// Copyright 2017-2020 Parity Technologies (UK) Ltd.
// This file is part of Polkadot.

// Polkadot 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.

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

//! Polkadot service. Specialized wrapper over substrate service.

pub mod chain_spec;
mod grandpa_support;

use sc_client::LongestChain;
use std::sync::Arc;
use std::time::Duration;
use polkadot_primitives::{parachain, Hash, BlockId, AccountId, Nonce, Balance};
#[cfg(feature = "full-node")]
use polkadot_network::{legacy::gossip::Known, protocol as network_protocol};
use service::{error::{Error as ServiceError}, ServiceBuilder};
use grandpa::{self, FinalityProofProvider as GrandpaFinalityProofProvider};
use inherents::InherentDataProviders;
use sc_executor::native_executor_instance;
use log::info;
pub use service::{
	AbstractService, Roles, PruningMode, TransactionPoolOptions, Error, RuntimeGenesis, ServiceBuilderCommand,
	TFullClient, TLightClient, TFullBackend, TLightBackend, TFullCallExecutor, TLightCallExecutor,
	Configuration, ChainSpec,
};
pub use service::config::{DatabaseConfig, PrometheusConfig, full_version_from_strs};
pub use sc_executor::NativeExecutionDispatch;
pub use sc_client::{ExecutionStrategy, CallExecutor, Client};
pub use sc_client_api::backend::Backend;
pub use sp_api::{Core as CoreApi, ConstructRuntimeApi, ProvideRuntimeApi, StateBackend};
pub use sp_runtime::traits::{HashFor, NumberFor};
pub use consensus_common::SelectChain;
pub use polkadot_primitives::parachain::{CollatorId, ParachainHost};
pub use polkadot_primitives::Block;
pub use sp_runtime::traits::{Block as BlockT, self as runtime_traits, BlakeTwo256};
pub use chain_spec::{PolkadotChainSpec, KusamaChainSpec};
#[cfg(not(target_os = "unknown"))]
pub use consensus::run_validation_worker;
pub use codec::Codec;
pub use polkadot_runtime;
pub use kusama_runtime;
use prometheus_endpoint::Registry;

native_executor_instance!(
	pub PolkadotExecutor,
	polkadot_runtime::api::dispatch,
	polkadot_runtime::native_version,
	frame_benchmarking::benchmarking::HostFunctions,
);

native_executor_instance!(
	pub KusamaExecutor,
	kusama_runtime::api::dispatch,
	kusama_runtime::native_version,
	frame_benchmarking::benchmarking::HostFunctions,
);

/// A set of APIs that polkadot-like runtimes must implement.
pub trait RuntimeApiCollection<Extrinsic: codec::Codec + Send + Sync + 'static> :
	sp_transaction_pool::runtime_api::TaggedTransactionQueue<Block>
	+ sp_api::ApiExt<Block, Error = sp_blockchain::Error>
	+ babe_primitives::BabeApi<Block>
	+ ParachainHost<Block>
	+ sp_block_builder::BlockBuilder<Block>
	+ system_rpc_runtime_api::AccountNonceApi<Block, AccountId, Nonce>
	+ pallet_transaction_payment_rpc_runtime_api::TransactionPaymentApi<Block, Balance, Extrinsic>
	+ sp_api::Metadata<Block>
	+ sp_offchain::OffchainWorkerApi<Block>
	+ sp_session::SessionKeys<Block>
	+ authority_discovery_primitives::AuthorityDiscoveryApi<Block>
where
	Extrinsic: RuntimeExtrinsic,
	<Self as sp_api::ApiExt<Block>>::StateBackend: sp_api::StateBackend<BlakeTwo256>,
{}

impl<Api, Extrinsic> RuntimeApiCollection<Extrinsic> for Api
where
	Api:
	sp_transaction_pool::runtime_api::TaggedTransactionQueue<Block>
	+ sp_api::ApiExt<Block, Error = sp_blockchain::Error>
	+ babe_primitives::BabeApi<Block>
	+ ParachainHost<Block>
	+ sp_block_builder::BlockBuilder<Block>
	+ system_rpc_runtime_api::AccountNonceApi<Block, AccountId, Nonce>
	+ pallet_transaction_payment_rpc_runtime_api::TransactionPaymentApi<Block, Balance, Extrinsic>
	+ sp_api::Metadata<Block>
	+ sp_offchain::OffchainWorkerApi<Block>
	+ sp_session::SessionKeys<Block>
	+ authority_discovery_primitives::AuthorityDiscoveryApi<Block>,
	Extrinsic: RuntimeExtrinsic,
	<Self as sp_api::ApiExt<Block>>::StateBackend: sp_api::StateBackend<BlakeTwo256>,
{}

