gistfile1.txt

SM = function(options) {
    console.log(options);
    options || (options = {});
    this.current = (options['start'] || this.current || 'start');
    this._transitions = {};
    this._leaves = {};
    this._enters = {};
    this._allowed = {};
};

_.extend(SM.prototype, Backbone.Events, {
    transitionRegExp: /transition\|\|(\w+)\|\|(\w+)/,
    leaveRegExp: /leave\|\|(\w+)/,
    enterRegExp: /enter\|\|(\w+)/,
    isAllowed: function(from) {
        var args = Array.prototype.slice.call(arguments);
        this._allowed[from] || (this._allowed[from] = []);
        if (this._allowed[from].length === 0) {
            return false;
        } else {
            var to = args[1];
            var available = this._allowed[from];
            if (to) {
                return _.any(available, function(t) {
                    return t === to;
                });
            } else {
                return this._allowed[from].length > 0;
            }
        }
    },

    toTransitionString: function(from, to) {
        return "transition||" + from + "||" + to;
    },

    toLeaveString: function(from) {
        return "leave||" + from;
    },

    toEnterString: function(to) {
        return "to||" + to;
    },

    ontransition: function(from, to, cb) {
        this.on(this.toTransitionString(from, to), cb);
        return this;
    },

    _transition: function(to) {
        var from = this.current;
        if (this.isAllowed(from, to)) {
            var args = Array.prototype.slice.call(arguments, 1);

            this._leave(from, args);

            var evt = this.toTransitionString(from, to);
            args.unshift(evt);
            this.trigger.apply(this, args);

            this._enter(to, args);

            return this;
        } else {
            console.log("ERROR! Invalid transition:", from, to);
        }
    },

    onleave: function(from, cb) {
        this.on(this.toLeaveString(from), cb);
        return this;
    },

    _leave: function(from, args) {
        var args = _.clone(args);
        var evt = this.toLeaveString(from);
        args.unshift(evt);
        this.trigger.apply(this, args);
        return this;
    },

    onenter: function(to, cb) {
        this.on(this.toEnterString(to), cb);
        return this;
    },

    enter: function(to) {
        var from = this.current;
        if (this.isAllowed(from, to)) {
            this._transition(to);
            this.current = to;
            return this;
        } else {
            console.log("ERROR! Unable to enter '" + to + "' state from '" + from + "'.");
        }
    },

    _enter: function(from, args) {
        var args = _.clone(args);
        var evt = this.toEnterString(from);
        args.unshift(evt);
        this.trigger.apply(this, args);
        return this;
    },

    addTransition: function(from, to) {
        if (from && to) {
            this._allowed[from] || (this._allowed[from] = []);
            this._allowed[from].push(to);
            return this;
        } else {
            console.log("ERROR! Transitions need to have a from state and a to state.");
        }
    }
});

SM.extend = Backbone.Model.extend;