feat: add event listeners

src/lua/events.rs

@@ -0,0 +1,79 @@
+use crate::State;
+use futures::executor::block_on;
+use mlua::{Function, Lua, Result, Table};
+use std::time::{SystemTime, UNIX_EPOCH};
+
+pub async fn register_functions(lua: &Lua, globals: &Table, state: State) -> Result<()> {
+    let l = state.event_listeners.clone();
+    globals.set(
+        "add_listener",
+        lua.create_function(
+            move |_, (event_type, callback, id): (String, Function, Option<String>)| {
+                let mut l = block_on(l.lock());
+
+                l.entry(event_type).or_default().push((
+                    id.unwrap_or(callback.info().name.unwrap_or(format!(
+                            "anonymous @ {}",
+                            SystemTime::now()
+                                .duration_since(UNIX_EPOCH)
+                                .unwrap_or_default()
+                                .as_millis()
+                        ))),
+                    callback,
+                ));
+                Ok(())
+            },
+        )?,
+    )?;
+
+    let l = state.event_listeners.clone();
+    globals.set(
+        "remove_listener",
+        lua.create_function(move |_, (event_type, target_id): (String, String)| {
+            let mut l = block_on(l.lock());
+
+            let empty = if let Some(listeners) = l.get_mut(&event_type) {
+                listeners.retain(|(id, _)| target_id != *id);
+                listeners.is_empty()
+            } else {
+                false
+            };
+            if empty {
+                l.remove(&event_type);
+            }
+
+            Ok(())
+        })?,
+    )?;
+
+    globals.set(
+        "get_listeners",
+        lua.create_function(move |lua, (): ()| {
+            let l = block_on(state.event_listeners.lock());
+
+            let listeners = lua.create_table()?;
+            for (event_type, callbacks) in l.iter() {
+                let type_listeners = lua.create_table()?;
+                for (id, callback) in callbacks {
+                    let listener = lua.create_table()?;
+                    let i = callback.info();
+                    if let Some(n) = i.name {
+                        listener.set("name", n)?;
+                    }
+                    if let Some(l) = i.line_defined {
+                        listener.set("line_defined", l)?;
+                    }
+                    if let Some(s) = i.source {
+                        listener.set("source", s)?;
+                    }
+                    type_listeners.set(id.to_owned(), listener)?;
+                }
+                listeners.set(event_type.to_owned(), type_listeners)?;
+            }
+
+            Ok(listeners)
+        })?,
+    )?;
+
+    Ok(())
+}