// 班级主页 — 日记墙 + 班级信息 + 成员 + 主题

import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:go_router/go_router.dart';
import 'package:nuanji_app/core/theme/app_colors.dart';
import 'package:nuanji_app/core/theme/app_radius.dart';
import 'package:nuanji_app/data/models/journal_entry.dart';
import 'package:nuanji_app/data/models/school_class.dart';
import 'package:nuanji_app/data/repositories/class_repository.dart';
import 'package:nuanji_app/data/repositories/journal_repository.dart';
import '../../auth/bloc/auth_bloc.dart';
import '../bloc/class_bloc.dart';
import '../widgets/comment_bottom_sheet.dart';

/// 班级主页 — 日记墙 + 班级信息
class ClassPage extends StatelessWidget {
  const ClassPage({super.key});

  @override
  Widget build(BuildContext context) {
    return BlocProvider(
      create: (context) => ClassBloc(
        classRepository: context.read<ClassRepository>(),
        journalRepository: context.read<JournalRepository>(),
      )..add(const ClassLoadMyClasses()),
      child: const _ClassView(),
    );
  }
}

class _ClassView extends StatelessWidget {
  const _ClassView();

  @override
  Widget build(BuildContext context) {
    return BlocBuilder<ClassBloc, ClassState>(
      builder: (context, state) {
        if (state is ClassLoading || state is ClassInitial) {
          return Scaffold(
            appBar: AppBar(title: const Text('班级')),
            body: Center(child: CircularProgressIndicator()),
          );
        }

        if (state is ClassError) {
          return Scaffold(
            appBar: AppBar(title: const Text('班级')),
            body: Center(child: Text(state.message)),
          );
        }

        if (state is ClassListLoaded) {
          return _ClassListView(classes: state.classes, colorScheme: Theme.of(context).colorScheme);
        }

        if (state is ClassDetailLoaded) {
          return _ClassDetailView(state: state);
        }

        return const SizedBox.shrink();
      },
    );
  }
}

// ===== 班级列表视图 =====

class _ClassListView extends StatelessWidget {
  const _ClassListView({required this.classes, required this.colorScheme});

  final List<SchoolClass> classes;
  final ColorScheme colorScheme;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('我的班级')),
      body: classes.isEmpty
          ? _buildEmptyState(context, colorScheme)
          : ListView(
              padding: const EdgeInsets.all(16),
              children: classes.map((cls) {
                return _ClassListCard(
                  cls: cls,
                  colorScheme: colorScheme,
                  onTap: () =>
                      context.read<ClassBloc>().add(ClassSelected(cls.id)),
                );
              }).toList(),
            ),
    );
  }

  Widget _buildEmptyState(BuildContext context, ColorScheme colorScheme) {
    return Center(
      child: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          Icon(Icons.groups_outlined, size: 64, color: colorScheme.onSurface.withValues(alpha: 0.2)),
          const SizedBox(height: 16),
          Text('还没有加入任何班级', style: Theme.of(context).textTheme.bodyLarge?.copyWith(
            color: colorScheme.onSurface.withValues(alpha: 0.5),
          )),
          const SizedBox(height: 24),
          FilledButton.tonal(
            onPressed: () => context.go('/class-code'),
            child: const Text('输入班级码加入'),
          ),
        ],
      ),
    );
  }
}

class _ClassListCard extends StatelessWidget {
  const _ClassListCard({
    required this.cls,
    required this.colorScheme,
    required this.onTap,
  });

  final SchoolClass cls;
  final ColorScheme colorScheme;
  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);

