// This file is part of Substrate.

// Copyright (C) 2020 Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: Apache-2.0

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// 	http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

pub mod storage;
pub mod utils;
mod mmr;

use crate::primitives::FullLeaf;
use sp_runtime::traits;

pub use self::mmr::{Mmr, Error};

/// Node type for runtime `T`.
pub type NodeOf<T, I, L> = Node<<T as crate::Config<I>>::Hashing, L>;

/// A node stored in the MMR.
pub type Node<H, L> = crate::primitives::DataOrHash<H, L>;

/// Default Merging & Hashing behavior for MMR.
pub struct Hasher<H, L>(sp_std::marker::PhantomData<(H, L)>);

impl<H: traits::Hash, L: FullLeaf> mmr_lib::Merge for Hasher<H, L> {
	type Item = Node<H, L>;

	fn merge(left: &Self::Item, right: &Self::Item) -> Self::Item {
		let mut concat = left.hash().as_ref().to_vec();
		concat.extend_from_slice(right.hash().as_ref());

		Node::Hash(<H as traits::Hash>::hash(&concat))
	}
}
