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

import '../../../core/network/api_exception.dart';
import '../../../core/theme/app_theme.dart';
import '../../../models/comment_item.dart';
import '../../../providers/auth_provider.dart';
import '../../../providers/comment_provider.dart';
import 'feed_overlays.dart';

/// 打开评论弹层（《01-开发文档》2.6 评论：一级 + 楼中楼二级回复）
/// [onCountChanged] 发表/删除成功后回调（delta=±1），用于同步 Feed 评论计数
Future<void> showCommentSheet(
  BuildContext context, {
  required int videoId,
  required void Function(int delta) onCountChanged,
}) {
  return showModalBottomSheet<void>(
    context: context,
    isScrollControlled: true,
    backgroundColor: AppColors.surface,
    shape: const RoundedRectangleBorder(
      borderRadius: BorderRadius.vertical(top: Radius.circular(12)),
    ),
    builder: (_) => CommentSheet(
      videoId: videoId,
      onCountChanged: onCountChanged,
    ),
  );
}

class CommentSheet extends ConsumerStatefulWidget {
  const CommentSheet({
    super.key,
    required this.videoId,
    required this.onCountChanged,
  });

  final int videoId;

  /// 评论计数变化回调（发表 +1 / 删除 -1）
  final void Function(int delta) onCountChanged;

  @override
  ConsumerState<CommentSheet> createState() => _CommentSheetState();
}

class _CommentSheetState extends ConsumerState<CommentSheet> {
  final _inputController = TextEditingController();
  final _scrollController = ScrollController();
  final _inputFocus = FocusNode();

  @override
  void initState() {
    super.initState();
    _scrollController.addListener(_onScroll);
  }

  @override
  void dispose() {
    _inputController.dispose();
    _scrollController.dispose();
    _inputFocus.dispose();
    super.dispose();
  }

  void _onScroll() {
    if (_scrollController.position.pixels >
        _scrollController.position.maxScrollExtent - 100) {
      ref.read(commentProvider(widget.videoId).notifier).loadMore();
    }
  }

  /// 发表（游客守卫：跳登录页）
  Future<void> _send() async {
    if (!ref.read(authProvider).isLoggedIn) {
      context.go('/login');
      return;
    }
    final content = _inputController.text.trim();
    if (content.isEmpty) return;
    final notifier = ref.read(commentProvider(widget.videoId).notifier);
    try {
      final result = await notifier.post(content);
      _inputController.clear();
      _inputFocus.unfocus();
      widget.onCountChanged(1);
      if (!mounted) return;
      final progress = result.rewardProgress;
      if (progress.rewardedThisTime) {
        showTopToast(context, '评论奖励 +${progress.rewardPoints} 积分');
      }
    } on ApiException catch (e) {
      if (mounted) showTopToast(context, e.message);
    } catch (_) {
      if (mounted) showTopToast(context, '发表失败，请重试');
    }
  }

  /// 删除确认（本人评论/本人视频下评论）
  Future<void> _confirmDelete(CommentItem comment, {int parentId = 0}) async {
    final ok = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        backgroundColor: AppColors.surface,
        title: const Text('删除评论', style: TextStyle(fontSize: 16)),
        content: const Text('确定删除这条评论吗？'),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(ctx, false),
            child: const Text('取消'),
          ),
          TextButton(
            onPressed: () => Navigator.pop(ctx, true),
            child: const Text('删除', style: TextStyle(color: AppColors.primary)),
          ),
        ],
      ),
    );
    if (ok != true || !mounted) return;
    try {
      await ref
          .read(commentProvider(widget.videoId).notifier)
          .remove(comment, parentId: parentId);
      widget.onCountChanged(-1);
    } on ApiException catch (e) {
      if (mounted) showTopToast(context, e.message);
    } catch (_) {
      if (mounted) showTopToast(context, '删除失败，请重试');
    }
  }

