import 'dart:io';

import 'package:cached_network_image/cached_network_image.dart';
import 'package:flutter/material.dart';
import 'package:flutter_cache_manager/flutter_cache_manager.dart';
import 'package:flutter_lucide/flutter_lucide.dart';
import 'package:gal/gal.dart';
import 'package:http/http.dart' as http;
import 'package:path_provider/path_provider.dart';
import 'package:video_player/video_player.dart';

import '../../core/theme/app_colors.dart';
import '../../core/theme/app_spacing.dart';
import '../../core/theme/app_typography.dart';
import '../../features/gallery/models/gallery_task_item.dart';
import '../../shared/widgets/top_nav_bar.dart';

/// Video Generation Result screen - matches Pencil cFA4T
class GenerationResultScreen extends StatefulWidget {
  const GenerationResultScreen({super.key, this.mediaItem});

  final GalleryMediaItem? mediaItem;

  @override
  State<GenerationResultScreen> createState() => _GenerationResultScreenState();
}

class _GenerationResultScreenState extends State<GenerationResultScreen> {
  VideoPlayerController? _videoController;
  bool _saving = false;
  bool _videoLoading = true;
  String? _videoLoadError;

  String? get _videoUrl => widget.mediaItem?.videoUrl;
  String? get _imageUrl => widget.mediaItem?.imageUrl;

  @override
  void initState() {
    super.initState();
    if (_videoUrl != null) {
      _initVideoFromCache();
    }
  }

  Future<void> _initVideoFromCache() async {
    if (_videoUrl == null) return;
    try {
      final file = await DefaultCacheManager().getSingleFile(_videoUrl!);
      if (!mounted) return;
      final controller = VideoPlayerController.file(file);
      await controller.initialize();
      if (!mounted) return;
      setState(() {
        _videoController = controller;
        _videoLoading = false;
      });
    } catch (e) {
      if (mounted) {
        setState(() {
          _videoLoading = false;
          _videoLoadError = e.toString();
        });
      }
    }
  }

  @override
  void dispose() {
    _videoController?.dispose();
    super.dispose();
  }

  Future<void> _saveToAlbum() async {
    if (widget.mediaItem == null) return;
    setState(() => _saving = true);

    try {
      final hasAccess = await Gal.hasAccess(toAlbum: true);
      if (!hasAccess) {
        final granted = await Gal.requestAccess(toAlbum: true);
        if (!granted) {
          throw Exception('Photo library access denied');
        }
      }

      if (_videoUrl != null) {
        final tempDir = await getTemporaryDirectory();
        final file = File(
            '${tempDir.path}/gallery_video_${DateTime.now().millisecondsSinceEpoch}.mp4');
        final response = await http.get(Uri.parse(_videoUrl!));
        if (response.statusCode != 200) {
          throw Exception('Failed to download video');
        }
        await file.writeAsBytes(response.bodyBytes);
        await Gal.putVideo(file.path);
        await file.delete();
      } else if (_imageUrl != null) {
        final tempDir = await getTemporaryDirectory();
        final file = File(
            '${tempDir.path}/gallery_image_${DateTime.now().millisecondsSinceEpoch}.jpg');
        final response = await http.get(Uri.parse(_imageUrl!));
        if (response.statusCode != 200) {
          throw Exception('Failed to download image');
        }
        await file.writeAsBytes(response.bodyBytes);
        await Gal.putImage(file.path);
        await file.delete();
      }

      if (mounted) {
        setState(() => _saving = false);
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('Saved to photo library')),
        );
      }
    } catch (e) {
      if (mounted) {
        setState(() => _saving = false);
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Save failed: $e')),
        );
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: AppColors.background,
      appBar: PreferredSize(
        preferredSize: const Size.fromHeight(56),
        child: TopNavBar(
          title: 'Video Ready',
          showBackButton: true,
          onBack: () => Navigator.of(context).pop(),
        ),
      ),
      body: widget.mediaItem == null
          ? Center(
              child: Text(
                'No media',
                style: TextStyle(color: AppColors.textSecondary),
              ),
            )
          : SingleChildScrollView(
              padding: const EdgeInsets.all(AppSpacing.screenPaddingLarge),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: [
                  _MediaDisplay(
                    videoUrl: _videoUrl,
                    imageUrl: _imageUrl,
                    videoController: _videoController,
                    videoLoading: _videoUrl != null ? _videoLoading : false,
                    videoLoadError: _videoLoadError,
                  ),
                  const SizedBox(height: AppSpacing.xxl),
                  _DownloadButton(
                    onDownload: _saving ? null : _saveToAlbum,
                    saving: _saving,
                  )
                ],
              ),
            ),
    );
  }
}

class _MediaDisplay extends StatelessWidget {
  const _MediaDisplay({
    this.videoUrl,
    this.imageUrl,
    this.videoController,
    this.videoLoading = false,
    this.videoLoadError,
  });

  final String? videoUrl;
  final String? imageUrl;
  final VideoPlayerController? videoController;
  final bool videoLoading;
  final String? videoLoadError;

