Pathfinder (#25)

Pathfinding is very much not done, but it works enough and I want to get this merged.
TODO: fast replanning, goals that aren't a single node, falling moves (it should be able to play the dropper), parkour moves

1 files changed, 78 insertions, 0 deletions

diff --git a/azalea-client/src/plugins.rs b/azalea-client/src/plugins.rs
new file mode 100644
index 00000000..1a3aa049
--- /dev/null
+++ b/azalea-client/src/plugins.rs
@@ -0,0 +1,78 @@
+use crate::{Client, Event};
+use async_trait::async_trait;
+use nohash_hasher::NoHashHasher;
+use std::{
+    any::{Any, TypeId},
+    collections::HashMap,
+    hash::BuildHasherDefault,
+};
+
+// kind of based on https://docs.rs/http/latest/src/http/extensions.rs.html
+/// A map of plugin ids to Plugin trait objects. The client stores this so we
+/// can keep the state for our plugins.
+///
+/// If you're using azalea, you should generate this from the `plugins!` macro.
+#[derive(Clone)]
+pub struct Plugins {
+    map: Option<HashMap<TypeId, Box<dyn Plugin>, BuildHasherDefault<NoHashHasher<u64>>>>,
+}
+
+impl Plugins {
+    pub fn new() -> Self {
+        Self { map: None }
+    }
+
+    pub fn add<T: Plugin>(&mut self, plugin: T) {
+        if self.map.is_none() {
+            self.map = Some(HashMap::with_hasher(BuildHasherDefault::default()));
+        }
+        self.map
+            .as_mut()
+            .unwrap()
+            .insert(TypeId::of::<T>(), Box::new(plugin));
+    }
+
+    pub fn get<T: Plugin>(&self) -> Option<&T> {
+        self.map
+            .as_ref()
+            .and_then(|map| map.get(&TypeId::of::<T>()))
+            .and_then(|boxed| (boxed.as_ref() as &dyn Any).downcast_ref::<T>())
+    }
+}
+
+impl IntoIterator for Plugins {
+    type Item = Box<dyn Plugin>;
+    type IntoIter = std::vec::IntoIter<Self::Item>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.map
+            .map(|map| map.into_iter().map(|(_, v)| v).collect::<Vec<_>>())
+            .unwrap_or_default()
+            .into_iter()
+    }
+}
+
+/// Plugins can keep their own personal state, listen to events, and add new functions to Client.
+#[async_trait]
+pub trait Plugin: Send + Sync + PluginClone + Any + 'static {
+    async fn handle(self: Box<Self>, event: Event, bot: Client);
+}
+
+/// An internal trait that allows Plugin to be cloned.
+#[doc(hidden)]
+pub trait PluginClone {
+    fn clone_box(&self) -> Box<dyn Plugin>;
+}
+impl<T> PluginClone for T
+where
+    T: 'static + Plugin + Clone,
+{
+    fn clone_box(&self) -> Box<dyn Plugin> {
+        Box::new(self.clone())
+    }
+}
+impl Clone for Box<dyn Plugin> {
+    fn clone(&self) -> Self {
+        self.clone_box()
+    }
+}