using OpenTK.Graphics.OpenGL4;
using OpenTK.Windowing.Common;
using OpenTK.Windowing.Common.Input;
using OpenTK.Windowing.Desktop;
using OpenTK.Windowing.GraphicsLibraryFramework;

namespace Voxel
{
    public class Window(int width, int height, string title) : GameWindow(GameWindowSettings.Default, new NativeWindowSettings() { ClientSize = (width, height), Title = title })
    {
        public readonly int Width = width;
        public readonly int Height = height;
        public uint frames = 0;
        public double timeElapsed = 0;

        public event Action<float, float> Update;
        public event Action Tick;

        private double _tickTime;
        public const double TICK_LENGTH = 1.0 / 20.0; // 20 TPS

        protected override void OnUpdateFrame(FrameEventArgs e)
        {
            base.OnUpdateFrame(e);

            _tickTime += e.Time;

            while (_tickTime >= TICK_LENGTH)
            {
                _tickTime -= TICK_LENGTH;
                Tick(); // run exactly once per tick
            }

            if (Input.GetKey(Keys.Escape))
            {
                Close();
            }

            if (Input.GetKey(Keys.F11))
            {
                if (!IsFullscreen)
                    WindowState = WindowState.Fullscreen;
                else
                    WindowState = WindowState.Normal;
            }
        }

        protected override void OnRenderFrame(FrameEventArgs e)
        {
            base.OnRenderFrame(e);

            GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit);

            frames++;
            timeElapsed += e.Time;
            float alpha = (float)(_tickTime / Window.TICK_LENGTH);
            float deltaTime = (float)e.Time;
            if (timeElapsed >= 1)
            {
                Console.WriteLine("FPS: " + frames.ToString());
                timeElapsed = 0;
                frames = 0;
            }

            Update.Invoke(deltaTime, alpha);

            Renderer.Render();

            SwapBuffers();
        }

        protected override void OnFramebufferResize(FramebufferResizeEventArgs e)
        {
            base.OnFramebufferResize(e);

            Camera.UpdateSize(e.Width, e.Height);

            GL.Viewport(0, 0, e.Width, e.Height);
        }

        protected override void OnLoad()
        {
            base.OnLoad();

            GL.ClearColor(0.72f, 0.88f, 0.97f, 1f);

            GL.Enable(EnableCap.CullFace);
            GL.Enable(EnableCap.DepthTest);
            GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapS, (int)TextureWrapMode.Repeat);
            GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapT, (int)TextureWrapMode.Repeat);

            CursorState = CursorState.Grabbed;
            VSync = VSyncMode.On;

            Camera.UpdateSize(Width, Height);
        }

        protected override void OnMouseMove(MouseMoveEventArgs e)
        {
            base.OnMouseMove(e);

            Camera.UpdateMouse(e.Delta);
        }

        protected override void OnKeyUp(KeyboardKeyEventArgs e)
        {
            base.OnKeyUp(e);
            Input.SetKey(e.Key, false);
        }

        protected override void OnKeyDown(KeyboardKeyEventArgs e)
        {
            base.OnKeyDown(e);
            Input.SetKey(e.Key, true);
        }

        protected override void OnMouseDown(MouseButtonEventArgs e)
        {
            base.OnMouseDown(e);
            Input.SetMouseButton(e.Button, true);
        }

        protected override void OnMouseUp(MouseButtonEventArgs e)
        {
            base.OnMouseUp(e);
            Input.SetMouseButton(e.Button, false);
        }

        protected override void OnMouseWheel(MouseWheelEventArgs e)
        {
            base.OnMouseWheel(e);
            Input.MouseWheel(e);
        }
    }
}