const isProduction = process.env.NODE_ENV === 'production'
const Koa = require('koa')
const url = require('url')
const ws = require('ws')
const Cookies=require('cookies');
const bodyparser=require('koa-bodyparser');
const templating=require('./templating');
const controller=require('./controller');
const WebSocketServer = ws.Server
const rest=require('./rest')
const app = new Koa()
//第一个middleware记录url以及页面执行时间
app.use(async (ctx, next) => {
    console.log(`Process ${ctx.method} ${ctx.url}`);
    var start = new Date().getTime()
        , execTime;
    await next();
    execTime = new Date().getTime() - start;
    ctx.set('X-Response-Time', `${execTime}ms`);
})
app.use(async (ctx, next) => {
    ctx.state.user = parseUser(ctx.cookies.get('name') || '');
    await next();
})
//第二个middleware处理静态文件
if (!isProduction) {
    let staticFiles = require('./static-files');
    app.use(staticFiles('/static/', '/node_modules/'));
}
//第三个middleware解析post请求
app.use(bodyparser());
//第四个middleware给ctx添加render方法 来使用nunjucks
app.use(templating('views', {
    noCache: !isProduction,
    watch: !isProduction,
    autoescape: isProduction
}));
//第五个middleware处理rest请求
app.use(rest.restify());
//最后一个middleware处理url路由
app.use(controller());

let server = app.listen(3001);


function createWebSocketServer(server, onConnection, onMessage, onClose, onError) {
    let wss = new WebSocketServer({
        server: server
    });
    wss.broadcast = data => {
        wss.clients.forEach(client => {
            client.send(data)
        })
    }
    onConnection = onConnection || (()=> console.log('[WebSocket] connected.'))
    onMessage = onMessage||(msg=>console.log('[WebSocket] message received'+msg))
    onClose=onClose||((code,message)=>console.log(`[WebSocket] closed:${code}-${message}`))
    onError=onError||(err=>console.log('[WebSocket] error:'+err))
    wss.on('connection', function (ws,req) {
        let location = url.parse(req.url, true)
        console.log('[WebSocketServer] connection:'+location.href)
        ws.on('message',onMessage)
        ws.on('close',onClose)  
        ws.on('error',onError)
        if(location.pathname!=='/ws/chat'){
            ws.close(4000,'Invalid URL');
        }
        let user = parseUser(req);
        console.log(req);
        if (!user) {
            ws.close(4001, 'Invalid user');
        }
        ws.user = user;
        ws.wss = wss;
        onConnection.apply(ws)
    });
}
var messageIndex = 0;
function createMessage(type, user, data) {
    messageIndex++;
    return JSON.stringify({
        id: messageIndex,
        type: type,
        user: user,
        data: data
    })
}

function onConnection(){
    let user=this.user,
    users=[],
    msg=createMessage('join',user,`${user.name} joined`);
    this.wss.broadcast(msg);
    this.wss.clients.forEach(client=>{
        users.push(client.user);
    })
    this.send(createMessage('list',user,users));
}

function onMessage(message){
    console.log(message);
    if(message&&message.trim()){
        let msg=createMessage('chat',this.user,message.trim());
        this.wss.broadcast(msg);
    }
}

function onClose(){
    let user=this.user;
    let msg=createMessage('left',user,`${user.name} is left`);
    this.wss.broadcast(msg);
}
function parseUser(obj) {
    if (!obj) return;
    console.log('try parse:' + obj);
    let s = '';
    if (typeof obj === 'string') {
        s = obj;
    } else if (obj.headers) {
        let cookies = new Cookies(obj, null);
        s = cookies.get('name');
    }
    if (s) {
        try {
            let user = JSON.parse(Buffer.from(s, 'base64').toString());
            console.log(`User:${user.name},ID:${user.id}`);
            return user;
        } catch (e) {
            console.log('报错了:' + e);
        }
    }
}
app.wss = createWebSocketServer(server,onConnection,onMessage,onClose);