pub trait RuntimeExtrinsic: codec::Codec + Send + Sync + 'static
{}

impl<E> RuntimeExtrinsic for E where E: codec::Codec + Send + Sync + 'static
{}

/// Can be called for a `Configuration` to check if it is a configuration for the `Kusama` network.
pub trait IsKusama {
	/// Returns if this is a configuration for the `Kusama` network.
	fn is_kusama(&self) -> bool;
}

impl IsKusama for &dyn ChainSpec {
	fn is_kusama(&self) -> bool {
		self.id().starts_with("kusama") || self.id().starts_with("ksm")
	}
}

// If we're using prometheus, use a registry with a prefix of `polkadot`.
fn set_prometheus_registry(config: &mut Configuration) -> Result<(), ServiceError> {
	if let Some(PrometheusConfig { registry, .. }) = config.prometheus_config.as_mut() {
		*registry = Registry::new_custom(Some("polkadot".into()), None)?;
	}

	Ok(())
}

/// Starts a `ServiceBuilder` for a full service.
///
/// Use this macro if you don't actually need the full service, but just the builder in order to
/// be able to perform chain operations.
macro_rules! new_full_start {
	($config:expr, $runtime:ty, $executor:ty) => {{
		set_prometheus_registry(&mut $config)?;

		let mut import_setup = None;
		let inherent_data_providers = inherents::InherentDataProviders::new();
		let builder = service::ServiceBuilder::new_full::<
			Block, $runtime, $executor
		>($config)?
			.with_select_chain(|_, backend| {
				Ok(sc_client::LongestChain::new(backend.clone()))
			})?
			.with_transaction_pool(|config, client, _fetcher| {
				let pool_api = sc_transaction_pool::FullChainApi::new(client.clone());
				let pool = sc_transaction_pool::BasicPool::new(config, std::sync::Arc::new(pool_api));
				Ok(pool)
			})?
			.with_import_queue(|config, client, mut select_chain, _| {
				let select_chain = select_chain.take()
					.ok_or_else(|| service::Error::SelectChainRequired)?;

				let grandpa_hard_forks = if config.expect_chain_spec().is_kusama() {
					grandpa_support::kusama_hard_forks()
				} else {
					Vec::new()
				};

				let (grandpa_block_import, grandpa_link) =
					grandpa::block_import_with_authority_set_hard_forks(
						client.clone(),
						&(client.clone() as Arc<_>),
						select_chain,
						grandpa_hard_forks,
					)?;

				let justification_import = grandpa_block_import.clone();

				let (block_import, babe_link) = babe::block_import(
					babe::Config::get_or_compute(&*client)?,
					grandpa_block_import,
					client.clone(),
				)?;

				let import_queue = babe::import_queue(
					babe_link.clone(),
					block_import.clone(),
					Some(Box::new(justification_import)),
					None,
					client,
					inherent_data_providers.clone(),
				)?;

				import_setup = Some((block_import, grandpa_link, babe_link));
				Ok(import_queue)
			})?
			.with_rpc_extensions(|builder| -> Result<polkadot_rpc::RpcExtension, _> {
				Ok(polkadot_rpc::create_full(builder.client().clone(), builder.pool()))
			})?;

		(builder, import_setup, inherent_data_providers)
	}}
}

/// Builds a new object suitable for chain operations.
pub fn new_chain_ops<Runtime, Dispatch, Extrinsic>(mut config: Configuration)
	-> Result<impl ServiceBuilderCommand<Block=Block>, ServiceError>
where
	Runtime: ConstructRuntimeApi<Block, service::TFullClient<Block, Runtime, Dispatch>> + Send + Sync + 'static,
	Runtime::RuntimeApi:
	RuntimeApiCollection<Extrinsic, StateBackend = sc_client_api::StateBackendFor<TFullBackend<Block>, Block>>,
	Dispatch: NativeExecutionDispatch + 'static,
	Extrinsic: RuntimeExtrinsic,
	<Runtime::RuntimeApi as sp_api::ApiExt<Block>>::StateBackend: sp_api::StateBackend<BlakeTwo256>,
{
	config.keystore = service::config::KeystoreConfig::InMemory;
	Ok(new_full_start!(config, Runtime, Dispatch).0)
}

