/**
 * Minimal hash-based SPA router.
 *
 * Route format:  { pattern: RegExp, title: string, template: string, onEnter: function(params, container) }
 *
 * The first matching route's onEnter is called with parsed params and a container element.
 * The container is cleared before each navigation.
 *
 * Usage:
 *   Router.add(/^\/(.+)\/info$/,          'Server',      'html/serverInfo.html',  ServerInfoPage);
 *   Router.add(/^\/(.+)\/player\/(.+)$/,  'Player Info', 'html/playerInfo.html', PlayerInfoPage);
 *   Router.start('#app-view');
 */
var Router = (function () {
  'use strict';

  var routes = [];
  var viewSelector = null;
  var currentCleanup = null;

  function add(pattern, title, template, onEnter) {
    routes.push({ pattern: pattern, title: title, template: template, onEnter: onEnter });
  }

  function navigate(hash) {
    // strip leading # and optional /
    var path = (hash || '').replace(/^#\/?/, '/');
    if (!path || path === '/') path = '/home';

    for (var i = 0; i < routes.length; i++) {
      var r = routes[i];
      var match = path.match(r.pattern);
      if (match) {
        // Store params for later use
        var container = document.querySelector(viewSelector);
        if (!container) return;

        // Cleanup previous page
        if (currentCleanup && typeof currentCleanup === 'function') {
          currentCleanup();
          currentCleanup = null;
        }

        // Clear container
        container.innerHTML = '';

        // Call onEnter with match groups + container
        if (typeof r.onEnter === 'function') {
          var result = r.onEnter(match, container);
          if (typeof result === 'function') {
            currentCleanup = result;
          }
        }
        return;
      }
    }
  }

  function start(selector) {
    viewSelector = selector;
    window.addEventListener('hashchange', function () {
      navigate(window.location.hash);
    });
    // Initial navigation
    if (window.location.hash) {
      navigate(window.location.hash);
    }
  }

  function go(hash) {
    window.location.hash = hash;
  }

  return {
    add: add,
    start: start,
    go: go,
    navigate: navigate
  };
})();