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use crate::create_instance_manager;
use async_trait::async_trait;
use core::future::Future;
use rustc_hash::FxHashMap;
use rustc_hash::FxHashSet;
use std::any::{type_name, Any, TypeId};
use std::fmt::Debug;
use std::sync::Arc;
use tokio::sync::RwLock;
pub type EventResult<E> = miette::Result<EventState<<E as Event>::Value>>;
pub trait Event: Send + Sync {
type Value;
}
pub enum EventState<V> {
Continue,
Stop,
Return(V),
}
#[async_trait]
pub trait Listener<E: Event>: Debug + Send + Sync {
fn is_once(&self) -> bool;
async fn on_emit(&mut self, event: &mut E) -> EventResult<E>;
}
pub type BoxedListener<E> = Box<dyn Listener<E>>;
#[async_trait]
pub trait ListenerFunc<E: Event>: Send + Sync {
async fn call(&self, event: &mut E) -> EventResult<E>;
}
#[async_trait]
impl<T: Send + Sync, F, E: Event> ListenerFunc<E> for T
where
T: Fn(&mut E) -> F,
F: Future<Output = EventResult<E>> + Send + 'static,
{
async fn call(&self, event: &mut E) -> EventResult<E> {
self(event).await
}
}
pub struct CallbackListener<E: Event> {
func: Box<dyn ListenerFunc<E>>,
once: bool,
}
#[async_trait]
impl<E: Event> Listener<E> for CallbackListener<E> {
fn is_once(&self) -> bool {
self.once
}
async fn on_emit(&mut self, event: &mut E) -> EventResult<E> {
self.func.call(event).await
}
}
impl<E: Event> Debug for CallbackListener<E> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct(if self.once {
"CallbackListener(once)"
} else {
"CallbackListener"
})
.finish()
}
}
#[derive(Debug, Default)]
pub struct Emitter<E: Event> {
pub listeners: Vec<BoxedListener<E>>,
}
impl<E: Event + 'static> Emitter<E> {
pub fn new() -> Self {
Emitter {
listeners: Vec::new(),
}
}
pub fn listen<L: Listener<E> + 'static>(&mut self, listener: L) -> &mut Self {
self.listeners.push(Box::new(listener));
self
}
pub fn on<L: ListenerFunc<E> + 'static>(&mut self, callback: L) -> &mut Self {
self.listeners.push(Box::new(CallbackListener {
func: Box::new(callback),
once: false,
}));
self
}
pub fn once<L: ListenerFunc<E> + 'static>(&mut self, callback: L) -> &mut Self {
self.listeners.push(Box::new(CallbackListener {
func: Box::new(callback),
once: true,
}));
self
}
pub async fn emit(&mut self, mut event: E) -> miette::Result<(E, Option<E::Value>)> {
let mut result = None;
let mut remove_indices = FxHashSet::default();
for (index, listener) in self.listeners.iter_mut().enumerate() {
if listener.is_once() {
remove_indices.insert(index);
}
match listener.on_emit(&mut event).await? {
EventState::Continue => continue,
EventState::Stop => break,
EventState::Return(value) => {
result = Some(value);
break;
}
}
}
let mut i = 0;
self.listeners.retain(|_| {
let remove = remove_indices.contains(&i);
i += 1;
!remove
});
Ok((event, result))
}
}
create_instance_manager!(EmitterManager, EmitterInstance);
impl EmitterManager {
pub async fn emit<E: Event + 'static>(
&mut self,
event: E,
) -> miette::Result<(E, Option<E::Value>)> {
self.get_mut::<Emitter<E>>().emit(event).await
}
}
impl<E: Event + 'static> EmitterInstance for Emitter<E> {}
pub type Emitters = Arc<RwLock<EmitterManager>>;