var Model = Backbone.Model.extend({
    url: function() {
        var url = Backbone.Model.prototype.url.call(this);
        return url[url.length - 1] == '/' ? url : url + '/';
    },
    
    adhoc: function(data) {
        var model = this;
        var options = {
            url: this.urlRoot + encodeURIComponent(this.id) + '/',
            contentType: 'application/json',
            data: JSON.stringify(data)
        };
        
        return (this.sync || Backbone.sync).call(this, 'update', model, options).then(function(serverAttrs) {
            model.set(serverAttrs);
        });
    }
});
var Project = Model.extend({
    idAttribute: '_id',
    urlRoot: '/projects/',
    
    switchColor: function() {
        var colorChain = [null, 'info', 'success', 'warning', 'danger'];
        var currentColorIndex = colorChain.indexOf(this.get('color') || null);
        var nextColor = colorChain[(currentColorIndex + 1) % colorChain.length];
        
        return this.adhoc({color: nextColor});
    }
});
var Task = Model.extend({
    idAttribute: '_id',
    urlRoot: '/tasks/'
});