using AdvenOfCode.Contracts;

namespace AoC_2025;

public class Day12 : IPuzzleSolver<long>
{
    private (int[] presentSizes, (int area, int[] presentCounts)[] regions) ParsePuzzleInput(string path)
    {
        var puzzleInput = File.ReadAllText(path)
            .Split($"{Environment.NewLine}{Environment.NewLine}", StringSplitOptions.TrimEntries)
            .ToList();
        var presentSizes = puzzleInput[..^1]
            .Select(s => s.Count(c => c == '#'))
            .ToArray();
        var regions = puzzleInput[^1]
            .Split(Environment.NewLine, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries)
            .Select(s => s.Split(':', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries))
            .Select(s => 
                (s[0].Split('x').Select(int.Parse).Aggregate((x, y) => x * y),
                 s[1].Split(' ').Select(int.Parse).ToArray()))
            .ToArray();
        return (presentSizes, regions);
    }

    public long SolvePart1(string pathToPuzzleInput)
    {
        var (presentSizes, regions) = ParsePuzzleInput(pathToPuzzleInput);
        var everythingFits =
            regions.Count(region => region.area >= GetMinTotalPresentArea(region.presentCounts, presentSizes));
        return everythingFits;
    }

    private int GetMinTotalPresentArea(int[] presentCounts, int[] presentSizes)
    {
        return presentCounts
            .Zip(presentSizes, (count, size) => count * size)
            .Sum();
    }

    public long SolvePart2(string pathToPuzzleInput)
    {
        return 0;
    }
}