Rococo <> Wococo messages relay (#1030)

* MessagesInstance -> BridgedMessagesInstance

* Chain::ID -> Bridge::THIS_CHAIN_ID+Bridge::BRIDGED_CHAIN_ID

* FromBridgedChainEncodedMessageCall<B> -> FromBridgedChainEncodedMessageCall<DecodedCall>

* impl Parameter for ()

* copypaste storage_map_final_key to avoid different runtime references/dummy runtimes

* moved dummy runtime from primitives to relay client

* Rococo <> Wococo messages relays

* send R<>W messages using relay

* fmt

* return Result from get_dispatch_info

* fix benchmarks compilation

* clippy

bridges/relays/bin-substrate/src/chains/millau.rs

@@ -23,7 +23,7 @@ use crate::cli::{
 };
 use bp_message_dispatch::{CallOrigin, MessagePayload};
 use codec::Decode;
-use frame_support::weights::{GetDispatchInfo, Weight};
+use frame_support::weights::{DispatchInfo, GetDispatchInfo, Weight};
 use relay_millau_client::Millau;
 use sp_version::RuntimeVersion;
 
@@ -62,6 +62,10 @@ impl CliEncodeCall for Millau {
 			},
 		})
 	}
+
+	fn get_dispatch_info(call: &millau_runtime::Call) -> anyhow::Result<DispatchInfo> {
+		Ok(call.get_dispatch_info())
+	}
 }
 
 impl CliChain for Millau {

bridges/relays/bin-substrate/src/chains/millau_messages_to_rialto.rs

@@ -126,20 +126,12 @@ impl SubstrateMessageLane for MillauMessagesToRialto {
 }
 
 /// Millau node as messages source.
-type MillauSourceClient = SubstrateMessagesSource<
-	Millau,
-	MillauMessagesToRialto,
-	millau_runtime::Runtime,
-	millau_runtime::WithRialtoMessagesInstance,
->;
+type MillauSourceClient =
+	SubstrateMessagesSource<Millau, MillauMessagesToRialto, millau_runtime::WithRialtoMessagesInstance>;
 
 /// Rialto node as messages target.
-type RialtoTargetClient = SubstrateMessagesTarget<
-	Rialto,
-	MillauMessagesToRialto,
-	rialto_runtime::Runtime,
-	rialto_runtime::WithMillauMessagesInstance,
->;
+type RialtoTargetClient =
+	SubstrateMessagesTarget<Rialto, MillauMessagesToRialto, rialto_runtime::WithMillauMessagesInstance>;
 
 /// Run Millau-to-Rialto messages sync.
 pub async fn run(

bridges/relays/bin-substrate/src/chains/mod.rs

@@ -21,8 +21,10 @@ pub mod millau_messages_to_rialto;
 pub mod rialto_headers_to_millau;
 pub mod rialto_messages_to_millau;
 pub mod rococo_headers_to_wococo;
+pub mod rococo_messages_to_wococo;
 pub mod westend_headers_to_millau;
 pub mod wococo_headers_to_rococo;
+pub mod wococo_messages_to_rococo;
 
 mod millau;
 mod rialto;
@@ -271,7 +273,10 @@ mod rococo_tests {
 			votes_ancestries: vec![],
 		};
 
-		let actual = bp_rococo::BridgeGrandpaWococoCall::submit_finality_proof(header.clone(), justification.clone());
+		let actual = relay_rococo_client::runtime::BridgeGrandpaWococoCall::submit_finality_proof(
+			header.clone(),
+			justification.clone(),
+		);
 		let expected = millau_runtime::BridgeGrandpaRialtoCall::<millau_runtime::Runtime>::submit_finality_proof(
 			header,
 			justification,

bridges/relays/bin-substrate/src/chains/rialto.rs

@@ -23,7 +23,7 @@ use crate::cli::{
 };
 use bp_message_dispatch::{CallOrigin, MessagePayload};
 use codec::Decode;
-use frame_support::weights::{GetDispatchInfo, Weight};
+use frame_support::weights::{DispatchInfo, GetDispatchInfo, Weight};
 use relay_rialto_client::Rialto;
 use sp_version::RuntimeVersion;
 