/// Create a new Polkadot service for a full node.
#[cfg(feature = "full-node")]
pub fn polkadot_new_full(
	config: Configuration,
	collating_for: Option<(CollatorId, parachain::Id)>,
	max_block_data_size: Option<u64>,
	authority_discovery_enabled: bool,
	slot_duration: u64,
	grandpa_pause: Option<(u32, u32)>,
)
	-> Result<(
		impl AbstractService<
			Block = Block,
			RuntimeApi = polkadot_runtime::RuntimeApi,
			Backend = TFullBackend<Block>,
			SelectChain = LongestChain<TFullBackend<Block>, Block>,
			CallExecutor = TFullCallExecutor<Block, PolkadotExecutor>,
		>,
		FullNodeHandles,
	), ServiceError>
{
	new_full(
		config,
		collating_for,
		max_block_data_size,
		authority_discovery_enabled,
		slot_duration,
		grandpa_pause,
	)
}

/// Create a new Kusama service for a full node.
#[cfg(feature = "full-node")]
pub fn kusama_new_full(
	config: Configuration,
	collating_for: Option<(CollatorId, parachain::Id)>,
	max_block_data_size: Option<u64>,
	authority_discovery_enabled: bool,
	slot_duration: u64,
	grandpa_pause: Option<(u32, u32)>,
)
	-> Result<(
		impl AbstractService<
			Block = Block,
			RuntimeApi = kusama_runtime::RuntimeApi,
			Backend = TFullBackend<Block>,
			SelectChain = LongestChain<TFullBackend<Block>, Block>,
			CallExecutor = TFullCallExecutor<Block, KusamaExecutor>,
		>,
		FullNodeHandles,
	), ServiceError>
{
	new_full(
		config,
		collating_for,
		max_block_data_size,
		authority_discovery_enabled,
		slot_duration,
		grandpa_pause,
	)
}

/// Handles to other sub-services that full nodes instantiate, which consumers
/// of the node may use.
#[cfg(feature = "full-node")]
pub struct FullNodeHandles {
	/// A handle to the Polkadot networking protocol.
	pub polkadot_network: Option<network_protocol::Service>,
}

/// Builds a new service for a full client.
#[cfg(feature = "full-node")]
pub fn new_full<Runtime, Dispatch, Extrinsic>(
	mut config: Configuration,
	collating_for: Option<(CollatorId, parachain::Id)>,
	max_block_data_size: Option<u64>,
	authority_discovery_enabled: bool,
	slot_duration: u64,
	grandpa_pause: Option<(u32, u32)>,
)
	-> Result<(
		impl AbstractService<
			Block = Block,
			RuntimeApi = Runtime,
			Backend = TFullBackend<Block>,
			SelectChain = LongestChain<TFullBackend<Block>, Block>,
			CallExecutor = TFullCallExecutor<Block, Dispatch>,
		>,
		FullNodeHandles,
	), ServiceError>
	where
		Runtime: ConstructRuntimeApi<Block, service::TFullClient<Block, Runtime, Dispatch>> + Send + Sync + 'static,
		Runtime::RuntimeApi:
			RuntimeApiCollection<Extrinsic, StateBackend = sc_client_api::StateBackendFor<TFullBackend<Block>, Block>>,
		Dispatch: NativeExecutionDispatch + 'static,
		Extrinsic: RuntimeExtrinsic,
		// Rust bug: https://github.com/rust-lang/rust/issues/24159
		<Runtime::RuntimeApi as sp_api::ApiExt<Block>>::StateBackend: sp_api::StateBackend<BlakeTwo256>,
{
	use sc_network::Event;
	use sc_client_api::ExecutorProvider;
	use futures::stream::StreamExt;