    return Card(
      margin: const EdgeInsets.only(bottom: 12),
      elevation: 0,
      shape: RoundedRectangleBorder(
        borderRadius: AppRadius.mdBorder,
        side: BorderSide(color: colorScheme.outlineVariant),
      ),
      child: InkWell(
        onTap: onTap,
        borderRadius: AppRadius.mdBorder,
        child: Padding(
          padding: const EdgeInsets.all(16),
          child: Row(
            children: [
              Container(
                width: 48,
                height: 48,
                decoration: BoxDecoration(
                  color: AppColors.secondary.withValues(alpha: 0.15),
                  borderRadius: BorderRadius.circular(12),
                ),
                alignment: Alignment.center,
                child: const Icon(Icons.school_rounded, color: AppColors.secondary),
              ),
              const SizedBox(width: 16),
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text(cls.name, style: theme.textTheme.titleSmall?.copyWith(fontWeight: FontWeight.w600)),
                    const SizedBox(height: 4),
                    Text(
                      '${cls.schoolName} · ${cls.memberCount} 人',
                      style: theme.textTheme.bodySmall?.copyWith(
                        color: colorScheme.onSurface.withValues(alpha: 0.5),
                      ),
                    ),
                  ],
                ),
              ),
              const Icon(Icons.chevron_right),
            ],
          ),
        ),
      ),
    );
  }
}

// ===== 班级详情视图（日记墙）=====

class _ClassDetailView extends StatelessWidget {
  const _ClassDetailView({required this.state});

  final ClassDetailLoaded state;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final colorScheme = theme.colorScheme;
    final classInfo = state.classInfo;

    return DefaultTabController(
      length: 3,
      child: Scaffold(
        appBar: AppBar(
          leading: IconButton(
            onPressed: () => context.read<ClassBloc>().add(const ClassLoadMyClasses()),
            icon: const Icon(Icons.arrow_back),
          ),
          title: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(classInfo.name),
              Text(
                '${classInfo.schoolName} · 班级码: ${classInfo.classCode}',
                style: theme.textTheme.labelSmall?.copyWith(
                  color: colorScheme.onSurface.withValues(alpha: 0.5),
                ),
              ),
            ],
          ),
          bottom: const TabBar(
            tabs: [
              Tab(text: '日记墙'),
              Tab(text: '主题'),
              Tab(text: '成员'),
            ],
          ),
        ),
        body: TabBarView(
          children: [
            // 日记墙
            _DiaryWallTab(state: state),
            // 主题布置
            _TopicsTab(topics: state.topics),
            // 成员列表
            _MembersTab(state: state),
          ],
        ),
      ),
    );
  }
}

// ===== 日记墙 Tab =====

class _DiaryWallTab extends StatelessWidget {
  const _DiaryWallTab({required this.state});

  final ClassDetailLoaded state;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final colorScheme = theme.colorScheme;

    if (state.isLoadingWall) {
      return const Center(child: CircularProgressIndicator());
    }

    if (state.diaryWall.isEmpty) {
      return Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Icon(Icons.auto_stories_outlined, size: 48, color: colorScheme.onSurface.withValues(alpha: 0.2)),
            const SizedBox(height: 12),
            Text('日记墙还是空的', style: theme.textTheme.bodyLarge?.copyWith(
              color: colorScheme.onSurface.withValues(alpha: 0.5),
            )),
            const SizedBox(height: 8),
            Text('分享你的日记到班级吧！', style: theme.textTheme.bodySmall?.copyWith(
              color: colorScheme.onSurface.withValues(alpha: 0.3),
            )),
          ],
        ),
      );
    }

    return ListView.builder(
      padding: const EdgeInsets.all(16),
      itemCount: state.diaryWall.length,
      itemBuilder: (context, index) {
        final journal = state.diaryWall[index];
        return _DiaryWallCard(journal: journal, comments: state.comments);
      },
    );
  }
}

class _DiaryWallCard extends StatelessWidget {
  const _DiaryWallCard({required this.journal, required this.comments});

  final JournalEntry journal;
  final List<Comment> comments;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final colorScheme = theme.colorScheme;
    final moodColor = AppColors.moodColors[journal.mood.value] ?? colorScheme.primary;

