// Copyright (C) Parity Technologies (UK) Ltd.
// This file is part of Cumulus.

// Cumulus 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.

// Cumulus 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 Cumulus.  If not, see <http://www.gnu.org/licenses/>.

//! Stock, pure Aura collators.
//!
//! This includes the [`basic`] collator, which only builds on top of the most recently
//! included parachain block, as well as the [`lookahead`] collator, which prospectively
//! builds on parachain blocks which have not yet been included in the relay chain.

use cumulus_relay_chain_interface::RelayChainInterface;
use polkadot_primitives::{
	Hash as RHash, Id as ParaId, OccupiedCoreAssumption, ValidationCodeHash,
};

pub mod basic;
pub mod lookahead;

/// Check the `local_validation_code_hash` against the validation code hash in the relay chain
/// state.
///
/// If the code hashes do not match, it prints a warning.
async fn check_validation_code_or_log(
	local_validation_code_hash: &ValidationCodeHash,
	para_id: ParaId,
	relay_client: &impl RelayChainInterface,
	relay_parent: RHash,
) {
	let state_validation_code_hash = match relay_client
		.validation_code_hash(relay_parent, para_id, OccupiedCoreAssumption::Included)
		.await
	{
		Ok(hash) => hash,
		Err(error) => {
			tracing::debug!(
				target: super::LOG_TARGET,
				%error,
				?relay_parent,
				%para_id,
				"Failed to fetch validation code hash",
			);
			return
		},
	};

	match state_validation_code_hash {
		Some(state) =>
			if state != *local_validation_code_hash {
				tracing::warn!(
					target: super::LOG_TARGET,
					%para_id,
					?relay_parent,
					?local_validation_code_hash,
					relay_validation_code_hash = ?state,
					"Parachain code doesn't match validation code stored in the relay chain state",
				);
			},
		None => {
			tracing::warn!(
				target: super::LOG_TARGET,
				%para_id,
				?relay_parent,
				"Could not find validation code for parachain in the relay chain state.",
			);
		},
	}
}