@@ -60,6 +60,10 @@ impl CliEncodeCall for Rialto {
 			},
 		})
 	}
+
+	fn get_dispatch_info(call: &rialto_runtime::Call) -> anyhow::Result<DispatchInfo> {
+		Ok(call.get_dispatch_info())
+	}
 }
 
 impl CliChain for Rialto {

bridges/relays/bin-substrate/src/chains/rialto_messages_to_millau.rs

@@ -126,20 +126,12 @@ impl SubstrateMessageLane for RialtoMessagesToMillau {
 }
 
 /// Rialto node as messages source.
-type RialtoSourceClient = SubstrateMessagesSource<
-	Rialto,
-	RialtoMessagesToMillau,
-	rialto_runtime::Runtime,
-	rialto_runtime::WithMillauMessagesInstance,
->;
+type RialtoSourceClient =
+	SubstrateMessagesSource<Rialto, RialtoMessagesToMillau, rialto_runtime::WithMillauMessagesInstance>;
 
 /// Millau node as messages target.
-type MillauTargetClient = SubstrateMessagesTarget<
-	Millau,
-	RialtoMessagesToMillau,
-	millau_runtime::Runtime,
-	millau_runtime::WithRialtoMessagesInstance,
->;
+type MillauTargetClient =
+	SubstrateMessagesTarget<Millau, RialtoMessagesToMillau, millau_runtime::WithRialtoMessagesInstance>;
 
 /// Run Rialto-to-Millau messages sync.
 pub async fn run(

bridges/relays/bin-substrate/src/chains/rococo.rs

@@ -14,11 +14,70 @@
 // 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/>.
 
-use crate::cli::{encode_message, CliChain};
-use frame_support::weights::Weight;
+use codec::Decode;
+use frame_support::weights::{DispatchClass, DispatchInfo, Pays, Weight};
 use relay_rococo_client::Rococo;
 use sp_version::RuntimeVersion;
 
+use crate::cli::{
+	bridge,
+	encode_call::{Call, CliEncodeCall},
+	encode_message, CliChain,
+};
+
+/// Weight of the `system::remark` call at Rococo.
+///
+/// This weight is larger (x2) than actual weight at current Rooco runtime to avoid unsuccessful
+/// calls in the future. But since it is used only in tests (and on test chains), this is ok.
+pub(crate) const SYSTEM_REMARK_CALL_WEIGHT: Weight = 2 * 1_345_000;
+
+impl CliEncodeCall for Rococo {
+	fn max_extrinsic_size() -> u32 {
+		bp_rococo::max_extrinsic_size()
+	}
+
+	fn encode_call(call: &Call) -> anyhow::Result<Self::Call> {
+		Ok(match call {
+			Call::Remark { remark_payload, .. } => {
+				relay_rococo_client::runtime::Call::System(relay_rococo_client::runtime::SystemCall::remark(
+					remark_payload.as_ref().map(|x| x.0.clone()).unwrap_or_default(),
+				))
+			}
+			Call::BridgeSendMessage {
+				lane,
+				payload,
+				fee,
+				bridge_instance_index,
+			} => match *bridge_instance_index {
+				bridge::ROCOCO_TO_WOCOCO_INDEX => {
+					let payload = Decode::decode(&mut &*payload.0)?;
+					relay_rococo_client::runtime::Call::BridgeMessagesWococo(
+						relay_rococo_client::runtime::BridgeMessagesWococoCall::send_message(lane.0, payload, fee.0),
+					)
+				}
+				_ => anyhow::bail!(
+					"Unsupported target bridge pallet with instance index: {}",
+					bridge_instance_index
+				),
+			},
+			_ => anyhow::bail!("The call is not supported"),
+		})
+	}
+
+	fn get_dispatch_info(call: &relay_rococo_client::runtime::Call) -> anyhow::Result<DispatchInfo> {
+		match *call {
+			relay_rococo_client::runtime::Call::System(relay_rococo_client::runtime::SystemCall::remark(_)) => {
+				Ok(DispatchInfo {
+					weight: SYSTEM_REMARK_CALL_WEIGHT,
+					class: DispatchClass::Normal,
+					pays_fee: Pays::Yes,
+				})
+			}
+			_ => anyhow::bail!("Unsupported Rococo call: {:?}", call),
+		}
+	}
+}
+
 impl CliChain for Rococo {
 	const RUNTIME_VERSION: RuntimeVersion = bp_rococo::VERSION;
 
