/**
 * Expose `Resource`.
 */

module.exports = Resource;

/**
 * Module dependencies.
 */
 
var asteroid = require('asteroid')
  , AsteroidModule = require('asteroid-module')
  , HttpContext = require('./http-context')
  , debug = require('debug')('asteroid:resource')
  , util = require('util')
  , inherits = util.inherits
  , assert = require('assert');
  
/**
 * Create a new `Resource` with the given `options`.
 *
 * @param {Object} options
 * @return {Resource}
 */

function Resource(options) {
  AsteroidModule.apply(this, arguments);
  
  // throw an error if args are not supplied
  assert(typeof options === 'object', 'Resource requires an options object');
  assert(options.path, 'Resource requires a path');
  
  // create the sub app
  var app = this.app = asteroid();
  
  this.options = options;
  
  debug('created with options', options);
  
  this.on('destroyed', function () {
    app.disuse(this.options.path);
  });
}

/**
 * Inherit from `AsteroidModule`.
 */

inherits(Resource, AsteroidModule);

/**
 * Mount the sub app on the given parent app at the configured path.
 */

Resource.prototype.mount = function (parent) {
  this.parent = parent;
  parent.use(this.options.path, this.app);
}

/**
 * Create an http context bound to the current resource.
 */

Resource.prototype.createContext = function (req, res, next) {
  return new HttpContext(this, req, res, next);
}

/**
 * Override `on` to determine how many arguments an event handler expects.
 */

Resource.prototype.on = function () {
  var fn = arguments[arguments.length - 1];
  
  if(typeof fn === 'function') {
    // parse expected arguments from function src
    // fn.listener handles the wrapped function during `.once()`
    var src = (fn.listener || fn).toString();
    fn._expects = src.split('{')[0].split(',').length;
  }
  
  AsteroidModule.prototype.on.apply(this, arguments);
}