bevy_persistence_database 0.3.0

use bevy::prelude::{App, World};

use crate::bevy::world_access::{DeferredWorldOperations, ImmediateWorldPtr};

pub(crate) fn insert_initial_immediate_world_ptr(app: &mut App) {
    let ptr: *mut World = app.world_mut() as *mut World;
    bevy::log::trace!(
        "PersistencePluginCore: inserting initial ImmediateWorldPtr {:p}",
        ptr
    );
    if app.world().get_resource::<ImmediateWorldPtr>().is_none() {
        app.insert_resource(ImmediateWorldPtr::new(ptr));
    } else {
        app.world_mut().resource_mut::<ImmediateWorldPtr>().set(ptr);
    }
}

/// Publishes the current world pointer so other systems can materialize results immediately.
pub(crate) fn publish_immediate_world_ptr(world: &mut World) {
    let ptr: *mut World = world as *mut World;
    if world.get_resource::<ImmediateWorldPtr>().is_none() {
        world.insert_resource(ImmediateWorldPtr::new(ptr));
    } else {
        world.resource_mut::<ImmediateWorldPtr>().set(ptr);
    }
}

/// Applies queued world mutations (e.g. entity spawns, component inserts) for this frame.
pub(crate) fn apply_deferred_world_ops(world: &mut World) {
    let mut pending = world.resource::<DeferredWorldOperations>().drain();
    for op in pending.drain(..) {
        op(world);
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::bevy::params::resource::PersistentRes;
    use crate::bevy::plugins::persistence_plugin::PersistencePlugins;
    use crate::core::db::connection::MockDatabaseConnection;
    use crate::core::session::PersistenceSession;
    use bevy::prelude::*;
    use bevy_persistence_database_derive::persist;
    use serde_json::json;
    use std::sync::Arc;

    #[derive(Clone)]
    #[persist(resource)]
    struct TestSettings {
        difficulty: f32,
        map_name: String,
    }

    #[derive(Resource, Default)]
    struct Capture {
        loaded: bool,
        map_name: Option<String>,
        difficulty: Option<f32>,
    }

    #[test]
    fn refreshes_immediate_world_ptr_before_startup_after_app_move() {
        let mut db = MockDatabaseConnection::new();
        db.expect_fetch_resource()
            .returning(|_, _| Box::pin(async {
                Ok(Some((json!({ "difficulty": 0.3, "map_name": "moved" }), 1)))
            }));
        db.expect_document_key_field().return_const("_key");

        let mut app = App::new();
        app.add_plugins(MinimalPlugins);
        app.add_plugins(PersistencePlugins::new(Arc::new(db)));

        {
            let mut session = app.world_mut().resource_mut::<PersistenceSession>();
            session.register_resource::<TestSettings>();
        }

        app.insert_resource(Capture::default());

        // Move the app to a new memory location after plugin construction.
        let mut relocated = Vec::new();
        relocated.push(app);
        let mut app = relocated.pop().expect("relocated app");

        app.add_systems(
            Update,
            |mut res: PersistentRes<TestSettings>, mut cap: ResMut<Capture>| {
                if let Some(gs) = res.get() {
                    cap.loaded = true;
                    cap.map_name = Some(gs.map_name.clone());
                    cap.difficulty = Some(gs.difficulty);
                }
            },
        );

        app.update();

        let cap = app.world().resource::<Capture>();
        assert!(cap.loaded, "resource should load even after app move");
        assert_eq!(cap.map_name.as_deref(), Some("moved"));
        assert_eq!(cap.difficulty, Some(0.3));
    }
}