feat: 实现所有用户共享刷题历史与权重数据后端服务及多端同步

server/server.js

@@ -0,0 +1,161 @@
+const http = require('http');
+const fs = require('fs');
+const path = require('path');
+
+const PORT = process.env.PORT || 3001;
+const DATA_DIR = path.join(__dirname, '../data');
+const DATA_FILE = path.join(DATA_DIR, 'quiz_stats.json');
+const QUESTIONS_FILE = path.join(__dirname, '../questions.json');
+
+// 保证数据目录存在
+if (!fs.existsSync(DATA_DIR)) {
+  fs.mkdirSync(DATA_DIR, { recursive: true });
+}
+
+// 内存中的状态缓存
+let state = {
+  weights: {},
+  history: [],
+  totalAnswered: 0
+};
+
+// 初始化状态
+function initState() {
+  if (fs.existsSync(DATA_FILE)) {
+    try {
+      const content = fs.readFileSync(DATA_FILE, 'utf-8');
+      state = JSON.parse(content);
+      console.log(`[Init] 已从文件载入全局数据，累计答题数: ${state.totalAnswered}`);
+      return;
+    } catch (e) {
+      console.error('[Init] 读取已有数据文件失败，将重新初始化:', e);
+    }
+  }
+
+  // 初始化默认权重
+  let defaultWeights = {};
+  if (fs.existsSync(QUESTIONS_FILE)) {
+    try {
+      const qData = JSON.parse(fs.readFileSync(QUESTIONS_FILE, 'utf-8'));
+      qData.forEach(q => {
+        defaultWeights[q.id] = 1;
+      });
+    } catch (e) {
+      console.error('[Init] 读取 questions.json 失败:', e);
+    }
+  }
+
+  state = {
+    weights: defaultWeights,
+    history: [],
+    totalAnswered: 0
+  };
+  saveState();
+}
+
+// 异步持久化保存
+function saveState() {
+  const tmpFile = `${DATA_FILE}.tmp`;
+  fs.writeFile(tmpFile, JSON.stringify(state, null, 2), 'utf-8', (err) => {
+    if (err) {
+      console.error('[Save] 保存临时数据文件失败:', err);
+      return;
+    }
+    fs.rename(tmpFile, DATA_FILE, (renameErr) => {
+      if (renameErr) {
+        console.error('[Save] 原子重命名数据文件失败:', renameErr);
+      }
+    });
+  });
+}
+
+initState();
+
+const server = http.createServer((req, res) => {
+  // 设置 CORS 标头
+  res.setHeader('Access-Control-Allow-Origin', '*');
+  res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS');
+  res.setHeader('Access-Control-Allow-Headers', 'Content-Type');
+
+  if (req.method === 'OPTIONS') {
+    res.writeHead(204);
+    res.end();
+    return;
+  }
+
+  const url = new URL(req.url, `http://${req.headers.host}`);
+  const pathname = url.pathname.replace(/^\/api/, ''); // 统一兼容 /api 前缀与无前缀
+
+  if (req.method === 'GET' && (pathname === '/stats' || pathname === '/stats/')) {
+    res.writeHead(200, { 'Content-Type': 'application/json; charset=utf-8' });
+    res.end(JSON.stringify(state));
+    return;
+  }
+
+  if (req.method === 'POST' && (pathname === '/answer' || pathname === '/answer/')) {
+    let body = '';
+    req.on('data', chunk => {
+      body += chunk;
+    });
+
+    req.on('end', () => {
+      try {
+        const payload = JSON.parse(body || '{}');
+        const questionId = Number(payload.questionId);
+        const isCorrect = Boolean(payload.isCorrect);
+
+        if (!questionId) {
+          res.writeHead(400, { 'Content-Type': 'application/json' });
+          res.end(JSON.stringify({ error: 'Missing questionId' }));
+          return;
+        }
+
+        // 更新历史记录（保留最近 100 条）
+        state.history.push(isCorrect);
+        if (state.history.length > 100) {
+          state.history = state.history.slice(-100);
+        }
+
+        // 更新全局总数
+        state.totalAnswered = (state.totalAnswered || 0) + 1;
+
+        // 更新题目权重
+        const currentWeight = state.weights[questionId] || 1;
+        if (isCorrect) {
+          state.weights[questionId] = Math.max(1, currentWeight - 1);
+        } else {
+          state.weights[questionId] = currentWeight + 3; // 答错大幅增加权重
+        }
+
+        saveState();
+
+        res.writeHead(200, { 'Content-Type': 'application/json; charset=utf-8' });
+        res.end(JSON.stringify({
+          success: true,
+          weights: state.weights,
+          history: state.history,
+          totalAnswered: state.totalAnswered
+        }));
+      } catch (err) {
+        console.error('[Error] 处理 /api/answer 异常:', err);
+        res.writeHead(500, { 'Content-Type': 'application/json' });
+        res.end(JSON.stringify({ error: 'Internal Server Error' }));
+      }
+    });
+    return;
+  }
+
+  if (req.method === 'POST' && (pathname === '/reset' || pathname === '/reset/')) {
+    initState();
+    res.writeHead(200, { 'Content-Type': 'application/json; charset=utf-8' });
+    res.end(JSON.stringify({ success: true, message: 'Stats reset' }));
+    return;
+  }
+
+  res.writeHead(404, { 'Content-Type': 'application/json' });
+  res.end(JSON.stringify({ error: 'Not Found' }));
+});
+
+server.listen(PORT, '0.0.0.0', () => {
+  console.log(`[Server] 全局刷题服务已启动，监听端口: ${PORT}`);
+});