  @override
  Widget build(BuildContext context) {
    final state = ref.watch(commentProvider(widget.videoId));
    final notifier = ref.read(commentProvider(widget.videoId).notifier);

    return SizedBox(
      height: MediaQuery.of(context).size.height * 0.7,
      child: Column(
        children: [
          // 头部：标题 + 关闭
          SizedBox(
            height: 48,
            child: Stack(
              children: [
                Center(
                  child: Text(
                    state.total > 0 ? '评论 ${state.total}' : '评论',
                    style: const TextStyle(
                      fontSize: 15,
                      fontWeight: FontWeight.w600,
                    ),
                  ),
                ),
                Positioned(
                  right: 4,
                  top: 0,
                  bottom: 0,
                  child: IconButton(
                    icon: const Icon(Icons.close, size: 20),
                    onPressed: () => Navigator.pop(context),
                  ),
                ),
              ],
            ),
          ),
          const Divider(height: 1),

          // 评论列表
          Expanded(child: _buildList(state, notifier)),

          // 回复目标提示条
          if (state.replyTarget != null)
            Container(
              width: double.infinity,
              color: AppColors.background,
              padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 6),
              child: Row(
                children: [
                  Expanded(
                    child: Text(
                      '回复 @${state.replyTarget!.nickname}',
                      style: const TextStyle(
                        color: AppColors.textSecondary,
                        fontSize: 12,
                      ),
                    ),
                  ),
                  GestureDetector(
                    onTap: () => notifier.setReplyTarget(null),
                    child: const Icon(Icons.close,
                        size: 16, color: AppColors.textSecondary),
                  ),
                ],
              ),
            ),

          // 输入区
          SafeArea(
            top: false,
            child: Padding(
              padding: EdgeInsets.only(
                left: 12,
                right: 12,
                top: 8,
                bottom: MediaQuery.of(context).viewInsets.bottom + 8,
              ),
              child: Row(
                children: [
                  Expanded(
                    child: TextField(
                      controller: _inputController,
                      focusNode: _inputFocus,
                      maxLength: 500,
                      maxLines: 1,
                      style: const TextStyle(fontSize: 14),
                      decoration: InputDecoration(
                        hintText: state.replyTarget == null
                            ? '说点什么...'
                            : '回复 @${state.replyTarget!.nickname}',
                        counterText: '',
                        isDense: true,
                        contentPadding: const EdgeInsets.symmetric(
                          horizontal: 12,
                          vertical: 10,
                        ),
                      ),
                      onTap: () {
                        // 游客点击输入框：守卫跳登录
                        if (!ref.read(authProvider).isLoggedIn) {
                          _inputFocus.unfocus();
                          context.go('/login');
                        }
                      },
                      onSubmitted: (_) => _send(),
                    ),
                  ),
                  const SizedBox(width: 8),
                  TextButton(
                    onPressed: state.posting ? null : _send,
                    child: Text(
                      state.posting ? '发送中' : '发送',
                      style: TextStyle(
                        color: state.posting
                            ? AppColors.textWeak
                            : AppColors.primary,
                        fontWeight: FontWeight.w600,
                      ),
                    ),
                  ),
                ],
              ),
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildList(CommentState state, CommentNotifier notifier) {
    if (state.isLoading) {
      return const Center(
        child: CircularProgressIndicator(color: AppColors.primary),
      );
    }
    if (state.loadFailed) {
      return Center(
        child: TextButton(
          onPressed: notifier.load,
          child: const Text('加载失败，点击重试',
              style: TextStyle(color: AppColors.primary)),
        ),
      );
    }
    if (state.items.isEmpty) {
      return const Center(
        child: Text('还没有评论，快来抢沙发',
            style: TextStyle(color: AppColors.textSecondary)),
      );
    }
    return ListView.builder(
      controller: _scrollController,
      padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 8),
      itemCount: state.items.length + (state.isLoadingMore ? 1 : 0),
      itemBuilder: (context, index) {
        if (index >= state.items.length) {
          return const Padding(
            padding: EdgeInsets.all(12),
            child: Center(
              child: SizedBox(
                width: 20,
                height: 20,
                child: CircularProgressIndicator(
                    strokeWidth: 2, color: AppColors.primary),
              ),
            ),
          );
        }
        final comment = state.items[index];
        final replies = state.replies[comment.commentId];
        return Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            CommentTile(
              comment: comment,
              canDelete: _canDelete(comment),
              onReply: () => _replyTo(comment, rootId: comment.commentId),
              onDelete: () => _confirmDelete(comment),
            ),
            // 回复展开入口
            if (comment.replyCount > 0)
              Padding(
                padding: const EdgeInsets.only(left: 44),
                child: GestureDetector(
                  onTap: () => notifier.toggleReplies(comment),
                  child: Text(
                    state.repliesLoading.contains(comment.commentId)
                        ? '加载中...'
                        : replies == null
                            ? '展开 ${comment.replyCount} 条回复'
                            : '收起回复',
                    style: const TextStyle(
                      color: AppColors.secondary,
                      fontSize: 12,
                    ),
                  ),
                ),
              ),
            // 二级回复列表
            if (replies != null)
              Padding(
                padding: const EdgeInsets.only(left: 44, top: 4),
                child: Column(
                  children: [
                    for (final reply in replies)
                      CommentTile(
                        comment: reply,
                        compact: true,
                        canDelete: _canDelete(reply),
                        onReply: () => _replyTo(
                          reply,
                          rootId: comment.commentId,
                        ),
                        onDelete: () => _confirmDelete(
                          reply,
                          parentId: comment.commentId,
                        ),
                      ),
                    if (comment.replyCount > replies.length)
                      Text(
                        '共 ${comment.replyCount} 条回复',
                        style: const TextStyle(
                          color: AppColors.textWeak,
                          fontSize: 12,
                        ),
                      ),
                  ],
                ),
              ),
          ],
        );
      },
    );
  }

