app.js

const express = require('express');
const mongoose = require('mongoose');

const app = express();
app.use(express.json());

// MongoDB 连接
mongoose.connect(process.env.MONGO_URI || 'mongodb://localhost:27017/devops_db', {
  serverSelectionTimeoutMS: 30000,
  connectTimeoutMS: 30000
}).then(() => {
  console.log('Connected to MongoDB');
  initDB();
}).catch(err => {
  console.error('MongoDB connection error:', err.message);
});

// 访问记录 Schema
const VisitSchema = new mongoose.Schema({
  count: { type: Number, default: 0 },
  updatedAt: { type: Date, default: Date.now }
});
const Visit = mongoose.model('Visit', VisitSchema);

// 初始化数据库
async function initDB() {
  const doc = await Visit.findOne();
  if (!doc) {
    await Visit.create({ count: 0 });
  }
}

// 首页
app.get('/', async (req, res) => {
  try {
    await initDB();
    const doc = await Visit.findOne();
    doc.count += 1;
    doc.updatedAt = new Date();
    await doc.save();

    res.send(`
      <html>
      <head><title>Node.js + MongoDB + Docker</title></head>
      <body style="font-family: Arial; max-width: 600px; margin: 80px auto; text-align: center;">
          <h1>🚀 Node.js + MongoDB + Docker Compose</h1>
          <p>This page has been visited <strong>${doc.count}</strong> time(s).</p>
          <p>Refresh the page to increment the counter.</p>
          <hr>
          <p style="color: gray;">Data is stored in MongoDB — survives container restart</p>
      </body>
      </html>
    `);
  } catch (e) {
    res.send(`
      <html>
      <body style="font-family: Arial; max-width: 600px; margin: 80px auto; text-align: center;">
          <h1>⚠️ Database not ready</h1>
          <p>Waiting for MongoDB to start...</p>
          <p style="color: gray;">Error: ${e.message}</p>
          <p>Please refresh the page in a few seconds.</p>
      </body>
      </html>
    `);
  }
});

// API 端点
app.get('/api/visits', async (req, res) => {
  const doc = await Visit.findOne();
  res.json({ count: doc ? doc.count : 0 });
});

// 健康检查
app.get('/health', (req, res) => {
  res.json({ status: 'ok' });
});

const PORT = process.env.PORT || 3000;
app.listen(PORT, '0.0.0.0', () => {
  console.log(`Server running on port ${PORT}`);
});