#include <gl\glew.h>
#include <gl\glfw3.h>
#include <Windows.h>
#include "OpenGLController.h"
#include "callback.h"


/////////////////////////////////////////////////////////////////////////
// public constructor/destructor

OpenGLController::OpenGLController() :
	iWidth(640),
	iHeight(480),
	camera(iWidth, iHeight)
{
	initDefault();
	processInit();
}

OpenGLController::OpenGLController(int oglMajor, int oglMinor) :
	iWidth(640),
	iHeight(480),
	camera(iWidth, iHeight)
{
	initDefault();
	iOglMajorVersion = oglMajor;
	iOglMinorVersion = oglMinor;
	processInit();
}

OpenGLController::~OpenGLController()
{
	glDeleteTextures(1, &gluiSamplerID);
	glfwTerminate();
}


/////////////////////////////////////////////////////////////////////////
// private functions

void OpenGLController::initDefault()
{
	iOglMajorVersion = 4;
	iOglMinorVersion = 5;
	iAntiAliasingLevel = 4;
	sWindowName = "MeshViewer 2.0 pre-alpha";

	stcMouse.leftHold = false;
	stcMouse.rightHold = false;
	stcMouse.middleHold = false;
	stcMouse.posX = 0;
	stcMouse.posY = 0;
	stcMouse.speed = 1;
}

void OpenGLController::processInit()
{
	startGLFW();
	createWindow();
	startGLEW();
	object = new Object("");
	setCallbackFunctions();
	
	// set background color
	glClearColor(0.5000f, 0.8000f, 1.0000f, 0.0000f);

	// enable z-order
	glEnable(GL_DEPTH_TEST);
	glDepthFunc(GL_LESS);

	// draw vertics only from one side
	glEnable(GL_CULL_FACE);

	
	gluiMatrixID = glGetUniformLocation(object->getShader(), "MVP"); //TODO: color shader
	gluiSamplerID = glGetUniformLocation(object->getShader(), "textureSampler");

}

void OpenGLController::startGLFW()
{
	if (!glfwInit())
	{
		MessageBox(NULL, "Failed to initialize GLFW", "MeshViewer 2.0 Error", MB_OK | MB_ICONERROR);
		exit(0);
	}

	glfwWindowHint(GLFW_SAMPLES, iAntiAliasingLevel);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, iOglMajorVersion);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, iOglMinorVersion);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
}

void OpenGLController::startGLEW()
{
	glewExperimental = true;

	if (glewInit() != GLEW_OK)
	{
		MessageBox(NULL, "Failed to initialize GLEW", "MeshViewer 2.0 Error", MB_OK | MB_ICONERROR);
		glfwTerminate();
		exit(0);
	}
}

void OpenGLController::createWindow()
{
	pWindow = glfwCreateWindow(iWidth, iHeight, sWindowName.c_str(), NULL, NULL);

	if (pWindow == NULL)
	{
		std::string message = "Your GPU does not support OpenGL ";
		message += iOglMajorVersion;
		message += ".";
		message += iOglMinorVersion;
		message += "\nTry to use older version";

		MessageBox(NULL, message.c_str(), "MeshViewer 2.0 Error", MB_OK | MB_ICONERROR);

		glfwTerminate();
		exit(0);
	}

	glfwSetWindowUserPointer(pWindow, this);

	glfwMakeContextCurrent(pWindow);
}

void OpenGLController::setCallbackFunctions()
{
	glfwSetMouseButtonCallback(pWindow, mouseButton);
	glfwSetCursorPosCallback(pWindow, mouseMove);
	glfwSetWindowSizeCallback(pWindow, windowResize);
	glfwSetScrollCallback(pWindow, mouseWheel);
	glfwSetKeyCallback(pWindow, keyPress);
}


/////////////////////////////////////////////////////////////////////////
// public getter

glm::mat4 OpenGLController::getMVPMatrix()
{
	return camera.getMatrix() * object->getMatrix();
}

GLFWwindow * OpenGLController::getWindow() const
{
	return pWindow;
}


/////////////////////////////////////////////////////////////////////////
// public functions

void OpenGLController::resize(int width, int height)
{
	camera.setSize(width, height);
}

void OpenGLController::addRotX(float value)
{
	object->add2x(value);
}

void OpenGLController::addRotY(float value)
{
	object->add2y(value);
}

void OpenGLController::addTransX(double value)
{
	camera.add2x(value);
}

void OpenGLController::addTransY(double value)
{
	camera.add2y(value);
}

void OpenGLController::addTransZ(double value)
{
	camera.add2z(value);
}

void OpenGLController::updateScene()
{
	// get new matrices

	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	// use shader prgm
	glUseProgram(object->getShader());

	// tell shader transformation
	glUniformMatrix4fv(gluiMatrixID, 1, GL_FALSE, &object->getMatrix()[0][0]);

	// bind texture in texture unit 0
	glActiveTexture(GL_TEXTURE0);
	glBindTexture(GL_TEXTURE_2D, object->getTextureID());
	// tell sampler to use texture unit 0
	glUniform1i(gluiSamplerID, 0);

	// open attribute position
	glEnableVertexAttribArray(0);
	glBindBuffer(GL_ARRAY_BUFFER, object->getVertexBufferID());
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);

	// open attribute uv
	glEnableVertexAttribArray(1);
	glBindBuffer(GL_ARRAY_BUFFER, object->getUVBufferID());
	glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 0, 0);
	
	//draw objects
	glDrawArrays(GL_TRIANGLES, 0, object->getVertexNumber());

	//close attributes
	glDisableVertexAttribArray(0);
	glDisableVertexAttribArray(1);

}