#include <iostream>
#include <SDL.h>

#include <bgfx/bgfx.h>
#include <bx/math.h>


struct PosColorVertex
{
    float x;
    float y;
    float z;
    uint32_t abgr;
};

static PosColorVertex cubeVertices[] =
    {
        {-1.0f,  1.0f,  1.0f, 0xff000000 },
        { 1.0f,  1.0f,  1.0f, 0xff0000ff },
        {-1.0f, -1.0f,  1.0f, 0xff00ff00 },
        { 1.0f, -1.0f,  1.0f, 0xff00ffff },
        {-1.0f,  1.0f, -1.0f, 0xffff0000 },
        { 1.0f,  1.0f, -1.0f, 0xffff00ff },
        {-1.0f, -1.0f, -1.0f, 0xffffff00 },
        { 1.0f, -1.0f, -1.0f, 0xffffffff },
    };

static const uint16_t cubeTriList[] =
    {
        0, 1, 2,
        1, 3, 2,
        4, 6, 5,
        5, 6, 7,
        0, 2, 4,
        4, 2, 6,
        1, 5, 3,
        5, 7, 3,
        0, 4, 1,
        4, 5, 1,
        2, 3, 6,
        6, 3, 7,
    };


bgfx::ShaderHandle loadShader(const char *FILENAME)
{
    FILE *file = fopen(FILENAME, "rb");
    fseek(file, 0, SEEK_END);
    long fileSize = ftell(file);
    fseek(file, 0, SEEK_SET);

    const bgfx::Memory *mem = bgfx::alloc(fileSize + 1);
    fread(mem->data, 1, fileSize, file);
    mem->data[mem->size - 1] = '\0';
    fclose(file);

    return bgfx::createShader(mem);
}


int main() {

    SDL_Init(SDL_INIT_EVERYTHING);

    SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_FORWARD_COMPATIBLE_FLAG);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);

    SDL_Window *window = SDL_CreateWindow("title", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 640, 360, SDL_WINDOW_OPENGL);

    bgfx::Init bgfxInit;
    bgfxInit.type = bgfx::RendererType::OpenGL; // Automatically choose a renderer.
    bgfxInit.resolution.width = 640;
    bgfxInit.resolution.height = 360;
    bgfxInit.resolution.reset = BGFX_RESET_VSYNC;
    bgfx::init(bgfxInit);

    bgfx::setViewClear(0, BGFX_CLEAR_COLOR | BGFX_CLEAR_DEPTH, 0x443355FF, 1.0f, 0);
    bgfx::setViewRect(0, 0, 0, 640, 360);


    bgfx::VertexDecl pcvDecl;
    pcvDecl.begin()
        .add(bgfx::Attrib::Position, 3, bgfx::AttribType::Float)
        .add(bgfx::Attrib::Color0, 4, bgfx::AttribType::Uint8, true)
        .end();
    bgfx::VertexBufferHandle vbh = bgfx::createVertexBuffer(bgfx::makeRef(cubeVertices, sizeof(cubeVertices)), pcvDecl);
    bgfx::IndexBufferHandle ibh = bgfx::createIndexBuffer(bgfx::makeRef(cubeTriList, sizeof(cubeTriList)));

    bgfx::ShaderHandle vsh = loadShader("/Users/sherjilozair/Desktop/Dev/bgfx/bgfx/examples/runtime/shaders/glsl/vs_cubes.bin");
    bgfx::ShaderHandle fsh = loadShader("/Users/sherjilozair/Desktop/Dev/bgfx/bgfx/examples/runtime/shaders/glsl/fs_cubes.bin");
    bgfx::ProgramHandle program = bgfx::createProgram(vsh, fsh, true);


    unsigned int counter = 0;
    while(!SDL_QuitRequested()) {

        const bx::Vec3 at = {0.0f, 0.0f,  0.0f};
        const bx::Vec3 eye = {0.0f, 0.0f, -5.0f};
        float view[16];
        bx::mtxLookAt(view, eye, at);
        float proj[16];
        bx::mtxProj(proj, 60.0f, float(640) / float(360), 0.1f, 100.0f, bgfx::getCaps()->homogeneousDepth);
        bgfx::setViewTransform(0, view, proj);

        bgfx::setVertexBuffer(0, vbh);
        bgfx::setIndexBuffer(ibh);

        bgfx::submit(0, program);

        bgfx::frame();
        counter++;

        SDL_GL_SwapWindow(window);
    }

    bgfx::shutdown();
    SDL_Quit();
    return 0;
}