisAlignment: multiLine
          ? CrossAxisAlignment.start
          : CrossAxisAlignment.center,
      children: [
        SizedBox(
          width: 90,
          child: Text(
            '$label:',
            style: AppTextStyles.bodyMedium.copyWith(color: Colors.black54),
          ),
        ),
        Expanded(
          child: Text(
            value,
            maxLines: multiLine ? null : 2,
            overflow: multiLine ? null : TextOverflow.ellipsis,
            style: AppTextStyles.bodyLarge,
          ),
        ),
      ],
    );
  }
}