(function () {
    var Events = {

        // Bind an event to a `callback` function. Passing `"all"` will bind
        // the callback to all events fired.
        on: function (name, callback, context) {
            if (!eventsApi(this, "on", name, [callback, context]) || !callback) return this;
            this._events || (this._events = {});
            var events = this._events[name] || (this._events[name] = []);
            events.push({callback: callback, context: context, ctx: context || this});
            return this;
        },

        // Bind an event to only be triggered a single time. After the first time
        // the callback is invoked, it will be removed.
        once: function (name, callback, context) {
            if (!eventsApi(this, "once", name, [callback, context]) || !callback) return this;
            var self = this;
            var once = _.once(function () {
                self.off(name, once);
                callback.apply(this, arguments);
            });
            once._callback = callback;
            return this.on(name, once, context);
        },

        // Remove one or many callbacks. If `context` is null, removes all
        // callbacks with that function. If `callback` is null, removes all
        // callbacks for the event. If `name` is null, removes all bound
        // callbacks for all events.
        off: function (name, callback, context) {
            if (!this._events || !eventsApi(this, "off", name, [callback, context])) return this;

            // Remove all callbacks for all events.
            if (!name && !callback && !context) {
                this._events = void 0;
                return this;
            }

            var names = name ? [name] : _.keys(this._events);
            for (var i = 0, length = names.length; i < length; i++) {
                name = names[i];

                // Bail out if there are no events stored.
                var events = this._events[name];
                if (!events) continue;

                // Remove all callbacks for this event.
                if (!callback && !context) {
                    delete this._events[name];
                    continue;
                }

                // Find any remaining events.
                var remaining = [];
                for (var j = 0, k = events.length; j < k; j++) {
                    var event = events[j];
                    if (
                        callback && callback !== event.callback &&
                        callback !== event.callback._callback ||
                        context && context !== event.context
                    ) {
                        remaining.push(event);
                    }
                }

                // Replace events if there are any remaining.  Otherwise, clean up.
                if (remaining.length) {
                    this._events[name] = remaining;
                } else {
                    delete this._events[name];
                }
            }

            return this;
        },

        un: function () {
            this.off.apply(this, arguments);
        },

        // Trigger one or many events, firing all bound callbacks. Callbacks are
        // passed the same arguments as `trigger` is, apart from the event name
        // (unless you're listening on `"all"`, which will cause your callback to
        // receive the true name of the event as the first argument).
        trigger: function (name) {
            if (!this._events) return this;
            var args = slice.call(arguments, 1);
            if (!eventsApi(this, "trigger", name, args)) return this;
            var events = this._events[name];
            var allEvents = this._events.all;
            if (events) triggerEvents(events, args);
            if (allEvents) triggerEvents(allEvents, arguments);
            return this;
        },

        fireEvent: function () {
            this.trigger.apply(this, arguments);
        },

        // Inversion-of-control versions of `on` and `once`. Tell *this* object to
        // listen to an event in another object ... keeping track of what it's
        // listening to.
        listenTo: function (obj, name, callback) {
            var listeningTo = this._listeningTo || (this._listeningTo = {});
            var id = obj._listenId || (obj._listenId = _.uniqueId("l"));
            listeningTo[id] = obj;
            if (!callback && typeof name === "object") callback = this;
            obj.on(name, callback, this);
            return this;
        },

        listenToOnce: function (obj, name, callback) {
            if (typeof name === "object") {
                for (var event in name) this.listenToOnce(obj, event, name[event]);
                return this;
            }
            if (eventSplitter.test(name)) {
                var names = name.split(eventSplitter);
                for (var i = 0, length = names.length; i < length; i++) {
                    this.listenToOnce(obj, names[i], callback);
                }
                return this;
            }
            if (!callback) return this;
            var once = _.once(function () {
                this.stopListening(obj, name, once);
                callback.apply(this, arguments);
            });
            once._callback = callback;
            return this.listenTo(obj, name, once);
        },

