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

#include <glm\gtc\matrix_transform.hpp>
#include "shader.hpp"
#include "Texture.h"
#include <iostream>

#define VERTEX_SHADER "Shader/TextureShader.vert"
#define FRAGMENT_SHADER "Shader/TextureShader.frag"
#define MAX_MODEL_COUNT 1000

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

OpenGLController* OpenGLController::getInstance(int oglMajor, int oglMinor)
{
	static OpenGLController *instace = new OpenGLController(oglMajor, oglMinor);
	return instace;
}

OpenGLController::~OpenGLController()
{
	glDeleteBuffers(1, &gluiVertexBufferID);
	glDeleteVertexArrays(1, &gluiVertexArrayID);
	glDeleteProgram(gluiShaderPrgmID);

	glDeleteTextures(1, &gluiSamplerID);
	glfwTerminate();

	while (!vModels.empty())
	{
		Modl* cursor = vModels.back();
		vModels.pop_back();
		
		delete cursor->uv;
		delete cursor->mesh;
		delete cursor->vertex;
		delete cursor;
	}
}


/////////////////////////////////////////////////////////////////////////
// private constructor

OpenGLController::OpenGLController(int oglMajor, int oglMinor)
{
	// adjust ogl version optional
	iOglMajorVersion = oglMajor;
	iOglMinorVersion = oglMinor;

	// run OGL
	processInit();
}

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

void OpenGLController::processInit()
{
	startGLFW();
	createWindow();
	startGLEW();
	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);

	// generate stuff
	glGenVertexArrays(1, &gluiVertexArrayID);
	glBindVertexArray(gluiVertexArrayID);

	glGenBuffers(1, &gluiVertexBufferID);

	// open attribute position
	glBindBuffer(GL_ARRAY_BUFFER, gluiVertexBufferID);
	glVertexAttribPointer(VERTEX_INDEX_XYZ, VERTEX_COMPONENTS_XYZ, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)VERTEX_OFFSET_XYZ);
	glVertexAttribPointer(VERTEX_INDEX_UV, VERTEX_COMPONENTS_UV, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)VERTEX_OFFSET_UV);
	glBindBuffer(GL_ARRAY_BUFFER, 0);

	// enable position, UV and mvp
	glEnableVertexAttribArray(0);
	glEnableVertexAttribArray(1);

	// get the painter ready
	try
	{
		gluiShaderPrgmID = LoadShaders(VERTEX_SHADER, FRAGMENT_SHADER);
	}
	catch (std::invalid_argument e)
	{
		MessageBox(NULL, e.what(), "MeshViewer 2.0 Error", MB_OK | MB_ICONERROR);
		exit(1);
	}

	gluiMatrixID = glGetUniformLocation(gluiShaderPrgmID, "MVP");
	gluiSamplerID = glGetUniformLocation(gluiShaderPrgmID, "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::createWindow()
{
	pWindow = glfwCreateWindow(iWidth, iHeight, sWindowName.c_str(), NULL, NULL);

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

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

		glfwTerminate();
		exit(0);
	}

	glfwSetWindowUserPointer(pWindow, this);
	glfwMakeContextCurrent(pWindow);
}

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

glm::mat4 OpenGLController::getMVPMatrix(unsigned int index)
{
	// Projection
	glm::mat4 m4x4Projection = glm::perspective(fFOV, float(iWidth) / float(iHeight), fMinView, fMaxView);
	
	// View
	glm::mat4 m4x4View = glm::lookAt(
		glm::vec3(dTranslationX, dTranslationY, dTranslationZ),
		glm::vec3(dTranslationX, dTranslationY, dTranslationZ - 1),
		glm::vec3(0, 1, 0)
	);

	// Model
	//TODO for all
	glm::mat4 m4x4Model = vModels[index]->m4x4Translation;
	
	// User controlled rotation
	glm::mat4 m4x4ModelRot = glm::mat4(1.0f);
	m4x4ModelRot = glm::rotate(m4x4ModelRot, fRotationX, glm::vec3(1, 0, 0));
	m4x4ModelRot = glm::rotate(m4x4ModelRot, fRotationY, glm::vec3(0, 1, 0));
	m4x4ModelRot = glm::rotate(m4x4ModelRot, fRotationZ, glm::vec3(0, 0, 1));

