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

import 'package:im_app/app/di/app_providers.dart';
import 'package:im_app/domain/entities/chat.dart';
import 'package:im_app/features/chat/di/chat_provider.dart';
import 'package:im_app/features/chat/di/chat_service_providers.dart';
import 'package:im_app/features/chat/presentation/chat_list_view_model.dart';

/// 聊天列表页
///
/// 从本地 DB Stream 读取会话列表，实时反映 WS 推送的新消息摘要。
/// 点击任意会话进入 [ChatDetailPage]（chatId + 名称作为路由参数）。
class ChatPage extends ConsumerWidget {
  const ChatPage({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final vm = ref.watch(chatListViewModelProvider.notifier);
    final chatsAsync = ref.watch(allChatsProvider);
    // 监听输入状态变化 → 触发列表重建（对齐 iOS @Published typing 全局更新）
    ref.watch(typingChangeProvider);

    return Scaffold(
      appBar: AppBar(
        title: const Text('消息'),
        actions: [
          IconButton(
            icon: const Icon(Icons.storage_outlined),
            tooltip: '数据库测试',
            onPressed: () => vm.goToDatabaseTest(context),
          ),
        ],
      ),
      body: chatsAsync.when(
        data: (chats) => chats.isEmpty
            ? const Center(child: Text('暂无会话'))
            : ListView.separated(
                itemCount: chats.length,
                separatorBuilder: (_, __) =>
                    const Divider(height: 1, indent: 72),
                itemBuilder: (context, index) =>
                    _ChatTile(chat: chats[index], vm: vm),
              ),
        loading: () => const Center(child: CircularProgressIndicator()),
        error: (e, _) => Center(child: Text('加载失败: $e')),
      ),
    );
  }
}

class _ChatTile extends ConsumerWidget {
  const _ChatTile({required this.chat, required this.vm});

  final Chat chat;
  final ChatListViewModel vm;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final name = chat.name ?? 'Chat ${chat.chatId ?? chat.id}';
    final lastMsg = chat.lastMsg ?? '';
    final unread = chat.unreadNum ?? 0;
    final sendTime = chat.lastTime;
    final timeStr = sendTime != null ? _formatTime(sendTime) : '';

    // 正在输入状态（对齐 iOS ConversationCell.typingText）
    final chatId = chat.chatId ?? chat.id;
    final myUid = ref.watch(authNotifierProvider).currentUid ?? 0;
    final typingMgr = ref.watch(typingIndicatorManagerProvider);
    final isGroup = (chat.typ ?? 1) == 2;
    final typingText = isGroup
        ? typingMgr.groupDisplayText(chatId: chatId, myUserId: myUid)
        : typingMgr.displayText(chatId: chatId, myUserId: myUid);

    return ListTile(
      leading: CircleAvatar(
        backgroundColor: Theme.of(context).colorScheme.primaryContainer,
        child: Text(
          name.isNotEmpty ? name[0].toUpperCase() : '?',
          style: TextStyle(
            color: Theme.of(context).colorScheme.onPrimaryContainer,
          ),
        ),
      ),
      title: Row(
        children: [
          Expanded(
            child: Text(name, maxLines: 1, overflow: TextOverflow.ellipsis),
          ),
          if (timeStr.isNotEmpty)
            Text(
              timeStr,
              style: Theme.of(context).textTheme.bodySmall?.copyWith(
                    color: Theme.of(context).colorScheme.outline,
                  ),
            ),
        ],
      ),
      subtitle: Row(
        children: [
          Expanded(
            child: typingText != null
                // 输入状态优先显示（绿色，对齐 iOS onlineGreen）
                ? Text(
                    typingText,
                    maxLines: 1,
                    overflow: TextOverflow.ellipsis,
                    style: Theme.of(context).textTheme.bodySmall?.copyWith(
                          color: Colors.green.shade600,
                        ),
                  )
                : Text(
                    lastMsg,
                    maxLines: 1,
                    overflow: TextOverflow.ellipsis,
                    style: Theme.of(context).textTheme.bodySmall?.copyWith(
                          color: Theme.of(context).colorScheme.outline,
                        ),
                  ),
          ),
          if (unread > 0)
            Container(
              margin: const EdgeInsets.only(left: 4),
              padding: const EdgeInsets.symmetric(horizontal: 6, vertical: 2),
              decoration: BoxDecoration(
                color: Theme.of(context).colorScheme.error,
                borderRadius: BorderRadius.circular(10),
              ),
              child: Text(
                unread > 99 ? '99+' : '$unread',
                style: Theme.of(context).textTheme.labelSmall?.copyWith(
                      color: Theme.of(context).colorScheme.onError,
                    ),
              ),
            ),
        ],
      ),
      onTap: () => vm.openChat(context, chat),
    );
  }

  String _formatTime(int unixSec) {
    final dt = DateTime.fromMillisecondsSinceEpoch(unixSec * 1000);
    final now = DateTime.now();
    if (dt.year == now.year &&
        dt.month == now.month &&
        dt.day == now.day) {
      return '${dt.hour.toString().padLeft(2, '0')}:'
          '${dt.minute.toString().padLeft(2, '0')}';
    }
    return '${dt.month}/${dt.day}';
  }
}