var httpcli =  function(){
    // LIFE-CYCLE CALLBACKS:

    // onLoad () {},

    // start () {},

    // update (dt) {},

    this.init=function(){
        this.cachemsg = [];
        this._needretry = false;
        this._retrycount = 3;
        this._retryms = 3000;
        this._runningcount = 0;
        this._maxrunning = 10;
        // this._retry_tid = setInterval(this._retry.bind(this), this._retryms);
    };

    this.httpGet=function(url, cbRes, cbErr){
        // var realurl = url;
        // if(urldata){
        //     if(realurl.indexOf("?") == -1){
        //         realurl += "?";
        //     }else{
        //         realurl += "&";
        //     }
        //     realurl += encodeURIComponent(urldata);
        // }
        return this.httpsend(url, null, cbRes, cbErr, 'GET');
    };

    this.httpPost=function(url, postdata, cbRes, cbErr){
        return this.httpsend(url, postdata, cbRes, cbErr, 'POST');
    };

    this.httpsend=function(url, urldata, cbRes, cbErr, smethod, isretry){
        if(this._runningcount < this._maxrunning){
            return this._httpsend(url, urldata, cbRes, cbErr, smethod, isretry);
        }else if(!isretry){
            let obj = {
                u: url,
                v: urldata,
                successcb: cbRes,
                errcb: cbErr
            };
            this.cachemsg.push(obj);
            return null;
        }
    };

    this._httpsend=function(url, urldata, cbRes, cbErr, smethod, isretry){
        this._runningcount++;
        let self = this;
        if(typeof(XMLHttpRequest) != 'undefined'){
            var xhr = new XMLHttpRequest();
            xhr.onreadystatechange = function () {
                if (xhr.readyState == 4){
                    self._runningcount--;
                    if(xhr.status >= 200 && xhr.status < 400) {
                        var response = xhr.responseText;
                        cbRes && cbRes(response);
                    }else{
                        if(!isretry && self._needretry){
                            let obj = {
                                u: url,
                                v: urldata,
                                successcb: cbRes,
                                errcb: cbErr
                            };
                            self.cachemsg.push(obj);
                        }else{
                            cbErr && cbErr(xhr.status, xhr.statusText);
                        }
                    }
                }
            };
            // xhr.onabort = function(){
            //     self._runningcount--;
            // };
            xhr.onerror = function(){
                self._runningcount--;
            };
            xhr.open(smethod, url, true);
            xhr.send(urldata);
            return xhr;
        }else if(typeof(wx) != 'undefined'){
            var jsobj = urldata? JSON.parse(urldata): null;
            var xhr = wx.request({
                url: url,
                data: jsobj,
                method: smethod,
                success: function(res){
                    console.log("[wx]request success!" + res.statusCode);
                    if(res.statusCode >= 200 && res.statusCode < 400) {
                        var restext = JSON.stringify(res.data);
                        cbRes && cbRes(restext);
                    }else{
                        cbErr && cbErr(res.statusCode, res.msg);
                    }
                },
                fail: function(res){
                    console.log("[wx]request fail!"+ JSON.stringify(res));
                    if(!isretry && self._needretry){
                        let obj = {
                            u: url,
                            v: urldata,
                            successcb: cbRes,
                            errcb: cbErr
                        };
                        self.cachemsg.push(obj);
                    }else{
                        cbErr && cbErr(-1, res.msg);
                    }
                    // cbErr && cbErr(-1, res.msg);
                },
                complete: function(){
                    self._runningcount--;
                    console.log("[wx]request complete!");
                }
              });
              return xhr;
        }
        return null;
    };

    this._retry=function(){
        if(this.cachemsg.length > 0){
            this.cachemsg.forEach(element => {
                let obj = element;
                if(obj.retrying){
                    return;
                }
                let bneedretry = false;
                if(!obj.retry_count){
                    obj.retry_count = 1;
                    obj.passtime = 0;
                }
                obj.passtime += this._retryms;
                bneedretry = (obj.passtime >= obj.retry_count * this._retryms);

                if(bneedretry && !obj.retrying){
                    obj.retrying = true;
                    let method = obj.v? 'POST': 'GET';
                    this.httpsend(obj.u, obj.v, (restext) => {
                        obj.successcb && obj.successcb(restext);
                        let idx = this.cachemsg.findIndex((element) => {
                            return element == obj;
                        });
                        if(idx != -1){
                            this.cachemsg.splice(idx, 1);
                        }
                    }, (errcode, errmsg) => {
                        obj.retrying = false;
                        obj.passtime = 0;
                        obj.retry_count++;
                        if(obj.retry_count >= this._retrycount){
                            obj.errcb && obj.errcb(errcode, errmsg);
                            let idx = this.cachemsg.findIndex((element) => {
                                return element == obj;
                            });
                            if(idx != -1){
                                this.cachemsg.splice(idx, 1);
                            }
                        }
                    }, method, true);
                }

            });
        }
    };

    this.setRetryCount=function(count){
        this.retrycount = count;
    };

    this.setRetryInterval=function(millsec){
        if(millsec != this._retryms){
            this._retryms = millsec;
            if(this._retry_tid){
                clearInterval(this._retry_tid);
                this._retry_tid = 0;
            }
        }
        if(!this._retry_tid){
            this._retry_tid = setInterval(this._retry.bind(this), this._retryms);
        }
    };

    this.setNeedRetry=function(needretry){
        this._needretry = needretry;
        // if(!this._needretry && this._retry_tid){
        //     clearInterval(this._retry_tid);
        //     this._retry_tid = 0;
        // }else if(this._needretry && !this._retry_tid){
        //     this._retry_tid = setInterval(this._retry.bind(this), this._retryms);
        // }
    }
};

module.exports = httpcli;