// Copyright 2019-2020 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/>.

use crate::Config;

use bp_message_lane::{
	source_chain::{LaneMessageVerifier, MessageDeliveryAndDispatchPayment, Sender, TargetHeaderChain},
	target_chain::{DispatchMessage, MessageDispatch, ProvedLaneMessages, ProvedMessages, SourceHeaderChain},
	InboundLaneData, LaneId, Message, MessageData, MessageKey, MessageNonce,
};
use codec::{Decode, Encode};
use frame_support::{impl_outer_event, impl_outer_origin, parameter_types, weights::Weight};
use sp_core::H256;
use sp_runtime::{
	testing::Header as SubstrateHeader,
	traits::{BlakeTwo256, IdentityLookup},
	Perbill,
};
use std::collections::BTreeMap;

pub type AccountId = u64;
pub type TestPayload = (u64, Weight);
pub type TestMessageFee = u64;
pub type TestRelayer = u64;

pub struct AccountIdConverter;

impl sp_runtime::traits::Convert<H256, AccountId> for AccountIdConverter {
	fn convert(hash: H256) -> AccountId {
		hash.to_low_u64_ne()
	}
}

#[derive(Clone, Eq, PartialEq, Debug)]
pub struct TestRuntime;

mod message_lane {
	pub use crate::Event;
}

impl_outer_event! {
	pub enum TestEvent for TestRuntime {
		frame_system<T>,
		message_lane<T>,
	}
}

impl_outer_origin! {
	pub enum Origin for TestRuntime where system = frame_system {}
}

parameter_types! {
	pub const BlockHashCount: u64 = 250;
	pub const MaximumBlockWeight: Weight = 1024;
	pub const MaximumBlockLength: u32 = 2 * 1024;
	pub const AvailableBlockRatio: Perbill = Perbill::one();
}

impl frame_system::Config for TestRuntime {
	type Origin = Origin;
	type Index = u64;
	type Call = ();
	type BlockNumber = u64;
	type Hash = H256;
	type Hashing = BlakeTwo256;
	type AccountId = AccountId;
	type Lookup = IdentityLookup<Self::AccountId>;
	type Header = SubstrateHeader;
	type Event = TestEvent;
	type BlockHashCount = BlockHashCount;
	type Version = ();
	type PalletInfo = ();
	type AccountData = ();
	type OnNewAccount = ();
	type OnKilledAccount = ();
	type BaseCallFilter = ();
	type SystemWeightInfo = ();
	type BlockWeights = ();
	type BlockLength = ();
	type DbWeight = ();
}

parameter_types! {
	pub const MaxMessagesToPruneAtOnce: u64 = 10;
	pub const MaxUnrewardedRelayerEntriesAtInboundLane: u64 = 16;
	pub const MaxUnconfirmedMessagesAtInboundLane: u64 = 32;
}

impl Config for TestRuntime {
	type Event = TestEvent;
	type MaxMessagesToPruneAtOnce = MaxMessagesToPruneAtOnce;
	type MaxUnrewardedRelayerEntriesAtInboundLane = MaxUnrewardedRelayerEntriesAtInboundLane;
	type MaxUnconfirmedMessagesAtInboundLane = MaxUnconfirmedMessagesAtInboundLane;

	type OutboundPayload = TestPayload;
	type OutboundMessageFee = TestMessageFee;

	type InboundPayload = TestPayload;
	type InboundMessageFee = TestMessageFee;
	type InboundRelayer = TestRelayer;

	type AccountIdConverter = AccountIdConverter;

	type TargetHeaderChain = TestTargetHeaderChain;
	type LaneMessageVerifier = TestLaneMessageVerifier;
	type MessageDeliveryAndDispatchPayment = TestMessageDeliveryAndDispatchPayment;

	type SourceHeaderChain = TestSourceHeaderChain;
	type MessageDispatch = TestMessageDispatch;
}

/// Account id of test relayer.
pub const TEST_RELAYER_A: AccountId = 100;

/// Account id of additional test relayer - B.
pub const TEST_RELAYER_B: AccountId = 101;

/// Account id of additional test relayer - C.
pub const TEST_RELAYER_C: AccountId = 102;

/// Error that is returned by all test implementations.
pub const TEST_ERROR: &str = "Test error";

/// Lane that we're using in tests.
pub const TEST_LANE_ID: LaneId = [0, 0, 0, 1];

/// Regular message payload.
pub const REGULAR_PAYLOAD: TestPayload = (0, 50);

/// Payload that is rejected by `TestTargetHeaderChain`.
pub const PAYLOAD_REJECTED_BY_TARGET_CHAIN: TestPayload = (1, 50);

/// Vec of proved messages, grouped by lane.
pub type MessagesByLaneVec = Vec<(LaneId, ProvedLaneMessages<Message<TestMessageFee>>)>;

/// Test messages proof.
#[derive(Debug, Encode, Decode, Clone, PartialEq, Eq)]
pub struct TestMessagesProof {
	pub result: Result<MessagesByLaneVec, ()>,
}

impl From<Result<Vec<Message<TestMessageFee>>, ()>> for TestMessagesProof {
	fn from(result: Result<Vec<Message<TestMessageFee>>, ()>) -> Self {
		Self {
			result: result.map(|messages| {
				let mut messages_by_lane: BTreeMap<LaneId, ProvedLaneMessages<Message<TestMessageFee>>> =
					BTreeMap::new();
				for message in messages {
					messages_by_lane
						.entry(message.key.lane_id)
						.or_default()
						.messages
						.push(message);
				}
				messages_by_lane.into_iter().collect()
			}),
		}
	}
}

