var specificity = require('route-order')();
var slash = require('express-slash');

function OKServer(options) {
  if (!(this instanceof OKServer)) return new OKServer(options);
  options = options || {};
  if (!options.express)
    throw new Error('No Express provided to OKServer');
  if (!options.app)
    throw new Error('No Express app provided to OKServer')
  if (!options.views)
    throw new Error('No views provided to OKServer');
  var views = options.views;
  var express = options.express;
  var app = this._app = options.app;
  Object.keys(views)
    .sort(specificity)
    .forEach(function(route) {
      // We want to enforce trailing slashes for middleware
      routeNoSlash = route.charAt(route.length - 1) === '/' ?
          route.slice(0, route.length - 1) : route;
      app.all(routeNoSlash, redirect(routeNoSlash));
      app.use(routeNoSlash + '/', views[route].middleware());
    });
  // This enforces trailing slashes for stuff that isn't middleware
  app.use(slash());

  /**
   * Create a handler which redirect all requests to
   * the same route with a trailing slash appended
   */
  function redirect(routeNoSlash) {
    return function(req, res) {
      res.redirect(301, routeNoSlash + '/');
    }
  }
}

OKServer.prototype.listen = function listen(port) {
  this._app.listen(port || 1337);
  return this;
};

module.exports = OKServer;