using Godot;
using System;

public partial class Camera2d : Camera2D
{
    private float targetZoom = 1.0f;
    private float minZoom = .1f;
    private float maxZoom = 1.0f;
    private float zoomIncrement = .1f;
    private float zoomRate = 8.0f;
    
    public override void _Ready()
    {
        // Print the size of the viewport.
        GD.Print("Viewport Resolution is: ", GetViewport().GetVisibleRect().Size);
    }

    public override void _Input(InputEvent @event)
    {
        // Mouse in viewport coordinates.
        if (@event is InputEventMouseButton eventMouseButton)
        {
            GD.Print("Mouse Click/Unclick at: ", eventMouseButton.Position);

            switch (eventMouseButton.ButtonIndex)
            {
                case MouseButton.Left:
                    Position = eventMouseButton.Position;
                    break;
                case MouseButton.WheelDown:
                    zoomIn();
                    break;
                case MouseButton.WheelUp:
                    zoomOut();
                    break;
                default:
                    break;
            }
        }
        else if (@event is InputEventMouseMotion eventMouseMotion)
        {
            Vector2 zoomThreshold = new Vector2(.2f, .2f); // When should the zoom doesnt be accounted
            Vector2 zoomThresholdSpeed = new Vector2(1.0f, 1.0f); // What value to use when the Threshold is reached
            
            GD.Print("Mouse Motion at: ", eventMouseMotion.Position);
            
            if (eventMouseMotion.ButtonMask == MouseButtonMask.Middle)
                Position -= eventMouseMotion.Relative * (Zoom < zoomThreshold ? zoomThresholdSpeed : Zoom);
        }

        GD.Print("Camera Position: ", Position);
    }

    public override void _PhysicsProcess(double delta)
    {
        Zoom = Lerp(Zoom, targetZoom * Vector2.One, zoomRate * (float)delta);
        if (Zoom.X == targetZoom)
            SetPhysicsProcess(false);
        
        GD.Print("Camera Zoom: ", Zoom);
    }

    private void zoomIn()
    {
        targetZoom = Single.Max(targetZoom - zoomIncrement, minZoom);
        SetPhysicsProcess(true);
    }

    private void zoomOut()
    {
        targetZoom = Single.Min(targetZoom + zoomIncrement, maxZoom);
        SetPhysicsProcess(true);
    }
    
    public static Vector2 Lerp(Vector2 from, Vector2 to, float weight) => from + (to - from) * weight;
}