using System.Diagnostics.CodeAnalysis;

namespace InverseOfLife;

public class Board
{

    [SetsRequiredMembers]
    public Board(int w, int h, bool qx = false, bool qy = false, bool useTracer = false)
    {
        Width = w;
        Height = h;
        QuotientX = qx;
        QuotientY = qy;
        Lives = new();
        if (useTracer)
            Tracer = new CellTracer();
    }

    public required int Width { get; init; }
    public required int Height { get; init; }
    public required bool QuotientX { get; init; }
    public required bool QuotientY { get; init; }
    public HashSet<(int, int)> Lives { get; internal set; }
    public CellTracer Tracer { get; init; }

    public void Toggle(int x, int y, bool initialConfig=false)
    {
        bool added = Lives.Add((x, y));
        if (!added)
        {
            Lives.Remove((x, y));
            if (initialConfig && Tracer is not null)
                Tracer.Contribution.Remove((x, y));
        }
        else if (initialConfig && Tracer is not null)
        {
            Tracer.Contribution[(x, y)] = new Dictionary<(int, int), double>
            {
                { (x, y), 1d }
            };
        }
    }

    public void Toggle((int x, int y) cell, bool initialConfig = false) => Toggle(cell.x, cell.y, initialConfig);

    public void Evaluate(int steps)
    {
        for(int i = 0; i< steps; i++)
            Evaluate();
    }

    public void Evaluate()
    {
        Dictionary<(int, int), int> neighbourCount = new();
        foreach ((int x, int y) in Lives)
        {
            if (!neighbourCount.ContainsKey((x, y)))
                neighbourCount[(x, y)] = 0;
            Populate(x, y, neighbourCount);
        }

        foreach ((int x, int y) in neighbourCount.Keys)
        {
            if (Lives.Contains((x, y)))
            {
                if (neighbourCount[(x, y)] != 2 && neighbourCount[(x, y)] != 3)
                {
                    Lives.Remove((x, y));
                    if (Tracer is not null)
                        Tracer.DeferredRemove((x, y));
                }
            }
            else
            {
                if (neighbourCount[(x, y)] == 3)
                {
                    Lives.Add((x, y));
                    if (Tracer is not null)
                        Tracer.DeferredAdd((x, y));
                }
            }
        }

        if (Tracer is not null)
            Tracer.BatchProcess();
    }

    public void Populate(int x, int y, Dictionary<(int, int), int> count)
    {
        for (int dx = -1; dx <= 1; dx++)
        {
            for (int dy = -1; dy <= 1; dy++)
            {
                if (dx == 0 && dy == 0)
                    continue;
                int nx = QuotientX ? (x + dx + Width) % Width : x + dx;
                int ny = QuotientY ? (y + dy + Height) % Height : y + dy;
                if(nx >= Width || nx < 0)
                    continue;
                if(ny >= Height || ny < 0)
                    continue;
                if (!count.ContainsKey((nx, ny)))
                    count[(nx, ny)] = 0;
                count[(nx, ny)] += 1;
                if (Tracer is not null)
                {
                    if (!Tracer.Parents.ContainsKey((nx, ny)))
                        Tracer.Parents[(nx, ny)] = new HashSet<(int, int)>();
                    Tracer.Parents[(nx, ny)].Add((x, y));
                }
            }
        }
    }

    public override string ToString()
    {
        
        var builder = new System.Text.StringBuilder();

        for (int y = 0; y < Height; y++)
        {
            for (int x = 0; x < Width; x++)
                builder.Append(Lives.Contains((x, y)) ? 'o' : ' ');

            builder.AppendLine();
        }

        return builder.ToString();
    }

    public HashSet<(int, int)>[] Frames(int steps)
    {
        HashSet<(int, int)>[] res = new HashSet<(int, int)>[steps];
        for (int i = 0; i < steps; i++)
        {
            Evaluate();
            res[i] = CopyLives();
        }
        return res;
    }

    private HashSet<(int, int)> CopyLives()
    {
        HashSet<(int, int)> res = new();
        foreach ((int, int) cell in Lives)
            res.Add(cell);
        return res;
    }

    public void Play(int generations, int delay = 200)
    {
        for (int i = 0; i < generations; i++)
        {
            Console.Clear();
            Console.WriteLine(ToString());
            Evaluate();
            Thread.Sleep(delay);
        }
    }
}