Add a brigadier example for use inside a bevy App (#146)

3 files changed, 199 insertions, 1 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 213c405d..28a49690 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -274,6 +274,8 @@ version = "0.10.0"
 dependencies = [
  "azalea-buf",
  "azalea-chat",
+ "bevy_app",
+ "bevy_ecs",
  "parking_lot",
 ]
 
diff --git a/azalea-brigadier/Cargo.toml b/azalea-brigadier/Cargo.toml
index 9f3ea7e7..a2636940 100644
--- a/azalea-brigadier/Cargo.toml
+++ b/azalea-brigadier/Cargo.toml
@@ -8,10 +8,14 @@ version = "0.10.0"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
+[dev-dependencies]
+bevy_app = "0.13.0"
+bevy_ecs = "0.13.0"
+
 [dependencies]
 azalea-buf = { path = "../azalea-buf", version = "0.10.0", optional = true }
 azalea-chat = { path = "../azalea-chat", version = "0.10.0", optional = true }
 parking_lot = "0.12.1"
 
 [features]
-azalea-buf = ["dep:azalea-buf", "dep:azalea-chat"]
+azalea-buf = ["dep:azalea-buf", "dep:azalea-chat", "azalea-chat/azalea-buf"]
diff --git a/azalea-brigadier/tests/bevy_app_usage.rs b/azalea-brigadier/tests/bevy_app_usage.rs
new file mode 100644
index 00000000..1ed1fc99
--- /dev/null
+++ b/azalea-brigadier/tests/bevy_app_usage.rs
@@ -0,0 +1,192 @@
+use std::sync::Arc;
+
+use azalea_brigadier::{
+    arguments::integer_argument_type::integer,
+    builder::{literal_argument_builder::literal, required_argument_builder::argument},
+    command_dispatcher::CommandDispatcher,
+    context::CommandContext,
+};
+use bevy_app::App;
+use bevy_ecs::{
+    component::Component,
+    query::With,
+    system::{Query, Resource, RunSystemOnce},
+    world::{FromWorld, World},
+};
+use parking_lot::Mutex;
+
+#[test]
+fn bevy_app() {
+    let mut app = App::new();
+
+    // Initialize the dispatcher using FromWorld
+    app.init_resource::<DispatchStorage>();
+
+    // Process commands from bevy
+    app.world
+        .run_system_once(DispatchStorage::bevy_process_commands);
+
+    // Verify spawned entities exist after processing commands
+    app.world
+        .run_system_once(DispatchStorage::verify_spawned_entities);
+}
+
+#[derive(Resource)]
+struct DispatchStorage {
+    /// The [`CommandDispatcher`].
+    ///
+    /// Processes incoming commands.
+    dispatch: CommandDispatcher<WorldAccessor>,
+    /// The world accessor.
+    ///
+    /// Allows the dispatcher to query the [`World`].
+    world: WorldAccessor,
+}
+
+/// Implement [`FromWorld`] to initialize the dispatcher.
+///
+/// Allows the dispatcher to query the [`World`]
+/// for generating commands on startup.
+impl FromWorld for DispatchStorage {
+    fn from_world(_: &mut World) -> Self {
+        let mut dispatch = CommandDispatcher::new();
+
+        // Register dispatcher commands
+        {
+            // Register the "spawn_entity" command
+            dispatch
+                .register(literal("spawn_entity").executes(DispatchStorage::command_spawn_entity));
+
+            // Register the "spawn_entity_num" command
+            dispatch.register(literal("spawn_entity_num").then(
+                argument("entities", integer()).executes(DispatchStorage::command_spawn_entity_num),
+            ));
+        }
+
+        Self {
+            dispatch,
+            world: WorldAccessor::empty(),
+        }
+    }
+}
+
+impl DispatchStorage {
+    /// A bevy system called to process commands.
+    fn bevy_process_commands(world: &mut World) {
+        world.resource_scope::<Self, _>(|bevy_world, mut storage| {
+            // NOTE: Initial swap to own bevy's `World`
+            //
+            // This is important, otherwise the dispatcher
+            // will only be able to access it's own empty `World`.
+            storage.world.swap(bevy_world);
+
+            let source = storage.world.clone();
+
+            // Test "spawn_entity"
+            {
+                println!("Testing 'spawn_entity' command");
+                let result = storage.dispatch.execute("spawn_entity", source.clone());
+
+                // Ensure the command was successful
+                assert_eq!(result, Ok(0));
+
+                // Query the World for the spawned entity
+                let mut world = source.lock();
+                let mut query = world.query_filtered::<(), With<SpawnedEntity>>();
+
+                // Ensure only one entity was spawned
+                let count = query.iter(&world).count();
+                println!("Spawned entities: {count}");
+                assert_eq!(count, 1);
+            }
+
+            // Test "spawn_entity_num"
+            {
+                println!("Testing 'spawn_entity_num' command");
+                let result = storage
+                    .dispatch
+                    .execute("spawn_entity_num 3", source.clone());
+
+                // Ensure the command was successful
+                assert_eq!(result, Ok(0));
+
+                // Query the World for spawned entities
+                let mut world = source.lock();
+                let mut query = world.query_filtered::<(), With<SpawnedEntity>>();
+
+                // Ensure three additional entities were spawned
+                let count = query.iter(&world).count();
+                println!("Spawned entities: {count}");
+                assert_eq!(count, 4);
+            }
+
+            // NOTE: Second swap to give bevy's `World` back
+            //
+            // It's even more important to give the `World` back
+            // after commands are executed, otherwise your app
+            // will be stuck with an empty `World`.
+            storage.world.swap(bevy_world);
+        });
+    }
+
+    /// A command called from the dispatcher.
+    ///
+    /// Spawns an entity with the [`SpawnedEntity`] component.
+    fn command_spawn_entity(context: &CommandContext<WorldAccessor>) -> i32 {
+        context.source.lock().spawn(SpawnedEntity);
+
+        0
+    }
+
+    /// A command called from the dispatcher.
+    ///
+    /// Spawns a number of entities with the [`SpawnedEntity`] component.
+    fn command_spawn_entity_num(context: &CommandContext<WorldAccessor>) -> i32 {
+        let num = context.argument("entities").unwrap();
+        let num = *num.downcast_ref::<i32>().unwrap();
+
+        for _ in 0..num {
+            context.source.lock().spawn(SpawnedEntity);
+        }
+
+        0
+    }
+
+    /// A bevy system called to verify four total entities was spawned.
+    fn verify_spawned_entities(query: Query<(), With<SpawnedEntity>>) {
+        assert_eq!(query.iter().count(), 4);
+    }
+}
+
+/// A wrapper around a [`World`] that allows for
+/// access from inside a [`CommandDispatcher`].
+#[derive(Clone)]
+struct WorldAccessor {
+    world: Arc<Mutex<World>>,
+}
+
+impl WorldAccessor {
+    /// Create a new empty [`WorldAccessor`].
+    fn empty() -> Self {
+        Self {
+            world: Arc::new(Mutex::new(World::new())),
+        }
+    }
+
+    /// Swap the internal [`World`] with the given one.
+    fn swap(&mut self, world: &mut World) {
+        std::mem::swap(&mut *self.lock(), world);
+    }
+}
+
+/// A marker [`Component`] used to test spawning entities from the dispatcher.
+#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, Hash, Component)]
+struct SpawnedEntity;
+
+/// Implemented for convenience.
+impl std::ops::Deref for WorldAccessor {
+    type Target = Arc<Mutex<World>>;
+    fn deref(&self) -> &Self::Target {
+        &self.world
+    }
+}