using Godot;

namespace FOU.Scripts.Elements;

public abstract class Liquid : Element {
    public const int MAX_VERTICAL_SPREAD = 3;

    protected Liquid(int x, int y, ref Chunk chunk) : base(x, y, chunk) {
        MarkForUpdate();
    }

    public override bool Update() {
        if (!base.Update()) return false;

        Tick();

        return true; // not necessarily end, subclasses could do some more things
    }

    protected virtual void Tick() {
        Vector2I randomDirection = RandomDirectionDown();
        if (randomDirection.Y != 0)
            randomDirection *= Vector2I.Left * (int)(GD.Randi() % MAX_VERTICAL_SPREAD);

        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);

        else if (Chunk.IsEmpty(Position + 1 * randomDirection))
            Chunk.Swap(this, Position + 1 * randomDirection);
        else if (Chunk.IsEmpty(Position - 1 * randomDirection * VERTICAL_OPPOSITE))
            Chunk.Swap(this, Position - 1 * randomDirection * VERTICAL_OPPOSITE);

        else if (Chunk.IsEmpty(Position + 2 * randomDirection))
            Chunk.Swap(this, Position + 2 * randomDirection);
        else if (Chunk.IsEmpty(Position - 2 * randomDirection * VERTICAL_OPPOSITE))
            Chunk.Swap(this, Position - 2 * randomDirection * VERTICAL_OPPOSITE);
    }

    public override void ActivateNeighbors() {

        Element n = Chunk.Get(Position + Vector2I.Up);
        if (n != null && !n.IsEmpty())
            n.Active = true;

        // only activate liquids left or right
        Element e = Chunk.Get(Position + Vector2I.Right);
        if (e != null && e.GetType() == typeof(Liquid))
            e.Active = true;

        Element s = Chunk.Get(Position + Vector2I.Down);
        if (null != s && s.GetType() == typeof(Liquid))
            s.Active = true;
    }
}