	let is_collator = collating_for.is_some();
	let is_authority = config.roles.is_authority() && !is_collator;
	let force_authoring = config.force_authoring;
	let max_block_data_size = max_block_data_size;
	let db_path = if let DatabaseConfig::Path { ref path, .. } = config.expect_database() {
		path.clone()
	} else {
		return Err("Starting a Polkadot service with a custom database isn't supported".to_string().into());
	};
	let disable_grandpa = config.disable_grandpa;
	let name = config.name.clone();
	let authority_discovery_enabled = authority_discovery_enabled;
	let sentry_nodes = config.network.sentry_nodes.clone();
	let slot_duration = slot_duration;

	// sentry nodes announce themselves as authorities to the network
	// and should run the same protocols authorities do, but it should
	// never actively participate in any consensus process.
	let participates_in_consensus = is_authority && !config.sentry_mode;

	let (builder, mut import_setup, inherent_data_providers) = new_full_start!(config, Runtime, Dispatch);

	let backend = builder.backend().clone();

	let service = builder
		.with_finality_proof_provider(|client, backend| {
			let provider = client as Arc<dyn grandpa::StorageAndProofProvider<_, _>>;
			Ok(Arc::new(GrandpaFinalityProofProvider::new(backend, provider)) as _)
		})?
		.build()?;

	let (block_import, link_half, babe_link) = import_setup.take()
		.expect("Link Half and Block Import are present for Full Services or setup failed before. qed");

	let client = service.client();
	let known_oracle = client.clone();

	let mut handles = FullNodeHandles { polkadot_network: None };
	let select_chain = if let Some(select_chain) = service.select_chain() {
		select_chain
	} else {
		info!("The node cannot start as an authority because it can't select chain.");
		return Ok((service, handles));
	};
	let gossip_validator_select_chain = select_chain.clone();

	let is_known = move |block_hash: &Hash| {
		use consensus_common::BlockStatus;

		match known_oracle.block_status(&BlockId::hash(*block_hash)) {
			Err(_) | Ok(BlockStatus::Unknown) | Ok(BlockStatus::Queued) => None,
			Ok(BlockStatus::KnownBad) => Some(Known::Bad),
			Ok(BlockStatus::InChainWithState) | Ok(BlockStatus::InChainPruned) => {
				match gossip_validator_select_chain.leaves() {
					Err(_) => None,
					Ok(leaves) => if leaves.contains(block_hash) {
						Some(Known::Leaf)
					} else {
						Some(Known::Old)
					},
				}
			}
		}
	};

	let polkadot_network_service = network_protocol::start(
		service.network(),
		network_protocol::Config {
			collating_for,
		},
		(is_known, client.clone()),
		client.clone(),
		service.spawn_task_handle(),
	).map_err(|e| format!("Could not spawn network worker: {:?}", e))?;

	if participates_in_consensus {
		let availability_store = {
			use std::path::PathBuf;

			let mut path = PathBuf::from(db_path);
			path.push("availability");

			#[cfg(not(target_os = "unknown"))]
			{
				av_store::Store::new(
					::av_store::Config {
						cache_size: None,
						path,
					},
					polkadot_network_service.clone(),
				)?
			}

			#[cfg(target_os = "unknown")]
			av_store::Store::new_in_memory(gossip)
		};

		polkadot_network_service.register_availability_store(availability_store.clone());

		let (validation_service_handle, validation_service) = consensus::ServiceBuilder {
			client: client.clone(),
			network: polkadot_network_service.clone(),
			collators: polkadot_network_service.clone(),
			spawner: service.spawn_task_handle(),
			availability_store: availability_store.clone(),
			select_chain: select_chain.clone(),
			keystore: service.keystore(),
			max_block_data_size,
		}.build();

		service.spawn_essential_task("validation-service", Box::pin(validation_service));

		let proposer = consensus::ProposerFactory::new(
			client.clone(),
			service.transaction_pool(),
			validation_service_handle,
			slot_duration,
			backend,
		);

		let select_chain = service.select_chain().ok_or(ServiceError::SelectChainRequired)?;
		let can_author_with =
			consensus_common::CanAuthorWithNativeVersion::new(client.executor().clone());

