using System.Text.RegularExpressions;

namespace Day19;

public partial class Parser
{
    [GeneratedRegex(@"^(\w+)\{(.*)\}")]
    private partial Regex RuleMatch();
    
    [GeneratedRegex(@"(\w)=(\d+)")]
    private partial Regex PartMatch();
    
    public Data Parse(string inputFile)
    {
        using var reader = File.OpenText(inputFile);

        var ruleMap = new Dictionary<string, Rule>();
        var parts = new List<Part>();
        
        while (!reader.EndOfStream)
        {
            var line = reader.ReadLine()!;
            if (string.IsNullOrWhiteSpace(line))
            {
                break;
            }

            var match = RuleMatch().Match(line);
            if (!match.Success)
            {
                throw new Exception($"Invalid rule line: {line}");
            }

            ruleMap[match.Groups[1].Value] = new Rule(match.Groups[2].Value);
        }
        
        while (!reader.EndOfStream)
        {
            var line = reader.ReadLine()!;
            var partDict = PartMatch().Matches(line).ToDictionary(m => m.Groups[1].Value, m => int.Parse(m.Groups[2].Value));
            parts.Add(new Part(partDict));
        }

        return new Data(ruleMap, parts);
    }
}