Konami Code in C#

Question

I am looking to have a C# application implement the Konami Code to display an Easter Egg. http://en.wikipedia.org/wiki/Konami_Code

What is the best way to do this?<

Answer 1

The answer can be found in Reactive Extensions. You need a sliding buffer for this to work. Meaning you have to compare the latest ten keystrokes with the Konami code. This works using two different statements

• A window to get a stream of streams (eventually leading to 10 simultaneous streams)
• A buffer to summarize each stream into an IList

The buffer within RX does both these tasks for us. Buffers the last 10 items and skips 1 (so effectively creates 10 buffers).

        var keysIO = Observable.FromEventPattern(this, "KeyDown")
                                    .Select(arg => arg.EventArgs.Key)
                                    .Buffer(10, 1)
                                    .Select(keys => Enumerable.SequenceEqual(keys, _konamiArray))
                                    .Where(result => result)
                                    .Subscribe(i =>
                                                    {
                                                        Debug.WriteLine("Found Konami");
                                                    });

EDIT: Removed the timed solution., too complex

EDIT II: I cracked the time-out solution as well. The beauty of SelectMany :-)

        var keysIO = Observable.FromEventPattern(this, "KeyDown")
                            .Select(e => e.EventArgs.Key)
                            .Window(10, 1)
                            .SelectMany(obs => obs.Buffer(TimeSpan.FromSeconds(10), 10))
                            .Where(keys => Enumerable.SequenceEqual(_konamiArray, keys))
                            .Subscribe(keys => Debug.Write("Found Konami"));