// system module

var http = require("http");

var https = require("https");

var url = require("url");

var path = require("path");

var qs = require("querystring");

var crypto = require('crypto'); // hash加密

// simple cache

var cache = require("memory-cache");

// app file

var conf = require("./config/config.js");

var route = require("./route/route.js");

http.createServer(function(req,res){

    var serverRes = res;

    var serverReq = req;

    var param = url.parse(req.url,true).query;

    var pathname = url.parse(req.url,true).pathname;

    var callback = param.callback;

    var noncestr = param.noncestr;

    var timestamp = param.timestamp;

    var needUrl = param.url;

    if(!needUrl || !noncestr || !timestamp){

        var chunk = JSON.stringify({

            errcode: 1,

            message: "参数不完整"

        });

        serverRes.end(callback+"("+chunk+")");

    }

    var getToken = function(){

        console.log("2.1.1");

        var data = {

            grant_type: "client_credential",

            appid: conf.wechat.AppID,

            secret: conf.wechat.AppSecret

        }

        var content = qs.stringify(data);

        var options = {

            hostname: "api.weixin.qq.com",

            port: "",

            path: "/cgi-bin/token?"+content,

            method: "GET"

        }

        var req = https.request(options,function(res){

            res.on('data', function (chunk) {

                console.log("2.1.2");

                var statusCode = res.statusCode;

                if(statusCode != 200){

                    var chunk = JSON.stringify({

                        code: statusCode,

                        message: "获取微信token失败"

                    });

                    serverRes.end(callback+"("+chunk+")");

                }

                var chunk = JSON.parse(chunk.toString());

                cache.put("token",chunk["access_token"],7200000,function(){

                    cache.del("token");

                });

                getTicket();

            });

        })

        req.on("error",function(err){

            console.log(err.message);

        })

        req.end();

    }

    var getTicket = function(){

        console.log("2.2.1");

        var data = {

            access_token: cache.get("token"),

            type: "jsapi"

        }

        var content = qs.stringify(data);

        var options = {

            hostname: "api.weixin.qq.com",

            port: "",

            path: "/cgi-bin/ticket/getticket?"+content,

            method: "GET"

        }

        var req = https.request(options,function(res){

            console.log("2.2.2");

            var statusCode = res.statusCode;

            if(statusCode != 200){

                var chunk = JSON.stringify({

                    code: statusCode,

                    message: "获取微信ticket失败"

                });

                serverRes.end(callback+"("+chunk+")");

            }

            res.on('data', function (chunk) {

                var chunkJSON = JSON.parse(chunk.toString());

                cache.put("ticket",chunkJSON.ticket,7200000,function(){

                    cache.del("ticket");

                });

                getSingature(chunkJSON.ticket);

            });

        })

        req.on("error",function(err){

            console.log(err.message);

        })

        req.end();

    }

    var getSingature = function(ticket){

        console.log(3.1);

        var data = {

            jsapi_ticket: ticket,

            noncestr: noncestr,

            timestamp: timestamp,

        };

        console.log(data);

        var content = qs.stringify(data);

        content+="&url="+needUrl;

        console.log(content);

        var shasum = crypto.createHash('sha1');

        shasum.update(content);

        var signature = shasum.digest("hex");

        console.log(signature);

        var chunk = JSON.stringify({

            errcode: 0,

            errmsg: "ok",

            signature: signature

        });

        serverRes.end(callback+"("+chunk+")");

    }

    /**

     * 临时先满足获取微信jsapi_ticket的需求，后续完善

     * 第一步 要想获取jsapi_ticket，首先要获取access_token（有效期7200s）

     * 第二步 通过得到的access_token,进一步获取jsapi_ticket（有效期7200s）

     * 由于获取jsapi_ticket的api调用次数非常有限，频繁刷新jsapi_ticket会导致api调用受限，

     * 影响自身业务，开发者必须在自己的服务全局缓存jsapi_ticket

     */

    if(pathname != "/getWechatSignature"){

        res.statusCode = 404;

        res.end();

        return;

    }

    // 检测缓存中是否有jsapi_ticket，

    // 如果有这直接用此ticket获取sha1签名

    var jsapi_ticket = cache.get("ticket");

    if(jsapi_ticket && jsapi_ticket != ""){

        console.log(1);

        getSingature(jsapi_ticket);

    }else{

        /**

         * 获取 access_token

         * 如果缓存中没有token，则调用微信接口获取token

         */

        var access_token = cache.get("token");

        if(!access_token || access_token == ""){

            console.log(2.1);

            getToken();

        }else{

            console.log(2.2);

            getTicket();

        }

    }

}).listen(conf.port);

console.log((new Date()).toLocaleString() + "server start on : " + conf.host + ":" + conf.port);