var pgClient;

exports.setConnection = function(client){
	pgClient = client;
}

/*************************************************************************
*************************** CRUD OPERTIONS ***************************
************************************************************************/
exports.getRecords = function(objectApiName, config, callback){
	var params = prepareReadParams(config);
	var query = 'SELECT * FROM salesforce.'+objectApiName;

	if(params.where){
		query += ' WHERE ' + params.where;
	}

	runQuery(query, params.vals, objectApiName , callback);
};


exports.saveRecord = function(objectApiName, body, callback){
	var params = prepareInsertParams(body);
	var query = 'INSERT INTO salesforce.'+objectApiName;

	if(params.fields){
		query += '('+params.fields+') VALUES(' + params.numbers + ') RETURNING *';
	}

	runQuery(query, params.vals, objectApiName , callback);
};

exports.editRecord = function(objectApiName, config, body, callback){
	var params = prepareUpdateParams(body, config);
	var query = 'UPDATE salesforce.'+objectApiName;

	if(params.set){
		query += ' SET ' + params.set;
	}

	if(params.where){
		query += ' WHERE ' + params.where;
	}

	runQuery(query, params.vals, objectApiName , callback);
};

exports.deleteRecord = function(objectApiName, IdToDelete, callback){
	var config = { Id : IdToDelete };
	var params = prepareReadParams(config);
	var query = 'DELETE FROM salesforce.'+objectApiName;

	if(params.where){
		query += ' WHERE ' + params.where;
	}

	runQuery(query, params.vals, objectApiName , callback);
};

function prepareUpdateParams(config, findWith){
	var vals = [];
	var set = '';
	var where = '';
	var counter = 1;
	if(config !== {}){
		for(var key in config){
			if(key != '__proto__'){
				set += set != '' ? ', ' + key +'=($'+counter + ')' : key +'=($'+counter + ')';
				vals.push(config[key]);
				counter++;
			}
		}
	}

	if(findWith !== {}){
		for(var key in findWith){
			where += where != '' ? ' AND '+ key + ' = ($'+ counter + ')': key + ' = ($'+ counter + ')';
			vals.push(findWith[key]);
		}
	}

	return {where : where, vals : vals, set : set};
}

function prepareReadParams(config){
	var vals = [];
	var where = '';
	if(config !== {}){
		var counter = 1;
		for(var key in config){
			where += where != '' ? ' AND '+ key + ' = $'+ counter : key + ' = $'+ counter;
			vals.push(config[key]);
			counter++;
		}
	}
	return {where : where, vals : vals};
}

function prepareInsertParams(config){
	var vals = [];
	var fields = '';
	var numbers = '';
	if(config !== {}){
		var counter = 1;
		for(var key in config){
			fields += fields != '' ? ',' + key : key;
			numbers += numbers != ''? ',' + '$' + counter : '$'+counter;
			vals.push(config[key]);
			counter++;
		}
	}
	return {fields : fields, numbers: numbers, vals : vals};
}

function runQuery(query, vals, type, callback){
	console.log('-->query', query);
	console.log('-->vals', vals);
	pgClient.query(query, vals, function(err, result){
		var res, error;
		if(!err){
			if(result.rows.length > 0){
        res = result.rows;
			}else{
				res = [];
			}
		}else{
			console.log('-->error', err);
			error = err;
		}
		callback(prepareResponse(error, res));
	});
};


function prepareResponse(err, result){
	var response = {success : false, data : ''};
	if (err){
		response.success 	= false;
		response.data    	=	'Error: ' + err;
	}
	else{
		response.success 	= true;
		response.data		= result;
	}

	return response;
}