/**

 * Created by Sorrow.X on 2017/10/25.

 */

const http = require('http');

const url  = require('url');

const net = require('net');

// 单例

let httpServer = (function() {

    let port = 8888;

    let server = null;

    let serverStartedCb = null;

    let noop = function() {};

    // 初始化http服务器

    let initServer = function({serverStarted}) {

        serverStartedCb = serverStarted || noop;

        startServer(increPort());

    };

    // 关闭服务器

    let closeServer = function() {

        if (server) {

            server.close();

            server = null;

        };

    };

    // 端口增加

    function increPort() {

        return ++port;

    };

    // 格式化url

    function format(str) {

        let obj = {};

        str = str.substr(str.indexOf('?') + 1);

        let arr = str.split('&');

        arr.forEach(function(item) {

            let a = item.split('=');

            obj[a[0]] = a[1];

        });

        return obj;

    };

    // 启动服务器

    function _server(port) {

        server = new http.Server();

        server.on('request',(req, res)=>{

            let content = {

                Code: -1,

                Body: {

                    message: 'request url error'

                }

            };

            if (req.url.indexOf('ball/queryUrl') > 0) {

                let obj = format(req.url);

                if (obj.type == '1') {

                    content.Code = 0;

                    content.Body = {

                        message: 'hi'

                    };

                };

            };

            //设置应答头信息

            res.writeHead(200,{'Content-Type':'text/plain'});

            res.write(JSON.stringify(content));

            res.end();

        });

        server.on('listening', () => {

            console.log("server listening, 端口号和url为: ", `localhost:${port}`);

            serverStartedCb(null);

        });

        server.on('connection', () => {

            console.log("server connection...");

        });

        server.on('close', () => {

            console.log('server close...');

        });

        server.on('error', (err) => {

            server.close();

            server = null;

            serverStartedCb(new Error(err));

            console.log('server error: ', err);

        });

        server.listen(port);

    };

    // 检测port是否被占用

    function probe(port, callback) {

        let server = net.createServer().listen(port);

        let calledOnce = false;

        let timeoutRef = setTimeout(function () {

            calledOnce = true;

            callback(false, port);

        }, 2000)

        timeoutRef.unref(); // 取消定时器

        let connected = false;

        server.on('listening', function() {

            clearTimeout(timeoutRef);

            if (server)

                server.close();

            if (!calledOnce) {

                calledOnce = true;

                callback(true, port); // true 表示未被占用

            };

        });

        server.on('error', function(err) {

            clearTimeout(timeoutRef);

            let result = true;

            if (err.code === 'EADDRINUSE')

                result = false; // 占用

            if (!calledOnce) {

                calledOnce = true;

                callback(result, port); // false 表示占用

            };

        });

    };

    function startServer(port){

        probe(port, function(bool, port) { // 端口被占用: bool 返回false; port：传入的端口号

            if (bool === true) { // 端口号未被占用

                _server(port);

            } else { // 已占用

                closeServer();

                _server(increPort());

            };

        });

    };

    let single;

    return function() {

        return single ? single : (single = {initServer, closeServer});

    };

}());

// module.exports = httpServer();

// test

var ballServer = httpServer();

var ballServer2 = httpServer();

console.log(ballServer === ballServer2); // 测试是否同一个对象

ballServer.initServer({

    serverStarted: function(err) {

        if (!err) {

            console.log('服务已启动: ');

        };

    }

});

// ballServer.closeServer();