#include <iostream>
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <unordered_map>

#include "GameClient.h"
#include "common/utils/Types.h"
#include "client/Keys.h"

struct InternGameClient
{
    ~InternGameClient()
    {
        if(window != nullptr)
        {
            glfwDestroyWindow(window);
        }
        if(glfwInitDone)
        {
            glfwTerminate();
        }
    }
    
    bool glfwInitDone = false;
    GLFWwindow* window = nullptr;
};

static const u64 NANOS_PER_TICK = 50000000;
static const float lagFactor = 1.0f / NANOS_PER_TICK;
static u64 timeFactor = 1;
static int width = 0;
static int height = 0;
static InternGameClient client;
static Keys keys;

static bool initGLFW()
{
    client.glfwInitDone = glfwInit();
    if(!client.glfwInitDone)
    {
        std::cout << "could not initialize GLFW\n";
        return true;
    }
    timeFactor = 1000000000 / glfwGetTimerFrequency();
    return false;
}

static bool initWindow(int w, int h, const char* windowName)
{
    width = w;
    height = h;
    
    glfwDefaultWindowHints();
    glfwWindowHint(GLFW_VISIBLE, 0);
    glfwWindowHint(GLFW_RESIZABLE, 1);
    
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    
    client.window = glfwCreateWindow(width, height, windowName, nullptr, nullptr);
    if(client.window == nullptr)
    {
        std::cout << "could not create window\n";
        return true;
    }
    glfwMakeContextCurrent(client.window);
    glfwSwapInterval(1);
    return false;
}

static bool initGLEW()
{
    GLenum err = glewInit();
    if(err != GLEW_OK)
    {
        std::cout << "could not initialize GLEW: " << glewGetErrorString(err) << "\n";
        return true;
    }
    std::cout << "using GLEW " << glewGetString(GLEW_VERSION) << "\n";
    return false;
}

static void initCallbacks()
{
    // GLFWwindow* w, int key, int scancode, int action, int mod
    glfwSetKeyCallback(client.window, [](GLFWwindow*, int key, int, int action, int)
    {
        if(action == GLFW_PRESS)
        {
            keys.press(key);
        }
        else if(action == GLFW_RELEASE)
        {
            keys.release(key);
        }
    });
    //glfwSetMouseButtonCallback(window, onMouseClick);
    //glfwSetFramebufferSizeCallback(window, onWindowResize); 
    //glfwSetCursorPosCallback(window, onMouseMove);
}

static void tick()
{
    std::cout << keys.down << std::endl;
    keys.tick();
}

static void renderTick(float /*lag*/)
{
}

static u64 getTimeNanos()
{
    return glfwGetTimerValue() * timeFactor;
}

static void loop()
{
    u64 lastTime = getTimeNanos();
    u64 lag = 0;
    while(!glfwWindowShouldClose(client.window))
    {
        renderTick(lag * lagFactor);
        glfwSwapBuffers(client.window);
        
        u64 newTime = getTimeNanos();
        lag += newTime - lastTime;
        lastTime = newTime;
        
        while(lag >= NANOS_PER_TICK)
        {
            lag -= NANOS_PER_TICK;
            tick();
        }
        glfwPollEvents();
    }
}

void GameClient::start(int w, int h, const char* windowName)
{
    if(initGLFW() || initWindow(w, h, windowName) || initGLEW())
    {
        return;
    }
    initCallbacks();
    glfwShowWindow(client.window);
    loop();
}

/*#include <iostream>
#include <cmath>

#include "client/GameClient.h"
#include "common/block/Blocks.h"
#include "client/rendering/block/BlockRenderers.h"
#include "client/rendering/entity/EntityRenderer.h"
#include "client/rendering/gui/StartMenu.h"

using namespace std;

GameClient::GameClient()
{    
    BlockRegistry::registerBlocks();
    BlockRenderers::init();

    keyManager.map(KEY_LEFT, GLFW_KEY_A);
    keyManager.map(KEY_RIGHT, GLFW_KEY_D);
    keyManager.map(KEY_UP, GLFW_KEY_W);
    keyManager.map(KEY_DOWN, GLFW_KEY_S);
    keyManager.map(KEY_JUMP, GLFW_KEY_SPACE);
    keyManager.map(KEY_SNEAK, GLFW_KEY_LEFT_SHIFT);
    
    keyManager.map(KEY_TEST, GLFW_KEY_T);
    
    mouseManager.map(MOUSE_LEFT, GLFW_MOUSE_BUTTON_1);
    
    activeGUI = new StartMenu();
}

GameClient::~GameClient()
{
    if(activeGUI != nullptr)
    {
        delete activeGUI;
    }
}

void GameClient::tick()
{
    tps.update();
    
    diffMouseY = 0;
    diffMouseX = 0;
    
    mouseManager.tick();
    keyManager.tick();
    
    if(activeGUI != nullptr)
    {
        GUI* newGUI = activeGUI->tick(keyManager, mouseManager);
        if(newGUI != activeGUI)
        {
            delete activeGUI;
            activeGUI = newGUI;
        }
    }
}

void GameClient::render3DTick(float lag)
{
    fps.update();
}

void GameClient::render2DTick(float lag)
{
    if(activeGUI != nullptr)
    {
        activeGUI->render2DTick(shader, directRenderer, lag);
    }
    
    Engine::setMixMode();
    shader.setToIdentity();
    shader.updateModelMatrix();
    
    string wusi;
    wusi = "FPS: " + to_string(fps.getUpdatesPerSecond());
    float y = directRenderer.drawString(10, 10, true, wusi);
    wusi = "TPS: " + to_string(tps.getUpdatesPerSecond());
    directRenderer.drawString(10, y, true, wusi);
}

void GameClient::onKeyEvent(int key, int scancode, int action, int mods)
{
    if(action == GLFW_PRESS)
    {
        keyManager.press(key);
    }
    else if(action == GLFW_RELEASE)
    {
        keyManager.release(key);
    }
}

double GameClient::transformMouse(double x)
{
    if(x >= -MOUSE_BORDER && x <= MOUSE_BORDER)
    {
        return x * x * x;
    }
    else if(x >= MOUSE_BORDER)
    {
        const double k = (3 * MOUSE_BORDER * MOUSE_BORDER);
        const double y = MOUSE_BORDER * MOUSE_BORDER * MOUSE_BORDER;
        const double d = y - k * MOUSE_BORDER;
        return k * x + d;
    }
    else
    {
        const double k = (3 * MOUSE_BORDER * MOUSE_BORDER);
        const double y = -MOUSE_BORDER * MOUSE_BORDER * MOUSE_BORDER;
        const double d = y - k * MOUSE_BORDER;
        return k * x + d;
    }
}

void GameClient::onMouseMove(double x, double y)
{
    if(mouseTrapped)
    {
        diffMouseX = transformMouse(oldMouseX - x) * (1 / (MOUSE_BORDER * MOUSE_BORDER * 3));
        diffMouseY = transformMouse(oldMouseY - y) * (1 / (MOUSE_BORDER * MOUSE_BORDER * 3));
        oldMouseX = x;
        oldMouseY = y;
    }
}

void GameClient::onMouseClick(int button, int action, int mods)
{
    if(action == GLFW_PRESS)
    {
        mouseManager.press(button);
    }
    else if(action == GLFW_RELEASE)
    {
        mouseManager.release(button);
    }
}*/