using OpenTK.Mathematics;

namespace Voxel
{
    static class Camera
    {
        public static Vector3 Position = new Vector3(-8, 16, -8);

        public static float Pitch = -22.5f;
        public static float Yaw = 0f;
        public static float FOV = 60f;
        public static float TargetFOV = FOV;
        public static float FOVLerpSpeed = 10f;
        public static float Speed = 5f;
        public static float ShiftSpeed = 20f;

        private static int _width;
        private static int _height;

        public static Matrix4 view =>
            Matrix4.LookAt(Position, Position + Front, Vector3.UnitY);

        public static Matrix4 projection;

        public static Vector3 Front
        {
            get
            {
                float yawOffset = Yaw - 90f;
                Vector3 front;
                front.X = MathF.Cos(MathHelper.DegreesToRadians(yawOffset)) * MathF.Cos(MathHelper.DegreesToRadians(Pitch));
                front.Y = MathF.Sin(MathHelper.DegreesToRadians(Pitch));
                front.Z = MathF.Sin(MathHelper.DegreesToRadians(yawOffset)) * MathF.Cos(MathHelper.DegreesToRadians(Pitch));
                return front.Normalized();
            }
        }

        public static void UpdateMouse(Vector2 delta)
        {
            float sensitivity = 0.1f;
            Yaw += delta.X * sensitivity;
            Pitch -= delta.Y * sensitivity;

            Pitch = MathHelper.Clamp(Pitch, -89f, 89f);
        }

        public static void UpdateProjection()
        {
            float fov = MathHelper.DegreesToRadians(FOV);
            float aspectRatio = _width / (float)_height;
            float near = 0.1f;
            float far = 1000f;

            projection = Matrix4.CreatePerspectiveFieldOfView(fov, aspectRatio, near, far);
        }

        public static void UpdateSize(int width, int height)
        {
            _width = width;
            _height = height;
            UpdateProjection();
        }

        public static void UpdateFOV(float deltaTime, float alpha)
        {
            float currentFOV = MathHelper.Lerp(FOV, TargetFOV, FOVLerpSpeed * deltaTime);
            Camera.FOV = currentFOV;
            Camera.UpdateProjection();
        }
    }
}