#include <SDL.h>
#include <stdio.h>
#include "glcxx.hpp"
#include "GL3/gl3w.h"
#include <iostream>

using namespace std;

std::shared_ptr<glcxx::Program> program;
std::shared_ptr<glcxx::Buffer> cube_buffer;
std::shared_ptr<glcxx::Array> cube_array;

#define WIDTH   800
#define HEIGHT  800

bool init(void)
{
    glClearColor (0.0, 0.0, 0.0, 0.0);
    glEnable(GL_DEPTH_TEST);
    glViewport(0, 0, WIDTH, HEIGHT);
    try
    {
        program = glcxx::Program::create(
            glcxx::Shader::create_from_file(GL_VERTEX_SHADER, "cube.v.glsl"),
            glcxx::Shader::create_from_file(GL_FRAGMENT_SHADER, "cube.f.glsl"),
            "position", 0,
            "normal", 1,
            "tex_coord", 2);

        cube_buffer = glcxx::Buffer::create(GL_ARRAY_BUFFER, GL_STATIC_DRAW,
                                            {-1, -1, -1,  0, 0, -1,  0, 0,
                                              1, -1, -1,  0, 0, -1,  1, 0,
                                              1,  1, -1,  0, 0, -1,  1, 1,
                                             -1,  1, -1,  0, 0, -1,  0, 1});
        cube_array = make_shared<glcxx::Array>();
        cube_array->bind();
        glEnableVertexAttribArray(0);
        glEnableVertexAttribArray(1);
        glEnableVertexAttribArray(2);
        glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), NULL);
        glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (void *)(3 * sizeof(GLfloat)));
        glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (void *)(6 * sizeof(GLfloat)));
    }
    catch (glcxx::Error & e)
    {
        cerr << "glcxx error: " << e.what() << endl;
        return false;
    }
    return true;
}

void display(SDL_Window * window)
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    SDL_GL_SwapWindow(window);
}

int main(int argc, char *argv[])
{
    if (SDL_Init(SDL_INIT_VIDEO))
    {
        printf("Failed to initialize SDL!\n");
        return 1;
    }

    atexit(SDL_Quit);

    SDL_Window * window = SDL_CreateWindow(argv[0],
                                           SDL_WINDOWPOS_UNDEFINED,
                                           SDL_WINDOWPOS_UNDEFINED,
                                           WIDTH,
                                           HEIGHT,
                                           SDL_WINDOW_OPENGL);
    if (!window)
    {
        printf("Failed to create window!\n");
        SDL_Quit();
        return 2;
    }

    SDL_GLContext gl_context = SDL_GL_CreateContext(window);

    if (gl3wInit())
    {
        cerr << "Failed to initialize GL3W" << endl;
        return 2;
    }
    if (!gl3wIsSupported(3, 0))
    {
        cerr << "OpenGL 3.0 is not supported!" << endl;
        return 2;
    }

    if (!init())
    {
        return 2;
    }

    display(window);
    SDL_Event event;
    while (SDL_WaitEvent(&event))
    {
        if (event.type == SDL_QUIT)
            break;
        else if (event.type == SDL_KEYDOWN)
        {
            if (event.key.keysym.sym == SDLK_ESCAPE)
                break;
            if (event.key.keysym.sym == SDLK_RETURN)
                display(window);
        }
    }
}