import std.stdio;
import derelict.sdl2.sdl;
import derelict.opengl3.gl3;
import glamour.vao;
import glamour.shader;
import glamour.vbo;
import gl3n.linalg;
static import logo;

extern(C) void GetDisplaySize(int * width, int * height, int * num_monitors);

int width;
int height;
GLint position_idx;
GLint view_idx;
GLint color_idx;
mat4 view_matrix;
Shader program;

void init()
{
    logo.init();
    glClearColor (0.0, 0.0, 0.0, 0.0);
    glViewport(0, 0, width, height);
    immutable string shader_src = `
vertex:
    uniform mat4 view;
    in vec2 position;
    void main(void)
    {
        gl_Position = view * vec4(position, 0.0, 1.0);
    }
fragment:
    uniform vec3 color;
    void main(void)
    {
        gl_FragColor = vec4(color, 1.0);
    }
        `;
    program = new Shader("program", shader_src);
    program.bind();
    position_idx = program.get_attrib_location("position");
    view_idx = program.get_uniform_location("view");
    color_idx = program.get_uniform_location("color");
}

void display(SDL_Window * window)
{
    glClear(GL_COLOR_BUFFER_BIT);

    view_matrix.make_identity();
    view_matrix.scale(height / cast(float)width, 1.0, 1.0);
    view_matrix.scale(0.25, 0.25, 0.25);

    program.bind();
    glUniformMatrix4fv(view_idx, 1, GL_TRUE, view_matrix.value_ptr);

    float[] color = [0.0, 93.0/255.0, 171.0/255.0];
    glUniform3fv(color_idx, 1, color.ptr);
    for (int i = 0; i < 6; i++)
    {
        logo.draw(logo.FACE, logo.GENTEX, i, position_idx);
    }

    color = [187.0/255.0, 188.0/255.0, 190.0/255.0];
    glUniform3fv(color_idx, 1, color.ptr);
    for (int i = 0; i < 11; i++)
    {
        logo.draw(logo.FACE, logo.CORPORATION, i, position_idx);
    }

    color = [1.0, 1.0, 1.0];
    glUniform3fv(color_idx, 1, color.ptr);
    for (int i = 0; i < 6; i++)
    {
        logo.draw(logo.WIRE, logo.GENTEX, i, position_idx);
    }

    for (int i = 0; i < 11; i++)
    {
        logo.draw(logo.WIRE, logo.CORPORATION, i, position_idx);
    }

    SDL_GL_SwapWindow(window);
}

int main()
{
    GetDisplaySize(&width, &height, null);
    if (width > 1920 * 2)
        width = 1920 * 2;   /* restrict to two monitors */

    DerelictSDL2.load();

    DerelictGL3.load();

    if (SDL_Init(SDL_INIT_EVERYTHING))
    {
        writeln("Failed to initialize SDL!");
        return 1;
    }

    SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, 1);
    SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, 4);

    SDL_Window * window = SDL_CreateWindow("Gentex ScreenSaver",
                                           SDL_WINDOWPOS_UNDEFINED,
                                           SDL_WINDOWPOS_UNDEFINED,
                                           width,
                                           height,
                                           SDL_WINDOW_OPENGL | SDL_WINDOW_BORDERLESS);

    SDL_GLContext context = SDL_GL_CreateContext(window);

    if (window == null)
    {
        writeln("Failed to create SDL window!");
        return 1;
    }

    DerelictGL3.reload();

    init();
    SDL_Event event;
    for (;;)
    {
        if (SDL_PollEvent(&event))
        {
            if (event.type == SDL_QUIT)
                break;
            else if (event.type == SDL_KEYDOWN)
            {
                if (event.key.keysym.scancode == SDL_SCANCODE_ESCAPE)
                    break;
            }
        }
        display(window);
    }

    SDL_GL_DeleteContext(context);

    SDL_DestroyWindow(window);

    SDL_Quit();

    return 0;
}