    return Card(
      margin: const EdgeInsets.only(bottom: 12),
      elevation: 0,
      shape: RoundedRectangleBorder(
        borderRadius: AppRadius.mdBorder,
        side: BorderSide(color: colorScheme.outlineVariant),
      ),
      child: InkWell(
        onTap: () => context.push('/editor?id=${journal.id}'),
        borderRadius: AppRadius.mdBorder,
        child: Padding(
          padding: const EdgeInsets.all(16),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              // 头部：作者 + 心情
              Row(
                children: [
                  CircleAvatar(
                    radius: 16,
                    backgroundColor: AppColors.rose.withValues(alpha: 0.2),
                    child: Text(
                      '同',
                      style: theme.textTheme.labelMedium?.copyWith(color: AppColors.rose),
                    ),
                  ),
                  const SizedBox(width: 8),
                  Expanded(
                    child: Text(
                      journal.title,
                      style: theme.textTheme.titleSmall?.copyWith(fontWeight: FontWeight.w600),
                    ),
                  ),
                  Container(
                    width: 28,
                    height: 28,
                    decoration: BoxDecoration(
                      shape: BoxShape.circle,
                      color: moodColor.withValues(alpha: 0.15),
                    ),
                    alignment: Alignment.center,
                    child: Text(_moodEmoji(journal.mood), style: const TextStyle(fontSize: 14)),
                  ),
                ],
              ),
              const SizedBox(height: 8),
              // 日期
              Text(
                '${journal.date.month}月${journal.date.day}日',
                style: theme.textTheme.bodySmall?.copyWith(
                  color: colorScheme.onSurface.withValues(alpha: 0.4),
                ),
              ),
              // 评语
              if (comments.isNotEmpty) ...[
                const SizedBox(height: 8),
                Container(
                  padding: const EdgeInsets.all(8),
                  decoration: BoxDecoration(
                    color: colorScheme.primaryContainer.withValues(alpha: 0.3),
                    borderRadius: AppRadius.smBorder,
                  ),
                  child: Row(
                    children: [
                      const Icon(Icons.rate_review_rounded, size: 14),
                      const SizedBox(width: 4),
                      Expanded(
                        child: Text(
                          comments.first.content,
                          style: theme.textTheme.bodySmall,
                          maxLines: 2,
                          overflow: TextOverflow.ellipsis,
                        ),
                      ),
                    ],
                  ),
                ),
              ],
              // 写评语按钮（仅老师可见）
              if (_isTeacher(context)) ...[
                const SizedBox(height: 8),
                TextButton.icon(
                  onPressed: () {
                    showModalBottomSheet(
                      context: context,
                      isScrollControlled: true,
                      builder: (_) => CommentBottomSheet(
                        journalId: journal.id,
                        studentName: journal.authorId, // TODO: 替换为真实昵称
                        onSubmit: (content) {
                          context.read<ClassBloc>().add(
                                CommentCreate(
                                  journalId: journal.id,
                                  content: content,
                                ),
                              );
                        },
                      ),
                    );
                  },
                  icon: const Icon(Icons.rate_review_outlined, size: 16),
                  label: const Text('写评语'),
                  style: TextButton.styleFrom(
                    padding: const EdgeInsets.symmetric(horizontal: 12),
                    minimumSize: const Size(0, 36),
                  ),
                ),
              ],
            ],
          ),
        ),
      ),
    );
  }

  /// 判断当前用户是否是老师
  bool _isTeacher(BuildContext context) {
    final authState = context.read<AuthBloc>().state;
    if (authState is Authenticated) {
      return authState.user.isTeacher;
    }
    return false;
  }

  String _moodEmoji(Mood mood) => switch (mood) {
        Mood.happy => '😊',
        Mood.calm => '😌',
        Mood.sad => '😢',
        Mood.angry => '😠',
        Mood.thinking => '🤔',
      };
}

