#![feature(link_args)]

extern crate gl;
extern crate gl_helpers;
extern crate glutin;
extern crate main_loop;
extern crate mat4;
extern crate vec3;

use gl::types::*;
use glutin::{Api, GlContext, GlRequest};
use std::f32;

use gl_helpers::*;

#[cfg(target_os = "emscripten")]
#[allow(unused_attributes)]
#[link_args = "-s OFFSCREENCANVAS_SUPPORT=1"]
extern "C" {}

static FB_DATA: [GLfloat; 16] = [
    // position     uv
    1f32, 1f32, 1f32, 1f32, -1f32, 1f32, 0f32, 1f32, 1f32, -1f32, 1f32,
    0f32, -1f32, -1f32, 0f32, 0f32,
];
static CUBE_DATA: [GLfloat; 288] = [
    1.0, 1.0, -1.0, 0.577349, 0.577349, -0.577349, 0.0, 0.0, 1.0, -1.0, -1.0, 0.577349, -0.577349,
    -0.577349, 1.0, 0.0, -1.0, -1.0, -1.0, -0.577349, -0.577349, -0.577349, 1.0, 1.0, 1.0, 1.0,
    1.0, 0.577349, 0.577349, 0.577349, 0.0, 0.0, -1.0, 1.0, 1.0, -0.577349, 0.577349, 0.577349,
    1.0, 0.0, -1.0, -1.0, 1.0, -0.577349, -0.577349, 0.577349, 1.0, 1.0, 1.0, 1.0, -1.0, 0.577349,
    0.577349, -0.577349, 0.0, 0.0, 1.0, 1.0, 1.0, 0.577349, 0.577349, 0.577349, 1.0, 0.0, 1.0,
    -1.0, 1.0, 0.577349, -0.577349, 0.577349, 1.0, 1.0, 1.0, -1.0, -1.0, 0.577349, -0.577349,
    -0.577349, 0.0, 0.0, 1.0, -1.0, 1.0, 0.577349, -0.577349, 0.577349, 1.0, 0.0, -1.0, -1.0, 1.0,
    -0.577349, -0.577349, 0.577349, 1.0, 1.0, -1.0, -1.0, -1.0, -0.577349, -0.577349, -0.577349,
    0.0, 0.0, -1.0, -1.0, 1.0, -0.577349, -0.577349, 0.577349, 1.0, 0.0, -1.0, 1.0, 1.0, -0.577349,
    0.577349, 0.577349, 1.0, 1.0, 1.0, 1.0, 1.0, 0.577349, 0.577349, 0.577349, 0.0, 0.0, 1.0, 1.0,
    -1.0, 0.577349, 0.577349, -0.577349, 1.0, 0.0, -1.0, 1.0, -1.0, -0.577349, 0.577349, -0.577349,
    1.0, 1.0, -1.0, 1.0, -1.0, -0.577349, 0.577349, -0.577349, 0.0, 1.0, 1.0, 1.0, -1.0, 0.577349,
    0.577349, -0.577349, 0.0, 0.0, -1.0, -1.0, -1.0, -0.577349, -0.577349, -0.577349, 1.0, 1.0,
    1.0, -1.0, 1.0, 0.577349, -0.577349, 0.577349, 0.0, 1.0, 1.0, 1.0, 1.0, 0.577349, 0.577349,
    0.577349, 0.0, 0.0, -1.0, -1.0, 1.0, -0.577349, -0.577349, 0.577349, 1.0, 1.0, 1.0, -1.0, -1.0,
    0.577349, -0.577349, -0.577349, 0.0, 1.0, 1.0, 1.0, -1.0, 0.577349, 0.577349, -0.577349, 0.0,
    0.0, 1.0, -1.0, 1.0, 0.577349, -0.577349, 0.577349, 1.0, 1.0, -1.0, -1.0, -1.0, -0.577349,
    -0.577349, -0.577349, 0.0, 1.0, 1.0, -1.0, -1.0, 0.577349, -0.577349, -0.577349, 0.0, 0.0,
    -1.0, -1.0, 1.0, -0.577349, -0.577349, 0.577349, 1.0, 1.0, -1.0, 1.0, -1.0, -0.577349,
    0.577349, -0.577349, 0.0, 1.0, -1.0, -1.0, -1.0, -0.577349, -0.577349, -0.577349, 0.0, 0.0,
    -1.0, 1.0, 1.0, -0.577349, 0.577349, 0.577349, 1.0, 1.0, -1.0, 1.0, 1.0, -0.577349, 0.577349,
    0.577349, 0.0, 1.0, 1.0, 1.0, 1.0, 0.577349, 0.577349, 0.577349, 0.0, 0.0, -1.0, 1.0, -1.0,
    -0.577349, 0.577349, -0.577349, 1.0, 1.0,
];
static CUBE_INDEX_DATA: [u16; 36] = [
    0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,
    26, 27, 28, 29, 30, 31, 32, 33, 34, 35,
];