@@ -30,7 +89,7 @@ impl CliChain for Rococo {
 	}
 
 	fn max_extrinsic_weight() -> Weight {
-		0
+		bp_wococo::max_extrinsic_weight()
 	}
 
 	fn encode_message(_message: encode_message::MessagePayload) -> Result<Self::MessagePayload, String> {

bridges/relays/bin-substrate/src/chains/rococo_headers_to_wococo.rs

@@ -61,10 +61,9 @@ impl SubstrateFinalitySyncPipeline for RococoFinalityToWococo {
 		header: RococoSyncHeader,
 		proof: GrandpaJustification<bp_rococo::Header>,
 	) -> Bytes {
-		let call = bp_wococo::Call::BridgeGrandpaRococo(bp_wococo::BridgeGrandpaRococoCall::submit_finality_proof(
-			header.into_inner(),
-			proof,
-		));
+		let call = relay_wococo_client::runtime::Call::BridgeGrandpaRococo(
+			relay_wococo_client::runtime::BridgeGrandpaRococoCall::submit_finality_proof(header.into_inner(), proof),
+		);
 		let genesis_hash = *self.target_client.genesis_hash();
 		let transaction = Wococo::sign_transaction(genesis_hash, &self.target_sign, transaction_nonce, call);
 

bridges/relays/bin-substrate/src/chains/rococo_messages_to_wococo.rs

@@ -0,0 +1,227 @@
+// Copyright 2019-2021 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/>.
+
+//! Rococo-to-Wococo messages sync entrypoint.
+
+use crate::messages_lane::{
+	select_delivery_transaction_limits, MessagesRelayParams, SubstrateMessageLane, SubstrateMessageLaneToSubstrate,
+};
+use crate::messages_source::SubstrateMessagesSource;
+use crate::messages_target::SubstrateMessagesTarget;
+
+use bp_messages::MessageNonce;
+use bp_runtime::{ROCOCO_CHAIN_ID, WOCOCO_CHAIN_ID};
+use bridge_runtime_common::messages::target::FromBridgedChainMessagesProof;
+use codec::Encode;
+use messages_relay::message_lane::MessageLane;
+use relay_rococo_client::{HeaderId as RococoHeaderId, Rococo, SigningParams as RococoSigningParams};
+use relay_substrate_client::{metrics::StorageProofOverheadMetric, Chain, TransactionSignScheme};
+use relay_wococo_client::{HeaderId as WococoHeaderId, SigningParams as WococoSigningParams, Wococo};
+use sp_core::{Bytes, Pair};
+use std::{ops::RangeInclusive, time::Duration};
+
+/// Rococo-to-Wococo message lane.
+pub type RococoMessagesToWococo =
+	SubstrateMessageLaneToSubstrate<Rococo, RococoSigningParams, Wococo, WococoSigningParams>;
+
+impl SubstrateMessageLane for RococoMessagesToWococo {
+	const OUTBOUND_LANE_MESSAGE_DETAILS_METHOD: &'static str = bp_wococo::TO_WOCOCO_MESSAGE_DETAILS_METHOD;
+	const OUTBOUND_LANE_LATEST_GENERATED_NONCE_METHOD: &'static str =
+		bp_wococo::TO_WOCOCO_LATEST_GENERATED_NONCE_METHOD;
+	const OUTBOUND_LANE_LATEST_RECEIVED_NONCE_METHOD: &'static str = bp_wococo::TO_WOCOCO_LATEST_RECEIVED_NONCE_METHOD;
+
+	const INBOUND_LANE_LATEST_RECEIVED_NONCE_METHOD: &'static str = bp_rococo::FROM_ROCOCO_LATEST_RECEIVED_NONCE_METHOD;
+	const INBOUND_LANE_LATEST_CONFIRMED_NONCE_METHOD: &'static str =
+		bp_rococo::FROM_ROCOCO_LATEST_CONFIRMED_NONCE_METHOD;
+	const INBOUND_LANE_UNREWARDED_RELAYERS_STATE: &'static str = bp_rococo::FROM_ROCOCO_UNREWARDED_RELAYERS_STATE;
+
+	const BEST_FINALIZED_SOURCE_HEADER_ID_AT_TARGET: &'static str = bp_rococo::BEST_FINALIZED_ROCOCO_HEADER_METHOD;
