import 'dart:developer' as developer;

import 'dart:io';

import 'package:flutter/material.dart';
import 'package:flutter_lucide/flutter_lucide.dart';
import 'package:http/http.dart' as http;
import 'package:image_picker/image_picker.dart';

import '../../core/auth/auth_service.dart';
import '../../core/theme/app_colors.dart';
import '../../core/theme/app_spacing.dart';
import '../../core/theme/app_typography.dart';
import '../../core/user/user_state.dart';
import '../../features/home/models/task_item.dart';
import '../../shared/widgets/top_nav_bar.dart';

import '../../core/api/services/image_api.dart';

/// Generate Video screen - matches Pencil mmLB5
class GenerateVideoScreen extends StatefulWidget {
  const GenerateVideoScreen({super.key, this.task});

  final TaskItem? task;

  @override
  State<GenerateVideoScreen> createState() => _GenerateVideoScreenState();
}

enum _Resolution { p480, p720 }

class _GenerateVideoScreenState extends State<GenerateVideoScreen> {
  File? _selectedImage;
  _Resolution _selectedResolution = _Resolution.p480;
  bool _isGenerating = false;

  int get _currentCredits {
    final task = widget.task;
    if (task == null) return 50;
    switch (_selectedResolution) {
      case _Resolution.p480:
        return task.credits480p ?? 50;
      case _Resolution.p720:
        return task.credits720p ?? 50;
    }
  }

  String get _heatmap =>
      _selectedResolution == _Resolution.p480 ? '480p' : '720p';

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      developer.log(
        'GenerateVideoScreen opened with task: ${widget.task}',
        name: 'GenerateVideoScreen',
      );
      debugPrint('[GenerateVideoScreen] task: ${widget.task}');
    });
  }

  Future<void> _showImageSourcePicker() async {
    final source = await showModalBottomSheet<ImageSource>(
      context: context,
      builder: (context) => SafeArea(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            ListTile(
              leading: const Icon(LucideIcons.image),
              title: const Text('Choose from gallery'),
              onTap: () => Navigator.pop(context, ImageSource.gallery),
            ),
            ListTile(
              leading: const Icon(LucideIcons.camera),
              title: const Text('Take photo'),
              onTap: () => Navigator.pop(context, ImageSource.camera),
            ),
          ],
        ),
      ),
    );
    if (source != null && mounted) {
      _pickImage(source);
    }
  }

  Future<void> _pickImage(ImageSource source) async {
    final picker = ImagePicker();
    final picked = await picker.pickImage(
      source: source,
      imageQuality: 85,
    );
    if (picked != null && mounted) {
      setState(() {
        _selectedImage = File(picked.path);
      });
    }
  }

  Future<void> _onGenerate() async {
    if (_selectedImage == null) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(
            content: Text('Please select an image first'),
            behavior: SnackBarBehavior.floating,
          ),
        );
      }
      return;
    }

    setState(() => _isGenerating = true);

    try {
      await AuthService.loginComplete;

      final file = _selectedImage!;
      final size = await file.length();
      final ext = file.path.split('.').last.toLowerCase();
      final contentType = ext == 'png'
          ? 'image/png'
          : ext == 'gif'
              ? 'image/gif'
              : 'image/jpeg';
      final fileName = 'img_${DateTime.now().millisecondsSinceEpoch}.$ext';

      final presignedRes = await ImageApi.getUploadPresignedUrl(
        fileName1: fileName,
        contentType: contentType,
        expectedSize: size,
      );

      if (!presignedRes.isSuccess || presignedRes.data == null) {
        throw Exception(presignedRes.msg.isNotEmpty
            ? presignedRes.msg
            : 'Failed to get upload URL');
      }

      final data = presignedRes.data as Map<String, dynamic>;
      final uploadUrl =
          data['bolster'] as String? ?? data['expound'] as String?;
      final filePath = data['recruit'] as String? ?? data['train'] as String?;
      final requiredHeaders = data['remap'] as Map<String, dynamic>?;

      if (uploadUrl == null ||
          uploadUrl.isEmpty ||
          filePath == null ||
          filePath.isEmpty) {
        throw Exception('Invalid presigned URL response');
      }

      final headers = <String, String>{};
      if (requiredHeaders != null) {
        for (final e in requiredHeaders.entries) {
          headers[e.key] = e.value?.toString() ?? '';
        }
      }
      if (!headers.containsKey('Content-Type')) {
        headers['Content-Type'] = contentType;
      }

      final bytes = await file.readAsBytes();
      final uploadResponse = await http.put(
        Uri.parse(uploadUrl),
        headers: headers,
        body: bytes,
      );

