import 'dart:async';
import 'dart:io';

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

import '../../core/api/api_config.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 '../../shared/widgets/top_nav_bar.dart';

import '../../core/api/services/image_api.dart';
import '../../core/api/services/user_api.dart';
import '../../features/gallery/models/gallery_task_item.dart';
import '../../shared/tab_selector_scope.dart';
import '../../shared/widgets/bottom_nav_bar.dart';

/// Progress states: 1=Queued 2=Processing 3=Completed 4=Timeout 5=Error 6=Aborted
/// Progress bar has 3 stages; states 3–6 are stage 3.
const _stateLabels = <int, String>{
  1: 'Queued',
  2: 'Processing',
  3: 'Completed',
  4: 'Timeout',
  5: 'Error',
  6: 'Aborted',
};

/// Stage progress: 1 -> 1/3, 2 -> 2/3, 3..6 -> 1.0
double _progressForState(int? state) {
  if (state == null) return 0;
  if (state == 1) return 1 / 3;
  if (state == 2) return 2 / 3;
  return 1.0; // 3, 4, 5, 6
}

int? _parseProgressTaskId(dynamic raw) {
  if (raw == null) return null;
  if (raw is int) return raw > 0 ? raw : null;
  if (raw is num) {
    final v = raw.toInt();
    return v > 0 ? v : null;
  }
  final v = int.tryParse(raw.toString());
  return (v != null && v > 0) ? v : null;
}

/// Build GalleryMediaItem from /v1/image/progress response (data = sidekick).
/// curate[].reconfigure = imgUrl, reconnect(imgType): 2=视频，1或其他=图片
GalleryMediaItem? _mediaItemFromProgressData(
  Map<String, dynamic> data, {
  int? taskId,
}) {
  final curate = data['curate'] as List<dynamic>?;
  if (curate == null || curate.isEmpty) return null;
  final first = curate.first;
  if (first is! Map<String, dynamic>) return null;
  final reconfigure = first['reconfigure'] as String?;
  if (reconfigure == null || reconfigure.isEmpty) return null;
  final reconnect = first['reconnect'];
  final imgType = reconnect is int
      ? reconnect
      : reconnect is num
          ? reconnect.toInt()
          : 1;
  if (imgType == 2) {
    return GalleryMediaItem(videoUrl: reconfigure, taskId: taskId);
  }
  return GalleryMediaItem(imageUrl: reconfigure, taskId: taskId);
}

/// Generate Video Progress screen - matches Pencil rSN3T (video), Eghqc (label)
class GenerateProgressScreen extends StatefulWidget {
  const GenerateProgressScreen({super.key, this.taskId, this.imagePath});

  final dynamic taskId;
  final String? imagePath;

  @override
  State<GenerateProgressScreen> createState() => _GenerateProgressScreenState();
}

class _GenerateProgressScreenState extends State<GenerateProgressScreen> {
  int? _state;
  Timer? _pollTimer;
  bool _isFetching = false;

  double get _progress => _progressForState(_state);

  void _onBack(BuildContext context) {
    final completed = _state == 3;
    if (!completed) {
      TabSelectorScope.maybeOf(context)?.selectTab(NavTab.gallery);
      Navigator.of(context).popUntil(ModalRoute.withName('/'));
    } else {
      Navigator.of(context).pop();
    }
  }

  @override
  void initState() {
    super.initState();
    if (widget.taskId != null) {
      _startPolling();
    } else {
      _state = 2;
    }
  }

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

  Future<void> _startPolling() async {
    await AuthService.loginComplete;
    _pollTimer = Timer.periodic(
      const Duration(seconds: 5),
      (_) => _fetchProgress(),
    );
    _fetchProgress();
  }

  Future<void> _fetchProgress() async {
    if (widget.taskId == null) return;
    if (_isFetching) return;

