import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';

import '../../core/theme/app_theme.dart';
import '../../providers/auth_provider.dart';
import '../../providers/upload_provider.dart';
import '../../services/upload_service.dart';
import '../feed/widgets/feed_overlays.dart';

/// 发布作品页（《03-接口文档》5.5/5.6）：
/// 三步：选视频 → 填信息（标题/描述/分类/标签） → 发布结果（进我的作品查看审核状态）
class UploadScreen extends ConsumerStatefulWidget {
  const UploadScreen({super.key});

  @override
  ConsumerState<UploadScreen> createState() => _UploadScreenState();
}

class _UploadScreenState extends ConsumerState<UploadScreen> {
  final _titleCtrl = TextEditingController();
  final _descCtrl = TextEditingController();
  final _tagsCtrl = TextEditingController();
  int? _categoryId;

  @override
  void dispose() {
    _titleCtrl.dispose();
    _descCtrl.dispose();
    _tagsCtrl.dispose();
    super.dispose();
  }

  /// 解析标签输入：空格/逗号/顿号分隔，去重，最多 5 个
  List<String> _parseTags() {
    return _tagsCtrl.text
        .split(RegExp(r'[\s,，、]+'))
        .map((e) => e.trim())
        .where((e) => e.isNotEmpty)
        .toSet()
        .take(5)
        .toList();
  }

  void _submit() {
    final title = _titleCtrl.text.trim();
    if (title.isEmpty) {
      showTopToast(context, '请填写标题');
      return;
    }
    if (_categoryId == null) {
      showTopToast(context, '请选择分类');
      return;
    }
    ref.read(uploadProvider.notifier).submit(
          title: title,
          description: _descCtrl.text.trim(),
          categoryId: _categoryId!,
          tags: _parseTags(),
        );
  }

  @override
  Widget build(BuildContext context) {
    final isLoggedIn = ref.watch(authProvider).isLoggedIn;
    if (!isLoggedIn) {
      return Scaffold(
        appBar: AppBar(title: const Text('发布作品')),
        body: Center(
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              const Icon(Icons.video_call_outlined,
                  size: 64, color: AppColors.textWeak),
              const SizedBox(height: 12),
              const Text('登录后发布你的作品',
                  style: TextStyle(color: AppColors.textSecondary)),
              const SizedBox(height: 16),
              ElevatedButton(
                onPressed: () => context.push('/login'),
                style:
                    ElevatedButton.styleFrom(minimumSize: const Size(160, 44)),
                child: const Text('去登录 / 注册'),
              ),
            ],
          ),
        ),
      );
    }

    // 发布失败：停留表单并提示服务端文案
    ref.listen(uploadProvider, (prev, next) {
      if (next.error.isNotEmpty && next.error != prev?.error) {
        showTopToast(context, next.error);
      }
    });

    final state = ref.watch(uploadProvider);
    return Scaffold(
      appBar: AppBar(title: const Text('发布作品')),
      body: switch (state.step) {
        UploadStep.pick => _PickStep(
            onPick: () => ref.read(uploadProvider.notifier).pickVideo(),
          ),
        UploadStep.edit || UploadStep.publishing => _EditStep(
            state: state,
            titleCtrl: _titleCtrl,
            descCtrl: _descCtrl,
            tagsCtrl: _tagsCtrl,
            categoryId: _categoryId,
            onCategoryChanged: (id) => setState(() => _categoryId = id),
            onReselect: () => ref.read(uploadProvider.notifier).reset(),
            onSubmit: _submit,
          ),
        UploadStep.done => _DoneStep(result: state.result),
      },
    );
  }
}

/// 第一步：选择视频
class _PickStep extends StatelessWidget {
  const _PickStep({required this.onPick});

  final VoidCallback onPick;

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          const Icon(Icons.cloud_upload_outlined,
              size: 72, color: AppColors.textWeak),
          const SizedBox(height: 16),
          const Text('选择相册中的视频',
              style: TextStyle(color: AppColors.textSecondary)),
          const SizedBox(height: 4),
          const Text('支持 mp4 / mov 等常见格式，不超过 500MB',
              style: TextStyle(color: AppColors.textWeak, fontSize: 12)),
          const SizedBox(height: 24),
          ElevatedButton(
            onPressed: onPick,
            style: ElevatedButton.styleFrom(minimumSize: const Size(180, 48)),
            child: const Text('选择视频'),
          ),
        ],
      ),
    );
  }
}