+	const BEST_FINALIZED_TARGET_HEADER_ID_AT_SOURCE: &'static str = bp_wococo::BEST_FINALIZED_WOCOCO_HEADER_METHOD;
+
+	type SourceChain = Rococo;
+	type TargetChain = Wococo;
+
+	fn source_transactions_author(&self) -> bp_rococo::AccountId {
+		(*self.source_sign.public().as_array_ref()).into()
+	}
+
+	fn make_messages_receiving_proof_transaction(
+		&self,
+		transaction_nonce: <Rococo as Chain>::Index,
+		_generated_at_block: WococoHeaderId,
+		proof: <Self as MessageLane>::MessagesReceivingProof,
+	) -> Bytes {
+		let (relayers_state, proof) = proof;
+		let call = relay_rococo_client::runtime::Call::BridgeMessagesWococo(
+			relay_rococo_client::runtime::BridgeMessagesWococoCall::receive_messages_delivery_proof(
+				proof,
+				relayers_state,
+			),
+		);
+		let genesis_hash = *self.source_client.genesis_hash();
+		let transaction = Rococo::sign_transaction(genesis_hash, &self.source_sign, transaction_nonce, call);
+		log::trace!(
+			target: "bridge",
+			"Prepared Wococo -> Rococo confirmation transaction. Weight: <unknown>/{}, size: {}/{}",
+			bp_rococo::max_extrinsic_weight(),
+			transaction.encode().len(),
+			bp_rococo::max_extrinsic_size(),
+		);
+		Bytes(transaction.encode())
+	}
+
+	fn target_transactions_author(&self) -> bp_wococo::AccountId {
+		(*self.target_sign.public().as_array_ref()).into()
+	}
+
+	fn make_messages_delivery_transaction(
+		&self,
+		transaction_nonce: <Wococo as Chain>::Index,
+		_generated_at_header: RococoHeaderId,
+		_nonces: RangeInclusive<MessageNonce>,
+		proof: <Self as MessageLane>::MessagesProof,
+	) -> Bytes {
+		let (dispatch_weight, proof) = proof;
+		let FromBridgedChainMessagesProof {
+			ref nonces_start,
+			ref nonces_end,
+			..
+		} = proof;
+		let messages_count = nonces_end - nonces_start + 1;
+
+		let call = relay_wococo_client::runtime::Call::BridgeMessagesRococo(
+			relay_wococo_client::runtime::BridgeMessagesRococoCall::receive_messages_proof(
+				self.relayer_id_at_source.clone(),
+				proof,
+				messages_count as _,
+				dispatch_weight,
+			),
+		);
+		let genesis_hash = *self.target_client.genesis_hash();
+		let transaction = Wococo::sign_transaction(genesis_hash, &self.target_sign, transaction_nonce, call);
+		log::trace!(
+			target: "bridge",
+			"Prepared Rococo -> Wococo delivery transaction. Weight: <unknown>/{}, size: {}/{}",
+			bp_wococo::max_extrinsic_weight(),
+			transaction.encode().len(),
+			bp_wococo::max_extrinsic_size(),
+		);
+		Bytes(transaction.encode())
+	}
+}
+
+/// Rococo node as messages source.
+type RococoSourceClient =
+	SubstrateMessagesSource<Rococo, RococoMessagesToWococo, relay_rococo_client::runtime::WithWococoMessagesInstance>;
+
+/// Wococo node as messages target.
+type WococoTargetClient =
+	SubstrateMessagesTarget<Wococo, RococoMessagesToWococo, relay_wococo_client::runtime::WithRococoMessagesInstance>;
+
+/// Run Rococo-to-Wococo messages sync.
+pub async fn run(
+	params: MessagesRelayParams<Rococo, RococoSigningParams, Wococo, WococoSigningParams>,
+) -> Result<(), String> {
+	let stall_timeout = Duration::from_secs(5 * 60);
