var _ = require("lodash"),
    Joi = require("joi");

module.exports = function(options){

    var internals = {
        options : {
            checkIntervalMs : 2000,
            warnDelayMs : 500,
            logger : {
                info : function(message) {
                    console.log(JSON.stringify(message));
                },
                warn : function(message) {
                    console.log(JSON.stringify(message));
                }
            }
        },
        schema : Joi.object().keys({
            checkIntervalMs : Joi.number().integer().min(1),
            warnDelayMs : Joi.number().integer().min(1),
            logger : Joi.object().pattern( /.*/, Joi.any()).keys({
                info : Joi.func().required(),
                warn : Joi.func().required()
            })
        })
    };

    validate(options);

    internals.options = _.assign(internals.options, options);

    function validate(options){
        Joi.validate(options, internals.schema, function(err){
            if(err){
                throw err;
            }
        });
    }

    setInterval(function(){
        var time = Date.now();
        setImmediate(function(){
            var message = {
                status : {
                    description : "event loop delay",
                    delta : Math.abs(Date.now() - time),
                    memory : process.memoryUsage()
                }
            };

            if(message.delta >= internals.options.warnDelayMs)
                internals.options.logger.warn(message);
            else
                internals.options.logger.info(message);
        });
    }, internals.options.checkIntervalMs);

};