namespace AOC2020;

/// <summary>
///     Day 17: <a href="https://adventofcode.com/2020/day/17" />
/// </summary>
public sealed class Day17() : Day(2020, 17, "Conway Cubes")
{
    private readonly Dictionary<(int x, int y, int z), char> _plane = [];
    private readonly Dictionary<(int x, int y, int z, int w), char> _plane4 = [];

    public override void ProcessInput()
    {
        var input = Input.ToList();

        for (var x = 0; x < 32; x++)
            for (var y = 0; y < 32; y++)
                for (var z = 0; z < 32; z++)
                    _plane[(x, y, z)] = '.';

        for (var x = 0; x < 32; x++)
            for (var y = 0; y < 32; y++)
                for (var z = 0; z < 32; z++)
                    for (var w = 0; w < 32; w++)
                        _plane4[(x, y, z, w)] = '.';

        for (var y = 0; y < input.Count; y++)
            for (var x = 0; x < input[y].Length; x++)
                _plane[(x, y, 0)] = input[y][x];

        for (var y = 0; y < input.Count; y++)
            for (var x = 0; x < input[y].Length; x++)
                _plane4[(x, y, 0, 0)] = input[y][x];
    }

    private static int Neighbors(IReadOnlyDictionary<(int x, int y, int z), char> plane, int x, int y, int z)
    {
        var neighbors = 0;

        foreach (var i in new[] { -1, 0, 1 })
            foreach (var j in new[] { -1, 0, 1 })
                foreach (var k in new[] { -1, 0, 1 })
                {
                    if (i == 0 && j == 0 && k == 0) continue;
                    if (plane[((x + i) & 31, (y + j) & 31, (z + k) & 31)] == '#') neighbors++;
                }

        return neighbors;
    }

    private static Dictionary<(int x, int y, int z), char> Iterate(
        IReadOnlyDictionary<(int x, int y, int z), char> prev)
    {
        var next = new Dictionary<(int x, int y, int z), char>();

        for (var z = 0; z < 32; z++)
            for (var y = 0; y < 32; y++)
                for (var x = 0; x < 32; x++)
                {
                    var active = Neighbors(prev, x, y, z);
                    if (prev[(x, y, z)] == '#')
                        next[(x, y, z)] = active is 2 or 3 ? '#' : '.';
                    else
                        next[(x, y, z)] = active == 3 ? '#' : '.';
                }

        return next;
    }

    private static int Neighbors4(IReadOnlyDictionary<(int x, int y, int z, int w), char> plane, int x, int y,
        int z, int w)
    {
        var neighbors = 0;

        foreach (var i in new[] { -1, 0, 1 })
            foreach (var j in new[] { -1, 0, 1 })
                foreach (var k in new[] { -1, 0, 1 })
                    foreach (var l in new[] { -1, 0, 1 })
                    {
                        if (i == 0 && j == 0 && k == 0 && l == 0) continue;
                        if (plane[((x + i) & 31, (y + j) & 31, (z + k) & 31, (w + l) & 31)] == '#') neighbors++;
                    }

        return neighbors;
    }

    private static Dictionary<(int x, int y, int z, int w), char> Iterate4(
        IReadOnlyDictionary<(int x, int y, int z, int w), char> prev)
    {
        var next = new Dictionary<(int x, int y, int z, int w), char>();

        for (var z = 0; z < 32; z++)
            for (var y = 0; y < 32; y++)
                for (var x = 0; x < 32; x++)
                    for (var w = 0; w < 32; w++)
                    {
                        var active = Neighbors4(prev, x, y, z, w);
                        if (prev[(x, y, z, w)] == '#')
                            next[(x, y, z, w)] = active is 2 or 3 ? '#' : '.';
                        else
                            next[(x, y, z, w)] = active == 3 ? '#' : '.';
                    }

        return next;
    }

    public override object Part1() =>
        Enumerable.Range(0, 6).Aggregate(_plane, (current, _) => Iterate(current)).Values.Count(v => v == '#');

    public override object Part2() =>
        Enumerable.Range(0, 6).Aggregate(_plane4, (current, _) => Iterate4(current)).Values.Count(v => v == '#');
}