// Copyright 2017-2020 Parity Technologies (UK) Ltd.
// This file is part of Substrate.

// Substrate is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// Substrate is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.

//! Primitives for Aura.

#![cfg_attr(not(feature = "std"), no_std)]

use codec::{Encode, Decode, Codec};
use sp_std::vec::Vec;
use sp_runtime::ConsensusEngineId;

pub mod inherents;

pub mod sr25519 {
	mod app_sr25519 {
		use sp_application_crypto::{app_crypto, key_types::AURA, sr25519};
		app_crypto!(sr25519, AURA);
	}

	/// An Aura authority keypair using S/R 25519 as its crypto.
	#[cfg(feature = "std")]
	pub type AuthorityPair = app_sr25519::Pair;

	/// An Aura authority signature using S/R 25519 as its crypto.
	pub type AuthoritySignature = app_sr25519::Signature;

	/// An Aura authority identifier using S/R 25519 as its crypto.
	pub type AuthorityId = app_sr25519::Public;
}

pub mod ed25519 {
	mod app_ed25519 {
		use sp_application_crypto::{app_crypto, key_types::AURA, ed25519};
		app_crypto!(ed25519, AURA);
	}

	/// An Aura authority keypair using Ed25519 as its crypto.
	#[cfg(feature = "std")]
	pub type AuthorityPair = app_ed25519::Pair;

	/// An Aura authority signature using Ed25519 as its crypto.
	pub type AuthoritySignature = app_ed25519::Signature;

	/// An Aura authority identifier using Ed25519 as its crypto.
	pub type AuthorityId = app_ed25519::Public;
}

/// The `ConsensusEngineId` of AuRa.
pub const AURA_ENGINE_ID: ConsensusEngineId = [b'a', b'u', b'r', b'a'];

/// The index of an authority.
pub type AuthorityIndex = u32;

/// An consensus log item for Aura.
#[derive(Decode, Encode)]
pub enum ConsensusLog<AuthorityId: Codec> {
	/// The authorities have changed.
	#[codec(index = "1")]
	AuthoritiesChange(Vec<AuthorityId>),
	/// Disable the authority with given index.
	#[codec(index = "2")]
	OnDisabled(AuthorityIndex),
}

sp_api::decl_runtime_apis! {
	/// API necessary for block authorship with aura.
	pub trait AuraApi<AuthorityId: Codec> {
		/// Return the slot duration in seconds for Aura.
		/// Currently, only the value provided by this type at genesis
		/// will be used.
		///
		/// Dynamic slot duration may be supported in the future.
		fn slot_duration() -> u64;

		// Return the current set of authorities.
		fn authorities() -> Vec<AuthorityId>;
	}
}