// This file is part of Substrate.

// Copyright (C) Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0

// This program 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.

// This program 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 this program. If not, see <https://www.gnu.org/licenses/>.

//! A method call executor interface.

use sc_executor::{RuntimeVersion, RuntimeVersionOf};
use sp_core::traits::CallContext;
use sp_externalities::Extensions;
use sp_runtime::traits::{Block as BlockT, HashingFor};
use sp_state_machine::{OverlayedChanges, StorageProof};
use std::cell::RefCell;

use crate::execution_extensions::ExecutionExtensions;
use sp_api::ProofRecorder;

/// Executor Provider
pub trait ExecutorProvider<Block: BlockT> {
	/// executor instance
	type Executor: CallExecutor<Block>;

	/// Get call executor reference.
	fn executor(&self) -> &Self::Executor;

	/// Get a reference to the execution extensions.
	fn execution_extensions(&self) -> &ExecutionExtensions<Block>;
}

/// Method call executor.
pub trait CallExecutor<B: BlockT>: RuntimeVersionOf {
	/// Externalities error type.
	type Error: sp_state_machine::Error;

	/// The backend used by the node.
	type Backend: crate::backend::Backend<B>;

	/// Returns the [`ExecutionExtensions`].
	fn execution_extensions(&self) -> &ExecutionExtensions<B>;

	/// Execute a call to a contract on top of state in a block of given hash.
	///
	/// No changes are made.
	fn call(
		&self,
		at_hash: B::Hash,
		method: &str,
		call_data: &[u8],
		context: CallContext,
	) -> Result<Vec<u8>, sp_blockchain::Error>;

	/// Execute a contextual call on top of state in a block of a given hash.
	///
	/// No changes are made.
	/// Before executing the method, passed header is installed as the current header
	/// of the execution context.
	fn contextual_call(
		&self,
		at_hash: B::Hash,
		method: &str,
		call_data: &[u8],
		changes: &RefCell<OverlayedChanges<HashingFor<B>>>,
		proof_recorder: &Option<ProofRecorder<B>>,
		call_context: CallContext,
		extensions: &RefCell<Extensions>,
	) -> sp_blockchain::Result<Vec<u8>>;

	/// Extract RuntimeVersion of given block
	///
	/// No changes are made.
	fn runtime_version(&self, at_hash: B::Hash) -> Result<RuntimeVersion, sp_blockchain::Error>;

	/// Prove the execution of the given `method`.
	///
	/// No changes are made.
	fn prove_execution(
		&self,
		at_hash: B::Hash,
		method: &str,
		call_data: &[u8],
	) -> Result<(Vec<u8>, StorageProof), sp_blockchain::Error>;
}