+	let relayer_id_at_rococo = (*params.source_sign.public().as_array_ref()).into();
+
+	let lane_id = params.lane_id;
+	let source_client = params.source_client;
+	let lane = RococoMessagesToWococo {
+		source_client: source_client.clone(),
+		source_sign: params.source_sign,
+		target_client: params.target_client.clone(),
+		target_sign: params.target_sign,
+		relayer_id_at_source: relayer_id_at_rococo,
+	};
+
+	// 2/3 is reserved for proofs and tx overhead
+	let max_messages_size_in_single_batch = bp_wococo::max_extrinsic_size() / 3;
+	// we don't know exact weights of the Wococo runtime. So to guess weights we'll be using
+	// weights from Rialto and then simply dividing it by x2.
+	let (max_messages_in_single_batch, max_messages_weight_in_single_batch) =
+		select_delivery_transaction_limits::<pallet_bridge_messages::weights::RialtoWeight<rialto_runtime::Runtime>>(
+			bp_wococo::max_extrinsic_weight(),
+			bp_wococo::MAX_UNREWARDED_RELAYER_ENTRIES_AT_INBOUND_LANE,
+		);
+	let (max_messages_in_single_batch, max_messages_weight_in_single_batch) = (
+		max_messages_in_single_batch / 2,
+		max_messages_weight_in_single_batch / 2,
+	);
+
+	log::info!(
+		target: "bridge",
+		"Starting Rococo -> Wococo messages relay.\n\t\
+			Rococo relayer account id: {:?}\n\t\
+			Max messages in single transaction: {}\n\t\
+			Max messages size in single transaction: {}\n\t\
+			Max messages weight in single transaction: {}",
+		lane.relayer_id_at_source,
+		max_messages_in_single_batch,
+		max_messages_size_in_single_batch,
+		max_messages_weight_in_single_batch,
+	);
+
+	messages_relay::message_lane_loop::run(
+		messages_relay::message_lane_loop::Params {
+			lane: lane_id,
+			source_tick: Rococo::AVERAGE_BLOCK_INTERVAL,
+			target_tick: Wococo::AVERAGE_BLOCK_INTERVAL,
+			reconnect_delay: relay_utils::relay_loop::RECONNECT_DELAY,
+			stall_timeout,
+			delivery_params: messages_relay::message_lane_loop::MessageDeliveryParams {
+				max_unrewarded_relayer_entries_at_target: bp_wococo::MAX_UNREWARDED_RELAYER_ENTRIES_AT_INBOUND_LANE,
+				max_unconfirmed_nonces_at_target: bp_wococo::MAX_UNCONFIRMED_MESSAGES_AT_INBOUND_LANE,
+				max_messages_in_single_batch,
+				max_messages_weight_in_single_batch,
+				max_messages_size_in_single_batch,
+				relayer_mode: messages_relay::message_lane_loop::RelayerMode::Altruistic,
+			},
+		},
+		RococoSourceClient::new(
+			source_client.clone(),
+			lane.clone(),
+			lane_id,
+			WOCOCO_CHAIN_ID,
+			params.target_to_source_headers_relay,
+		),
+		WococoTargetClient::new(
+			params.target_client,
+			lane,
+			lane_id,
+			ROCOCO_CHAIN_ID,
+			params.source_to_target_headers_relay,
+		),
+		relay_utils::relay_metrics(
+			Some(messages_relay::message_lane_loop::metrics_prefix::<
+				RococoMessagesToWococo,
+			>(&lane_id)),
+			params.metrics_params,
+		)
+		.standalone_metric(|registry, prefix| {
+			StorageProofOverheadMetric::new(
+				registry,
+				prefix,
+				source_client.clone(),
+				"rococo_storage_proof_overhead".into(),
+				"Rococo storage proof overhead".into(),
+			)
+		})?
+		.into_params(),
+		futures::future::pending(),
+	)
+	.await
+}

