Add process event bus to backtest engine

crates/fidc-core/src/event_bus.rs

@@ -0,0 +1,55 @@
+use std::collections::BTreeMap;
+
+use crate::events::{ProcessEvent, ProcessEventKind};
+
+type ProcessEventListener = Box<dyn FnMut(&ProcessEvent)>;
+
+#[derive(Default)]
+pub struct ProcessEventBus {
+    listeners: BTreeMap<ProcessEventKind, Vec<ProcessEventListener>>,
+    any_listeners: Vec<ProcessEventListener>,
+}
+
+impl ProcessEventBus {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    pub fn add_listener<F>(&mut self, kind: ProcessEventKind, listener: F)
+    where
+        F: FnMut(&ProcessEvent) + 'static,
+    {
+        self.listeners
+            .entry(kind)
+            .or_default()
+            .push(Box::new(listener));
+    }
+
+    pub fn prepend_listener<F>(&mut self, kind: ProcessEventKind, listener: F)
+    where
+        F: FnMut(&ProcessEvent) + 'static,
+    {
+        self.listeners
+            .entry(kind)
+            .or_default()
+            .insert(0, Box::new(listener));
+    }
+
+    pub fn add_any_listener<F>(&mut self, listener: F)
+    where
+        F: FnMut(&ProcessEvent) + 'static,
+    {
+        self.any_listeners.push(Box::new(listener));
+    }
+
+    pub fn publish(&mut self, event: &ProcessEvent) {
+        if let Some(listeners) = self.listeners.get_mut(&event.kind) {
+            for listener in listeners {
+                listener(event);
+            }
+        }
+        for listener in &mut self.any_listeners {
+            listener(event);
+        }
+    }
+}