#include <glew/glew.h>
#include "myglwidget.h"
#include "scene.h"
#include "glassert.h"
#include "camera.h"
#include "sphere.h"
#include "phongmaterial.h"
#include "skybox.h"
#include "utils.h"
#include "texture.h"
#include <iostream>
#include <glm/glm.hpp>
#include <QKeyEvent>
#include <QMouseEvent>

MyGLWidget::MyGLWidget(QWidget *parent) :
    QGLWidget(parent),
    scene(NULL)
{}

MyGLWidget::~MyGLWidget()
{
    if(scene != NULL)
        delete(scene);
}

void MyGLWidget::initializeGL()
{
    makeCurrent();

    GLenum err = glewInit(); // init and check glew
    if (GLEW_OK != err)
    {
        std::cerr << "Warning: glewInit failed!" << std::endl;
    }
    if (!GLEW_ARB_vertex_program   ||
        !GLEW_ARB_fragment_program ||
        !GLEW_ARB_texture_float    ||
        !GLEW_ARB_draw_buffers     ||
        !GLEW_ARB_framebuffer_object)
    {
        std::cerr << "Warning: Shaders not supported!" << std::endl;
    }

    std::cout << "OpenGL version " << glGetString(GL_VERSION) << std::endl;
    std::cout << "GLSL version " << glGetString(GL_SHADING_LANGUAGE_VERSION) << std::endl;
    std::cout.flush();

    glAssert(glEnable(GL_DEPTH_TEST));
    glAssert(glEnable(GL_CULL_FACE));
    glAssert(glEnable(GL_TEXTURE_2D));
    glAssert(glViewport(0, 0, width(), height()));

    buildScene();
    controller.setScene(scene);
}

void MyGLWidget::buildScene()
{
    scene = new Scene();
    Camera* cam = new Camera(width(), height());
    cam->moveTo(glm::vec3(-1, 0, 0));
    cam->lookAt(glm::vec3(0, 0, 0));
    scene->setCamera(cam);
    Mesh* myGrid = new Sphere(2);
    myGrid->initGL();
    QString vertSource = Utils::fileToString("../phong.vert");
    QString fragSource = Utils::fileToString("../phong.frag");
    Shader* shader = new Shader(&vertSource, &fragSource);
    PhongMaterial* mat = new PhongMaterial(shader);
    Texture* tex = new Texture("../data/noise.png");
    mat->setTexture(tex);
    QString filenames[6] = {
        "../data/skybox_lf", "../data/skybox_rt",
        "../data/skybox_up", "../data/skybox_dn",
        "../data/skybox_bk", "../data/skybox_ft"
    };
    SkyBox* skybox = new SkyBox(filenames);
    scene->addEntity(skybox);
    scene->addEntity(myGrid, mat);
}

void MyGLWidget::resizeGL(int width, int height)
{
    glAssert(glViewport(0, 0, width, height));
    scene->getCamera()->resize(width, height);
    updateGL();
}

void MyGLWidget::paintGL()
{
    glAssert(glClearColor(0.60, 0.65, 0.75, 1.0));
    glAssert(glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT));
    scene->drawEntities();
}

void MyGLWidget::mouseMoveEvent(QMouseEvent *e)
{
    controller.mouseMove(e->pos().x() - last.x(), e->pos().y() - last.y());
    last = e->pos();
    updateGL();
}

void MyGLWidget::mousePressEvent(QMouseEvent* e)
{
    controller.mouseEvent(e->button(), true);
    last = e->pos();
    updateGL();
}
void MyGLWidget::mouseReleaseEvent(QMouseEvent* e)
{
    controller.mouseEvent(e->button(), false);
    updateGL();
}

void MyGLWidget::keyPressEvent(QKeyEvent *e)
{
    controller.mouseEvent(e->key(), true);
    updateGL();
}
void MyGLWidget::keyReleaseEvent(QKeyEvent *e)
{
    controller.mouseEvent(e->key(), false);
    updateGL();
}