bridges/relays/bin-substrate/src/chains/wococo.rs

@@ -14,11 +14,64 @@
 // 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/>.
 
-use crate::cli::{encode_message, CliChain};
-use frame_support::weights::Weight;
+use codec::Decode;
+use frame_support::weights::{DispatchClass, DispatchInfo, Pays, Weight};
 use relay_wococo_client::Wococo;
 use sp_version::RuntimeVersion;
 
+use crate::cli::{
+	bridge,
+	encode_call::{Call, CliEncodeCall},
+	encode_message, CliChain,
+};
+
+impl CliEncodeCall for Wococo {
+	fn max_extrinsic_size() -> u32 {
+		bp_wococo::max_extrinsic_size()
+	}
+
+	fn encode_call(call: &Call) -> anyhow::Result<Self::Call> {
+		Ok(match call {
+			Call::Remark { remark_payload, .. } => {
+				relay_wococo_client::runtime::Call::System(relay_wococo_client::runtime::SystemCall::remark(
+					remark_payload.as_ref().map(|x| x.0.clone()).unwrap_or_default(),
+				))
+			}
+			Call::BridgeSendMessage {
+				lane,
+				payload,
+				fee,
+				bridge_instance_index,
+			} => match *bridge_instance_index {
+				bridge::WOCOCO_TO_ROCOCO_INDEX => {
+					let payload = Decode::decode(&mut &*payload.0)?;
+					relay_wococo_client::runtime::Call::BridgeMessagesRococo(
+						relay_wococo_client::runtime::BridgeMessagesRococoCall::send_message(lane.0, payload, fee.0),
+					)
+				}
+				_ => anyhow::bail!(
+					"Unsupported target bridge pallet with instance index: {}",
+					bridge_instance_index
+				),
+			},
+			_ => anyhow::bail!("The call is not supported"),
+		})
+	}
+
+	fn get_dispatch_info(call: &relay_wococo_client::runtime::Call) -> anyhow::Result<DispatchInfo> {
+		match *call {
+			relay_wococo_client::runtime::Call::System(relay_wococo_client::runtime::SystemCall::remark(_)) => {
+				Ok(DispatchInfo {
+					weight: crate::chains::rococo::SYSTEM_REMARK_CALL_WEIGHT,
+					class: DispatchClass::Normal,
+					pays_fee: Pays::Yes,
+				})
+			}
+			_ => anyhow::bail!("Unsupported Rococo call: {:?}", call),
+		}
+	}
+}
+
 impl CliChain for Wococo {
 	const RUNTIME_VERSION: RuntimeVersion = bp_wococo::VERSION;
 
@@ -30,7 +83,7 @@ impl CliChain for Wococo {
 	}
 
 	fn max_extrinsic_weight() -> Weight {
-		0
+		bp_wococo::max_extrinsic_weight()
 	}
 
 	fn encode_message(_message: encode_message::MessagePayload) -> Result<Self::MessagePayload, String> {

bridges/relays/bin-substrate/src/chains/wococo_headers_to_rococo.rs

@@ -67,10 +67,9 @@ impl SubstrateFinalitySyncPipeline for WococoFinalityToRococo {
 		header: WococoSyncHeader,
 		proof: GrandpaJustification<bp_wococo::Header>,
 	) -> Bytes {
-		let call = bp_rococo::Call::BridgeGrandpaWococo(bp_rococo::BridgeGrandpaWococoCall::submit_finality_proof(
-			header.into_inner(),
-			proof,
-		));
+		let call = relay_rococo_client::runtime::Call::BridgeGrandpaWococo(
+			relay_rococo_client::runtime::BridgeGrandpaWococoCall::submit_finality_proof(header.into_inner(), proof),
+		);
 		let genesis_hash = *self.target_client.genesis_hash();
 		let transaction = Rococo::sign_transaction(genesis_hash, &self.target_sign, transaction_nonce, call);
 

