// See https://aka.ms/new-console-template for more information
using AdventCommon;

int p1exampleSln = Part01("example-input.txt");
int p1puzzleSln = Part01("puzzle-input.txt");

Console.WriteLine("Part01 Example Points: " + p1exampleSln);
Console.WriteLine("Part01 Puzzle Points: " + p1puzzleSln);

int p2exampleSln = Part02("example-input.txt");
int p2puzzleSln = Part02("puzzle-input.txt");

Console.WriteLine("Part02 Example Points: " + p2exampleSln);
Console.WriteLine("Part02 Puzzle Points: " + p2puzzleSln);

int Part01(string fileName)
{
    var input = new Day04Input(fileName);

    int sum = 0;
    foreach (var c in input.Cards)
    {
        sum += c.Points;
    }

    return sum;
}

int Part02(string fileName)
{
    var input = new Day04Input(fileName);

    Dictionary<int, int>    CardCopies = new Dictionary<int, int>();

    // Initial state -- 1 of each
    for (int i = 0;  i < input.Cards.Count; i++)
    {
        CardCopies.Add(i + 1, 1);
    }

    // Start with card 1 and work to the end
    for (int i = 0; i < input.Cards.Count; i++)
    {
        Day04Input.Card card = input.GetCardNumber(i + 1);
        int numberOfCards = CardCopies[i + 1];
        var matches = card.MatchingNumbers;

        for (int cardNum = 0; cardNum < numberOfCards; cardNum++)
        {
            for (int j = 0; j < matches.Count; j++)
            {
                CardCopies[i + 2 + j]++;
            }
        }
    }

    int sum = 0;
    foreach (var c in CardCopies)
    {
        sum += c.Value;
    }
    
    return sum;
}

class Day04Input : PuzzleInput
{
    public class Card
    {
        public List<int>    WinningNumbers { get; private set; } = new List<int>();
        public List<int>    ScratchedNumbers { get; private set; } = new List<int> ();
        public int          CardNumber { get; private set; }

        public Card(string line)
        {
            // Extract card number
            CardNumber = Int32.Parse(line.Split(':', StringSplitOptions.RemoveEmptyEntries)[0].Split(' ', StringSplitOptions.RemoveEmptyEntries)[1]);

            // extract numbers
            string winningNumbers = line.Split(":")[1].Split('|', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries)[0];
            string scratchedNumbers = line.Split(":")[1].Split('|', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries)[1];

            // parse the winning numbers
            foreach (var winningNumber in winningNumbers.Split(' ', StringSplitOptions.RemoveEmptyEntries))
            {
                WinningNumbers.Add(Int32.Parse(winningNumber));
            }

            // parse the scratchers
            foreach (var scratchedNumber in scratchedNumbers.Split(' ', StringSplitOptions.RemoveEmptyEntries))
            {
                ScratchedNumbers.Add(Int32.Parse(scratchedNumber));
            }
        }

        public int Points
        {
            get
            {
                int points = 0;
                
                foreach (var scratched in ScratchedNumbers)
                {
                    if (WinningNumbers.Contains(scratched))
                    {
                        if (points == 0) points = 1;
                        else points *= 2;
                    }
                }

                return points;
            }
        }

        public List<int> MatchingNumbers
        {
            get 
            { 
                List<int> matches = new List<int>();

                foreach (var scratched in ScratchedNumbers)
                {
                    if (WinningNumbers.Contains(scratched))
                    {
                        matches.Add(scratched);
                    }
                }

                return matches;
            }
        }
    }

    public List<Card> Cards { get; private set; } = new List<Card>();

    public Card GetCardNumber(int num)
    {
        if (Cards[num - 1].CardNumber != num) throw new InvalidDataException();

        return Cards[num - 1];
    }

    public Day04Input(string fileName)
        : base(fileName)
    { 
        foreach (var line in Lines)
        {
            Cards.Add(new Card(line));
        }
    }
}