static FB_VERTEX: &'static str = "
    attribute vec2 position;
    attribute vec2 uv;

    varying vec2 v_uv;

    void main() {
        gl_Position = vec4(position, 0.0, 1.0);
        v_uv = uv;
    }
";
#[cfg(any(target_os = "emscripten", target_os = "android"))]
static FB_FRAGMENT: &'static str = "
    precision mediump float;

    uniform sampler2D diffuse;

    varying vec2 v_uv;

    void main() {
        gl_FragColor = texture2D(diffuse, v_uv);
    }
";
#[cfg(not(any(target_os = "emscripten", target_os = "android")))]
static FB_FRAGMENT: &'static str = "
    uniform sampler2D diffuse;

    varying vec2 v_uv;

    void main() {
        gl_FragColor = texture2D(diffuse, v_uv);
    }
";

static CUBE_VERTEX: &'static str = "
    uniform mat4 projection;
    uniform mat4 model_view;
    uniform vec3 light;

    attribute vec3 position;
    attribute vec3 normal;
    attribute vec2 uv;

    varying vec3 v_light;
    varying vec3 v_normal;
    varying vec2 v_uv;

    void main() {
        gl_Position = projection * model_view * vec4(position, 1.0);
        v_light = normalize(light - position);
        v_normal = normal;
        v_uv = uv;
    }
";
#[cfg(any(target_os = "emscripten", target_os = "android"))]
static CUBE_FRAGMENT: &'static str = "
    precision mediump float;

    varying vec3 v_light;
    varying vec3 v_normal;
    varying vec2 v_uv;

    void main() {
        vec3 light_dir = v_light;
        vec3 color = vec3(v_uv, 0.5);
        vec3 intensity = vec3(0.75, 0.75, 0.75);
        float dprod = dot(light_dir, v_normal);

        if (dprod > 0.75) {
            intensity = vec3(1.0, 1.0, 1.0);
        } else if (dprod > 0.25) {
            intensity = vec3(0.8, 0.8, 0.8);
        }

        gl_FragColor = vec4(color * intensity, 1.0);
    }
";
#[cfg(not(any(target_os = "emscripten", target_os = "android")))]
static CUBE_FRAGMENT: &'static str = "
    varying vec3 v_light;
    varying vec3 v_normal;
    varying vec2 v_uv;

    void main() {
        vec3 light_dir = v_light;
        vec3 color = vec3(v_uv, 0.5);
        vec3 intensity = vec3(0.75, 0.75, 0.75);
        float dprod = dot(light_dir, v_normal);

        if (dprod > 0.75) {
            intensity = vec3(1.0, 1.0, 1.0);
        } else if (dprod > 0.25) {
            intensity = vec3(0.8, 0.8, 0.8);
        }

        gl_FragColor = vec4(color * intensity, 1.0);
    }
";

fn main() {
    let mut screen_width = 1024_usize;
    let mut screen_height = 768_usize;

