src/main/java/com/example/myproject/service/UserMessageService.java

package com.example.myproject.service;

import com.example.myproject.entity.UserMessages;
import com.example.myproject.repository.UserMessagesRepository;
import com.example.myproject.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.Optional;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Date;
import java.util.stream.Collectors;

@Service
public class UserMessageService {

    @Autowired
    private UserMessagesRepository userMessagesRepository;

    @Autowired
    private UserRepository userRepository;

    // 发送私信
    public Map<String, Object> sendMessage(Long senderId, Long receiverId, String content) {
        UserMessages message = new UserMessages();
        message.setSenderId(senderId);
        message.setReceiverId(receiverId);
        message.setContent(content);
        message.setTime(new Date());
        UserMessages savedMessage = userMessagesRepository.save(message);

        // 返回响应
        Map<String, Object> response = new HashMap<>();
        response.put("status", "success");
        response.put("message", "私信发送成功");
        response.put("message_id", savedMessage.getMessageId());
        return response;
    }

    // 获取当前用户的所有消息
    public Map<String, Object> getUserMessages(Long userId) {
        // 查询当前用户发送和接收的所有消息
        List<UserMessages> messages = userMessagesRepository.findBySenderIdOrReceiverId(userId, userId);

        // 获取发送者和接收者的用户名
        List<Map<String, Object>> messageDetails = messages.stream()
                .map(message -> {
                    Map<String, Object> messageMap = new HashMap<>();
                    messageMap.put("message_id", message.getMessageId());
                    messageMap.put("sender_id", message.getSenderId());
                    messageMap.put("receiver_id", message.getReceiverId());
                    messageMap.put("content", message.getContent());
                    messageMap.put("timestamp", message.getTime());
                    String senderUsername = userRepository.findById(message.getSenderId())
                            .map(user -> user.getUsername())
                            .orElse("Unknown");
                    messageMap.put("sender_username", senderUsername);
                    String receiverUsername = userRepository.findById(message.getReceiverId())
                            .map(user -> user.getUsername())
                            .orElse("Unknown");
                    messageMap.put("receiver_username", receiverUsername);

                    return messageMap;
                })
                .collect(Collectors.toList());

        Map<String, Object> response = new HashMap<>();
        response.put("status", "success");
        response.put("messages", messageDetails);
        return response;
    }

    // 获取单条消息的详情
    public Map<String, Object> getMessage(Long messageId) {
        Optional<UserMessages> optionalMessage = userMessagesRepository.findById(messageId);

        if (optionalMessage.isPresent()) {
            UserMessages message = optionalMessage.get();

            // 获取发送者和接收者的用户名
            String senderUsername = userRepository.findById(message.getSenderId())
                    .map(user -> user.getUsername())
                    .orElse("Unknown");
            String receiverUsername = userRepository.findById(message.getReceiverId())
                    .map(user -> user.getUsername())
                    .orElse("Unknown");

            // 构建响应数据
            Map<String, Object> response = new HashMap<>();
            Map<String, Object> messageDetails = new HashMap<>();
            messageDetails.put("message_id", message.getMessageId());
            messageDetails.put("sender_id", message.getSenderId());
            messageDetails.put("sender_username", senderUsername);
            messageDetails.put("receiver_id", message.getReceiverId());
            messageDetails.put("receiver_username", receiverUsername);
            messageDetails.put("content", message.getContent());
            messageDetails.put("timestamp", message.getTime());

            response.put("status", "success");
            response.put("message", messageDetails);
            return response;
        } else {
            Map<String, Object> errorResponse = new HashMap<>();
            errorResponse.put("status", "error");
            errorResponse.put("message", "Message not found");
            return errorResponse;
        }
    }


}