        // Tell this object to stop listening to either specific events ... or
        // to every object it's currently listening to.
        stopListening: function (obj, name, callback) {
            var listeningTo = this._listeningTo;
            if (!listeningTo) return this;
            var remove = !name && !callback;
            if (!callback && typeof name === "object") callback = this;
            if (obj) (listeningTo = {})[obj._listenId] = obj;
            for (var id in listeningTo) {
                obj = listeningTo[id];
                obj.off(name, callback, this);
                if (remove || _.isEmpty(obj._events)) delete this._listeningTo[id];
            }
            return this;
        }

    };

    // Regular expression used to split event strings.
    var eventSplitter = /\s+/;

    // Implement fancy features of the Events API such as multiple event
    // names `"change blur"` and jQuery-style event maps `{change: action}`
    // in terms of the existing API.
    var eventsApi = function (obj, action, name, rest) {
        if (!name) return true;

        // Handle event maps.
        if (typeof name === "object") {
            for (var key in name) {
                obj[action].apply(obj, [key, name[key]].concat(rest));
            }
            return false;
        }

        // Handle space separated event names.
        if (eventSplitter.test(name)) {
            var names = name.split(eventSplitter);
            for (var i = 0, length = names.length; i < length; i++) {
                obj[action].apply(obj, [names[i]].concat(rest));
            }
            return false;
        }

        return true;
    };

    // A difficult-to-believe, but optimized internal dispatch function for
    // triggering events. Tries to keep the usual cases speedy (most internal
    // BI events have 3 arguments).
    var triggerEvents = function (events, args) {
        var ev, i = -1, l = events.length, a1 = args[0], a2 = args[1], a3 = args[2];
        switch (args.length) {
            case 0:
                while (++i < l) (ev = events[i]).callback.call(ev.ctx);
                return;
            case 1:
                while (++i < l) (ev = events[i]).callback.call(ev.ctx, a1);
                return;
            case 2:
                while (++i < l) (ev = events[i]).callback.call(ev.ctx, a1, a2);
                return;
            case 3:
                while (++i < l) (ev = events[i]).callback.call(ev.ctx, a1, a2, a3);
                return;
            default:
                while (++i < l) (ev = events[i]).callback.apply(ev.ctx, args);
                return;
        }
    };

    // BI.Router
    // ---------------

    // Routers map faux-URLs to actions, and fire events when routes are
    // matched. Creating a new one sets its `routes` hash, if not set statically.
    var Router = BI.Router = function (options) {
        options || (options = {});
        if (options.routes) this.routes = options.routes;
        this._bindRoutes();
        this._init.apply(this, arguments);
    };

    // Cached regular expressions for matching named param parts and splatted
    // parts of route strings.
    var optionalParam = /\((.*?)\)/g;
    var namedParam = /(\(\?)?:\w+/g;
    var splatParam = /\*\w+/g;
    var escapeRegExp = /[\-{}\[\]+?.,\\\^$|#\s]/g;

    // Set up all inheritable **BI.Router** properties and methods.
    _.extend(Router.prototype, Events, {

        // _init is an empty function by default. Override it with your own
        // initialization logic.
        _init: function () {
        },

        // Manually bind a single named route to a callback. For example:
        //
        //     this.route('search/:query/p:num', 'search', function(query, num) {
        //       ...
        //     });
        //
        route: function (route, name, callback) {
            if (!_.isRegExp(route)) route = this._routeToRegExp(route);
            if (_.isFunction(name)) {
                callback = name;
                name = "";
            }
            if (!callback) callback = this[name];
            var router = this;
            BI.history.route(route, function (fragment) {
                var args = router._extractParameters(route, fragment);
                if (router.execute(callback, args, name) !== false) {
                    router.trigger.apply(router, ["route:" + name].concat(args));
                    router.trigger("route", name, args);
                    BI.history.trigger("route", router, name, args);
                }
            });
            return this;
        },

