#[macro_use]
extern crate glium;
use glium::Surface;

#[path = "../book/tuto-07-teapot.rs"]
mod teapot;

fn main() {
    let event_loop = glium::winit::event_loop::EventLoop::builder()
        .build()
        .expect("event loop building");
    let (window, display) = glium::backend::glutin::SimpleWindowBuilder::new()
        .with_title("Glium tutorial #9")
        .build(&event_loop);

    let positions = glium::VertexBuffer::new(&display, &teapot::VERTICES).unwrap();
    let normals = glium::VertexBuffer::new(&display, &teapot::NORMALS).unwrap();
    let indices = glium::IndexBuffer::new(&display, glium::index::PrimitiveType::TrianglesList,
                                        &teapot::INDICES).unwrap();

    let vertex_shader_src = r#"
        #version 150

        in vec3 position;
        in vec3 normal;

        out vec3 v_normal;

        uniform mat4 matrix;

        void main() {
            v_normal = transpose(inverse(mat3(matrix))) * normal;
            gl_Position = matrix * vec4(position, 1.0);
        }
    "#;

    let fragment_shader_src = r#"
        #version 150

        in vec3 v_normal;
        out vec4 color;
        uniform vec3 u_light;

        void main() {
            float brightness = dot(normalize(v_normal), normalize(u_light));
            vec3 dark_color = vec3(0.6, 0.0, 0.0);
            vec3 regular_color = vec3(1.0, 0.0, 0.0);
            color = vec4(mix(dark_color, regular_color, brightness), 1.0);
        }
    "#;

    let program = glium::Program::from_source(&display, vertex_shader_src, fragment_shader_src,
                                            None).unwrap();

    #[allow(deprecated)]
    event_loop.run(move |ev, window_target| {
        match ev {
            glium::winit::event::Event::WindowEvent { event, .. } => match event {
                glium::winit::event::WindowEvent::CloseRequested => {
                    window_target.exit();
                },
                // We now need to render everyting in response to a RedrawRequested event due to the animation
                glium::winit::event::WindowEvent::RedrawRequested => {
                    let mut target = display.draw();
                    target.clear_color_and_depth((0.0, 0.0, 1.0, 1.0), 1.0);

                    let matrix = [
                        [0.01, 0.0, 0.0, 0.0],
                        [0.0, 0.01, 0.0, 0.0],
                        [0.0, 0.0, 0.01, 0.0],
                        [0.0, 0.0, 0.0, 1.0f32]
                    ];

                    let light = [-1.0, 0.4, 0.9f32];

                    let params = glium::DrawParameters {
                        depth: glium::Depth {
                            test: glium::draw_parameters::DepthTest::IfLess,
                            write: true,
                            .. Default::default()
                        },
                        .. Default::default()
                    };

                    target.draw((&positions, &normals), &indices, &program,
                                &uniform! { matrix: matrix, u_light: light }, &params).unwrap();
                    target.finish().unwrap();
                },
                // Because glium doesn't know about windows we need to resize the display
                // when the window's size has changed.
                glium::winit::event::WindowEvent::Resized(window_size) => {
                    display.resize(window_size.into());
                },
                _ => (),
            },
            // By requesting a redraw in response to a AboutToWait event we get continuous rendering.
            // For applications that only change due to user input you could remove this handler.
            glium::winit::event::Event::AboutToWait => {
                window.request_redraw();
            },
            _ => (),
        }
    })
    .unwrap();
}