var url = require('url');
var NotFoundError = require('./error').NotFound;
var RouteNode = require('./route-node');
var utils = require('./utils');

var assign = utils.assign;
var isArray = utils.isArray;
var isFunction = utils.isFunction;
var isString = utils.isString;
var noop = utils.noop;

function Router() {
  this.routes = new RouteNode();
}

assign(Router.prototype, {
  add: function add(path, handler) {
    return this.routes.add(this._uriToParts(path), handler);
  },

  route: function route(path, options, done) {
    if (done == null && isFunction(options)) {
      done = options;
      options = {};
    }
    options = options || {};
    var routeArray = this._uriToParts(path);
    done = done || noop;

    function _routeCallback(err, func, context, args) {
      if (err) {
        return done(err);
      } else {
        if (isFunction(func)) {
          return done(null, func.apply(context, args));
        } else {
          return done(new NotFoundError('not found', {location: path}));
        }
      }
    }

    return this.routes.get(routeArray, (options.args || []), _routeCallback);
  },

  _uriToParts: function _uriToParts(uri) {
    if (isString(uri)) {
      return url.parse(uri)
        .pathname
        .split('/')
        .filter(function (str) { return str !== ''; });
    } else if (isArray(uri)) {
      return uri.reduce(this._uriToPartsReducer.bind(this), []);
    }
  },

  _uriToPartsReducer: function _uriToPartsReducer(memo, item) {
    if (isArray(item)) {
      return memo.concat(item);
    } else if (isString(item)) {
      return memo.concat(this._uriToParts(item));
    } else {
      return memo.concat(item);
    }
  }
});

Router.isNotFound = function isNotFound(err) {
  return err instanceof NotFoundError;
};

module.exports = Router;