		let block_import = availability_store.block_import(
			block_import,
			client.clone(),
			service.spawn_task_handle(),
			service.keystore(),
		)?;

		let babe_config = babe::BabeParams {
			keystore: service.keystore(),
			client,
			select_chain,
			block_import,
			env: proposer,
			sync_oracle: service.network(),
			inherent_data_providers: inherent_data_providers.clone(),
			force_authoring,
			babe_link,
			can_author_with,
		};

		let babe = babe::start_babe(babe_config)?;
		service.spawn_essential_task("babe", babe);

		if authority_discovery_enabled {
			let network = service.network();
			let network_event_stream = network.event_stream();
			let dht_event_stream = network_event_stream.filter_map(|e| async move { match e {
				Event::Dht(e) => Some(e),
				_ => None,
			}}).boxed();
			let authority_discovery = authority_discovery::AuthorityDiscovery::new(
				service.client(),
				network,
				sentry_nodes,
				service.keystore(),
				dht_event_stream,
				service.prometheus_registry(),
			);
			service.spawn_task("authority-discovery", authority_discovery);
		}
	}

	// if the node isn't actively participating in consensus then it doesn't
	// need a keystore, regardless of which protocol we use below.
	let keystore = if participates_in_consensus {
		Some(service.keystore())
	} else {
		None
	};

	let config = grandpa::Config {
		// FIXME substrate#1578 make this available through chainspec
		gossip_duration: Duration::from_millis(1000),
		justification_period: 512,
		name: Some(name),
		observer_enabled: false,
		keystore,
		is_authority,
	};

	let enable_grandpa = !disable_grandpa;
	if enable_grandpa {
		// start the full GRANDPA voter
		// NOTE: unlike in substrate we are currently running the full
		// GRANDPA voter protocol for all full nodes (regardless of whether
		// they're validators or not). at this point the full voter should
		// provide better guarantees of block and vote data availability than
		// the observer.

		// add a custom voting rule to temporarily stop voting for new blocks
		// after the given pause block is finalized and restarting after the
		// given delay.
		let voting_rule = match grandpa_pause {
			Some((block, delay)) => {
				info!("GRANDPA scheduled voting pause set for block #{} with a duration of {} blocks.",
					block,
					delay,
				);

				grandpa::VotingRulesBuilder::default()
					.add(grandpa_support::PauseAfterBlockFor(block, delay))
					.build()
			},
			None =>
				grandpa::VotingRulesBuilder::default()
					.build(),
		};

		let grandpa_config = grandpa::GrandpaParams {
			config,
			link: link_half,
			network: service.network(),
			inherent_data_providers: inherent_data_providers.clone(),
			telemetry_on_connect: Some(service.telemetry_on_connect_stream()),
			voting_rule,
			prometheus_registry: service.prometheus_registry(),
		};

		service.spawn_essential_task(
			"grandpa-voter",
			grandpa::run_grandpa_voter(grandpa_config)?
		);
	} else {
		grandpa::setup_disabled_grandpa(
			service.client(),
			&inherent_data_providers,
			service.network(),
		)?;
	}

	handles.polkadot_network = Some(polkadot_network_service);
	Ok((service, handles))
}

/// Create a new Polkadot service for a light client.
pub fn polkadot_new_light(
	config: Configuration,
)
	-> Result<impl AbstractService<
		Block = Block,
		RuntimeApi = polkadot_runtime::RuntimeApi,
		Backend = TLightBackend<Block>,
		SelectChain = LongestChain<TLightBackend<Block>, Block>,
		CallExecutor = TLightCallExecutor<Block, PolkadotExecutor>,
	>, ServiceError>
{
	new_light(config)
}

/// Create a new Kusama service for a light client.
pub fn kusama_new_light(
	config: Configuration,
)
	-> Result<impl AbstractService<
		Block = Block,
		RuntimeApi = kusama_runtime::RuntimeApi,
		Backend = TLightBackend<Block>,
		SelectChain = LongestChain<TLightBackend<Block>, Block>,
		CallExecutor = TLightCallExecutor<Block, KusamaExecutor>,
	>, ServiceError>
{
	new_light(config)
}

