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use crate::entity::EntityId;
use crate::event_bus::Event;
use std::any::{Any, TypeId};
/// Macro for defining events with automatic Event trait implementation
#[macro_export]
macro_rules! define_event {
// Struct with fields and optional validation
(
$(#[$meta:meta])*
$vis:vis struct $name:ident {
$($field:ident : $ty:ty),* $(,)?
}
$(validate($this:ident) $validate_body:block)?
) => {
$(#[$meta])*
#[derive(Clone, Debug)]
$vis struct $name {
$(pub $field : $ty),*
}
impl Event for $name {
fn event_type_id(&self) -> TypeId {
TypeId::of::<Self>()
}
fn as_any(&self) -> &dyn Any {
self
}
fn event_name(&self) -> &str {
stringify!($name)
}
fn validate(&self) -> $crate::error::Result<()> {
$(
let $this = self;
return $validate_body;
)?
#[allow(unreachable_code)]
Ok(())
}
}
};
// Unit struct (no fields)
(
$(#[$meta:meta])*
$vis:vis struct $name:ident;
) => {
$(#[$meta])*
#[derive(Clone, Debug)]
$vis struct $name;
impl Event for $name {
fn event_type_id(&self) -> TypeId {
TypeId::of::<Self>()
}
fn as_any(&self) -> &dyn Any {
self
}
fn event_name(&self) -> &str {
stringify!($name)
}
}
};
}
// Game State Enum (not an event itself, but data for one)
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum GameState {
Playing,
Paused,
Menu,
GameOver,
}
// ==================================================================================
// Event Definitions
// ==================================================================================
define_event! {
/// Player took damage
pub struct PlayerDamaged {
entity: EntityId,
damage: f32,
source: String,
}
validate(ev) {
if ev.damage < 0.0 {
return Err(crate::error::EcsError::ValidationError(
"Damage cannot be negative".into(),
));
}
Ok(())
}
}
define_event! {
/// Enemy defeated
pub struct EnemyDefeated {
entity: EntityId,
reward: u32,
}
}
define_event! {
/// Player level up
pub struct PlayerLevelUp {
entity: EntityId,
new_level: u32,
}
}
define_event! {
/// Game state changed
pub struct GameStateChanged {
old_state: GameState,
new_state: GameState,
}
}
// Manual definition for InputAction because of complex new() method and specific field types
// The macro doesn't support custom impl blocks easily alongside the definition without more complexity.
/// Input action
#[derive(Clone, Debug)]
pub struct InputAction {
pub action: smallvec::SmallVec<[u8; 32]>,
pub value: f32,
}
impl InputAction {
pub fn new(action: &str, value: f32) -> Self {
Self {
action: smallvec::SmallVec::from_slice(action.as_bytes()),
value,
}
}
pub fn action_name(&self) -> &str {
std::str::from_utf8(&self.action).unwrap_or("InvalidUTF8")
}
}
impl Event for InputAction {
fn event_type_id(&self) -> TypeId {
TypeId::of::<Self>()
}
fn as_any(&self) -> &dyn Any {
self
}
fn event_name(&self) -> &str {
"InputAction"
}
fn validate(&self) -> crate::error::Result<()> {
if self.action.is_empty() {
return Err(crate::error::EcsError::ValidationError(
"Action name cannot be empty".into(),
));
}
Ok(())
}
}
define_event! {
/// Inventory item added
pub struct ItemAdded {
entity: EntityId,
item_id: String,
quantity: u32,
}
}
define_event! {
/// Collision occurred
pub struct Collision {
entity_a: EntityId,
entity_b: EntityId,
}
}