bridges/relays/bin-substrate/src/chains/wococo_messages_to_rococo.rs

@@ -0,0 +1,227 @@
+// Copyright 2019-2021 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/>.
+
+//! Wococo-to-Rococo messages sync entrypoint.
+
+use crate::messages_lane::{
+	select_delivery_transaction_limits, MessagesRelayParams, SubstrateMessageLane, SubstrateMessageLaneToSubstrate,
+};
+use crate::messages_source::SubstrateMessagesSource;
+use crate::messages_target::SubstrateMessagesTarget;
+
+use bp_messages::MessageNonce;
+use bp_runtime::{ROCOCO_CHAIN_ID, WOCOCO_CHAIN_ID};
+use bridge_runtime_common::messages::target::FromBridgedChainMessagesProof;
+use codec::Encode;
+use messages_relay::message_lane::MessageLane;
+use relay_rococo_client::{HeaderId as RococoHeaderId, Rococo, SigningParams as RococoSigningParams};
+use relay_substrate_client::{metrics::StorageProofOverheadMetric, Chain, TransactionSignScheme};
+use relay_wococo_client::{HeaderId as WococoHeaderId, SigningParams as WococoSigningParams, Wococo};
+use sp_core::{Bytes, Pair};
+use std::{ops::RangeInclusive, time::Duration};
+
+/// Wococo-to-Rococo message lane.
+pub type WococoMessagesToRococo =
+	SubstrateMessageLaneToSubstrate<Wococo, WococoSigningParams, Rococo, RococoSigningParams>;
+
+impl SubstrateMessageLane for WococoMessagesToRococo {
+	const OUTBOUND_LANE_MESSAGE_DETAILS_METHOD: &'static str = bp_rococo::TO_ROCOCO_MESSAGE_DETAILS_METHOD;
+	const OUTBOUND_LANE_LATEST_GENERATED_NONCE_METHOD: &'static str =
+		bp_rococo::TO_ROCOCO_LATEST_GENERATED_NONCE_METHOD;
+	const OUTBOUND_LANE_LATEST_RECEIVED_NONCE_METHOD: &'static str = bp_rococo::TO_ROCOCO_LATEST_RECEIVED_NONCE_METHOD;
+
+	const INBOUND_LANE_LATEST_RECEIVED_NONCE_METHOD: &'static str = bp_wococo::FROM_WOCOCO_LATEST_RECEIVED_NONCE_METHOD;
+	const INBOUND_LANE_LATEST_CONFIRMED_NONCE_METHOD: &'static str =
+		bp_wococo::FROM_WOCOCO_LATEST_CONFIRMED_NONCE_METHOD;
+	const INBOUND_LANE_UNREWARDED_RELAYERS_STATE: &'static str = bp_wococo::FROM_WOCOCO_UNREWARDED_RELAYERS_STATE;
+
+	const BEST_FINALIZED_SOURCE_HEADER_ID_AT_TARGET: &'static str = bp_wococo::BEST_FINALIZED_WOCOCO_HEADER_METHOD;
+	const BEST_FINALIZED_TARGET_HEADER_ID_AT_SOURCE: &'static str = bp_rococo::BEST_FINALIZED_ROCOCO_HEADER_METHOD;
+
+	type SourceChain = Wococo;
+	type TargetChain = Rococo;
+
+	fn source_transactions_author(&self) -> bp_wococo::AccountId {
+		(*self.source_sign.public().as_array_ref()).into()
+	}
+
+	fn make_messages_receiving_proof_transaction(
+		&self,
+		transaction_nonce: <Wococo as Chain>::Index,
+		_generated_at_block: RococoHeaderId,
+		proof: <Self as MessageLane>::MessagesReceivingProof,
+	) -> Bytes {
+		let (relayers_state, proof) = proof;
+		let call = relay_wococo_client::runtime::Call::BridgeMessagesRococo(
+			relay_wococo_client::runtime::BridgeMessagesRococoCall::receive_messages_delivery_proof(
+				proof,
+				relayers_state,
+			),
+		);
+		let genesis_hash = *self.source_client.genesis_hash();
+		let transaction = Wococo::sign_transaction(genesis_hash, &self.source_sign, transaction_nonce, call);
+		log::trace!(
+			target: "bridge",
+			"Prepared Rococo -> Wococo confirmation transaction. Weight: <unknown>/{}, size: {}/{}",
+			bp_wococo::max_extrinsic_weight(),
+			transaction.encode().len(),
+			bp_wococo::max_extrinsic_size(),
+		);
+		Bytes(transaction.encode())
+	}
+
+	fn target_transactions_author(&self) -> bp_rococo::AccountId {
+		(*self.target_sign.public().as_array_ref()).into()
+	}
+
+	fn make_messages_delivery_transaction(
+		&self,
+		transaction_nonce: <Rococo as Chain>::Index,
+		_generated_at_header: WococoHeaderId,
+		_nonces: RangeInclusive<MessageNonce>,
+		proof: <Self as MessageLane>::MessagesProof,
+	) -> Bytes {
+		let (dispatch_weight, proof) = proof;
+		let FromBridgedChainMessagesProof {
+			ref nonces_start,
+			ref nonces_end,
+			..
+		} = proof;
+		let messages_count = nonces_end - nonces_start + 1;
+
+		let call = relay_rococo_client::runtime::Call::BridgeMessagesWococo(
+			relay_rococo_client::runtime::BridgeMessagesWococoCall::receive_messages_proof(
+				self.relayer_id_at_source.clone(),
+				proof,
+				messages_count as _,
+				dispatch_weight,
+			),
