use macroquad::prelude::{self as mq, UniformDesc};

#[macroquad::main("Normal Shading")]
async fn main() {
    let vertex = include_str!("shader.vert");
    let fragment = include_str!("shader.frag");

    let material = mq::load_material(
        mq::ShaderSource::Glsl { vertex, fragment },
        mq::MaterialParams {
            pipeline_params: mq::PipelineParams {
                depth_test: mq::Comparison::LessOrEqual,
                depth_write: true,
                ..Default::default()
            },
            uniforms: vec![UniformDesc::new(
                "render_normals_bool",
                mq::UniformType::Int1,
            )],
            ..Default::default()
        },
    )
    .unwrap();
    material.set_uniform("render_normals_bool", 1);

    loop {
        mq::clear_background(mq::GRAY);
        mq::set_camera(&mq::Camera3D {
            position: mq::vec3(4.0, 4.0, 4.0),
            target: mq::vec3(0.0, 0.0, 0.0),
            up: mq::vec3(0.0, 1.0, 0.0),
            ..Default::default()
        });

        mq::gl_use_material(&material);

        draw_cuboid(mq::vec3(3.0, 0.0, 0.0), mq::vec3(1.0, 2.0, 3.0), mq::RED);

        mq::gl_use_default_material();
        mq::set_default_camera();
        mq::next_frame().await;
    }
}

pub fn generate_normals_smooth(vertexes: &mut Vec<mq::Vertex>, indices: &[u16]) {
    for v in vertexes.iter_mut() {
        v.normal = mq::vec4(0.0, 0.0, 0.0, 0.0);
    }

    for i in 0..(indices.len() / 3) {
        let idx0 = indices[i * 3 + 0] as usize;
        let idx1 = indices[i * 3 + 1] as usize;
        let idx2 = indices[i * 3 + 2] as usize;

        let pos0 = vertexes[idx0].position;
        let pos1 = vertexes[idx1].position;
        let pos2 = vertexes[idx2].position;

        let side1 = pos1 - pos0;
        let side2 = pos2 - pos0;
        let normal = side1.cross(side2);

        let normal_vec4 = mq::vec4(normal.x, normal.y, normal.z, 0.0);

        vertexes[idx0].normal = vertexes[idx0].normal + normal_vec4;
        vertexes[idx1].normal = vertexes[idx1].normal + normal_vec4;
        vertexes[idx2].normal = vertexes[idx2].normal + normal_vec4;
    }

    for v in vertexes.iter_mut() {
        v.normal.z = 0.0;
        let normalized = v.normal.normalize();
        v.normal = normalized;
    }
}
pub fn draw_cuboid(center: mq::Vec3, size: mq::Vec3, color: mq::Color) {
    use mq::{Vec2, Vec3, Vertex};
    let hs = size * 0.5;
    let mut positions = [
        Vec3::new(-hs.x, -hs.y, -hs.z),
        Vec3::new(hs.x, -hs.y, -hs.z),
        Vec3::new(hs.x, hs.y, -hs.z),
        Vec3::new(-hs.x, hs.y, -hs.z),
        Vec3::new(-hs.x, -hs.y, hs.z),
        Vec3::new(hs.x, -hs.y, hs.z),
        Vec3::new(hs.x, hs.y, hs.z),
        Vec3::new(-hs.x, hs.y, hs.z),
    ];
    for i in 0..positions.len() {
        positions[i] += center;
    }

    let faces = [
        ([0, 1, 2, 3], Vec3::new(0.0, 0.0, -1.0)), // Back
        ([5, 4, 7, 6], Vec3::new(0.0, 0.0, 1.0)),  // Front
        ([4, 0, 3, 7], Vec3::new(-1.0, 0.0, 0.0)), // Left
        ([1, 5, 6, 2], Vec3::new(1.0, 0.0, 0.0)),  // Right
        ([3, 2, 6, 7], Vec3::new(0.0, 1.0, 0.0)),  // Up
        ([4, 5, 1, 0], Vec3::new(0.0, -1.0, 0.0)), // Down
    ];

    let uvs = [
        Vec2::new(0.0, 0.0),
        Vec2::new(1.0, 0.0),
        Vec2::new(1.0, 1.0),
        Vec2::new(0.0, 1.0),
    ];

    let mut vertices = [Vertex {
        position: mq::Vec3::ZERO,
        uv: mq::Vec2::ZERO,
        color: color.into(),
        normal: mq::Vec4::ZERO,
    }; 24];

    let mut vi = 0;
    for (face, normal) in faces.iter() {
        for (j, &corner) in face.iter().enumerate() {
            let pos = positions[corner];
            vertices[vi] = Vertex {
                position: mq::vec3(pos.x, pos.y, pos.z),
                uv: mq::vec2(uvs[j].x, uvs[j].y),
                color: color.into(),
                normal: mq::vec4(normal.x, normal.y, normal.z, 0.0),
            };
            vi += 1;
        }
    }

    let mut indices = [0u16; 36];
    for i in 0..6 {
        let base = (i * 4) as u16;
        let offset = i * 6;
        indices[offset + 0] = base;
        indices[offset + 1] = base + 1;
        indices[offset + 2] = base + 2;
        indices[offset + 3] = base;
        indices[offset + 4] = base + 2;
        indices[offset + 5] = base + 3;
    }
    generate_normals_smooth(&mut vertices.into(), &indices);

    unsafe {
        mq::get_internal_gl()
            .quad_gl
            .draw_mode(mq::DrawMode::Triangles);
        mq::get_internal_gl().quad_gl.geometry(&vertices, &indices);
    }
}