module.exports = function(self) {

    self.setup = function() {
        self.super_.setup.call(this);

        let disableMethods = {
            'create': true,
            'replaceOrCreate': true,
            'patchOrCreate': true,
            'upsert': true,
            'updateOrCreate': true,
            'exists': true,
            'find': true,
            'findOne': true,
            'findById': true,
            'deleteById': true,
            'replaceById': true,
            'updateAttributes': false,
            'createChangeStream': true,
            'updateAll': true,
            'upsertWithWhere': true,
            'count': true
        };

        for(let method in disableMethods) {
            //this.disableRemoteMethod(method, disableMethods[method]);
        }
    };

    self.defineScope = function(serverFilter) {
        this.remoteMethodCtx('list', {
            accepts: [
                {
                    arg: 'filter', 
                    type: 'object', 
                    description: 'Filter defining where'
                }
            ],
            returns: { 
                type: [this.modelName],
                root: true
            },
            http: {
                verb: 'get',
                path: '/list'
            }
        });

        this.list = function(ctx, clientFilter, cb) {
            var where = {"and": []};
            (clientFilter) ? where.and.push(clientFilter.where) : undefined;
            (serverFilter) ? where.and.push(serverFilter.where) : undefined;
            
            var order = (clientFilter && clientFilter.order) ? clientFilter.order : (serverFilter && serverFilter.order) ? serverFilter.order : undefined;
            var limit = (serverFilter && serverFilter.limit) ? serverFilter.limit : (clientFilter && clientFilter.limit) ? clientFilter.limit : undefined;

            var filter = {"where": where, "order": order, "limit": limit};
            filter = removeEmpty(filter);

            this.find(filter, function(err, states) {
                (!err) ? cb(null, states) : cb(err, null);
            });
        };
    };

    self.rawSql = function(query, params, cb) {
        this.dataSource.connector.execute(query, params, function(error, response) {
            cb(error, response);
        });
    };

    self.remoteMethodCtx = function(methodName, args) {
        if(args.accepts !== undefined && Array.isArray(args.accepts)) {
           var ctx = {
               arg: 'context', 
               type: 'object', 
               http: function(ctx) { 
                   return ctx; 
                }
            }
           args.accepts.unshift(ctx);          
        }
        this.remoteMethod(methodName, args);
    };

    self.connectToService = function(ctx, dataSource) {
        this.app.dataSources[dataSource].connector.remotes.auth = {
            bearer: new Buffer(ctx.req.accessToken.id).toString('base64'),
            sendImmediately: true
        };
    };

    self.disconnectFromService = function(dataSource) {
        this.app.dataSources[dataSource].connector.remotes.auth = {
            bearer: new Buffer("").toString('base64'),
            sendImmediately: true
        };
    };

    self.installMethod = function(methodName, filterCb) {
        this.remoteMethod(methodName, {
            description: 'List items using a filter',
            accessType: 'READ',
            accepts: [
                {
                    arg: 'filter',
                    type: 'object',
                    required: true,
                    description: 'Filter defining where',
                    http: function(ctx) {
                        return ctx.req.query;
                    }
                }
            ],
            returns: {
                arg: 'data', 
                type: [this.modelName],
                root: true
            },
            http: {
                verb: 'get',
                path: `/${methodName}`
            }
        });

        this[methodName] = (params, cb) => {
            let filter = removeEmpty(filterCb(params));
            var response = {}

            function returnValues(){
                if(response.instances !== undefined && response.count !== undefined)
                    cb(null, response);
            }

            function error(){
                cb(null, response);
            }

            this.find(filter, function(err, instances) {
                if(!err){
                    response.instances = instances;
                    returnValues();
                }
                else{
                    error();
                }
                    
            })
            
            this.count(filter.where, function(err, totalCount){
                if(!err){
                    response.count = totalCount;
                    returnValues();
                }
                else{
                    error();
                }
                    
            })
        };

    };
}

function removeEmpty(o) {
    if(Array.isArray(o)) {
        let array = [];
        for(let item of o) {
            let i = removeEmpty(item);
            if(!isEmpty(item))
                array.push(item);
        };
        if(array.length > 0)
            return array;
    }
    else if (typeof o === 'object') {
        let object = {};
        for(let key in o) {
            let i = removeEmpty(o[key]);
            if(!isEmpty(i))
                object[key] = i;                
        }
        if(Object.keys(object).length > 0)
            return object;
    }
    else if (!isEmpty(o))
        return o;

    return undefined;
}

function isEmpty(value) {
    return value === undefined || value === "";
}