  @override
  Widget build(BuildContext context) {
    return Container(
      height: 360,
      decoration: BoxDecoration(
        color: AppColors.textPrimary,
        borderRadius: BorderRadius.circular(16),
        border: Border.all(color: AppColors.border, width: 1),
      ),
      child: ClipRRect(
        borderRadius: BorderRadius.circular(16),
        child: videoUrl != null && videoController != null
            ? _VideoPlayer(
                controller: videoController!,
              )
            : videoUrl != null && videoLoading
                ? Container(
                    color: AppColors.textPrimary,
                    alignment: Alignment.center,
                    child: const CircularProgressIndicator(
                      color: AppColors.surface,
                    ),
                  )
                : videoUrl != null && videoLoadError != null
                    ? Container(
                        color: AppColors.textPrimary,
                        alignment: Alignment.center,
                        child: Text(
                          'Load failed',
                          style: TextStyle(color: AppColors.surface),
                        ),
                      )
                    : imageUrl != null
                        ? CachedNetworkImage(
                            imageUrl: imageUrl!,
                            fit: BoxFit.cover,
                            placeholder: (_, __) => _Placeholder(),
                            errorWidget: (_, __, ___) => _Placeholder(),
                          )
                        : _Placeholder(),
      ),
    );
  }
}

class _VideoPlayer extends StatefulWidget {
  const _VideoPlayer({required this.controller});

  final VideoPlayerController controller;

  @override
  State<_VideoPlayer> createState() => _VideoPlayerState();
}

class _VideoPlayerState extends State<_VideoPlayer> {
  @override
  void initState() {
    super.initState();
    widget.controller.addListener(_listener);
  }

  @override
  void dispose() {
    widget.controller.removeListener(_listener);
    super.dispose();
  }

  void _listener() {
    if (mounted) setState(() {});
  }

  @override
  Widget build(BuildContext context) {
    if (!widget.controller.value.isInitialized) {
      return Container(
        color: AppColors.textPrimary,
        child: const Center(
          child: CircularProgressIndicator(color: AppColors.surface),
        ),
      );
    }

    return Stack(
      fit: StackFit.expand,
      alignment: Alignment.center,
      children: [
        FittedBox(
          fit: BoxFit.contain,
          child: SizedBox(
            width: widget.controller.value.size.width > 0
                ? widget.controller.value.size.width
                : 16,
            height: widget.controller.value.size.height > 0
                ? widget.controller.value.size.height
                : 9,
            child: VideoPlayer(widget.controller),
          ),
        ),
        Center(
          child: GestureDetector(
            onTap: () {
              if (widget.controller.value.isPlaying) {
                widget.controller.pause();
              } else {
                widget.controller.play();
              }
            },
            child: Container(
              width: 64,
              height: 64,
              decoration: BoxDecoration(
                color: AppColors.surface.withValues(alpha: 0.8),
                shape: BoxShape.circle,
              ),
              child: Icon(
                widget.controller.value.isPlaying
                    ? LucideIcons.pause
                    : LucideIcons.play,
                size: 32,
                color: AppColors.textPrimary,
              ),
            ),
          ),
        ),
      ],
    );
  }
}

class _Placeholder extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      color: AppColors.textPrimary,
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          Icon(
            LucideIcons.play,
            size: 72,
            color: AppColors.surface.withValues(alpha: 0.5),
          ),
          const SizedBox(height: AppSpacing.lg),
          Text(
            'Your video is ready',
            style: AppTypography.bodyRegular.copyWith(
              color: AppColors.surface.withValues(alpha: 0.6),
            ),
          ),
        ],
      ),
    );
  }
}

class _DownloadButton extends StatelessWidget {
  const _DownloadButton({
    required this.onDownload,
    this.saving = false,
  });

  final VoidCallback? onDownload;
  final bool saving;

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: onDownload,
      child: Container(
        height: 52,
        decoration: BoxDecoration(
          color: saving ? AppColors.surfaceAlt : AppColors.primary,
          borderRadius: BorderRadius.circular(14),
          boxShadow: saving
              ? null
              : [
                  BoxShadow(
                    color: AppColors.primaryShadow.withValues(alpha: 0.25),
                    blurRadius: 6,
                    offset: const Offset(0, 2),
                  ),
                ],
        ),
        child: Row(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            if (saving)
              const SizedBox(
                width: 20,
                height: 20,
                child: CircularProgressIndicator(
                  strokeWidth: 2,
                  color: AppColors.textSecondary,
                ),
              )
            else
              Icon(LucideIcons.download, size: 20, color: AppColors.surface),
            const SizedBox(width: AppSpacing.md),
            Text(
              saving ? 'Saving...' : 'Save to Album',
              style: AppTypography.bodyMedium.copyWith(
                color: AppColors.surface,
              ),
            ),
          ],
        ),
      ),
    );
  }
}

class _ShareButton extends StatelessWidget {
  const _ShareButton({required this.onShare});

  final VoidCallback onShare;

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: onShare,
      child: Container(
        height: 52,
        decoration: BoxDecoration(
          color: AppColors.surface,
          borderRadius: BorderRadius.circular(14),
          border: Border.all(color: AppColors.border),
          boxShadow: [
            BoxShadow(
              color: AppColors.shadowLight,
              blurRadius: 6,
              offset: const Offset(0, 2),
            ),
          ],
        ),
        child: Row(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Icon(LucideIcons.share_2, size: 20, color: AppColors.primary),
            const SizedBox(width: AppSpacing.md),
            Text(
              'Share',
              style: AppTypography.bodyMedium.copyWith(
                color: AppColors.textPrimary,
              ),
            ),
          ],
        ),
      ),
    );
  }
}