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

/// 对话消息列表
class ChatMessagesView extends ConsumerWidget {
  final ScrollController scrollCtrl;
  final List<ChatMessage> messages;

  const ChatMessagesView({super.key, required this.scrollCtrl, required this.messages});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final chatState = ref.watch(chatProvider);

    if (messages.isEmpty) {
      return Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Icon(Icons.chat_bubble_outline, size: 48, color: Colors.grey[300]),
            const SizedBox(height: 12),
            Text('开始和 AI 健康管家对话吧', style: Theme.of(context).textTheme.bodyMedium),
          ],
        ),
      );
    }

    return ListView.builder(
      controller: scrollCtrl,
      reverse: true,
      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
      itemCount: messages.length,
      itemBuilder: (context, index) {
        final msg = messages[messages.length - 1 - index];
        return _buildMessageBubble(context, msg, chatState);
      },
    );
  }

  Widget _buildMessageBubble(BuildContext context, ChatMessage msg, ChatState chatState) {
    final isUser = msg.isUser;
    return Align(
      alignment: isUser ? Alignment.centerRight : Alignment.centerLeft,
      child: Container(
        margin: const EdgeInsets.only(bottom: 12),
        constraints: BoxConstraints(maxWidth: MediaQuery.of(context).size.width * 0.78),
        padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 12),
        decoration: BoxDecoration(
          color: isUser ? const Color(0xFF635BFF) : Colors.white,
          borderRadius: BorderRadius.circular(16),
          border: isUser ? null : const Border(left: BorderSide(color: Color(0xFF635BFF), width: 3)),
        ),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            if (!isUser && chatState.isStreaming && msg.content.isEmpty)
              _buildThinkingIndicator()
            else
              Text(
                msg.content.isEmpty && !isUser ? '...' : msg.content,
                style: TextStyle(fontSize: 16, color: isUser ? Colors.white : const Color(0xFF1A1A1A)),
              ),
            if (!isUser && msg.content.isNotEmpty && !chatState.isStreaming)
              Padding(
                padding: const EdgeInsets.only(top: 8),
                child: Text(
                  'AI 健康管家 · 仅供参考',
                  style: TextStyle(fontSize: 12, color: Colors.grey[400]),
                ),
              ),
          ],
        ),
      ),
    );
  }

  Widget _buildThinkingIndicator() {
    return const Row(
      mainAxisSize: MainAxisSize.min,
      children: [
        SizedBox(width: 14, height: 14, child: CircularProgressIndicator(strokeWidth: 2)),
        SizedBox(width: 8),
        Text('思考中...', style: TextStyle(fontSize: 14, color: Color(0xFF999999))),
      ],
    );
  }
}