// Copyright (C) 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/>.

//! Everything required to run benchmarks of messages module, based on
//! `bridge_runtime_common::messages` implementation.

#![cfg(feature = "runtime-benchmarks")]

use crate::{
	messages::{
		source::FromBridgedChainMessagesDeliveryProof, target::FromBridgedChainMessagesProof,
		AccountIdOf, BridgedChain, HashOf, MessageBridge, ThisChain,
	},
	messages_generation::{
		encode_all_messages, encode_lane_data, prepare_message_delivery_storage_proof,
		prepare_messages_storage_proof,
	},
};

use bp_messages::MessagePayload;
use bp_polkadot_core::parachains::ParaHash;
use bp_runtime::{Chain, Parachain, StorageProofSize, UnderlyingChainOf};
use codec::Encode;
use frame_support::weights::Weight;
use pallet_bridge_messages::benchmarking::{MessageDeliveryProofParams, MessageProofParams};
use sp_runtime::traits::{Header, Zero};
use sp_std::prelude::*;
use xcm::latest::prelude::*;

/// Prepare inbound bridge message according to given message proof parameters.
fn prepare_inbound_message(
	params: &MessageProofParams,
	successful_dispatch_message_generator: impl Fn(usize) -> MessagePayload,
) -> MessagePayload {
	// we only care about **this** message size when message proof needs to be `Minimal`
	let expected_size = match params.size {
		StorageProofSize::Minimal(size) => size as usize,
		_ => 0,
	};

	// if we don't need a correct message, then we may just return some random blob
	if !params.is_successful_dispatch_expected {
		return vec![0u8; expected_size]
	}

	// else let's prepare successful message.
	let msg = successful_dispatch_message_generator(expected_size);
	assert!(
		msg.len() >= expected_size,
		"msg.len(): {} does not match expected_size: {}",
		expected_size,
		msg.len()
	);
	msg
}

/// Prepare proof of messages for the `receive_messages_proof` call.
///
/// In addition to returning valid messages proof, environment is prepared to verify this message
/// proof.
///
/// This method is intended to be used when benchmarking pallet, linked to the chain that
/// uses GRANDPA finality. For parachains, please use the `prepare_message_proof_from_parachain`
/// function.
pub fn prepare_message_proof_from_grandpa_chain<R, FI, B>(
	params: MessageProofParams,
	message_generator: impl Fn(usize) -> MessagePayload,
) -> (FromBridgedChainMessagesProof<HashOf<BridgedChain<B>>>, Weight)
where
	R: pallet_bridge_grandpa::Config<FI, BridgedChain = UnderlyingChainOf<BridgedChain<B>>>,
	FI: 'static,
	B: MessageBridge,
{
	// prepare storage proof
	let (state_root, storage_proof) = prepare_messages_storage_proof::<B>(
		params.lane,
		params.message_nonces.clone(),
		params.outbound_lane_data.clone(),
		params.size,
		prepare_inbound_message(&params, message_generator),
		encode_all_messages,
		encode_lane_data,
	);

	// update runtime storage
	let (_, bridged_header_hash) = insert_header_to_grandpa_pallet::<R, FI>(state_root);

	(
		FromBridgedChainMessagesProof {
			bridged_header_hash,
			storage_proof,
			lane: params.lane,
			nonces_start: *params.message_nonces.start(),
			nonces_end: *params.message_nonces.end(),
		},
		Weight::MAX / 1000,
	)
}

/// Prepare proof of messages for the `receive_messages_proof` call.
///
/// In addition to returning valid messages proof, environment is prepared to verify this message
/// proof.
///
/// This method is intended to be used when benchmarking pallet, linked to the chain that
/// uses parachain finality. For GRANDPA chains, please use the
/// `prepare_message_proof_from_grandpa_chain` function.
pub fn prepare_message_proof_from_parachain<R, PI, B>(
	params: MessageProofParams,
	message_generator: impl Fn(usize) -> MessagePayload,
) -> (FromBridgedChainMessagesProof<HashOf<BridgedChain<B>>>, Weight)
where
	R: pallet_bridge_parachains::Config<PI>,
	PI: 'static,
	B: MessageBridge,
	UnderlyingChainOf<BridgedChain<B>>: Chain<Hash = ParaHash> + Parachain,
{
	// prepare storage proof
	let (state_root, storage_proof) = prepare_messages_storage_proof::<B>(
		params.lane,
		params.message_nonces.clone(),
		params.outbound_lane_data.clone(),
		params.size,
		prepare_inbound_message(&params, message_generator),
		encode_all_messages,
		encode_lane_data,
	);

	// update runtime storage
	let (_, bridged_header_hash) =
		insert_header_to_parachains_pallet::<R, PI, UnderlyingChainOf<BridgedChain<B>>>(state_root);

	(
		FromBridgedChainMessagesProof {
			bridged_header_hash,
			storage_proof,
			lane: params.lane,
			nonces_start: *params.message_nonces.start(),
			nonces_end: *params.message_nonces.end(),
		},
		Weight::MAX / 1000,
	)
}

/// Prepare proof of messages delivery for the `receive_messages_delivery_proof` call.
///
/// This method is intended to be used when benchmarking pallet, linked to the chain that
/// uses GRANDPA finality. For parachains, please use the
/// `prepare_message_delivery_proof_from_parachain` function.
pub fn prepare_message_delivery_proof_from_grandpa_chain<R, FI, B>(
	params: MessageDeliveryProofParams<AccountIdOf<ThisChain<B>>>,
) -> FromBridgedChainMessagesDeliveryProof<HashOf<BridgedChain<B>>>
where
	R: pallet_bridge_grandpa::Config<FI, BridgedChain = UnderlyingChainOf<BridgedChain<B>>>,
	FI: 'static,
	B: MessageBridge,
{
	// prepare storage proof
	let lane = params.lane;
	let (state_root, storage_proof) = prepare_message_delivery_storage_proof::<B>(
		params.lane,
		params.inbound_lane_data,
		params.size,
	);

