#include "glew.h"
#include "freeglut.h"
#include "glm.hpp"
#include "ext.hpp"
#include <iostream>
#include <cmath>
#include <vector>

#include "Shader_Loader.h"
#include "Render_Utils.h"
#include "Camera.h"
#include "Texture.h"
#include "Physics.h"
#include "Skybox.h"

#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"

Core::Shader_Loader shaderLoader;
GLuint programColor;
GLuint programTexture;
GLuint programSkybox;
GLuint cubemapTexture;
GLuint skyboxVAO, skyboxVBO;

obj::Model planeModel;
obj::Model boxModel;
obj::Model shipModel;
obj::Model boosterModel;
obj::Model platformModel;
obj::Model craneModel;
obj::Model lampModel;
glm::mat4 boxModelMatrix;
GLuint boxTexture, groundTexture, shipTexture, stoneTexture, redTex;
Core::RenderContext planeContext, boxContext, shipContext, boosterContext, platformContext, craneContext, lampContext;

glm::vec3 cameraPos = glm::vec3(0, 10, 25);
glm::vec3 cameraDir;
glm::vec3 cameraSide;
float cameraAngle = 0;
glm::mat4 cameraMatrix, perspectiveMatrix;

glm::vec3 lightDir = glm::normalize(glm::vec3(0.5, -1, -0.5));
glm::vec3 lightPos = glm::vec3(-15.75, 2, 0);


// Initalization of physical scene (PhysX)
Physics pxScene(9.8f /* gravity (m/s^2) */);

// fixed timestep for stable and deterministic simulation
const double physicsStepTime = 1.f / 60.f;
double physicsTimeToProcess = 0;

// physical objects
PxRigidStatic *planeBody = nullptr;
PxMaterial *planeMaterial = nullptr;
PxRigidDynamic *boxBody = nullptr;
PxMaterial *boxMaterial = nullptr;

std::vector<std::string> faces
{
    "textures/skybox/stars.jpeg",
    "textures/skybox/stars.jpeg",
    "textures/skybox/stars.jpeg",
    "textures/skybox/stars.jpeg",
    "textures/skybox/stars.jpeg",
    "textures/skybox/stars.jpeg",
};


void initRenderables()
{
    // load models
    planeModel = obj::loadModelFromFile("models/plane.obj");
    boxModel = obj::loadModelFromFile("models/box.obj");
    shipModel = obj::loadModelFromFile("models/ship.obj");
    boosterModel = obj::loadModelFromFile("models/booster.obj");
    platformModel = obj::loadModelFromFile("models/platform4.obj");
    craneModel = obj::loadModelFromFile("models/crane.obj");
    lampModel = obj::loadModelFromFile("models/lamp2.obj");

    // load textures
    groundTexture = Core::LoadTexture("textures/sand.jpg");
    boxTexture = Core::LoadTexture("textures/a.jpg");
    shipTexture = Core::LoadTexture("textures/ship.png");
    stoneTexture = Core::LoadTexture("textures/stone.png");
    redTex = Core::LoadTexture("textures/redTex.png");

    planeContext.initFromOBJ(planeModel);
    boxContext.initFromOBJ(boxModel);
    shipContext.initFromOBJ(shipModel);
    boosterContext.initFromOBJ(boosterModel);
    platformContext.initFromOBJ(platformModel);
    craneContext.initFromOBJ(craneModel);
    lampContext.initFromOBJ(lampModel);
}

void initPhysicsScene()
{
}

void updateTransforms()
{
    // Here we retrieve the current transforms of the objects from the physical simulation.
    auto actorFlags = PxActorTypeFlag::eRIGID_DYNAMIC | PxActorTypeFlag::eRIGID_STATIC;
    PxU32 nbActors = pxScene.scene->getNbActors(actorFlags);
    if (nbActors)
    {
        std::vector<PxRigidActor*> actors(nbActors);
        pxScene.scene->getActors(actorFlags, (PxActor**)&actors[0], nbActors);
        for (auto actor : actors)
        {
            // We use the userData of the objects to set up the proper model matrices.
            if (!actor->userData) continue;
            glm::mat4 *modelMatrix = (glm::mat4*)actor->userData;

            // get world matrix of the object (actor)
            PxMat44 transform = actor->getGlobalPose();
            auto &c0 = transform.column0;
            auto &c1 = transform.column1;
            auto &c2 = transform.column2;
            auto &c3 = transform.column3;

            // set up the model matrix used for the rendering
            *modelMatrix = glm::mat4(
                c0.x, c0.y, c0.z, c0.w,
                c1.x, c1.y, c1.z, c1.w,
                c2.x, c2.y, c2.z, c2.w,
                c3.x, c3.y, c3.z, c3.w);
        }
    }
}

void keyboard(unsigned char key, int x, int y)
{
    float angleSpeed = 0.1f;
    float moveSpeed = 0.5f;
    switch (key)
    {
    case 'z': cameraAngle -= angleSpeed; break;
    case 'x': cameraAngle += angleSpeed; break;
    case 'w': cameraPos += cameraDir * moveSpeed; break;
    case 's': cameraPos -= cameraDir * moveSpeed; break;
    case 'd': cameraPos += cameraSide * moveSpeed; break;
    case 'a': cameraPos -= cameraSide * moveSpeed; break;
    case 'e': cameraPos += glm::cross(cameraDir, glm::vec3(1, 0, 0)) * moveSpeed; break;
    case 'q': cameraPos -= glm::cross(cameraDir, glm::vec3(1, 0, 0)) * moveSpeed; break;
    }
}