+		);
+		let genesis_hash = *self.target_client.genesis_hash();
+		let transaction = Rococo::sign_transaction(genesis_hash, &self.target_sign, transaction_nonce, call);
+		log::trace!(
+			target: "bridge",
+			"Prepared Wococo -> Rococo delivery transaction. Weight: <unknown>/{}, size: {}/{}",
+			bp_rococo::max_extrinsic_weight(),
+			transaction.encode().len(),
+			bp_rococo::max_extrinsic_size(),
+		);
+		Bytes(transaction.encode())
+	}
+}
+
+/// Wococo node as messages source.
+type WococoSourceClient =
+	SubstrateMessagesSource<Wococo, WococoMessagesToRococo, relay_wococo_client::runtime::WithRococoMessagesInstance>;
+
+/// Rococo node as messages target.
+type RococoTargetClient =
+	SubstrateMessagesTarget<Rococo, WococoMessagesToRococo, relay_rococo_client::runtime::WithWococoMessagesInstance>;
+
+/// Run Wococo-to-Rococo messages sync.
+pub async fn run(
+	params: MessagesRelayParams<Wococo, WococoSigningParams, Rococo, RococoSigningParams>,
+) -> Result<(), String> {
+	let stall_timeout = Duration::from_secs(5 * 60);
+	let relayer_id_at_wococo = (*params.source_sign.public().as_array_ref()).into();
+
+	let lane_id = params.lane_id;
+	let source_client = params.source_client;
+	let lane = WococoMessagesToRococo {
+		source_client: source_client.clone(),
+		source_sign: params.source_sign,
+		target_client: params.target_client.clone(),
+		target_sign: params.target_sign,
+		relayer_id_at_source: relayer_id_at_wococo,
+	};
+
+	// 2/3 is reserved for proofs and tx overhead
+	let max_messages_size_in_single_batch = bp_rococo::max_extrinsic_size() / 3;
+	// we don't know exact weights of the Rococo runtime. So to guess weights we'll be using
+	// weights from Rialto and then simply dividing it by x2.
+	let (max_messages_in_single_batch, max_messages_weight_in_single_batch) =
+		select_delivery_transaction_limits::<pallet_bridge_messages::weights::RialtoWeight<rialto_runtime::Runtime>>(
+			bp_rococo::max_extrinsic_weight(),
+			bp_rococo::MAX_UNREWARDED_RELAYER_ENTRIES_AT_INBOUND_LANE,
+		);
+	let (max_messages_in_single_batch, max_messages_weight_in_single_batch) = (
+		max_messages_in_single_batch / 2,
+		max_messages_weight_in_single_batch / 2,
+	);
+
+	log::info!(
+		target: "bridge",
+		"Starting Wococo -> Rococo messages relay.\n\t\
+			Wococo relayer account id: {:?}\n\t\
+			Max messages in single transaction: {}\n\t\
+			Max messages size in single transaction: {}\n\t\
+			Max messages weight in single transaction: {}",
+		lane.relayer_id_at_source,
+		max_messages_in_single_batch,
+		max_messages_size_in_single_batch,
+		max_messages_weight_in_single_batch,
+	);
+
+	messages_relay::message_lane_loop::run(
+		messages_relay::message_lane_loop::Params {
+			lane: lane_id,
+			source_tick: Wococo::AVERAGE_BLOCK_INTERVAL,
+			target_tick: Rococo::AVERAGE_BLOCK_INTERVAL,
+			reconnect_delay: relay_utils::relay_loop::RECONNECT_DELAY,
+			stall_timeout,
+			delivery_params: messages_relay::message_lane_loop::MessageDeliveryParams {
+				max_unrewarded_relayer_entries_at_target: bp_rococo::MAX_UNREWARDED_RELAYER_ENTRIES_AT_INBOUND_LANE,
+				max_unconfirmed_nonces_at_target: bp_rococo::MAX_UNCONFIRMED_MESSAGES_AT_INBOUND_LANE,
+				max_messages_in_single_batch,
+				max_messages_weight_in_single_batch,
+				max_messages_size_in_single_batch,
+				relayer_mode: messages_relay::message_lane_loop::RelayerMode::Altruistic,
+			},
+		},
+		WococoSourceClient::new(
+			source_client.clone(),
+			lane.clone(),
+			lane_id,
+			ROCOCO_CHAIN_ID,
+			params.target_to_source_headers_relay,
+		),
+		RococoTargetClient::new(
+			params.target_client,
+			lane,
+			lane_id,
+			WOCOCO_CHAIN_ID,
+			params.source_to_target_headers_relay,
+		),
+		relay_utils::relay_metrics(
+			Some(messages_relay::message_lane_loop::metrics_prefix::<
+				WococoMessagesToRococo,
+			>(&lane_id)),
+			params.metrics_params,
+		)
+		.standalone_metric(|registry, prefix| {
+			StorageProofOverheadMetric::new(
+				registry,
+				prefix,
+				source_client.clone(),
+				"wococo_storage_proof_overhead".into(),
+				"Wococo storage proof overhead".into(),
+			)
+		})?
+		.into_params(),
+		futures::future::pending(),
+	)
+	.await
+}