// index.js
// 通过require获取两个node内置模块
const http = require('http');
const nUrl = require('url');
// '127.0.0.1'表明只有本机可访问，'0.0.0.0'表示所有人可访问
const hostname = '127.0.0.1';
const port = 3000;
// 通过http.createServer获取一个server实例
// 其中(req, res) => {}，在服务器每次接收到请求时都会被执行
const server = http.createServer((req, res) => {
  let method = req.method; // 客户端请求方法
  let url = nUrl.parse(req.url); // 将请求url字符串转换为node的url对象
  // 如果客户端GET请求'/'，会执行这个分支里面的逻辑
  if (method === 'GET' && url.pathname === '/') {
    res.statusCode = 200;
    res.setHeader('Content-Type', 'text/plain');
    res.end('Hello World');
    return;
  }
  // 如果客户端GET请求'/api/user'，会执行这个分支里面的逻辑
  if (method === 'GET' && url.pathname === '/api/user') {
    res.statusCode = 200;
    res.setHeader('Content-Type', 'application/json');
    res.end(JSON.stringify({
      code: 0,
      msg: '',
      result: {
        username: 'shasharoman'
      }
    }));
    return;
  }
  // 没有匹配其他分支的话，执行以下逻辑
  res.statusCode = 404;
  res.setHeader('Content-Type', 'text/plain');
  res.end('Not Found');
});
// server开始监听，等待请求到来
server.listen(port, hostname, () => {
  console.log(`Server running at http://${hostname}:${port}/`);
});

// config.js
exports = module.exports = {
  hostname: '127.0.0.1',
  port: '3000'
};

// route.js
exports = module.exports = [{
  method: 'GET',
  path: '/api/user',
  impl: 'account.userById'
}, {
  method: 'POST',
  path: '/api/user',
  impl: 'account.createUser'
}];

// controller/account.js
exports.userById = userById;
exports.createUser = createUser;
function userById(req, res) {
  res.end('waiting for impl.');
}
function createUser(req, res) {
  res.end('waiting for impl.');
}

// controller/index.js
exports.account = require('./account');

// index.js
const http = require('http');
const nUrl = require('url');
const config = require('./config');
const controller = require('./controller');
const route = require('./route').map(item => {
  console.log(`route ${item.method}:${item.path}`);
  let tuple = item.impl.split('.');
  item.impl = controller[tuple[0]][tuple[1]];
  return item;
});
const server = http.createServer((req, res) => {
  let method = req.method;
  let url = nUrl.parse(req.url);
  let matchRoute = route.find(item => {
    return item.method === method && item.path === url.pathname;
  });
  if (matchRoute) {
    matchRoute.impl(req, res);
    return;
  }
  res.statusCode = 404;
  res.setHeader('Content-Type', 'text/plain');
  res.end('Not Found');
});
server.listen(config.port, config.hostname, () => {
  console.log(`Server running at http://${config.hostname}:${config.port}/`);
});