console.log('hello world');

setTimeout(function () {
    console.log("3 seconds have passed 2");
}, 3000);

// 箭头函数，es6的写法
setTimeout(() => {
    console.log("3 seconds have passed 1");
}, 3000);

// 每间隔2秒不断执行
setInterval(function () {
    console.log("2 seconds have passed");
}, 2000);


var time = 0
var timer = setInterval(function () {
    time += 2;
    console.log(time + " seconds have passed");
    if (time > 6) {
        clearInterval(timer);
        console.log("clearInterval")
    }
}, 2000)

// 输出当前目录 和 带绝对路径的文件名
console.log(__dirname)
console.log(__filename)

console.log('end')
console.dir(global)

function sayHi() {
    console.log('Hi')
}

sayHi() // 调用函数

// 将匿名函数赋给变量
var sayBye = function (name) {
    console.log(name + ' Bye')
}

sayBye()

// 第一个参数是函数
function callFunction(fun, name) {
    fun(name)
}

callFunction(sayBye, 'able')
// 或者
callFunction(function (name) {
    console.log(name + ' Bye')
}, 'able')

// counter.js
var counter = function (arr) {
    return "There are " + arr.length + " elements in array"
}

var adder = function (a, b) {
    return `the sum of the 2 numbers is ${a+b}`
}

var pi = 3.14

// 只有一个时可以这样导入
// module.exports = counter

/*
module.exports.counter = counter
module.exports.adder = adder
module.exports.pi = pi
*/

module.exports = {
    counter: counter,
    adder: adder,
    pi: pi,
}
/* 对象可以简写
module.exports = {
    counter,
    adder,
    pi,
}
*/

//p4.js
var stuff = require('./count')

console.log(stuff.counter(['ruby', 'nodejs', 'react']))
console.log(stuff.adder(3, 2))
console.log(stuff.pi)

var events = require('events')
var util = require('util')

// 事件 对象
var myEmitter = new events.EventEmitter()

// 绑定 事件名称 和 回调函数
myEmitter.on('someEvent', function (message) {
    console.log(message)
})

// 触发实践，使用事件名称
myEmitter.emit('someEvent', 'The event was emitted')

// 创建对象
var Person = function (name) {
    this.name = name
}

// 继承，让Person类具有事件对象的特性，绑定和触发事件
util.inherits(Person, events.EventEmitter)
// 新建对象
var xiaoming = new Person('xiaoming')
var lili = new Person('lili')

var person = [xiaoming, lili]

// 循环person数组，绑定事件
person.forEach(function (person) {
    person.on('speak', function (message) {
        console.log(person.name + ' said: ' + message)
    })
})

// 触发事件
xiaoming.emit('speak', 'hi')
lili.emit('speak', 'I want a curry')

var fs = require('fs')

// 同步读写文件，顺序执行，如果读取时间很长，会阻塞进程
var readMe = fs.readFileSync('readMe.txt', 'utf8')
fs.writeFileSync('writeMe.txt', readMe)

console.log(readMe)
console.log('finished sync')

// 异步读写文件
// 异步事件，Nodejs 维护一个事件队列，注册事件，完成后执行主线程
// 当主线程空闲时，取出执行事件，从线程池中发起线程执行事件， 当事件执行完成后通知主线程。这就是异步高效的原因。

var readMe = fs.readFile('readMe.txt', 'utf8', function (err, data) {
    fs.writeFile('writeMe.txt', data, function () {
        console.log('writeMe has finished')
    })
})

console.log('end')

var fs = require('fs')

// 异步删除文件
fs.unlink('writeMe.txt', function () {
    console.log('delete writeMe.txt file')
})

// 同步创建和删除目录
fs.mkdirSync('stuff')
fs.rmdirSync('stuff')