    _isFetching = true;
    try {
      final res = await ImageApi.getProgress(
        sentinel: ApiConfig.appId,
        tree: widget.taskId.toString(),
        asset: UserState.userId.value,
      );

      if (!res.isSuccess || res.data == null) return;

      final data = res.data as Map<String, dynamic>;
      final state = (data['listing'] as num?)?.toInt();

      if (!mounted) return;

      setState(() => _state = state);

      switch (state) {
        case 3: // 完成
          _pollTimer?.cancel();
          // 生成成功后同步更新积分
          final userId = UserState.userId.value;
          if (userId != null && userId.isNotEmpty) {
            try {
              final accountRes = await UserApi.getAccount(
                sentinel: ApiConfig.appId,
                asset: userId,
              );
              if (accountRes.isSuccess && accountRes.data != null) {
                final accountData = accountRes.data as Map<String, dynamic>?;
                final credits = accountData?['reveal'] as int?;
                if (credits != null) {
                  UserState.setCredits(credits);
                }
              }
            } catch (_) {}
          }
          if (!mounted) return;
          final mediaItem = _mediaItemFromProgressData(
            data,
            taskId: _parseProgressTaskId(widget.taskId),
          );
          Navigator.of(context).pushReplacementNamed(
            '/result',
            arguments: mediaItem,
          );
          break;
        case 4:
        case 5:
        case 6: // 超时 / 错误 / 中止
          _pollTimer?.cancel();
          break;
      }
    } catch (_) {}
    finally {
      _isFetching = false;
    }
  }

  @override
  Widget build(BuildContext context) {
    final labelText = _stateLabels[_state] ?? 'Queued';

    return Scaffold(
      backgroundColor: AppColors.background,
      appBar: PreferredSize(
        preferredSize: const Size.fromHeight(56),
        child: TopNavBar(
          title: 'Generating',
          showBackButton: true,
          onBack: () => _onBack(context),
        ),
      ),
      body: SingleChildScrollView(
        padding: const EdgeInsets.all(AppSpacing.screenPaddingLarge),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            _VideoPreview(imagePath: widget.imagePath),
            const SizedBox(height: AppSpacing.xxl),
            Text(
              'Generating may take some time. Please wait patiently.',
              textAlign: TextAlign.center,
              style: AppTypography.bodyRegular.copyWith(
                color: AppColors.textSecondary,
              ),
            ),
            const SizedBox(height: AppSpacing.xxl),
            _ProgressSection(progress: _progress, label: labelText),
          ],
        ),
      ),
    );
  }
}

/// Video area rSN3T: show uploaded image with crop (BoxFit.cover)
class _VideoPreview extends StatelessWidget {
  const _VideoPreview({this.imagePath});

  final String? imagePath;

  @override
  Widget build(BuildContext context) {
    final hasImage = imagePath != null &&
        imagePath!.isNotEmpty &&
        File(imagePath!).existsSync();

    return Container(
      height: 360,
      decoration: BoxDecoration(
        color: AppColors.surfaceAlt,
        borderRadius: BorderRadius.circular(16),
        border: Border.all(color: AppColors.border, width: 1),
      ),
      clipBehavior: Clip.antiAlias,
      child: hasImage
          ? Image.file(
              File(imagePath!),
              fit: BoxFit.cover,
              width: double.infinity,
              height: double.infinity,
            )
          : Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                const Icon(
                  LucideIcons.film,
                  size: 64,
                  color: AppColors.textSecondary,
                ),
                const SizedBox(height: AppSpacing.lg),
                Text(
                  'Previewing',
                  style: AppTypography.bodyRegular.copyWith(
                    color: AppColors.textSecondary,
                  ),
                ),
              ],
            ),
    );
  }
}

/// Progress bar: 3 stages. Label shows state (Queued|Processing|Completed|Timeout|Error|Aborted)
class _ProgressSection extends StatelessWidget {
  const _ProgressSection({required this.progress, required this.label});

  final double progress;
  final String label;

  @override
  Widget build(BuildContext context) {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.stretch,
      children: [
        Text(
          label,
          style: AppTypography.bodyMedium.copyWith(
            fontSize: 16,
            fontWeight: FontWeight.w600,
            color: AppColors.textPrimary,
          ),
        ),
        const SizedBox(height: AppSpacing.lg),
        LayoutBuilder(
          builder: (context, constraints) {
            final fillWidth = constraints.maxWidth * progress.clamp(0.0, 1.0);
            return Stack(
              children: [
                Container(
                  height: 8,
                  decoration: BoxDecoration(
                    color: AppColors.border,
                    borderRadius: BorderRadius.circular(4),
                  ),
                ),
                Positioned(
                  left: 0,
                  top: 0,
                  bottom: 0,
                  child: Container(
                    width: fillWidth,
                    decoration: BoxDecoration(
                      color: AppColors.primary,
                      borderRadius: BorderRadius.circular(4),
                    ),
                  ),
                ),
              ],
            );
          },
        ),
      ],
    );
  }
}