lyra-engine/lyra-ecs/src/bundle.rs

use std::{any::{TypeId, Any}, ptr::NonNull, mem::size_of};

use crate::{component::Component, component_info::ComponentInfo, DynTypeId};

pub trait Bundle {
    /// Get a list of type ids that this bundle is storing
    fn type_ids(&self) -> Vec<DynTypeId>;

    /// Get ComponentInfo's for the components in this bundle
    fn info(&self) -> Vec<ComponentInfo>;

    /// Take the bundle by calling the closure with pointers to each component, its type and size.
    /// The closure is expected to take ownership of the pointer.
    fn take(self, f: impl FnMut(NonNull<u8>, DynTypeId, usize));
}

// The macro below can implement this for us, but this is here for development
impl<C1: Component> Bundle for (C1,) {
    fn type_ids(&self) -> Vec<DynTypeId> {
        vec![DynTypeId::of::<C1>()]
    }

    fn info(&self) -> Vec<ComponentInfo> {
        vec![ComponentInfo::new::<C1>()]
    }

    fn take(self, mut f: impl FnMut(NonNull<u8>, DynTypeId, usize)) {
        let (c1, ) = self;

        f(NonNull::from(&c1).cast(), DynTypeId::of::<C1>(), size_of::<C1>());
    }
}

macro_rules! impl_bundle_tuple {
    ( $($name: ident),+ ) => (
        #[allow(non_snake_case)]
        impl<$($name: Component),+> Bundle for ($($name,)+) {
            fn type_ids(&self) -> Vec<DynTypeId> {
                // these names wont follow rust convention, but its a macro so deal with it
                let ($($name),+) = self;
                vec![$(DynTypeId::of::<$name>()),+]
            }

            fn info(&self) -> Vec<ComponentInfo> {
                vec![$(ComponentInfo::new::<$name>()),+]
            }

            fn take(self, mut f: impl FnMut(NonNull<u8>, DynTypeId, usize)) {
                // these names wont follow rust convention, but its a macro so deal with it
                let ($($name),+) = self;

                $(f(NonNull::from(&$name).cast(), DynTypeId::of::<$name>(), size_of::<$name>());)+
            }
        }
    );
}

// hopefully 16 components in a bundle is enough
impl_bundle_tuple! { C1, C2 }
impl_bundle_tuple! { C1, C2, C3 }
impl_bundle_tuple! { C1, C2, C3, C4 }
impl_bundle_tuple! { C1, C2, C3, C4, C5 }
impl_bundle_tuple! { C1, C2, C3, C4, C5, C6 }
impl_bundle_tuple! { C1, C2, C3, C4, C5, C6, C7 }
impl_bundle_tuple! { C1, C2, C3, C4, C5, C6, C7, C8 }
impl_bundle_tuple! { C1, C2, C3, C4, C5, C6, C7, C8, C9 }
impl_bundle_tuple! { C1, C2, C3, C4, C5, C6, C7, C8, C9, C10 }
impl_bundle_tuple! { C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11 }
impl_bundle_tuple! { C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12 }
impl_bundle_tuple! { C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13 }
impl_bundle_tuple! { C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14 }
impl_bundle_tuple! { C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15 }
impl_bundle_tuple! { C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16 }

/// A bundle of components 
#[derive(Default)]
pub struct DynamicBundle {
    bundle: Vec<(NonNull<u8>, ComponentInfo)>,
}

impl DynamicBundle {
    pub fn new() -> Self {
        Self::default()
    }

    /// Push a type known to rust to this bundle
    pub fn push<C>(&mut self, comp: C)
    where
        C: Component
    {
        let info = ComponentInfo::new::<C>();
        let data = NonNull::from(&comp).cast::<u8>();

        self.bundle.push((data, info));
    }

    /// Push an unknown type to the bundle
    pub fn push_unknown(&mut self, data: NonNull<u8>, info: ComponentInfo) {
        self.bundle.push((data, info));
    }
}

impl Bundle for DynamicBundle {
    fn type_ids(&self) -> Vec<DynTypeId> {
        self.bundle.iter().map(|b| b.1.type_id).collect()
    }

    fn info(&self) -> Vec<ComponentInfo> {
        self.bundle.iter().map(|b| b.1.clone()).collect()
    }

    fn take(self, mut f: impl FnMut(NonNull<u8>, DynTypeId, usize)) {
        for (data, info) in self.bundle.iter() {
            f(data.clone(), info.type_id, info.layout.size);
        }
    }
}