// Copyright 2019-2020 Parity Technologies (UK) Ltd.
// This file is part of Parity Bridges Common.

// Parity Bridges Common 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.

// Parity Bridges Common 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 Parity Bridges Common.  If not, see <http://www.gnu.org/licenses/>.

//! Defines traits which represent a common interface for Substrate pallets which want to
//! incorporate bridge functionality.

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

use core::clone::Clone;
use core::cmp::Eq;
use core::fmt::Debug;
use parity_scale_codec::{Codec, EncodeLike};

/// A type that can be used as a parameter in a dispatchable function.
///
/// When using `decl_module` all arguments for call functions must implement this trait.
pub trait Parameter: Codec + EncodeLike + Clone + Eq + Debug {}
impl<T> Parameter for T where T: Codec + EncodeLike + Clone + Eq + Debug {}

/// A base trait for pallets which want to keep track of a full set of headers from a bridged chain.
pub trait BaseHeaderChain {
	/// Transaction type.
	type Transaction: Parameter;
	/// Transaction inclusion proof type.
	type TransactionInclusionProof: Parameter;

	/// Verify that transaction is a part of given block.
	///
	/// Returns Some(transaction) if proof is valid and None otherwise.
	fn verify_transaction_inclusion_proof(proof: &Self::TransactionInclusionProof) -> Option<Self::Transaction>;
}