        // Execute a route handler with the provided parameters.  This is an
        // excellent place to do pre-route setup or post-route cleanup.
        execute: function (callback, args, name) {
            if (callback) callback.apply(this, args);
        },

        // Simple proxy to `BI.history` to save a fragment into the history.
        navigate: function (fragment, options) {
            BI.history.navigate(fragment, options);
            return this;
        },

        // Bind all defined routes to `BI.history`. We have to reverse the
        // order of the routes here to support behavior where the most general
        // routes can be defined at the bottom of the route map.
        _bindRoutes: function () {
            if (!this.routes) return;
            this.routes = _.result(this, "routes");
            var route, routes = _.keys(this.routes);
            while ((route = routes.pop()) != null) {
                this.route(route, this.routes[route]);
            }
        },

        // Convert a route string into a regular expression, suitable for matching
        // against the current location hash.
        _routeToRegExp: function (route) {
            route = route.replace(escapeRegExp, "\\$&")
                .replace(optionalParam, "(?:$1)?")
                .replace(namedParam, function (match, optional) {
                    return optional ? match : "([^/?]+)";
                })
                .replace(splatParam, "([^?]*?)");
            return new RegExp("^" + route + "(?:\\?([\\s\\S]*))?$");
        },

        // Given a route, and a URL fragment that it matches, return the array of
        // extracted decoded parameters. Empty or unmatched parameters will be
        // treated as `null` to normalize cross-browser behavior.
        _extractParameters: function (route, fragment) {
            var params = route.exec(fragment).slice(1);
            return _.map(params, function (param, i) {
                // Don't decode the search params.
                if (i === params.length - 1) return param || null;
                return param ? decodeURIComponent(param) : null;
            });
        }

    });

    // History
    // ----------------

    // Handles cross-browser history management, based on either
    // [pushState](http://diveintohtml5.info/history.html) and real URLs, or
    // [onhashchange](https://developer.mozilla.org/en-US/docs/DOM/window.onhashchange)
    // and URL fragments. If the browser supports neither (old IE, natch),
    // falls back to polling.
    var History = function () {
        this.handlers = [];
        this.checkUrl = _.bind(this.checkUrl, this);

        // Ensure that `History` can be used outside of the browser.
        if (typeof window !== "undefined") {
            this.location = _global.location;
            this.history = _global.history;
        }
    };

    // Cached regex for stripping a leading hash/slash and trailing space.
    var routeStripper = /^[#\/]|\s+$/g;

    // Cached regex for stripping leading and trailing slashes.
    var rootStripper = /^\/+|\/+$/g;

    // Cached regex for stripping urls of hash.
    var pathStripper = /#.*$/;

    // Has the history handling already been started?
    History.started = false;

    // Set up all inheritable **BI.History** properties and methods.
    _.extend(History.prototype, Events, {

        // The default interval to poll for hash changes, if necessary, is
        // twenty times a second.
        interval: 50,

        // Are we at the app root?
        atRoot: function () {
            var path = this.location.pathname.replace(/[^\/]$/, "$&/");
            return path === this.root && !this.getSearch();
        },

        // In IE6, the hash fragment and search params are incorrect if the
        // fragment contains `?`.
        getSearch: function () {
            var match = this.location.href.replace(/#.*/, "").match(/\?.+/);
            return match ? match[0] : "";
        },

        // Gets the true hash value. Cannot use location.hash directly due to bug
        // in Firefox where location.hash will always be decoded.
        getHash: function (window) {
            var match = (window || this).location.href.match(/#(.*)$/);
            return match ? match[1] : "";
        },

        // Get the pathname and search params, without the root.
        getPath: function () {
            var path = decodeURI(this.location.pathname + this.getSearch());
            var root = this.root.slice(0, -1);
            if (!path.indexOf(root)) path = path.slice(root.length);
            return path.charAt(0) === "/" ? path.slice(1) : path;
        },