// 异步
fs.mkdir('stuff', function () {
    fs.readFile('readMe.txt', 'utf8', function (err, data) {
        fs.writeFile('./stuff/writeMe.txt', data, function () {
            console.log('copy successfully')
        })
    })
})

var fs = require('fs')

var myReadStream = fs.createReadStream(__dirname + '/readMe.txt')
myReadStream.setEncoding('utf8')
var myWriteStream = fs.createWriteStream(__dirname + '/writeMe.txt')
var data = ''

myReadStream.on('data', function (chunk) {
    console.log('new chunk received')
    // console.log(chunk)
    myWriteStream.write(chunk)
})

myReadStream.on('end', function () {
    console.log(data)
})

var writeData = 'hello world'
myWriteStream.write(writeData)
myWriteStream.end()
myWriteStream.on('finish', function () {
    console.log('finished')
})

// 使用管道，代码量更少
myReadStream.pipe(myWriteStream)

var http = require('http')

var server = http.createServer(function (req, res) {
    console.log('request received')
    res.writeHead(200, { 'Content-Type': 'text/plain' })
    // res.write('Hello from out application')
    // res.end()
    // 或
    res.end('Hello from out application')
})

server.listen(3000, '127.0.0.1')
console.log('server started on http://127.0.0.1:3000')

var myObj = {
        name: 'able',
        job: 'programmer',
        age: 27
    }
    res.end(JSON.stringify(myObj))

var http = require('http')
var fs = require('fs')

var onRequest = function (req, res) {
    console.log('request received')
    res.writeHead(200, { 'Content-Type': 'text/html' })
    // res.writeHead(200, { 'Content-Type': 'text/plain' })
    var myReadStream = fs.createReadStream(__dirname + '/index.html', 'utf8')
    myReadStream.pipe(res)
}

var server = http.createServer(onRequest)
server.listen(3000)
console.log('server started on http://127.0.0.1:3000')

// server.js
var http = require('http')
var fs = require('fs')

function startServer() {
    var onRequest = function (req, res) {
        console.log('request received')
        res.writeHead(200, { 'Content-Type': 'text/html' })

        var myReadStream = fs.createReadStream(__dirname + '/index.html', 'utf8')
        myReadStream.pipe(res)
    }
    var server = http.createServer(onRequest)
    server.listen(3000)
    console.log('server started on http://127.0.0.1:3000')
}

module.exports.startServer = startServer

// 调用
var server = require('./server')

server.startServer()

unction startServer() {
    var onRequest = function (req, res) {
        console.log('request received ' + req.url)

        if (req.url === '/' || req.url === '/home') {
            res.writeHead(200, { 'Content-Type': 'text/html' })
            fs.createReadStream(__dirname + '/index.html', 'utf8').pipe(res)
        } else if (req.url === '/review') {
            res.writeHead(200, { 'Content-Type': 'text/html' })
            fs.createReadStream(__dirname + '/review.html', 'utf8').pipe(res)
        } else if (req.url === '/api/v1/records') {
            res.writeHead(200, { 'Content-Type': 'application/json' })
            var jsonObj = {
                name: 'able'
            }
            res.end(JSON.stringify(jsonObj))
        } else {
            res.writeHead(200, { 'Content-Type': 'text/html' })
            fs.createReadStream(__dirname + '/404.html', 'utf8').pipe(res)
        }
    }
    var server = http.createServer(onRequest)
    server.listen(3000)
    console.log('server started on http://127.0.0.1:3000')
}

// 接收请求数据，然后处理，查看request 类型
var data = ""
req.on("error", function (err) {
    console.error(err)
}).on("data", function (chunk) {
    data += chunk
}).on("end", function () {
    if (req.mothod === "POST") {
        if (data.length > 1e6) {
            req.connection.destroy() // 如果数据很大，就断开
        }
        route(handle, pathname, res, querystring.parse(data))
    } else {
        var params = url.parse(req.url, true).query
        route(handle, pathname, res, params)
    }
})
// 或者
// var data = []
// data.push(chunk)
// data = Buffer.concat(data).toString()