#include <iostream>
#include <vector>
#include <glad/glad.h>

#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>

#ifdef __linux__
#include <unistd.h>
#endif
#ifdef _WIN32
#include <windows.h>
#endif

#include "Controller.h"
#include "Texture.h"
#include "Mesh.h"

Controller::Controller() {
    if(!glfwInit()) exit(-1);

    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    #ifdef _DEBUG
    glfwWindowHint(GLFW_OPENGL_DEBUG_CONTEXT, GL_TRUE);
    #endif

    glfwSetErrorCallback(error_callback);

    gameWindow = new Window();
    gameEventHandler = new EventHandler(gameWindow->getGLFWwindow());
    camera = new Camera(90.0f, gameWindow->getWindowWidth(), gameWindow->getWindowHeight());
}

Controller::~Controller() {
    delete gameWindow;
    delete gameEventHandler;
    glfwTerminate();
}

void Controller::run() {
    glClearColor(0.15f, 0.15f, 0.15f, 1.0f);

    ShaderProgram shaderProgram("res/shaders/basic.vs", "res/shaders/basic.fs");
    shaderProgram.bind();

    std::vector<Vertex> vertices {
        Vertex{
            glm::vec3(-0.5f, -0.5f, 0.0f),
            glm::vec2(0.0f, 0.0f),
            glm::vec3(0.0f, 0.0f, 0.0f),
            glm::vec3(0.0f, 0.0f, 0.0f),
            glm::vec3(0.0f, 0.0f, 0.0f),
            glm::vec4(1.0f, 0.0f, 0.0f, 1.0f)},
        Vertex{
            glm::vec3(0.5f, -0.5f, 0.0f),
            glm::vec2(1.0f, 0.0f),
            glm::vec3(0.0f, 0.0f, 0.0f),
            glm::vec3(0.0f, 0.0f, 0.0f),
            glm::vec3(0.0f, 0.0f, 0.0f),
            glm::vec4(0.0f, 1.0f, 0.0f, 1.0f)},
        Vertex{
            glm::vec3(-0.5f, 0.5f, 0.0f),
            glm::vec2(0.0f, 1.0f),
            glm::vec3(0.0f, 0.0f, 0.0f),
            glm::vec3(0.0f, 0.0f, 0.0f),
            glm::vec3(0.0f, 0.0f, 0.0f),
            glm::vec4(0.0f, 0.0f, 1.0f, 1.0f)},
        Vertex{
            glm::vec3(0.5f, 0.5f, 0.0f),
            glm::vec2(1.0f, 1.0f),
            glm::vec3(0.0f, 0.0f, 0.0f),
            glm::vec3(0.0f, 0.0f, 0.0f),
            glm::vec3(0.0f, 0.0f, 0.0f),
            glm::vec4(0.0f, 0.0f, 1.0f, 1.0f)}
    };

    std::vector<uint32_t> indices {
        0, 1, 2,
        1, 2, 3
    };

    std::vector<Texture*> textures {
        new Texture("res/tex2.png", texture_diffuse),
        new Texture("res/tex1.png", texture_diffuse)
    };

    Mesh mesh1(vertices, indices, textures);

    glm::mat4 model = glm::mat4(1.0f);
    
    camera->translate(glm::vec3(0.0f, 0.0f, 2.5f));

    // This is the game loop
    while(!glfwWindowShouldClose(gameWindow->getGLFWwindow())) {
        // Timing
        limit_framerate();

        #ifdef _DEBUG
        static uint8_t frameCount = 250;
        if(frameCount++ == 255) {
            std::cout << "FPS: " << 1/deltaTime << std::endl;
            frameCount = 0;
        }
        #endif

        // Update game
        // ...
        shaderProgram.setUniform("mix_val", (float) (sin(glfwGetTime())*sin(glfwGetTime())));
        model = glm::rotate(model, (float)(this->deltaTime*0.005), glm::vec3(0.0f, 1.0f, 0.0f));

        //camera->lookAtTarget(glm::vec3(0.0f, 0.0f, 0.0f));
        camera->lookForward();
        camera->updateVPM();
        glm::mat4 modelViewProj = camera->getViewProj() * model;
        shaderProgram.setUniform("u_modelViewProj", modelViewProj);

        // Render and buffer swap
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        for(int i=0;i<20;i++) {
            mesh1.draw(&shaderProgram);
            model = glm::translate(model, glm::vec3(0.0f, 0.0f, -1.0f));
            camera->updateVPM();
            glm::mat4 modelViewProj = camera->getViewProj() * model;
            shaderProgram.setUniform("u_modelViewProj", modelViewProj);
        }
        model = glm::translate(model, glm::vec3(0.0f, 0.0f, 20.0f));

        glfwSwapBuffers(gameWindow->getGLFWwindow());
            
        // Update window size
        if(gameWindow->checkWindowWasResized())
            updateWindowSize();

        // Check events, handle input
        gameEventHandler->handleEvents();

        camera->updatePositionFromKeyboardInput(gameEventHandler->getCameraActionRegister(), deltaTime);
        camera->updateDirectionFromMouseInput(gameEventHandler->getCursorDeltaX(), gameEventHandler->getCursorDeltaY());
    }

    delete textures[0];

}

void Controller::limit_framerate() {
    static double startingTime = 0.0;
    static double lastTime = 0.0;

    lastTime = glfwGetTime() - startingTime;

    double frameTime = 1/(double)MAX_FPS;
    if(frameTime > lastTime) {
        #ifdef __linux__
        usleep((frameTime - lastTime) * 1000000);
        #endif
        #ifdef _WIN32
        Sleep((frameTime - lastTime) * 1000);
        #endif
    }

    deltaTime = glfwGetTime() - startingTime;

    startingTime = glfwGetTime();
}

// GLFW error function
void Controller::error_callback(int error, const char* description) {
    (void)error;
    fprintf(stderr, "Error: %s\n", description);
}

void Controller::updateWindowSize() {
    camera->updateAspectRatio(gameWindow->getWindowWidth(), gameWindow->getWindowHeight());
    gameEventHandler->setFirstMouseInput(1);
}