        // Get the cross-browser normalized URL fragment from the path or hash.
        getFragment: function (fragment) {
            if (fragment == null) {
                if (this._hasPushState || !this._wantsHashChange) {
                    fragment = this.getPath();
                } else {
                    fragment = this.getHash();
                }
            }
            return fragment.replace(routeStripper, "");
        },

        // Start the hash change handling, returning `true` if the current URL matches
        // an existing route, and `false` otherwise.
        start: function (options) {
            if (History.started) throw new Error("BI.history has already been started");
            History.started = true;

            // Figure out the initial configuration. Do we need an iframe?
            // Is pushState desired ... is it available?
            this.options = _.extend({root: "/"}, this.options, options);
            this.root = this.options.root;
            this._wantsHashChange = this.options.hashChange !== false;
            this._hasHashChange = "onhashchange" in window;
            this._wantsPushState = !!this.options.pushState;
            this._hasPushState = !!(this.options.pushState && this.history && this.history.pushState);
            this.fragment = this.getFragment();

            // Normalize root to always include a leading and trailing slash.
            this.root = ("/" + this.root + "/").replace(rootStripper, "/");

            // Transition from hashChange to pushState or vice versa if both are
            // requested.
            if (this._wantsHashChange && this._wantsPushState) {

                // If we've started off with a route from a `pushState`-enabled
                // browser, but we're currently in a browser that doesn't support it...
                if (!this._hasPushState && !this.atRoot()) {
                    var root = this.root.slice(0, -1) || "/";
                    this.location.replace(root + "#" + this.getPath());
                    // Return immediately as browser will do redirect to new url
                    return true;

                    // Or if we've started out with a hash-based route, but we're currently
                    // in a browser where it could be `pushState`-based instead...
                } else if (this._hasPushState && this.atRoot()) {
                    this.navigate(this.getHash(), {replace: true});
                }

            }

            // Proxy an iframe to handle location events if the browser doesn't
            // support the `hashchange` event, HTML5 history, or the user wants
            // `hashChange` but not `pushState`.
            if (!this._hasHashChange && this._wantsHashChange && (!this._wantsPushState || !this._hasPushState)) {
                var iframe = document.createElement("iframe");
                iframe.src = "javascript:0";
                iframe.style.display = "none";
                iframe.tabIndex = -1;
                var body = document.body;
                // Using `appendChild` will throw on IE < 9 if the document is not ready.
                this.iframe = body.insertBefore(iframe, body.firstChild).contentWindow;
                this.iframe.document.open().close();
                this.iframe.location.hash = "#" + this.fragment;
            }

            // Add a cross-platform `addEventListener` shim for older browsers.
            var addEventListener = _global.addEventListener || function (eventName, listener) {
                return attachEvent("on" + eventName, listener);
            };

            // Depending on whether we're using pushState or hashes, and whether
            // 'onhashchange' is supported, determine how we check the URL state.
            if (this._hasPushState) {
                addEventListener("popstate", this.checkUrl, false);
            } else if (this._wantsHashChange && this._hasHashChange && !this.iframe) {
                addEventListener("hashchange", this.checkUrl, false);
            } else if (this._wantsHashChange) {
                this._checkUrlInterval = setInterval(this.checkUrl, this.interval);
            }

            if (!this.options.silent) return this.loadUrl();
        },

        // Disable BI.history, perhaps temporarily. Not useful in a real app,
        // but possibly useful for unit testing Routers.
        stop: function () {
            // Add a cross-platform `removeEventListener` shim for older browsers.
            var removeEventListener = _global.removeEventListener || function (eventName, listener) {
                return detachEvent("on" + eventName, listener);
            };

            // Remove window listeners.
            if (this._hasPushState) {
                removeEventListener("popstate", this.checkUrl, false);
            } else if (this._wantsHashChange && this._hasHashChange && !this.iframe) {
                removeEventListener("hashchange", this.checkUrl, false);
            }

