// 示例：使用Node.js和Express创建基本API端点
const express = require('express');
const app = express();
const bodyParser = require('body-parser');

app.use(bodyParser.json());

// 模拟数据库
let tweets = [];
let users = [];

// 用户注册
app.post('/api/register', (req, res) => {
  const { username, email, password } = req.body;
  users.push({ id: users.length + 1, username, email, password });
  res.status(201).json({ message: 'User registered successfully' });
});

// 发布推文
app.post('/api/tweets', (req, res) => {
  const { userId, content } = req.body;
  tweets.push({ 
    id: tweets.length + 1, 
    userId, 
    content, 
    createdAt: new Date(),
    likes: 0,
    retweets: 0
  });
  res.status(201).json({ message: 'Tweet posted successfully' });
});

// 获取用户时间线
app.get('/api/timeline/:userId', (req, res) => {
  const userTweets = tweets.filter(t => t.userId == req.params.userId);
  res.json(userTweets);
});

app.listen(3000, () => console.log('API server running on port 3000'));

// 示例：使用React获取和显示推文
import React, { useState, useEffect } from 'react';
import axios from 'axios';

function TweetTimeline({ userId }) {
  const [tweets, setTweets] = useState([]);
  
  useEffect(() => {
    axios.get(`/api/timeline/${userId}`)
      .then(response => setTweets(response.data))
      .catch(error => console.error(error));
  }, [userId]);

  return (
    <div>
      {tweets.map(tweet => (
        <div key={tweet.id} className="tweet">
          <p>{tweet.content}</p>
          <small>{new Date(tweet.createdAt).toLocaleString()}</small>
        </div>
      ))}
    </div>
  );
}

-- 用户表
CREATE TABLE users (
  id SERIAL PRIMARY KEY,
  username VARCHAR(50) UNIQUE NOT NULL,
  email VARCHAR(100) UNIQUE NOT NULL,
  password_hash VARCHAR(255) NOT NULL,
  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

-- 推文表
CREATE TABLE tweets (
  id SERIAL PRIMARY KEY,
  user_id INTEGER REFERENCES users(id),
  content TEXT NOT NULL,
  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
  like_count INTEGER DEFAULT 0,
  retweet_count INTEGER DEFAULT 0
);

-- 关注关系表
CREATE TABLE follows (
  follower_id INTEGER REFERENCES users(id),
  followee_id INTEGER REFERENCES users(id),
  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (follower_id, followee_id)
);