const webpackHotMiddleware = require('webpack-hot-middleware');
const PassThrough = require('stream').PassThrough;

module.exports = (compiler, opts) => {
  const middleware = webpackHotMiddleware(compiler, opts);
  return async (ctx, next) => {
    let stream = new PassThrough();
    ctx.body = stream;
    await middleware(
      ctx.req,
      {
        write: stream.write.bind(stream),
        // 如果以后有坑，就请注意：不建议直接使用 ctx.res 原生 response 方法，这样就跳过 koa 的处理了。https://koa.bootcss.com/#ctx-res
        // write: data => {
        //   ctx.res.write(data);
        // },
        writeHead: (status, headers) => {
          ctx.status = status;
          ctx.set(headers);
        },
        end: () => {
          // ctx.res.end();
          ctx.body = '';
        }
      },
      next
    );
  };
};