#include <iostream>
#include <fstream>

#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>

#include <imgui.h>
#include <imgui_impl_glfw.h>
#include <imgui_impl_opengl3.h>

#include <camera.h>
#include <cubeFactory.h>

void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void processInput(GLFWwindow* window);
void mouse_callback(GLFWwindow* window, double xpos, double ypos);
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset);

int SCR_WIDTH = 800;
int SCR_HEIGHT = 800;

Camera camera(glm::vec3(0.0f, 0.0f, 20.0f));
float lastX = SCR_WIDTH / 2.0f;
float lastY = SCR_HEIGHT / 2.0f;
bool firstMouse = true;

float deltaTime = 0.0f;
float lastFrame = 0.0f;
float elapsedTime = 0.0f;

//glm::vec3 lightPos(1.2f, 1.0f, 2.0f);

int main() 
{
	IMGUI_CHECKVERSION();
	ImGui::CreateContext();
	ImGuiIO& io = ImGui::GetIO();
	io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;
	io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;
	io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;

	std::cout << "Starting GLFW context, OpenGL 3.3" << std::endl;
	glfwInit();
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

	GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearningOpenGl", NULL, NULL);
	if (window == NULL) {
		std::cout << "Failed to create GLFW window" << std::endl;
		glfwTerminate();
		return -1;
	}

	glfwMakeContextCurrent(window);
	glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
	glfwSetCursorPosCallback(window, mouse_callback);
	glfwSetScrollCallback(window, scroll_callback);

	glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);

	if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {
		std::cout << "Failed to initialize GLAD" << std::endl;
		return -1;
	}

	glEnable(GL_DEPTH_TEST);

	std::cout << "Loaded GLFW context, OpenGL 3.3" << std::endl;

	CubeFactory cubeFactory;

	float offset = 2.0f;
	int xAmount = 10;
	int yAmount = 10;
	int zAmount = 10;

	for (int x = 0; x < xAmount; x++)
	{
		for (int y = 0; y < yAmount; y++)
		{
			for (int z = 0; z < zAmount; z++)
			{
				glm::vec3 position = glm::vec3(	(x * offset) - (xAmount * offset / 2.0f), 
												(y * offset) - (yAmount * offset / 2.0f),
												(z * offset) - (zAmount * offset / 2.0f));	
				glm::vec3 scale = glm::vec3(1.0f, 1.0f, 1.0f);
				glm::vec3 rotation = glm::vec3(0.0f, 0.0f, 0.0f);
				glm::vec3 color = glm::vec3(x/10.0f, y/10.0f, z/10.0f);

				cubeFactory.addCube(position, scale, rotation, color);
			}
		}
	}

	//std::cout << "Amount of cubes: " << cubeFactory.getCubes().size() << std::endl;
	
	float r = 0.05f, g = 0.05f, b = 0.05f;

	while (!glfwWindowShouldClose(window)) {
		//timing
		float currentFrame = glfwGetTime();
		deltaTime = currentFrame - lastFrame;
		lastFrame = currentFrame;
		elapsedTime += deltaTime;

		//input
		processInput(window);

		glClearColor(r, g, b, 1.0f);
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

		// view/projection transformations
		glm::mat4 projection = glm::perspective(glm::radians(camera.Zoom), (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100.0f);
		glm::mat4 view = camera.GetViewMatrix();

		glm::vec3 lightPos = glm::vec3(100.2f, 100.0f, 200.0f);

		cubeFactory.render(view, projection, lightPos, deltaTime);

		//check and call
		glfwSwapBuffers(window);
		glfwPollEvents();
	}

	//cubeFactory.clear();
	glfwTerminate();
	return 0;
}

void framebuffer_size_callback(GLFWwindow* window, int width, int height) 
{
	glViewport(0, 0, width, height);
}

void processInput(GLFWwindow* window) 
{
	if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS) {
		glfwSetWindowShouldClose(window, true);
	}

	const float cameraSpeed = 5.0f * deltaTime;
	if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS) 
		camera.ProcessKeyboard(FORWARD, deltaTime);
	if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)
		camera.ProcessKeyboard(BACKWARD, deltaTime);
	if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
		camera.ProcessKeyboard(LEFT, deltaTime);
	if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)
		camera.ProcessKeyboard(RIGHT, deltaTime);
}

void mouse_callback(GLFWwindow* window, double xposIn, double yposIn)
{
	//std::cout << "Mouse callback" << std::endl;
	float xpos = static_cast<float>(xposIn);
	float ypos = static_cast<float>(yposIn);

	if (firstMouse)
	{
		lastX = xpos;
		lastY = ypos;
		firstMouse = false;
	}

	float xoffset = xpos - lastX;
	float yoffset = lastY - ypos;

	lastX = xpos;
	lastY = ypos;

	camera.ProcessMouseMovement(xoffset, yoffset);
}

void scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
{
	camera.ProcessMouseScroll(static_cast<float>(yoffset));
}