void mouse(int x, int y)
{
}

glm::mat4 createCameraMatrix()
{
    cameraDir = glm::normalize(glm::vec3(cosf(cameraAngle - glm::radians(90.0f)), 0, sinf(cameraAngle - glm::radians(90.0f))));
    glm::vec3 up = glm::vec3(0, 1, 0);
    cameraSide = glm::cross(cameraDir, up);

    return Core::createViewMatrix(cameraPos, cameraDir, up);
}

void drawObjectColor(Core::RenderContext context, glm::mat4 modelMatrix, glm::vec3 color)
{
    GLuint program = programColor;

    glUseProgram(program);

    glUniform3f(glGetUniformLocation(program, "objectColor"), color.x, color.y, color.z);
    glUniform3f(glGetUniformLocation(program, "lightDir"), lightDir.x, lightDir.y, lightDir.z);

    glm::mat4 transformation = perspectiveMatrix * cameraMatrix * modelMatrix;
    glUniformMatrix4fv(glGetUniformLocation(program, "modelViewProjectionMatrix"), 1, GL_FALSE, (float*)&transformation);
    glUniformMatrix4fv(glGetUniformLocation(program, "modelMatrix"), 1, GL_FALSE, (float*)&modelMatrix);

    Core::DrawContext(context);

    glUseProgram(0);
}

void drawObjectTexture(Core::RenderContext context, glm::mat4 modelMatrix, GLuint textureId)
{
    GLuint program = programTexture;

    glUseProgram(program);

    glUniform3f(glGetUniformLocation(program, "lightDir"), lightDir.x, lightDir.y, lightDir.z);
    glUniform3f(glGetUniformLocation(program, "lightPos"), lightPos.x, lightPos.y, lightPos.z);
    Core::SetActiveTexture(textureId, "textureSampler", program, 0);

    glm::mat4 transformation = perspectiveMatrix * cameraMatrix * modelMatrix;
    glUniformMatrix4fv(glGetUniformLocation(program, "modelViewProjectionMatrix"), 1, GL_FALSE, (float*)&transformation);
    glUniformMatrix4fv(glGetUniformLocation(program, "modelMatrix"), 1, GL_FALSE, (float*)&modelMatrix);

    Core::DrawContext(context);

    glUseProgram(0);
}

void renderScene()
{
    double time = glutGet(GLUT_ELAPSED_TIME) / 1000.0;
    static double prevTime = time;
    double dtime = time - prevTime;
    prevTime = time;

    // Update physics
    if (dtime < 1.f) {
        physicsTimeToProcess += dtime;
        while (physicsTimeToProcess > 0) {
            // here we perform the physics simulation step
            pxScene.step(physicsStepTime);
            physicsTimeToProcess -= physicsStepTime;
        }
    }

    // Update of camera and perspective matrices
    cameraMatrix = createCameraMatrix();
    perspectiveMatrix = Core::createPerspectiveMatrix(0.1f, 1000.f);

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glClearColor(0.0f, 0.1f, 0.3f, 1.0f);
    glUseProgram(programTexture);

    // Drawing skybox
    Skybox::drawSkybox(programSkybox, cameraMatrix, perspectiveMatrix, cubemapTexture);

    glUniform3f(glGetUniformLocation(programTexture, "lightPos"), 0, 0, 0);

    // update transforms from physics simulation
    updateTransforms();

    // render models
    drawObjectTexture(planeContext, glm::translate(glm::vec3(0, 0, 0)), groundTexture);
    drawObjectTexture(shipContext, glm::translate(glm::vec3(0,3,0)), shipTexture); // boxModelMatrix was updated in updateTransforms()
    drawObjectTexture(boosterContext, glm::translate(glm::vec3(0, 3, 0)), shipTexture);
    drawObjectTexture(platformContext, glm::rotate(glm::radians(90.f), glm::vec3(0.f, 1.f, 0.f)), stoneTexture);
    drawObjectTexture(craneContext, glm::rotate(glm::radians(90.f), glm::vec3(0.f, 1.f, 0.f)), redTex);
    drawObjectColor(lampContext, glm::translate(glm::vec3(lightPos)) * glm::rotate(glm::radians(90.f), glm::vec3(0.f, 1.f, 0.f)), glm::vec3(1, 1, 1));
    glutSwapBuffers();
}

void init()
{
    srand((unsigned int)time(0));
    glEnable(GL_DEPTH_TEST);
    programColor = shaderLoader.CreateProgram("shaders/shader_color.vert", "shaders/shader_color.frag");
    programTexture = shaderLoader.CreateProgram("shaders/shader_tex.vert", "shaders/shader_tex.frag");
    programSkybox = shaderLoader.CreateProgram("shaders/shader_skybox.vert", "shaders/shader_skybox.frag");

    cubemapTexture = Skybox::loadCubemap(faces);
    initRenderables();
    initPhysicsScene();
}

void shutdown()
{
    shaderLoader.DeleteProgram(programColor);
    shaderLoader.DeleteProgram(programTexture);

    planeContext.initFromOBJ(planeModel);
    boxContext.initFromOBJ(boxModel);
    shipContext.initFromOBJ(shipModel);
    boosterContext.initFromOBJ(boosterModel);
    platformContext.initFromOBJ(platformModel);
    craneContext.initFromOBJ(craneModel);
    lampContext.initFromOBJ(lampModel);
}

void idle()
{
    glutPostRedisplay();
}

int main(int argc, char ** argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
    glutInitWindowPosition(200, 200);
    glutInitWindowSize(600, 600);
    glutCreateWindow("Projekt");
    glewInit();

    init();
    glutKeyboardFunc(keyboard);
    glutPassiveMotionFunc(mouse);
    glutDisplayFunc(renderScene);
    glutIdleFunc(idle);

    glutMainLoop();

    shutdown();

    return 0;
}