            // Clean up the iframe if necessary.
            if (this.iframe) {
                document.body.removeChild(this.iframe.frameElement);
                this.iframe = null;
            }

            // Some environments will throw when clearing an undefined interval.
            if (this._checkUrlInterval) clearInterval(this._checkUrlInterval);
            History.started = false;
        },

        // Add a route to be tested when the fragment changes. Routes added later
        // may override previous routes.
        route: function (route, callback) {
            this.handlers.unshift({route: route, callback: callback});
        },

        // Checks the current URL to see if it has changed, and if it has,
        // calls `loadUrl`, normalizing across the hidden iframe.
        checkUrl: function (e) {
            var current = this.getFragment();

            // If the user pressed the back button, the iframe's hash will have
            // changed and we should use that for comparison.
            if (current === this.fragment && this.iframe) {
                current = this.getHash(this.iframe);
            }

            if (current === this.fragment) return false;
            if (this.iframe) this.navigate(current);
            this.loadUrl();
        },

        // Attempt to load the current URL fragment. If a route succeeds with a
        // match, returns `true`. If no defined routes matches the fragment,
        // returns `false`.
        loadUrl: function (fragment) {
            fragment = this.fragment = this.getFragment(fragment);
            return _.some(this.handlers, function (handler) {
                if (handler.route.test(fragment)) {
                    handler.callback(fragment);
                    return true;
                }
            });
        },

        // Save a fragment into the hash history, or replace the URL state if the
        // 'replace' option is passed. You are responsible for properly URL-encoding
        // the fragment in advance.
        //
        // The options object can contain `trigger: true` if you wish to have the
        // route callback be fired (not usually desirable), or `replace: true`, if
        // you wish to modify the current URL without adding an entry to the history.
        navigate: function (fragment, options) {
            if (!History.started) return false;
            if (!options || options === true) options = {trigger: !!options};

            // Normalize the fragment.
            fragment = this.getFragment(fragment || "");

            // Don't include a trailing slash on the root.
            var root = this.root;
            if (fragment === "" || fragment.charAt(0) === "?") {
                root = root.slice(0, -1) || "/";
            }
            var url = root + fragment;

            // Strip the hash and decode for matching.
            fragment = decodeURI(fragment.replace(pathStripper, ""));

            if (this.fragment === fragment) return;
            this.fragment = fragment;

            // If pushState is available, we use it to set the fragment as a real URL.
            if (this._hasPushState) {
                this.history[options.replace ? "replaceState" : "pushState"]({}, document.title, url);

                // If hash changes haven't been explicitly disabled, update the hash
                // fragment to store history.
            } else if (this._wantsHashChange) {
                this._updateHash(this.location, fragment, options.replace);
                if (this.iframe && (fragment !== this.getHash(this.iframe))) {
                    // Opening and closing the iframe tricks IE7 and earlier to push a
                    // history entry on hash-tag change.  When replace is true, we don't
                    // want this.
                    if (!options.replace) this.iframe.document.open().close();
                    this._updateHash(this.iframe.location, fragment, options.replace);
                }

                // If you've told us that you explicitly don't want fallback hashchange-
                // based history, then `navigate` becomes a page refresh.
            } else {
                return this.location.assign(url);
            }
            if (options.trigger) return this.loadUrl(fragment);
        },

        // Update the hash location, either replacing the current entry, or adding
        // a new one to the browser history.
        _updateHash: function (location, fragment, replace) {
            if (replace) {
                var href = location.href.replace(/(javascript:|#).*$/, "");
                location.replace(href + "#" + fragment);
            } else {
                // Some browsers require that `hash` contains a leading #.
                location.hash = "#" + fragment;
            }
        }

    });

    // Create the default BI.history.
    BI.history = new History;
}());
//# sourceMappingURL=router.js.map