서브스레드 작성과 브로드캐스팅 구현

 const sio = require('socket.io');
 const db = require('./db');
+const hash = require('./hash');
 
 let io;
 module.exports = {
     init(http) {
         io = sio(http);
         io.on('connection', (socket) => {
-            socket.on('init', (id) => {
+            socket.on('init', async(id) => {
+                let thread = await db.get('thread').findOne(id);
+                if(!thread) {
+                    socket.close();
+                    return;
+                }
                 console.log(`init ${id}`);
-                db.get('subthread').find({parent: id}, {sort: '+_id'}).each((thread, _) => {
+                db.get('subthread').find({parent: thread._id}, {sort: '+_id'}).each((thread, _) => {
                     socket.emit('thread', thread);
+                }).then(() => {
+                    socket.join(`thread-${thread._id}`);
+                    console.log(`join thread-${thread._id}`);
+                });
+                socket.on('write', async(content) => {
+                    console.log(`write ${content}`);
+                    let subthread = await db.get('subthread').insert({parent: thread._id, writer: hash(thread._id, socket.handshake.address), content, no: ++thread.count});
+                    db.get('thread').update(thread._id, {$set: {count: thread.count, lastUpdated: Date.now()}});
+                    io.to(`thread-${thread._id}`).emit('thread', subthread);
+                    console.log(`broadcast thread-${thread._id}`);
                 });
             });
         });