	// update runtime storage
	let (_, bridged_header_hash) = insert_header_to_grandpa_pallet::<R, FI>(state_root);

	FromBridgedChainMessagesDeliveryProof {
		bridged_header_hash: bridged_header_hash.into(),
		storage_proof,
		lane,
	}
}

/// Prepare proof of messages delivery for the `receive_messages_delivery_proof` call.
///
/// This method is intended to be used when benchmarking pallet, linked to the chain that
/// uses parachain finality. For GRANDPA chains, please use the
/// `prepare_message_delivery_proof_from_grandpa_chain` function.
pub fn prepare_message_delivery_proof_from_parachain<R, PI, B>(
	params: MessageDeliveryProofParams<AccountIdOf<ThisChain<B>>>,
) -> FromBridgedChainMessagesDeliveryProof<HashOf<BridgedChain<B>>>
where
	R: pallet_bridge_parachains::Config<PI>,
	PI: 'static,
	B: MessageBridge,
	UnderlyingChainOf<BridgedChain<B>>: Chain<Hash = ParaHash> + Parachain,
{
	// prepare storage proof
	let lane = params.lane;
	let (state_root, storage_proof) = prepare_message_delivery_storage_proof::<B>(
		params.lane,
		params.inbound_lane_data,
		params.size,
	);

	// update runtime storage
	let (_, bridged_header_hash) =
		insert_header_to_parachains_pallet::<R, PI, UnderlyingChainOf<BridgedChain<B>>>(state_root);

	FromBridgedChainMessagesDeliveryProof {
		bridged_header_hash: bridged_header_hash.into(),
		storage_proof,
		lane,
	}
}

/// Insert header to the bridge GRANDPA pallet.
pub(crate) fn insert_header_to_grandpa_pallet<R, GI>(
	state_root: bp_runtime::HashOf<R::BridgedChain>,
) -> (bp_runtime::BlockNumberOf<R::BridgedChain>, bp_runtime::HashOf<R::BridgedChain>)
where
	R: pallet_bridge_grandpa::Config<GI>,
	GI: 'static,
	R::BridgedChain: bp_runtime::Chain,
{
	let bridged_block_number = Zero::zero();
	let bridged_header = bp_runtime::HeaderOf::<R::BridgedChain>::new(
		bridged_block_number,
		Default::default(),
		state_root,
		Default::default(),
		Default::default(),
	);
	let bridged_header_hash = bridged_header.hash();
	pallet_bridge_grandpa::initialize_for_benchmarks::<R, GI>(bridged_header);
	(bridged_block_number, bridged_header_hash)
}

/// Insert header to the bridge parachains pallet.
pub(crate) fn insert_header_to_parachains_pallet<R, PI, PC>(
	state_root: bp_runtime::HashOf<PC>,
) -> (bp_runtime::BlockNumberOf<PC>, bp_runtime::HashOf<PC>)
where
	R: pallet_bridge_parachains::Config<PI>,
	PI: 'static,
	PC: Chain<Hash = ParaHash> + Parachain,
{
	let bridged_block_number = Zero::zero();
	let bridged_header = bp_runtime::HeaderOf::<PC>::new(
		bridged_block_number,
		Default::default(),
		state_root,
		Default::default(),
		Default::default(),
	);
	let bridged_header_hash = bridged_header.hash();
	pallet_bridge_parachains::initialize_for_benchmarks::<R, PI, PC>(bridged_header);
	(bridged_block_number, bridged_header_hash)
}

/// Returns callback which generates `BridgeMessage` from Polkadot XCM builder based on
/// `expected_message_size` for benchmark.
pub fn generate_xcm_builder_bridge_message_sample(
	destination: InteriorLocation,
) -> impl Fn(usize) -> MessagePayload {
	move |expected_message_size| -> MessagePayload {
		// For XCM bridge hubs, it is the message that
		// will be pushed further to some XCM queue (XCMP/UMP)
		let location = xcm::VersionedInteriorLocation::V4(destination.clone());
		let location_encoded_size = location.encoded_size();

		// we don't need to be super-precise with `expected_size` here
		let xcm_size = expected_message_size.saturating_sub(location_encoded_size);
		let xcm_data_size = xcm_size.saturating_sub(
			// minus empty instruction size
			Instruction::<()>::ExpectPallet {
				index: 0,
				name: vec![],
				module_name: vec![],
				crate_major: 0,
				min_crate_minor: 0,
			}
			.encoded_size(),
		);

		log::trace!(
			target: "runtime::bridge-benchmarks",
			"generate_xcm_builder_bridge_message_sample with expected_message_size: {}, location_encoded_size: {}, xcm_size: {}, xcm_data_size: {}",
			expected_message_size, location_encoded_size, xcm_size, xcm_data_size,
		);

		let xcm = xcm::VersionedXcm::<()>::V4(
			vec![Instruction::<()>::ExpectPallet {
				index: 0,
				name: vec![42; xcm_data_size],
				module_name: vec![],
				crate_major: 0,
				min_crate_minor: 0,
			}]
			.into(),
		);

		// this is the `BridgeMessage` from polkadot xcm builder, but it has no constructor
		// or public fields, so just tuple
		// (double encoding, because `.encode()` is called on original Xcm BLOB when it is pushed
		// to the storage)
		(location, xcm).encode().encode()
	}
}