using Godot;

namespace FOU.Scripts.Elements;

public class Element{

    public Chunk Chunk;
    public Vector2I Position;

    protected int Density;
    protected int DiffuseSpeed = 10;
    protected Color color = Colors.Black;
    protected const int MAX_DIFFUSE_SPEED = 100;
    protected const int STEPS_UNTIL_INACTIVE = 500;

    protected const float MAX_COLOR_VARIANCE = 0.1f;
    protected static readonly Vector2I VERTICAL_OPPOSITE = new Vector2I(-1, 1);

    private bool active = false;
    private int lastUpdate = -1;
    private int lastMove = 0;
    private Color originalColor;
    private bool markedForUpdate = false;

    public Element(Element e) {
        Position = e.Position;
        Chunk = e.Chunk;
        lastMove = Engine.GetFramesDrawn();
    }

    public Element(int x, int y, Chunk chunk) {
        Position.X = x;
        Position.Y = y;
        Chunk = chunk;
        lastMove = Engine.GetFramesDrawn();
        Active = false;
    }

    public bool Active {
        get => active;
        set {
            if (active == value) return;

            active = value;
            Chunk.SetElementActive(this, value);
            if (!active)
                ResetColor();
            else
                Moved();
        }
    }

    public Color Color => color;

    /// <summary>
    /// base update method, checks if anything is to do at all
    /// </summary>
    /// <param name="currentFrame"></param>
    /// <returns>false if there is nothing to do</returns>
    public virtual bool Update() {
        if (!Active) return false;

        int frame = Engine.GetFramesDrawn();
        if (lastMove + STEPS_UNTIL_INACTIVE < frame)
            Active = false;
        if (lastUpdate == frame)
            return false; // already updated this frame

        lastUpdate = frame;

        return true;
    }

    public override string ToString() {
        return $"{GetType()} {Position}[{Chunk.Index}] {active}";
    }

    protected virtual void Tick() {
        Vector2I randomDirection = RandomDirectionDown();

        if (Chunk.IsEmpty(Position + Vector2I.Down))
            Chunk.Swap(this, Position + Vector2I.Down);

        else if (Chunk.IsEmpty(Position + randomDirection))
            Chunk.Swap(this, Position + randomDirection);

        else if (Chunk.IsEmpty(Position + randomDirection * VERTICAL_OPPOSITE))
            Chunk.Swap(this, Position + randomDirection * VERTICAL_OPPOSITE);

        if (GD.Randi() % MAX_DIFFUSE_SPEED > DiffuseSpeed) return; // ascend slower

        if (Chunk.Get(Position + randomDirection)?.Density < Density)
            Chunk.Swap(this, Position + Vector2I.Down);
    }

    protected Vector2I RandomDirectionDown() {
        int randomDirection = GD.Randi() % 2 != 0 ? 1 : -1;

        return Vector2I.Down // maybe also side
            + (GD.Randi() % 2 != 0 ? Vector2I.Zero : Vector2I.Right * randomDirection);
    }

    protected Color AddColorVariance(Color baseColor) {
        Color c = baseColor;
        c.R += (GD.Randf() - 1) * MAX_COLOR_VARIANCE;
        c.G += (GD.Randf() - 1) * MAX_COLOR_VARIANCE;
        c.B += (GD.Randf() - 1) * MAX_COLOR_VARIANCE;

        originalColor = c;
        return c;
    }

    public void ResetColor() {
        color = originalColor;
        MarkForUpdate();
    }

    public void SetDebugColor(Color color) {
        if (!Main.Instance.DebugMode) return;

        this.color = color;
    }

    public void Moved() {
        lastMove = Engine.GetFramesDrawn();
        MarkForUpdate();
    }

    public bool MarkedForUpdate() {
        return markedForUpdate;
    }

    public void MarkForUpdate(bool mark = true) {
        markedForUpdate = true;
    }
}