#include "main.h"
#include <iostream>
HGLRC hRC;

// Declare a global callback variable
ErrorCallback glErrorCallback = nullptr;

bool _HAS_VIEWPORT_BEEN_SETUP = false;
unsigned int VIEWPORT_WIDTH = 0;
unsigned int VIEWPORT_HEIGHT = 0;

// Function to set the error callback
DLL_API void SetGLErrorCallback(ErrorCallback callback)
{
	glErrorCallback = callback;
}

DLL_API void InitializeOpenGL(HWND hWnd)
{
	HDC hdc = GetDC(hWnd);
	
	// Set pixel format
	PIXELFORMATDESCRIPTOR pfd;
	ZeroMemory(&pfd, sizeof(pfd));
	pfd.nSize = sizeof(pfd);
	pfd.nVersion = 1;
	pfd.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER;
	pfd.iPixelType = PFD_TYPE_RGBA;
	pfd.cColorBits = 32;
	pfd.cDepthBits = 24;
	pfd.cStencilBits = 8;

	int pixelFormat = ChoosePixelFormat(hdc, &pfd);
	SetPixelFormat(hdc, pixelFormat, &pfd);

	hRC = wglCreateContext(hdc);
	wglMakeCurrent(hdc, hRC);	

	GLenum err = glewInit();
	if (err != GLEW_OK) {
		// Handle GLEW initialization error

		if (glErrorCallback)
		{
			const char* errorMessage = reinterpret_cast<const char*>(glewGetErrorString(err));
			glErrorCallback(err, errorMessage);
		}

		wglMakeCurrent(NULL, NULL);
		wglDeleteContext(hRC);
		ReleaseDC(hWnd, hdc);

		return;
	}
}

DLL_API void RenderFrame()
{
	if (!_HAS_VIEWPORT_BEEN_SETUP)
	{
		return;
	}

	glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
	glClear(GL_COLOR_BUFFER_BIT);


	glViewport(0, 0, VIEWPORT_WIDTH, VIEWPORT_HEIGHT);

	// Set up vertex data
	float vertices[] = {
		 0.0f,  0.5f,  0.0f,
		 0.5f, -0.5f,  0.0f,
		-0.5f, -0.5f,  0.0f
	};

	unsigned int vao;
	glGenVertexArrays(1, &vao);
	glBindVertexArray(vao);

	unsigned int vbo;
	glGenBuffers(1, &vbo);
	glBindBuffer(GL_ARRAY_BUFFER, vbo);

	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

	glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(float), (void*)0);

	glDrawArrays(GL_TRIANGLES, 0, 3);

	glDeleteBuffers(1, &vbo);
	glDeleteVertexArrays(1, &vao);

	SwapBuffers(wglGetCurrentDC());
}

DLL_API void SetupViewport(int width, int height)
{	
	VIEWPORT_WIDTH = width;
	VIEWPORT_HEIGHT = height;

	_HAS_VIEWPORT_BEEN_SETUP = true;
}