AdventOfCode23/Day20/SignalProcessor.cs

namespace Day20;

public class SignalProcessor
{
    private readonly IDictionary<string, Module> _modules = new Dictionary<string, Module>();
    
    public SignalProcessor(Dictionary<string, (Module m, string[] outputs)> modules)
    {
        foreach (var kvp in modules)
        {
            _modules[kvp.Key] = kvp.Value.m;
            foreach (var o in kvp.Value.outputs)
            {
                Module? dst;
                if (modules.TryGetValue(o, out var t))
                {
                    dst = modules[o].m;
                }
                else
                {
                    _modules.TryAdd(o, new SinkModule(o));
                    dst = _modules[o];
                }
                
                kvp.Value.m.AddOutput(dst);
                dst.AddInput(kvp.Value.m);
            }
        }
    }

    public HiLo Push(int count)
    {
        var visited = new HashSet<string>();
        var stateCounts = new List<HiLo>();
        var state = MachineState();
        var iterations = 0;
        var result = HiLo.Zero;

        while (!visited.Contains(state) && iterations < count)
        {
            Console.WriteLine(state);
            visited.Add(state);
            var hilo = PushTheButton();
            
            stateCounts.Add(hilo);
            result = result.Add(hilo);
            state = MachineState();
            iterations++;
        }

        if (iterations == 0)
        {
            throw new InvalidOperationException("WTF?");
        }

        if (iterations < count)
        {
            Console.WriteLine($"Cycle @ {iterations} with state {state}");
            var cycles = count / iterations;
            result = result.Multiply(cycles);
            var remainder = count % iterations;
            for (var i = 0; i < remainder; i++)
            {
                result = result.Add(stateCounts[i]);
            }
        }

        return result;
    }

    public HiLo PushTheButton()
    {
        var count = HiLo.Zero;
        var queue = new Queue<Pulse>();
        queue.Enqueue(new Pulse("button", "broadcaster", false));
        
        while (queue.Count > 0)
        {
            var pulse = queue.Dequeue();
            Console.WriteLine($"Sending {pulse.Value} from {pulse.Source} to {pulse.Destination}");
            var dst = _modules[pulse.Destination];
            count = count.Add(pulse);
            foreach (var outPulse in dst.Process(pulse))
            {
                queue.Enqueue(outPulse);
            }
        }
        
        return count;
    }

    private string MachineState()
    {
        return string.Join("|", _modules.Select(kvp => kvp.Value.GetState()));
    }
}