use bevy::prelude::*;
use q_service::prelude::*;

# #[derive(Resource, Debug, Default)]
# pub struct MyOtherService;
# impl Service for MyOtherService {
#    fn build(_) {}
# }
# #[derive(Resource)]
# pub struct MyResource;
# #[derive(Asset)]
# pub struct MyAsset;

// Declare your service like this.
// Services must implement these three traits.
#[derive(Resource, Debug, Default)]
pub struct MyService {
    // you can have data here if you want.
}
impl Service for MyService {
    // This function will build the service at registration.
    // This is where you define the service's behavior --
    // its dependencies, systems, and lifecycle hooks.
    fn build(scope: &mut ServiceScope) {
        // Depend on other services...
        scope.add_dep::<MyOtherService>()
            // resources...
            .add_resource::<MyResource>()
            // ... or assets.
            .add_asset::<MyAsset>("my/asset/path.toml");

        // Add systems with all the flexibility you're used to.
        scope.add_systems(
            Update,
            (sys_a, sys_b)
                .chain()
                .run_if(my_condition)
        );

        // Define service behavior with possibly-asychrnonous
        // (de)initialization hooks.
        scope.init_with(my_init)
            .deinit_with(my_deinit);

        // React to state changes immediately with service hooks.
        scope.on_up(my_up)
            .on_down(my_down);
    }
}

// You can react to changes using observers...
fn observe_status_update(trigger: Trigger<EnterServiceState<MyService>>>) {
    // ...
}

// ... or EventReaders
fn read_state_change(reader: EventReader<ServiceStateChange<MyService>>) {
    // ...
}

#[derive(Default, Debug)]
struct MyPlugin;
impl Plugin for MyPlugin {
    fn build(app: &mut App) {
        // Add your service to a plugin,
        // or directly on the application.
        app.add_service::<MyService>();
    }
}