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use intuicio_core::{IntuicioStruct, registry::Registry};
use intuicio_derive::*;
use serde::{Deserialize, Serialize};
/// Represents an entity with a unique `id` and a `generation` to track lifecycle and version.
#[derive(
IntuicioStruct, Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize,
)]
#[intuicio(module_name = "ecs_entity")]
pub struct Entity {
#[intuicio(ignore)]
pub(crate) id: u32,
#[intuicio(ignore)]
pub(crate) generation: u32,
}
impl Default for Entity {
fn default() -> Self {
Self::INVALID
}
}
#[intuicio_methods(module_name = "ecs_entity")]
impl Entity {
/// A constant representing an invalid `Entity`, which is the result of an invalid `id`.
pub const INVALID: Self = unsafe { Self::new_unchecked(u32::MAX, 0) };
/// Creates a new `Entity` with the specified `id` and `generation` if the `id` is valid.
/// Returns `None` if the `id` is invalid (e.g., equals `u32::MAX`).
pub const fn new(id: u32, generation: u32) -> Option<Self> {
if id < u32::MAX {
Some(Self { id, generation })
} else {
None
}
}
/// # Safety
///
/// This method is unsafe because it bypasses the validity check for `id` and `generation`.
/// It's the caller's responsibility to ensure the `id` and `generation` are appropriate,
/// as an invalid `id` (such as `u32::MAX`) could cause undefined behavior in the ECS system.
pub const unsafe fn new_unchecked(id: u32, generation: u32) -> Self {
Self { id, generation }
}
/// Returns `true` if the `Entity` is valid, meaning the `id` is not equal to `u32::MAX`.
#[intuicio_method()]
pub const fn is_valid(self) -> bool {
self.id < u32::MAX
}
/// Returns the `id` of the `Entity`.
#[intuicio_method()]
pub const fn id(self) -> u32 {
self.id
}
/// Returns the `generation` of the `Entity`.
#[intuicio_method()]
pub const fn generation(self) -> u32 {
self.generation
}
/// Converts the `Entity` into a `u64` representation combining the `generation` and `id`.
#[intuicio_method()]
pub const fn to_u64(self) -> u64 {
((self.generation as u64) << 32) | self.id as u64
}
/// Converts a `u64` value back into an `Entity`, decoding the `generation` and `id`.
#[intuicio_method()]
pub const fn from_u64(value: u64) -> Self {
Self {
generation: (value >> 32) as u32,
id: value as u32,
}
}
/// Increments the `generation` of the `Entity`. This method is typically used when an entity
/// is reused or updated to prevent conflicts.
pub(crate) const fn bump_generation(mut self) -> Self {
self.generation = self.generation.wrapping_add(1);
self
}
}
impl std::fmt::Display for Entity {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
if self.is_valid() {
write!(f, "@{}:#{}", self.id, self.generation)
} else {
write!(f, "@none:#{}", self.generation)
}
}
}
impl Entity {
/// Registers the `Entity` type and its associated methods in the given registry.
pub fn install(registry: &mut Registry) {
registry.add_type(Self::define_struct(registry));
registry.add_function(Self::is_valid__define_function(registry));
registry.add_function(Self::id__define_function(registry));
registry.add_function(Self::generation__define_function(registry));
registry.add_function(Self::to_u64__define_function(registry));
registry.add_function(Self::from_u64__define_function(registry));
}
}
/// A structure to store entities in a dense array.
#[derive(Debug, Default, Clone, PartialEq, Eq)]
pub struct EntityDenseMap {
inner: Vec<Entity>,
}
impl EntityDenseMap {
/// Creates a new `EntityDenseMap` with the specified initial capacity, ensuring it is a power of two.
pub fn with_capacity(mut capacity: usize) -> Self {
capacity = capacity.next_power_of_two().max(1);
Self {
inner: Vec::with_capacity(capacity),
}
}
/// Tells if there are no eentities stored.
pub fn is_empty(&self) -> bool {
self.inner.is_empty()
}
/// Returns number of entities stored.
pub fn len(&self) -> usize {
self.inner.len()
}
/// Clears the map, removing all entities from it.
pub fn clear(&mut self) {
self.inner.clear();
}
/// Inserts a new entity into the map.
/// Returns `Err(index)` if the entity already exists, otherwise `Ok(index)` with the insertion index.
pub fn insert(&mut self, entity: Entity) -> Result<usize, usize> {
if let Some(index) = self.index_of(entity) {
Err(index)
} else {
if self.inner.len() == self.inner.capacity() {
self.inner.reserve_exact(self.inner.capacity());
}
let index = self.inner.len();
self.inner.push(entity);
Ok(index)
}
}
/// Removes an entity from the map and returns its index if it was found.
pub fn remove(&mut self, entity: Entity) -> Option<usize> {
let index = self.index_of(entity)?;
self.inner.swap_remove(index);
if self.inner.len() == self.inner.capacity() / 2 {
self.inner.shrink_to_fit();
}
Some(index)
}
/// Checks whether the specified entity is present in the map.
pub fn contains(&self, entity: Entity) -> bool {
self.inner.contains(&entity)
}
/// Finds the index of the specified entity in the map.
pub fn index_of(&self, entity: Entity) -> Option<usize> {
self.inner.iter().position(|e| *e == entity)
}
/// Retrieves the entity at the given index if available.
pub fn get(&self, index: usize) -> Option<Entity> {
self.inner.get(index).copied()
}
/// Returns an iterator over the entities in the map.
pub fn iter(&self) -> impl Iterator<Item = Entity> + '_ {
self.inner.iter().copied()
}
/// Returns slice to all entities.
pub fn entities(&self) -> &[Entity] {
&self.inner
}
}