	// Return MVP
	return m4x4Projection * m4x4View * m4x4ModelRot * m4x4Model;
}


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

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


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

void OpenGLController::resize(int width, int height)
{
	iWidth = width;
	iHeight = height;
}

void OpenGLController::addRotX(float value)
{
	fRotationX += value;
}

void OpenGLController::addRotY(float value)
{
	fRotationY += value;
}

void OpenGLController::addTransX(double value)
{
	dTranslationX += value;
}

void OpenGLController::addTransY(double value)
{
	dTranslationY += value;
}

void OpenGLController::addTransZ(double value)
{
	dTranslationZ += value;
}

void OpenGLController::updateScene()
{
	// get new matrices
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	// use shader prgm
	glUseProgram(gluiShaderPrgmID);

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

	int instanceOffset(0);

	for (int modelIndex = 0; modelIndex < vModels.size(); modelIndex++)
	{
		glUniformMatrix4fv(gluiMatrixID, 1, GL_FALSE, &getMVPMatrix(modelIndex)[0][0]);

		glDrawArrays(GL_TRIANGLES, instanceOffset, vModels[modelIndex]->meshSize);

		instanceOffset += vModels[modelIndex]->meshSize;
	}

	glfwSwapBuffers(pWindow);
	glfwPollEvents();
}

void OpenGLController::loadMsh(const char * path)
{
	// get data
	try
	{
		Object obj(path);
		vModels = obj.getModels();
	}
	catch (std::invalid_argument e)
	{
		MessageBox(NULL, e.what(), "MeshViewer 2.0 Error", MB_OK | MB_ICONERROR);
		exit(1);
	}

	glGenTextures(1, &gluiTextureID);
	glBindTexture(GL_TEXTURE_2D, gluiTextureID);

	try
	{
		////TODO: for all
		if (vModels.front()->texture == "")
			throw std::invalid_argument("no texture name");

		std::string tempPath = path;

		while (tempPath.back() != '/' && tempPath.back() != '\\')
			tempPath.pop_back();

		TextureTGA tempTex(std::string(tempPath + vModels.front()->texture).c_str());
		glTexImage2D(GL_TEXTURE_2D,
					 0,
					 tempTex.hasAlpha() ? GL_RGBA : GL_RGB,
					 tempTex.getWidth(),
					 tempTex.getHeight(),
					 0, tempTex.hasAlpha() ? GL_BGRA : GL_BGR,
					 GL_UNSIGNED_BYTE,
					 tempTex.getData().data()
					);
	}
	catch (std::invalid_argument e)
	{
		GLubyte solidColor[4] = { 255, 0, 0, 255};
		glTexImage2D(GL_TEXTURE_2D,
					 0,
					 GL_RGBA,
					 1,
					 1,
					 0,
					 GL_RGBA,
					 GL_UNSIGNED_BYTE,
					 (const GLvoid*)solidColor
					);
	}

	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
	glGenerateMipmap(GL_TEXTURE_2D);

	////TODO: for all
	std::vector<Vertex> tempBufferData;
	
	for (auto& it : vModels)
	{
		for (unsigned int i = 0; i < it->meshSize; i++)
		{
			Vertex tempVertex;
			tempVertex.position[0] = (GLfloat)it->vertex[it->mesh[i] * 3];
			tempVertex.position[1] = (GLfloat)it->vertex[it->mesh[i] * 3 + 1];
			tempVertex.position[2] = (GLfloat)it->vertex[it->mesh[i] * 3 + 2];

			if (it->uv == NULL)
			{
				tempVertex.uv[0] = 1.0;
				tempVertex.uv[1] = 1.0;
			}
			else
			{
				tempVertex.uv[0] = (GLfloat)it->uv[it->mesh[i] * 2];
				tempVertex.uv[1] = (GLfloat)it->uv[it->mesh[i] * 2 + 1];
			}

			tempBufferData.push_back(tempVertex);
		}
	}

	glBindBuffer(GL_ARRAY_BUFFER, gluiVertexBufferID);
	glBufferData(
		GL_ARRAY_BUFFER,
		sizeof(Vertex) * tempBufferData.size(),
		tempBufferData.data(),
		GL_STATIC_DRAW
	);
	glBindBuffer(GL_ARRAY_BUFFER, 0);

}