    let mut events_loop = glutin::EventsLoop::new();
    let window = glutin::WindowBuilder::new()
        .with_title("Cube")
        .with_maximized(true);
    let context = {
        let builder = glutin::ContextBuilder::new().with_vsync(true);

        if cfg!(target_os = "android") {
            builder.with_gl(GlRequest::Specific(Api::OpenGlEs, (2, 0)))
        } else {
            builder
        }
    };
    let gl_window = glutin::GlWindow::new(window, context, &events_loop).unwrap();

    unsafe {
        gl_window.make_current().unwrap();
        gl::load_with(|symbol| gl_window.get_proc_address(symbol) as *const _);
    }

    let gl_info = GLInfo::new();
    println!("{}", gl_info.version());
    println!(
        "OpenGL version: {:?}.{:?}, GLSL version {:?}.{:?}0",
        gl_info.major(),
        gl_info.minor(),
        gl_info.glsl_major(),
        gl_info.glsl_minor()
    );

    gl_set_defaults();

    if let Some(logical_size) = gl_window.get_inner_size() {
        let physical_size = logical_size.to_physical(gl_window.get_hidpi_factor());
        screen_width = physical_size.width as usize;
        screen_height = physical_size.height as usize;
        gl_window.resize(physical_size);
        gl_set_viewport(0, 0, screen_width, screen_height);
    }

    static SIZE: usize = 8_usize;
    let fb_program = GLProgram::new(FB_VERTEX, FB_FRAGMENT);

    let mut fb_texture = GLTexture::new_null_2d(
        screen_width / SIZE,
        screen_height / SIZE,
        InternalFormat::RGBA,
        DataFormat::RGBA,
        DataKind::UnsignedByte,
        FilterMode::None,
        Wrap::Clamp,
        false,
    );

    let fb_framebuffer = GLFramebuffer::new(&fb_texture, &[Attachment::Color(0)], 0);
    let fb_renderbuffer = GLRenderbuffer::new(
        InternalFormat::DepthComponent16,
        Attachment::Depth,
        screen_width / SIZE,
        screen_height / SIZE,
    );

    let mut fb_vertex_array = GLVertexArray::new();

    fb_vertex_array.bind();

    let fb_buffer = GLBuffer::new(BufferTarget::Array, 4, Usage::StaticDraw, &FB_DATA);

    fb_buffer.bind();
    fb_vertex_array.add_attribute(&fb_buffer, fb_program.get_attribute("position"), 0);
    fb_vertex_array.add_attribute(&fb_buffer, fb_program.get_attribute("uv"), 2);

    let cube_program = GLProgram::new(CUBE_VERTEX, CUBE_FRAGMENT);

    let mut cube_vertex_array = GLVertexArray::new();

    cube_vertex_array.bind();

    let cube_buffer = GLBuffer::new(BufferTarget::Array, 8, Usage::StaticDraw, &CUBE_DATA);
    let cube_index_buffer = GLBuffer::new(
        BufferTarget::ElementArray,
        0,
        Usage::StaticDraw,
        &CUBE_INDEX_DATA,
    );

    cube_buffer.bind();
    cube_vertex_array.add_attribute(&cube_buffer, cube_program.get_attribute("position"), 0);
    cube_vertex_array.add_attribute(&cube_buffer, cube_program.get_attribute("normal"), 3);
    cube_vertex_array.add_attribute(&cube_buffer, cube_program.get_attribute("uv"), 5);
    cube_index_buffer.bind();

    let fov = 45_f32 * (f32::consts::PI / 180_f32);
    //let ortho_size: f32 = 2_f32;

    let origin = vec3::new(0_f32, 0_f32, 0_f32);
    let up = vec3::new(0_f32, 0_f32, 1_f32);

    let mut camera = mat4::new_identity::<f32>();
    let mut camera_position = vec3::new(6_f32, 6_f32, 4_f32);
    let mut light_position = vec3::new(2_f32, 2_f32, 2_f32);

