var server = require("./server");

var router = require("./router");

var requestHandlers = require("./requestHandlers");

var handle = {}

handle["/"] = requestHandlers.start;

handle["/start"] = requestHandlers.start;

handle["/upload"] = requestHandlers.upload;

handle["/show"] = requestHandlers.show;

server.start(router.route, handle);

var http = require("http");

var url = require("url");

function start(route, handle) {

  function onRequest(request, response) {

    var pathname = url.parse(request.url).pathname;

    console.log("Request for " + pathname + " received.");

    route(handle, pathname, response, request);

  }

  http.createServer(onRequest).listen(3000);

  console.log("Server has started.");

}

exports.start = start;

var querystring = require("querystring"),

    fs = require("fs"),

    formidable = require("formidable");

function start(response) {

    console.log("Request handler 'start' was called.");

    var body = '<html>'+

        '<head>'+

        '<meta http-equiv="Content-Type" content="text/html; '+

        'charset=UTF-8" />'+

        '</head>'+

        '<body>'+

        '<form action="/upload" enctype="multipart/form-data" '+

        'method="post">'+

        '<input type="file" name="upload" multiple="multiple">'+

        '<input type="submit" value="Upload file" />'+

        '</form>'+

        '</body>'+

        '</html>';

    response.writeHead(200, {"Content-Type": "text/html"});

    response.write(body);

    response.end();

}

function upload(response, request) {

    console.log("Request handler 'upload' was called.");

    var form = new formidable.IncomingForm();

    form.uploadDir = "D:\\min\\nodejsExample2\\tmp";

    console.log("about to parse1");

    form.parse(request, function(error, fields, files) {

        console.log("parsing done");

        console.log(files.upload.path);

        fs.renameSync(files.upload.path, "D:\\min\\nodejsExample2\\tmp\\test.png");

        response.writeHead(200, {"Content-Type": "text/html"});

        response.write("received image:<br/>");

        response.write("<img src='/show' />");

        response.end();

  });

}

function show(response) {

    console.log("Request handler 'show' was called.");

    fs.readFile("D:\\min\\nodejsExample2\\tmp\\test.png", "binary", function(error, file) {

        if(error) {

            response.writeHead(500, {"Content-Type": "text/plain"});

            response.write(error + "\n");

            response.end();

        } else {

            response.writeHead(200, {"Content-Type": "image/png"});

            response.write(file, "binary");

            response.end();

        }

    });

}

exports.start = start;

exports.upload = upload;

exports.show = show;

function route(handle, pathname, response, request) {

    console.log("About to route a request for " + pathname);

    if (typeof handle[pathname] === 'function') {

        handle[pathname](response, request);

    } else {

        console.log("No request handler found for " + pathname);

        response.writeHead(404, {"Content-Type": "text/html"});

        response.write("404 Not found");

        response.end();

    }

}

exports.route = route;

//this is async 异步

/*

 fs.readFile调用时所做的工作只是将异步式I/O请求发送给了操作系统，然后立即返回并执行后面的语句，执行完以后进入事件循环监听事件。

 当fs接收到I/O请求完成的事件时，事件循环会主动调用回调函数以完成后续工作。

 */

var fs = require('fs');

fs.readFile('file.txt', 'utf-8', function(err, data){

    if (err){

        console.error(err);

    } else {

        console.log(data);

    }

});

//this is sync 同步

var fs = require('fs');

var data = fs.readFileSync('file.txt', 'utf-8');

console.log(data);

console.log('end.');