// We can't use service::TLightClient due to
// Rust bug: https://github.com/rust-lang/rust/issues/43580
type TLocalLightClient<Runtime, Dispatch> =  Client<
	sc_client::light::backend::Backend<sc_client_db::light::LightStorage<Block>, BlakeTwo256>,
	sc_client::light::call_executor::GenesisCallExecutor<
		sc_client::light::backend::Backend<sc_client_db::light::LightStorage<Block>, BlakeTwo256>,
		sc_client::LocalCallExecutor<
			sc_client::light::backend::Backend<
				sc_client_db::light::LightStorage<Block>,
				BlakeTwo256
			>,
			sc_executor::NativeExecutor<Dispatch>
		>
	>,
	Block,
	Runtime
>;

/// Builds a new service for a light client.
pub fn new_light<Runtime, Dispatch, Extrinsic>(
	mut config: Configuration,
)
	-> Result<impl AbstractService<
		Block = Block,
		RuntimeApi = Runtime,
		Backend = TLightBackend<Block>,
		SelectChain = LongestChain<TLightBackend<Block>, Block>,
		CallExecutor = TLightCallExecutor<Block, Dispatch>,
	>, ServiceError>
where
	Runtime: Send + Sync + 'static,
	Runtime::RuntimeApi: RuntimeApiCollection<
		Extrinsic,
		StateBackend = sc_client_api::StateBackendFor<TLightBackend<Block>, Block>
	>,
	Dispatch: NativeExecutionDispatch + 'static,
	Extrinsic: RuntimeExtrinsic,
	Runtime: sp_api::ConstructRuntimeApi<
		Block,
		TLocalLightClient<Runtime, Dispatch>,
	>,
{
	set_prometheus_registry(&mut config)?;

	let inherent_data_providers = InherentDataProviders::new();

	ServiceBuilder::new_light::<Block, Runtime, Dispatch>(config)?
		.with_select_chain(|_, backend| {
			Ok(LongestChain::new(backend.clone()))
		})?
		.with_transaction_pool(|config, client, fetcher| {
			let fetcher = fetcher
				.ok_or_else(|| "Trying to start light transaction pool without active fetcher")?;
			let pool_api = sc_transaction_pool::LightChainApi::new(client.clone(), fetcher.clone());
			let pool = sc_transaction_pool::BasicPool::with_revalidation_type(
				config, Arc::new(pool_api), sc_transaction_pool::RevalidationType::Light,
			);
			Ok(pool)
		})?
		.with_import_queue_and_fprb(|_config, client, backend, fetcher, _select_chain, _| {
			let fetch_checker = fetcher
				.map(|fetcher| fetcher.checker().clone())
				.ok_or_else(|| "Trying to start light import queue without active fetch checker")?;
			let grandpa_block_import = grandpa::light_block_import(
				client.clone(), backend, &(client.clone() as Arc<_>), Arc::new(fetch_checker)
			)?;

			let finality_proof_import = grandpa_block_import.clone();
			let finality_proof_request_builder =
				finality_proof_import.create_finality_proof_request_builder();

			let (babe_block_import, babe_link) = babe::block_import(
				babe::Config::get_or_compute(&*client)?,
				grandpa_block_import,
				client.clone(),
			)?;

			// FIXME: pruning task isn't started since light client doesn't do `AuthoritySetup`.
			let import_queue = babe::import_queue(
				babe_link,
				babe_block_import,
				None,
				Some(Box::new(finality_proof_import)),
				client,
				inherent_data_providers.clone(),
			)?;

			Ok((import_queue, finality_proof_request_builder))
		})?
		.with_finality_proof_provider(|client, backend| {
			let provider = client as Arc<dyn grandpa::StorageAndProofProvider<_, _>>;
			Ok(Arc::new(GrandpaFinalityProofProvider::new(backend, provider)) as _)
		})?
		.with_rpc_extensions(|builder|
			-> Result<polkadot_rpc::RpcExtension, _> {
			let fetcher = builder.fetcher()
				.ok_or_else(|| "Trying to start node RPC without active fetcher")?;
			let remote_blockchain = builder.remote_backend()
				.ok_or_else(|| "Trying to start node RPC without active remote blockchain")?;

			Ok(polkadot_rpc::create_light(builder.client().clone(), remote_blockchain, fetcher, builder.pool()))
		})?
		.build()
}