/// 第二步：填写作品信息（发布中显示进度）
class _EditStep extends ConsumerWidget {
  const _EditStep({
    required this.state,
    required this.titleCtrl,
    required this.descCtrl,
    required this.tagsCtrl,
    required this.categoryId,
    required this.onCategoryChanged,
    required this.onReselect,
    required this.onSubmit,
  });

  final UploadState state;
  final TextEditingController titleCtrl;
  final TextEditingController descCtrl;
  final TextEditingController tagsCtrl;
  final int? categoryId;
  final ValueChanged<int> onCategoryChanged;
  final VoidCallback onReselect;
  final VoidCallback onSubmit;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final publishing = state.publishing;
    final fileName = state.file?.name ?? '';
    final sizeMB = (state.fileSize / 1024 / 1024).toStringAsFixed(1);
    final asyncCategories = ref.watch(uploadCategoriesProvider);

    return ListView(
      padding: const EdgeInsets.all(16),
      children: [
        // 已选视频信息
        Container(
          padding: const EdgeInsets.all(12),
          decoration: BoxDecoration(
            color: AppColors.surface,
            borderRadius: BorderRadius.circular(8),
          ),
          child: Row(
            children: [
              const Icon(Icons.videocam_outlined,
                  color: AppColors.textSecondary),
              const SizedBox(width: 8),
              Expanded(
                child: Text(
                  '$fileName（$sizeMB MB）',
                  maxLines: 1,
                  overflow: TextOverflow.ellipsis,
                  style: const TextStyle(fontSize: 13),
                ),
              ),
              if (!publishing)
                TextButton(
                    onPressed: onReselect, child: const Text('重新选择')),
            ],
          ),
        ),
        const SizedBox(height: 16),
        TextField(
          controller: titleCtrl,
          enabled: !publishing,
          maxLength: 100,
          decoration: const InputDecoration(
            labelText: '标题',
            hintText: '给你的作品起个标题（必填）',
          ),
        ),
        const SizedBox(height: 8),
        TextField(
          controller: descCtrl,
          enabled: !publishing,
          maxLength: 500,
          maxLines: 3,
          decoration: const InputDecoration(
            labelText: '简介',
            hintText: '补充介绍一下（选填）',
          ),
        ),
        const SizedBox(height: 8),
        const Text('分类', style: TextStyle(color: AppColors.textSecondary)),
        const SizedBox(height: 8),
        asyncCategories.when(
          loading: () => const LinearProgressIndicator(),
          error: (_, __) => const Text('分类加载失败',
              style: TextStyle(color: AppColors.textWeak, fontSize: 12)),
          data: (categories) => Wrap(
            spacing: 8,
            runSpacing: 8,
            children: [
              for (final c in categories)
                ChoiceChip(
                  label: Text(c.name),
                  selected: categoryId == c.categoryId,
                  onSelected:
                      publishing ? null : (_) => onCategoryChanged(c.categoryId),
                ),
            ],
          ),
        ),
        const SizedBox(height: 16),
        TextField(
          controller: tagsCtrl,
          enabled: !publishing,
          decoration: const InputDecoration(
            labelText: '标签',
            hintText: '空格分隔，最多 5 个（选填）',
          ),
        ),
        const SizedBox(height: 24),
        if (publishing) ...[
          LinearProgressIndicator(value: state.progress / 100),
          const SizedBox(height: 8),
          Text(
            state.progress < 100 ? '上传中 ${state.progress}%' : '发布中…',
            textAlign: TextAlign.center,
            style:
                const TextStyle(color: AppColors.textSecondary, fontSize: 12),
          ),
        ] else
          ElevatedButton(
            onPressed: onSubmit,
            style: ElevatedButton.styleFrom(minimumSize: const Size(0, 48)),
            child: const Text('发布'),
          ),
      ],
    );
  }
}

/// 第三步：发布结果（引导去我的作品查看审核进度）
class _DoneStep extends StatelessWidget {
  const _DoneStep({required this.result});

  final PublishResult? result;

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Padding(
        padding: const EdgeInsets.all(24),
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            const Icon(Icons.check_circle_outline,
                size: 72, color: AppColors.secondary),
            const SizedBox(height: 16),
            const Text('发布成功',
                style: TextStyle(fontSize: 18, fontWeight: FontWeight.w700)),
            const SizedBox(height: 8),
            Text(
              '当前状态：${result?.statusText ?? '待审核'}，审核通过后自动上架',
              textAlign: TextAlign.center,
              style:
                  const TextStyle(color: AppColors.textSecondary, fontSize: 13),
            ),
            const SizedBox(height: 24),
            ElevatedButton(
              onPressed: () => context.pushReplacement('/mine/works'),
              style:
                  ElevatedButton.styleFrom(minimumSize: const Size(180, 44)),
              child: const Text('查看我的作品'),
            ),
            TextButton(
              onPressed: () => Navigator.of(context).maybePop(),
              child: const Text('返回',
                  style: TextStyle(color: AppColors.textSecondary)),
            ),
          ],
        ),
      ),
    );
  }
}