  /// 本人评论可删（本人视频下他人评论的删除依赖视频作者身份，一期仅支持自删）
  bool _canDelete(CommentItem comment) {
    final user = ref.read(authProvider).user;
    return user != null && user.userId == comment.userId;
  }

  void _replyTo(CommentItem comment, {required int rootId}) {
    if (!ref.read(authProvider).isLoggedIn) {
      context.go('/login');
      return;
    }
    ref.read(commentProvider(widget.videoId).notifier).setReplyTarget(
          ReplyTarget(
            parentId: rootId,
            replyToUserId: comment.userId,
            nickname: comment.nickname,
          ),
        );
    _inputFocus.requestFocus();
  }
}

/// 单条评论（一级/二级通用，compact 为二级样式）
class CommentTile extends StatelessWidget {
  const CommentTile({
    super.key,
    required this.comment,
    required this.onReply,
    required this.onDelete,
    this.canDelete = false,
    this.compact = false,
  });

  final CommentItem comment;
  final VoidCallback onReply;
  final VoidCallback onDelete;

  /// 是否可删除（本人评论）
  final bool canDelete;

  /// 二级回复紧凑样式
  final bool compact;

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onLongPress: canDelete ? onDelete : null,
      child: Padding(
        padding: EdgeInsets.symmetric(vertical: compact ? 4 : 8),
        child: Row(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            // 头像
            CircleAvatar(
              radius: compact ? 12 : 16,
              backgroundColor: AppColors.background,
              backgroundImage: comment.avatarUrl.isNotEmpty
                  ? CachedNetworkImageProvider(comment.avatarUrl)
                  : null,
              child: comment.avatarUrl.isEmpty
                  ? Text(
                      comment.nickname.isNotEmpty
                          ? comment.nickname.characters.first
                          : '友',
                      style: TextStyle(
                        color: Colors.white,
                        fontSize: compact ? 10 : 13,
                      ),
                    )
                  : null,
            ),
            const SizedBox(width: 8),
            // 昵称 + 内容 + 操作
            Expanded(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(
                    '${comment.nickname} · ${_formatTime(comment.createdAt)}',
                    style: const TextStyle(
                      color: AppColors.textSecondary,
                      fontSize: 12,
                    ),
                  ),
                  const SizedBox(height: 2),
                  Text(
                    comment.content,
                    style: const TextStyle(fontSize: 14),
                  ),
                  const SizedBox(height: 2),
                  GestureDetector(
                    onTap: onReply,
                    child: const Text(
                      '回复',
                      style: TextStyle(
                        color: AppColors.textWeak,
                        fontSize: 12,
                      ),
                    ),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }

  /// 时间紧凑显示："2026-10-14 10:00:00" → "10-14 10:00"；"刚刚"原样
  static String _formatTime(String raw) {
    if (raw.length >= 16) return raw.substring(5, 16);
    return raw;
  }
}