    let mut projection = mat4::new_identity::<f32>();
    mat4::perspective(
        &mut projection,
        &fov,
        &(screen_width as f32 / screen_height as f32),
        &0.0001_f32,
        &1024_f32,
    );

    let mut model_view = mat4::new_identity::<f32>();

    main_loop::glutin::run(&mut events_loop, move |events, ms_f64| {
        let ms = ms_f64 as f32;

        for event in events {
            match event {
                glutin::Event::WindowEvent {
                    event: glutin::WindowEvent::CloseRequested,
                    ..
                } => {
                    return main_loop::ControlFlow::Break;
                }
                glutin::Event::WindowEvent {
                    event: glutin::WindowEvent::Resized(logical_size),
                    ..
                } => {
                    let physical_size = logical_size.to_physical(gl_window.get_hidpi_factor());

                    gl_window.resize(physical_size);

                    screen_width = physical_size.width as usize;
                    screen_height = physical_size.height as usize;

                    fb_texture.resize_null_2d(screen_width / SIZE, screen_height / SIZE);
                    fb_framebuffer.set(&fb_texture, &[Attachment::Color(0)], 0);
                    fb_renderbuffer.set(
                        InternalFormat::DepthComponent16,
                        Attachment::Depth,
                        screen_width / SIZE,
                        screen_height / SIZE,
                    );
                    /*
                    let aspect = w as f32 / h as f32;
                    let r = ortho_size * aspect;
                    let l = -r;
                    let t = ortho_size;
                    let b = -t;
                    mat4::orthographic(&mut projection, t, r, b, l, 0.0001_f32, 1024_f32);
                    */
                    mat4::perspective(
                        &mut projection,
                        &fov,
                        &(screen_width as f32 / screen_height as f32),
                        &0.0001_f32,
                        &1024_f32,
                    );
                }
                _ => (),
            }
        }

        light_position[0] = (ms * 0.001f32).sin() * 6_f32;
        light_position[1] = (ms * 0.001f32).cos() * 6_f32;
        light_position[2] = (ms * 0.001f32).sin() * 6_f32;

        camera_position[0] = (ms * 0.001f32).sin() * 6_f32;
        camera_position[1] = (ms * 0.001f32).cos() * 6_f32;
        camera_position[2] = 3.5_f32 + ((ms * 0.001f32).sin() * 3_f32);

        mat4::look_at(&mut camera, &camera_position, &origin, &up);
        mat4::set_position(&mut camera, &camera_position);
        mat4::inv(&mut model_view, &camera);

        fb_framebuffer.bind();
        fb_renderbuffer.bind();

        gl_set_viewport(0, 0, screen_width / SIZE, screen_height / SIZE);
        gl_set_clear_color(&[0.3, 0.3, 0.3, 1.0]);
        gl_clear(true, true, true);

        cube_program.bind();

        cube_vertex_array.bind();
        cube_vertex_array.enable_attributes();

        cube_program
            .get_uniform("projection")
            .set_mat4f(&projection);
        cube_program
            .get_uniform("model_view")
            .set_mat4f(&model_view);
        cube_program.get_uniform("light").set_3f(&light_position);

        gl_draw_elements(DrawMode::Triangles, 36, IndexKind::UnsignedShort, 0);

        fb_framebuffer.unbind();
        fb_renderbuffer.unbind();

        gl_set_viewport(0, 0, screen_width, screen_height);
        gl_set_clear_color(&[0.3, 0.3, 0.3, 1.0]);
        gl_clear(true, true, true);

        fb_program.bind();
        fb_vertex_array.bind();
        fb_vertex_array.enable_attributes();

        fb_program
            .get_uniform("diffuse")
            .set_sampler_2d(&fb_texture, 0);

        gl_draw_arrays(DrawMode::TriangleStrip, 0, 4);
        gl_window.swap_buffers().unwrap();

        main_loop::ControlFlow::Continue
    });
}