      if (uploadResponse.statusCode < 200 || uploadResponse.statusCode >= 300) {
        throw Exception('Upload failed: ${uploadResponse.statusCode}');
      }

      final userId = UserState.userId.value;
      if (userId == null || userId.isEmpty) {
        throw Exception('User not logged in');
      }

      final createRes = await ImageApi.createTask(
        asset: userId,
        guild: filePath,
        allowance: false,
        cipher: widget.task?.taskType ?? '',
        congregation: widget.task?.templateName ?? '',
        heatmap: _heatmap,
        ext: widget.task?.ext,
      );

      if (!createRes.isSuccess) {
        throw Exception(
            createRes.msg.isNotEmpty ? createRes.msg : 'Failed to create task');
      }

      final taskData = createRes.data as Map<String, dynamic>?;
      final taskId = taskData?['tree'];

      if (!mounted) return;
      Navigator.of(context)
          .pushReplacementNamed('/progress', arguments: taskId);
    } catch (e, st) {
      developer.log('Generate failed: $e', name: 'GenerateVideoScreen');
      debugPrint('[GenerateVideoScreen] error: $e\n$st');
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text(
                'Generation failed: ${e.toString().replaceAll('Exception: ', '')}'),
            behavior: SnackBarBehavior.floating,
          ),
        );
      }
    } finally {
      if (mounted) {
        setState(() => _isGenerating = false);
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: AppColors.background,
      appBar: PreferredSize(
        preferredSize: const Size.fromHeight(56),
        child: TopNavBar(
          title: 'Generate Video',
          credits: UserCreditsData.of(context)?.creditsDisplay ?? '--',
          showBackButton: true,
          onBack: () => Navigator.of(context).pop(),
          onCreditsTap: () => Navigator.of(context).pushNamed('/recharge'),
        ),
      ),
      body: SingleChildScrollView(
        padding: const EdgeInsets.all(AppSpacing.screenPaddingLarge),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            _CreditsCard(
              credits: UserCreditsData.of(context)?.creditsDisplay ?? '--',
            ),
            const SizedBox(height: AppSpacing.xxl),
            _UploadArea(
              selectedImage: _selectedImage,
              onUpload: _showImageSourcePicker,
            ),
            const SizedBox(height: AppSpacing.xxl),
            _ResolutionToggle(
              selected: _selectedResolution,
              onChanged: (r) => setState(() => _selectedResolution = r),
            ),
            const SizedBox(height: AppSpacing.xxl),
            _GenerateButton(
              onGenerate: _onGenerate,
              isLoading: _isGenerating,
              credits: _currentCredits.toString(),
            ),
          ],
        ),
      ),
    );
  }
}

class _CreditsCard extends StatelessWidget {
  const _CreditsCard({required this.credits});

  final String credits;

  @override
  Widget build(BuildContext context) {
    return Container(
      padding: const EdgeInsets.symmetric(
        horizontal: AppSpacing.xxl,
        vertical: AppSpacing.xl,
      ),
      decoration: BoxDecoration(
        color: AppColors.primary,
        borderRadius: BorderRadius.circular(16),
        border: Border.all(
          color: AppColors.primary.withValues(alpha: 0.5),
        ),
        boxShadow: [
          BoxShadow(
            color: AppColors.primaryShadow.withValues(alpha: 0.25),
            blurRadius: 8,
            offset: const Offset(0, 2),
          ),
        ],
      ),
      child: Row(
        children: [
          Icon(LucideIcons.sparkles, size: 28, color: AppColors.surface),
          const SizedBox(width: AppSpacing.md),
          Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                'Available Credits',
                style: AppTypography.bodyRegular.copyWith(
                  color: AppColors.surface.withValues(alpha: 0.8),
                ),
              ),
              Text(
                credits,
                style: AppTypography.bodyLarge.copyWith(
                  fontSize: 32,
                  fontWeight: FontWeight.w700,
                  color: AppColors.surface,
                ),
              ),
            ],
          ),
        ],
      ),
    );
  }
}

class _UploadArea extends StatelessWidget {
  const _UploadArea({
    required this.selectedImage,
    required this.onUpload,
  });

  final File? selectedImage;
  final VoidCallback onUpload;

