using System.Drawing;
using System.Numerics;

using Silk.NET.GLFW;
using Silk.NET.OpenGL;

namespace DaggerFramework.Rendering
{
    /// <summary>
    /// A standard, OpenGL-based renderer.
    /// </summary>
    public class StandardRenderer : Renderer
    {
        /// <inheritdoc />
        public override Vector2 WindowSize => throw new NotImplementedException();
        /// <inheritdoc />
        public override bool ShouldRun => throw new NotImplementedException();

        public override Vector2 MonitorSize => throw new NotImplementedException();

        public override int TargetFps { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
        public override bool VSync { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
        public override string WindowTitle { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }



        /// <inheritdoc />
        public override void Initialize(RendererSettings settings)
        {

        }

        /// <inheritdoc />
        public override void CreateAndInitialize(WindowSettings windowSettings, RendererSettings renderSettings)
        {
            CreateWindow(windowSettings);
            Initialize(renderSettings);
        }

        public override void BeginFrame()
        {
            _glfw.PollEvents();
            _gl.Viewport(new Size((int)_windowSize.X, (int)_windowSize.Y));
        }

        /// <inheritdoc />
        public override void EndFrame()
        {
            // throw new NotImplementedException();
            EndFrameUnsafe();
        }

        /// <inheritdoc />
        public override void ClearBackground(Color color)
        {
            _gl.ClearColor(color.ToSystemColor());
            _gl.Clear((uint)ClearBufferMask.ColorBufferBit);
        }

        /// <inheritdoc />
        public override void Shutdown()
        {
            CloseWindowUnsafe();
            _glfw.Terminate();
        }

        /// <inheritdoc />
        public override void DrawCircle(float radius, Color color)
        {
            throw new NotImplementedException();
        }

        /// <inheritdoc />
        public override void DrawDebugText(string text, int fontSize, Color color)
        {
            throw new NotImplementedException();
        }

        /// <inheritdoc />
        public override void DrawRectangle(Vector2 size, Color color)
        {
            throw new NotImplementedException();
        }

        /// <inheritdoc />
        public override void DrawTexture(Texture2d texture, Color tint)
        {
            throw new NotImplementedException();
        }

        /// <inheritdoc />
        protected override double GetFrameTime()
        {
            return 0.0;
        }

        /// <inheritdoc />
        protected override void SetTargetFps(int fps)
        {
            return;
        }

        /// <inheritdoc />
        public override void SetTransform(Vector2 position, Vector2 offset, float rotation = 0)
        {
            throw new NotImplementedException();
        }

        /// <inheritdoc />
        public override void SetTransform(Matrix4x4 transform)
        {
            throw new NotImplementedException();
        }

        /// <inheritdoc />
        protected override void SetWindowTitle(string title)
        {
            SetWindowTitleUnsafe(title);
        }

        /// <inheritdoc />
        protected override void SetWindowVSync(bool value)
        {
            throw new NotImplementedException();
        }

        /// <inheritdoc />
        protected override bool WindowShouldClose() => WindowShouldCloseUnsafe();

        private unsafe void CreateWindowUnsafe(string title, Vector2 size)
        {
            _glfw = GlfwProvider.GLFW.Value;
            _glfw.Init();

            _glfw.WindowHint(WindowHintInt.ContextVersionMajor, 4);
            _glfw.WindowHint(WindowHintInt.ContextVersionMinor, 6);
            _windowHandle = _glfw.CreateWindow((int)size.X, (int)size.Y, title, null, null);

            _glfw.MakeContextCurrent(_windowHandle);
            _gl = GL.GetApi(_glfw.GetProcAddress);
            _glfw.SwapInterval(1);

            _windowSize = size;
        }
        private unsafe void CloseWindowUnsafe() => _glfw.DestroyWindow(_windowHandle);
        private unsafe bool WindowShouldCloseUnsafe() => _glfw.WindowShouldClose(_windowHandle);
        private unsafe void SetWindowTitleUnsafe(string title) => _glfw.SetWindowTitle(_windowHandle, title);
        private unsafe void EndFrameUnsafe()
        {
            _glfw.SwapBuffers(_windowHandle);
        }

        public override void DrawSdfText(string text, int fontSize, Color color)
        {
            throw new NotImplementedException();
        }

        public override void BeginCamera2d(Vector2 offset, Vector2 target, float rotation, float zoom)
        {
            throw new NotImplementedException();
        }

        public override void EndCamera2d()
        {
            throw new NotImplementedException();
        }

        public override void CreateWindow(WindowSettings windowSettings)
        {
            throw new NotImplementedException();
        }

        protected override int GetMonitorWidth(int monitorId)
        {
            throw new NotImplementedException();
        }

        protected override int GetMonitorHeight(int monitorId)
        {
            throw new NotImplementedException();
        }

        protected override int GetCurrentMonitor()
        {
            throw new NotImplementedException();
        }

        public override void DrawText(Font font, string text, Color color)
        {
            throw new NotImplementedException();
        }

        private GL _gl;
        private Glfw _glfw;
        private unsafe WindowHandle* _windowHandle;
        private Vector2 _windowSize;
    }
}