//! Traits for describing Cyborg's scene representation.
//!
//! TODO this will all need to be replaced in favor of a way to represent
//! querying component and resource data framework-agnostically

use crate::storage::mesh::MeshHandle;

#[derive(Clone, Debug)]
pub struct Transform {
    pub transform: glam::Mat4,
}

#[derive(Clone, Debug)]
pub struct Mesh {
    pub mesh: MeshHandle,
}

#[repr(C)]
#[derive(Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]
pub struct DebugVertex {
    pub position: [f32; 3],
    pub color: [f32; 3],
}

pub const DEBUG_VERTEX_ATTRS: &[wgpu::VertexAttribute] =
    &wgpu::vertex_attr_array![0 => Float32x3, 1 => Float32x3];

impl DebugVertex {
    pub fn desc() -> wgpu::VertexBufferLayout<'static> {
        wgpu::VertexBufferLayout {
            array_stride: std::mem::size_of::<Self>() as wgpu::BufferAddress,
            step_mode: wgpu::VertexStepMode::Vertex,
            attributes: DEBUG_VERTEX_ATTRS,
        }
    }
}

pub type DebugIndex = u32;

#[derive(Clone, Default)]
pub struct DebugDrawList {
    pub vertices: Vec<DebugVertex>,
    pub indices: Vec<DebugIndex>,
}

impl DebugDrawList {
    pub fn clear(&mut self) {
        self.vertices.clear();
        self.indices.clear();
    }

    pub fn merge(&mut self, other: &Self) {
        self.vertices.extend_from_slice(&other.vertices);

        let is_offset = self.indices.len();
        self.indices.reserve(is_offset + other.indices.len());

        for index in other.indices.iter() {
            if *index < (other.vertices.len() as DebugIndex) {
                self.indices.push(index + is_offset as DebugIndex);
            }
        }
    }
}