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: onUpload,
      child: Container(
        height: 280,
        decoration: BoxDecoration(
          color: AppColors.surfaceAlt,
          borderRadius: BorderRadius.circular(16),
          border: Border.all(
            color: AppColors.border,
            width: 2,
          ),
        ),
        clipBehavior: Clip.antiAlias,
        child: selectedImage != null
            ? Image.file(
                selectedImage!,
                fit: BoxFit.cover,
                width: double.infinity,
                height: double.infinity,
              )
            : Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  Icon(
                    LucideIcons.image_plus,
                    size: 48,
                    color: AppColors.textMuted,
                  ),
                  const SizedBox(height: AppSpacing.lg),
                  SizedBox(
                    width: 280,
                    child: Text(
                      'Please upload an image as the base for generation',
                      textAlign: TextAlign.center,
                      style: AppTypography.bodyRegular.copyWith(
                        color: AppColors.textSecondary,
                      ),
                    ),
                  ),
                ],
              ),
      ),
    );
  }
}

class _ResolutionToggle extends StatelessWidget {
  const _ResolutionToggle({
    required this.selected,
    required this.onChanged,
  });

  final _Resolution selected;
  final ValueChanged<_Resolution> onChanged;

  @override
  Widget build(BuildContext context) {
    return Row(
      children: [
        Expanded(
          child: GestureDetector(
            onTap: () => onChanged(_Resolution.p480),
            child: Container(
              height: 48,
              decoration: BoxDecoration(
                color: selected == _Resolution.p480
                    ? AppColors.primary
                    : AppColors.surfaceAlt,
                borderRadius: BorderRadius.circular(12),
                border: Border.all(
                  color: selected == _Resolution.p480
                      ? AppColors.primary.withValues(alpha: 0.5)
                      : AppColors.border,
                  width: selected == _Resolution.p480 ? 1 : 2,
                ),
              ),
              alignment: Alignment.center,
              child: Text(
                '480P',
                style: AppTypography.bodyMedium.copyWith(
                  color: selected == _Resolution.p480
                      ? AppColors.surface
                      : AppColors.textSecondary,
                  fontWeight: FontWeight.w600,
                ),
              ),
            ),
          ),
        ),
        const SizedBox(width: 12),
        Expanded(
          child: GestureDetector(
            onTap: () => onChanged(_Resolution.p720),
            child: Container(
              height: 48,
              decoration: BoxDecoration(
                color: selected == _Resolution.p720
                    ? AppColors.primary
                    : AppColors.surfaceAlt,
                borderRadius: BorderRadius.circular(12),
                border: Border.all(
                  color: selected == _Resolution.p720
                      ? AppColors.primary.withValues(alpha: 0.5)
                      : AppColors.border,
                  width: selected == _Resolution.p720 ? 1 : 2,
                ),
              ),
              alignment: Alignment.center,
              child: Text(
                '720P',
                style: AppTypography.bodyMedium.copyWith(
                  color: selected == _Resolution.p720
                      ? AppColors.surface
                      : AppColors.textSecondary,
                  fontWeight: FontWeight.w600,
                ),
              ),
            ),
          ),
        ),
      ],
    );
  }
}

class _GenerateButton extends StatelessWidget {
  const _GenerateButton({
    required this.onGenerate,
    this.isLoading = false,
    this.credits = '50',
  });

  final VoidCallback onGenerate;
  final bool isLoading;
  final String credits;

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: isLoading ? null : onGenerate,
      child: Opacity(
        opacity: isLoading ? 0.6 : 1,
        child: Container(
          height: 56,
          decoration: BoxDecoration(
            color: AppColors.primary,
            borderRadius: BorderRadius.circular(16),
            boxShadow: [
              BoxShadow(
                color: AppColors.primaryShadow.withValues(alpha: 0.25),
                blurRadius: 8,
                offset: const Offset(0, 2),
              ),
            ],
          ),
          child: Row(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              if (isLoading)
                const SizedBox(
                  width: 24,
                  height: 24,
                  child: CircularProgressIndicator(
                    strokeWidth: 2,
                    color: AppColors.surface,
                  ),
                )
              else
                Text(
                  'Generate Video',
                  style: AppTypography.bodyMedium.copyWith(
                    color: AppColors.surface,
                  ),
                ),
              if (!isLoading) ...[
                const SizedBox(width: AppSpacing.md),
                Container(
                  padding: const EdgeInsets.symmetric(
                    horizontal: 10,
                    vertical: AppSpacing.xs,
                  ),
                  decoration: BoxDecoration(
                    color: AppColors.surface.withValues(alpha: 0.2),
                    borderRadius: BorderRadius.circular(8),
                  ),
                  child: Row(
                    mainAxisSize: MainAxisSize.min,
                    children: [
                      Icon(
                        LucideIcons.sparkles,
                        size: 16,
                        color: AppColors.surface,
                      ),
                      const SizedBox(width: AppSpacing.xs),
                      Text(
                        credits,
                        style: AppTypography.bodyRegular.copyWith(
                          color: AppColors.surface,
                          fontWeight: FontWeight.w600,
                        ),
                      ),
                    ],
                  ),
                ),
              ],
            ],
          ),
        ),
      ),
    );
  }
}