const query  = require("querystring");
const base64 = require('js-base64').Base64;

var API = {
    parse:function(req,res){
        var url = req.url;
        var URLParse = URL.parse(url,true);
        var URLArr = URLParse.pathname.split('/');
        //Only GET
        req.param = URLParse.query;
        // console.log(URLParse.query);
        API._checkRouter(URLArr[1],req,res);
        // }else{
        //     var postdata = "";
        //     req.addListener("data",function(postchunk){
        //         postdata += postchunk;
        //     })

        //     //POST结束输出结果
        //     req.addListener("end",function(){
        //         req.param = query.parse(postdata);
        //         API._checkRouter(URLArr[1],req,res);
        //     })
        // }
    },
    _checkRouter:function(path,req,res){
        // console.log(req.param);
        switch(path){
            case 'getlink':
                if(req.param['key'] && req.param['key']!='' && req.param['url'] && req.param['url']!=''){
                    UserDB.findOne({key:req.param['key']},function(err,data){
                        if(!err && data){
                            var oldLink = req.param['url'];
                            if(req.param['base64'] && req.param['base64']==0){
                                if(oldLink.match(/http:\/\//)){
                                    MongoHandler.getlink(req.param['key'],oldLink,res);
                                }else{
                                    API._onError(ErrorMsg.URL_WRONG,res);
                                    return;
                                }
                            }else{
                                oldLink = base64.decode(oldLink);
                                if(oldLink.match(/http:\/\//)){
                                    MongoHandler.getlink(req.param['key'],oldLink,res);
                                }else{
                                    API._onError(ErrorMsg.URL_WRONG,res);
                                    return;
                                }
                            }
                        }else{
                            API._onError(ErrorMsg.KEY_WRONG,res);
                        }
                    });
                }else{
                    if(!req.param['key']){
                        API._onError(ErrorMsg.KEY_LOST,res);
                        return;
                    }
                    if(!req.param['url']){
                        API._onError(ErrorMsg.URL_LOST,res);
                        return;
                    }
                }
                break;
            case 'check':
                break;
            default:
                res.writeHead(404, {'Content-Type': 'text/html'});
                res.end('404');
        }
    },
    _onError:function(msg,res){
        var data = {success:0,msg:msg,short:'',long:''};
        res.writeHead(200, {'Content-Type': 'text/json'});
        res.write(JSON.stringify(data));
        res.end();
    }
}

var MongoHandler = {
    getlink:function(key,url,res){
        var baseLink;
        baseLink = base64.encode(url);
        // console.log(baseLink,newLink);
        LinkDB.findOne({long:baseLink},function(err,oldOne){
            if(!err){
                var data = {success:1,msg:'',short:'http://l2s.ch/',long:url};
                if(oldOne){
                    data.short += oldOne.short;
                    res.writeHead(200, {'Content-Type': 'text/json'});
                    res.write(JSON.stringify(data));
                    res.end();
                }else{
                    var newLink,count = COUNT.link+1;
                    newLink = count.toString(16);
                    LinkDB.update({key:key,long:baseLink},{$set:{short:newLink}},{upsert:true},function(err,result){
                        if(!err && result){
                            data.short += newLink;
                            res.writeHead(200, {'Content-Type': 'text/json'});
                            res.write(JSON.stringify(data));
                            res.end();
                            COUNT.link++;
                            CountDB.update({},{$inc:{link:1}},{upsert:true});
                        }else{
                            API._onError(ErrorMsg.MAKE_ERROR,res);
                        }
                    });
                }
            }else{
                API._onError(ErrorMsg.MAKE_ERROR,res);
            }
        });
    }
}

const ErrorMsg = {
    NONE:'',
    KEY_LOST    :'Key is missing',
    KEY_WRONG   :'Key is incorrect',
    URL_LOST    :'URL is missing ',
    URL_WRONG   :'URL must start with "http://"',
    MAKE_ERROR  :'Short link generate error,please contact with l2s.ch'
}

module.exports = API;