var vm = Backbone.ViewManager = {};

vm.Core = (function() {
    var _regions = {};

    return {
        // register a region
        // name: a unique name for this region
        // selector: a DOM selector for this region
        addRegion: function(name, selector) {
            _regions[name] = {
                el: $(selector)
            };
        },

        // render a new view in a region
        // region: the name of the region
        // newView: the Backbone view object to render
        swap: function(region, newView) {
            region = _regions[region];

            if (!region) {
                return false;
            }

            // if a current view exists in region, unset and remove it
            if (region.view) {
                region.view.unsetView();
                region.view.unset();
            }

            // set the new view as current for the region
            region.view = newView;

            // render the new view into the region
            region.el.empty().html(newView.render().el);
        }
    };
})();


// a simple Base view
vm.BaseView = Backbone.View.extend({

    templateData: {},

    // to render the template on the view, just add a 'template'
    // variable to it which is the ID of the template on the page
    // 
    // NOTE: this is only a demo for simple views. write your own
    // render() method in your view if you have special requirements
    render: function() {
        if (this.template) {
            var template = _.template($(this.template).html());

            $(this.el).html(template(this.templateData));
        }
        return this;
    },

    // clean up before removing the view
    unset: function() {
        // turn off all bindings on the view
        this.off();

        // remove self from the page
        this.remove();
    },

    // NOTE: override this in a view to run any custom code before unset()
    // eg. turning off extra bindings
    unsetView: function() {
        // ...
    }

});