// This file is part of Substrate.

// Copyright (C) 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.

use crate::{build_executor, LiveState, SharedParams, State, LOG_TARGET};
use sc_executor::sp_wasm_interface::HostFunctions;
use sp_runtime::traits::{Block as BlockT, NumberFor};
use std::{fmt::Debug, str::FromStr};
use substrate_rpc_client::{ws_client, StateApi};

/// Configurations of the [`crate::Command::CreateSnapshot`].
#[derive(Debug, Clone, clap::Parser)]
pub struct CreateSnapshotCmd {
	/// The source of the snapshot. Must be a remote node.
	#[clap(flatten)]
	pub from: LiveState,

	/// The snapshot path to write to.
	///
	/// If not provided `<spec-name>-<spec-version>@<block-hash>.snap` will be used.
	pub snapshot_path: Option<String>,
}

/// inner command for `Command::CreateSnapshot`.
pub(crate) async fn create_snapshot<Block, HostFns>(
	shared: SharedParams,
	command: CreateSnapshotCmd,
) -> sc_cli::Result<()>
where
	Block: BlockT + serde::de::DeserializeOwned,
	Block::Hash: serde::de::DeserializeOwned,
	Block::Header: serde::de::DeserializeOwned,
	<Block::Hash as FromStr>::Err: Debug,
	NumberFor<Block>: FromStr,
	<NumberFor<Block> as FromStr>::Err: Debug,
	HostFns: HostFunctions,
{
	let snapshot_path = command.snapshot_path;
	if !matches!(shared.runtime, crate::Runtime::Existing) {
		return Err("creating a snapshot is only possible with --runtime existing.".into())
	}

	let path = match snapshot_path {
		Some(path) => path,
		None => {
			let rpc = ws_client(&command.from.uri).await.unwrap();
			let remote_spec = StateApi::<Block::Hash>::runtime_version(&rpc, None).await.unwrap();
			let path_str = format!(
				"{}-{}@{}.snap",
				remote_spec.spec_name.to_lowercase(),
				remote_spec.spec_version,
				command.from.at.clone().unwrap_or("latest".to_owned())
			);
			log::info!(target: LOG_TARGET, "snapshot path not provided (-s), using '{}'", path_str);
			path_str.into()
		},
	};

	let executor = build_executor::<HostFns>(&shared);
	let _ = State::Live(command.from)
		.into_ext::<Block, HostFns>(&shared, &executor, Some(path.into()), false)
		.await?;

	Ok(())
}