using System.Text.RegularExpressions;

namespace Day20;

public partial class Parser
{
    [GeneratedRegex(@"(broadcaster|([%&-])(\w+)) -> (.*)")]
    private partial Regex LineMatch();
    
    public SignalProcessor Parse(string inputFile)
    {
        using var reader = File.OpenText(inputFile);

        var modules = new Dictionary<string, (Module m, string[] outputs)>();
        while (!reader.EndOfStream)
        {
            var line = reader.ReadLine()!;
            var match = LineMatch().Match(line);
            if (!match.Success)
            {
                throw new Exception($"Unable to parse line {line}");
            }

            Module? module;
            if (match.Groups[1].Value == "broadcaster")
            {
                module = new BroadcastModule("broadcaster");
                modules["broadcaster"] = (module, GetOutputs(match));
            }
            else
            {
                if (match.Groups[2].Value == "%")
                {
                    module = new FlipFlopModule(match.Groups[3].Value);
                }
                else if (match.Groups[2].Value == "&")
                {
                    module = new ConjunctionModule(match.Groups[3].Value);
                }
                else if (match.Groups[2].Value == "-")
                {
                    module = new SinkModule(match.Groups[3].Value);
                }
                else
                {
                    throw new Exception($"Unknown module type: {match.Groups[2].Value}");
                }

                modules[match.Groups[3].Value] = (module, GetOutputs(match));
            }
        }

        return new SignalProcessor(modules);
    }

    private static string[] GetOutputs(Match match)
    {
        return match.Groups[4].Value
            .Split(',', StringSplitOptions.TrimEntries | StringSplitOptions.RemoveEmptyEntries)
            .ToArray();
    }
}