//! Communication between Kira and a low-level audio API.

#[cfg(feature = "cpal")]
pub mod cpal;
pub mod mock;
mod renderer;
pub(crate) mod resources;

pub use renderer::*;

#[cfg(feature = "cpal")]
/// The default backend used by [`AudioManager`](crate::AudioManager)s.
///
/// If the `cpal` feature is enabled, this will be the cpal backend. Otherwise,
/// it will be the mock backend.
pub type DefaultBackend = cpal::CpalBackend;
#[cfg(not(feature = "cpal"))]
/// The default backend used by [`AudioManager`](crate::AudioManager)s.
///
/// If the `cpal` feature is enabled, this will be the cpal backend. Otherwise,
/// it will be the mock backend.
pub type DefaultBackend = mock::MockBackend;

/// Connects a [`Renderer`] to a lower level audio API.
pub trait Backend: Sized {
	/// Settings for this backend.
	type Settings;

	/// Errors that can occur when using this backend.
	type Error;

	/// Starts the backend and returns itself and the initial sample rate.
	fn setup(
		settings: Self::Settings,
		internal_buffer_size: usize,
	) -> Result<(Self, u32), Self::Error>;

	/// Sends the renderer to the backend to start audio playback.
	fn start(&mut self, renderer: Renderer) -> Result<(), Self::Error>;
}