'use strict';

var _ = require('lodash');

var Func = function Func(name, handler) {

this.name = name;

this.handler = handler;

if (!_.isString(this.name) || !this.name.length) {

throw new Error('"' + this.name + '" is not a valid function name');

}

if (!_.isFunction(this.handler)) {

throw new Error('Function handlers must be functions');

}

};

Func.prototype.processResponse = function processResponse(cb) {

return function(err, output) {

if (err) return cb(err);

if (!output) {

return cb(new Error('Function failed to provide valid output. Provided: "' + output + '"'));

}

if (_.isObject(output)) {

try {

output = JSON.stringify(output);

} catch(err) {

return cb(err);

}

}

if (typeof output !== 'string') {

output = output.toString();

}

cb(null, output);

};

};

Func.prototype.call = function call(context, data, cb) {

return this.handler.call(context, data, this.processResponse(cb));

};

module.exports = Func;