// ===== 主题 Tab =====

class _TopicsTab extends StatelessWidget {
  const _TopicsTab({required this.topics});

  final List<TopicAssignment> topics;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final colorScheme = theme.colorScheme;

    if (topics.isEmpty) {
      return Center(
        child: Text('暂无主题布置', style: theme.textTheme.bodyLarge?.copyWith(
          color: colorScheme.onSurface.withValues(alpha: 0.5),
        )),
      );
    }

    return ListView.builder(
      padding: const EdgeInsets.all(16),
      itemCount: topics.length,
      itemBuilder: (context, index) {
        final topic = topics[index];
        final isOverdue = topic.dueDate != null && topic.dueDate!.isBefore(DateTime.now());

        return Card(
          margin: const EdgeInsets.only(bottom: 12),
          elevation: 0,
          shape: RoundedRectangleBorder(
            borderRadius: AppRadius.mdBorder,
            side: BorderSide(color: colorScheme.outlineVariant),
          ),
          child: InkWell(
            onTap: () => context.push('/editor?topic=${topic.id}'),
            borderRadius: AppRadius.mdBorder,
            child: Padding(
              padding: const EdgeInsets.all(16),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Row(
                    children: [
                      const Icon(Icons.assignment_outlined, size: 20),
                      const SizedBox(width: 8),
                      Expanded(
                        child: Text(
                          topic.title,
                          style: theme.textTheme.titleSmall?.copyWith(fontWeight: FontWeight.w600),
                        ),
                      ),
                      if (topic.isActive && !isOverdue)
                        Container(
                          padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 2),
                          decoration: BoxDecoration(
                            color: AppColors.secondary.withValues(alpha: 0.15),
                            borderRadius: BorderRadius.circular(6),
                          ),
                          child: Text('进行中', style: theme.textTheme.labelSmall?.copyWith(color: AppColors.secondary)),
                        ),
                    ],
                  ),
                  if (topic.description != null) ...[
                    const SizedBox(height: 8),
                    Text(topic.description!, style: theme.textTheme.bodyMedium),
                  ],
                  if (topic.dueDate != null) ...[
                    const SizedBox(height: 8),
                    Text(
                      '截止: ${topic.dueDate!.month}月${topic.dueDate!.day}日',
                      style: theme.textTheme.bodySmall?.copyWith(
                        color: isOverdue ? colorScheme.error : colorScheme.onSurface.withValues(alpha: 0.5),
                      ),
                    ),
                  ],
                ],
              ),
            ),
          ),
        );
      },
    );
  }
}

// ===== 成员 Tab =====

class _MembersTab extends StatelessWidget {
  const _MembersTab({required this.state});

  final ClassDetailLoaded state;

  @override
  Widget build(BuildContext context) {
    if (state.isLoadingMembers) {
      return const Center(child: CircularProgressIndicator());
    }

    final theme = Theme.of(context);

    return ListView.builder(
      padding: const EdgeInsets.all(16),
      itemCount: state.members.length,
      itemBuilder: (context, index) {
        final member = state.members[index];
        final isTeacher = member.role == 'teacher';

        return ListTile(
          leading: CircleAvatar(
            backgroundColor: isTeacher
                ? AppColors.accent.withValues(alpha: 0.15)
                : AppColors.secondary.withValues(alpha: 0.15),
            child: Text(
              (member.nickname ?? '?').characters.first,
              style: TextStyle(
                color: isTeacher ? AppColors.accent : AppColors.secondary,
                fontWeight: FontWeight.bold,
              ),
            ),
          ),
          title: Text(member.nickname ?? '未知'),
          trailing: isTeacher
              ? Container(
                  padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 2),
                  decoration: BoxDecoration(
                    color: AppColors.accent.withValues(alpha: 0.1),
                    borderRadius: BorderRadius.circular(6),
                  ),
                  child: Text('老师', style: theme.textTheme.labelSmall?.copyWith(color: AppColors.accent)),
                )
              : null,
        );
      },
    );
  }
}