/// Target header chain that is used in tests.
#[derive(Debug, Default)]
pub struct TestTargetHeaderChain;

impl TargetHeaderChain<TestPayload, TestRelayer> for TestTargetHeaderChain {
	type Error = &'static str;

	type MessagesDeliveryProof = Result<(LaneId, InboundLaneData<TestRelayer>), ()>;

	fn verify_message(payload: &TestPayload) -> Result<(), Self::Error> {
		if *payload == PAYLOAD_REJECTED_BY_TARGET_CHAIN {
			Err(TEST_ERROR)
		} else {
			Ok(())
		}
	}

	fn verify_messages_delivery_proof(
		proof: Self::MessagesDeliveryProof,
	) -> Result<(LaneId, InboundLaneData<TestRelayer>), Self::Error> {
		proof.map_err(|_| TEST_ERROR)
	}
}

/// Lane message verifier that is used in tests.
#[derive(Debug, Default)]
pub struct TestLaneMessageVerifier;

impl LaneMessageVerifier<AccountId, TestPayload, TestMessageFee> for TestLaneMessageVerifier {
	type Error = &'static str;

	fn verify_message(
		_submitter: &Sender<AccountId>,
		delivery_and_dispatch_fee: &TestMessageFee,
		_lane: &LaneId,
		_payload: &TestPayload,
	) -> Result<(), Self::Error> {
		if *delivery_and_dispatch_fee != 0 {
			Ok(())
		} else {
			Err(TEST_ERROR)
		}
	}
}

/// Message fee payment system that is used in tests.
#[derive(Debug, Default)]
pub struct TestMessageDeliveryAndDispatchPayment;

impl TestMessageDeliveryAndDispatchPayment {
	/// Reject all payments.
	pub fn reject_payments() {
		frame_support::storage::unhashed::put(b":reject-message-fee:", &true);
	}

	/// Returns true if given fee has been paid by given submitter.
	pub fn is_fee_paid(submitter: AccountId, fee: TestMessageFee) -> bool {
		frame_support::storage::unhashed::get(b":message-fee:") == Some((Sender::Signed(submitter), fee))
	}

	/// Returns true if given relayer has been rewarded with given balance. The reward-paid flag is
	/// cleared after the call.
	pub fn is_reward_paid(relayer: AccountId, fee: TestMessageFee) -> bool {
		let key = (b":relayer-reward:", relayer, fee).encode();
		frame_support::storage::unhashed::take::<bool>(&key).is_some()
	}
}

impl MessageDeliveryAndDispatchPayment<AccountId, TestMessageFee> for TestMessageDeliveryAndDispatchPayment {
	type Error = &'static str;

	fn pay_delivery_and_dispatch_fee(
		submitter: &Sender<AccountId>,
		fee: &TestMessageFee,
		_relayer_fund_account: &AccountId,
	) -> Result<(), Self::Error> {
		if frame_support::storage::unhashed::get(b":reject-message-fee:") == Some(true) {
			return Err(TEST_ERROR);
		}

		frame_support::storage::unhashed::put(b":message-fee:", &(submitter, fee));
		Ok(())
	}

	fn pay_relayer_reward(
		_confirmation_relayer: &AccountId,
		relayer: &AccountId,
		fee: &TestMessageFee,
		_relayer_fund_account: &AccountId,
	) {
		let key = (b":relayer-reward:", relayer, fee).encode();
		frame_support::storage::unhashed::put(&key, &true);
	}
}

/// Source header chain that is used in tests.
#[derive(Debug)]
pub struct TestSourceHeaderChain;

impl SourceHeaderChain<TestMessageFee> for TestSourceHeaderChain {
	type Error = &'static str;

	type MessagesProof = TestMessagesProof;

	fn verify_messages_proof(
		proof: Self::MessagesProof,
		_messages_count: MessageNonce,
	) -> Result<ProvedMessages<Message<TestMessageFee>>, Self::Error> {
		proof
			.result
			.map(|proof| proof.into_iter().collect())
			.map_err(|_| TEST_ERROR)
	}
}

/// Source header chain that is used in tests.
#[derive(Debug)]
pub struct TestMessageDispatch;

impl MessageDispatch<TestMessageFee> for TestMessageDispatch {
	type DispatchPayload = TestPayload;

	fn dispatch_weight(message: &DispatchMessage<TestPayload, TestMessageFee>) -> Weight {
		match message.data.payload.as_ref() {
			Ok(payload) => payload.1,
			Err(_) => 0,
		}
	}

	fn dispatch(_message: DispatchMessage<TestPayload, TestMessageFee>) {}
}

/// Return test lane message with given nonce and payload.
pub fn message(nonce: MessageNonce, payload: TestPayload) -> Message<TestMessageFee> {
	Message {
		key: MessageKey {
			lane_id: TEST_LANE_ID,
			nonce,
		},
		data: message_data(payload),
	}
}

/// Return message data with valid fee for given payload.
pub fn message_data(payload: TestPayload) -> MessageData<TestMessageFee> {
	MessageData {
		payload: payload.encode(),
		fee: 1,
	}
}

/// Run message lane test.
pub fn run_test<T>(test: impl FnOnce() -> T) -> T {
	let t = frame_system::GenesisConfig::default()
		.build_storage::<TestRuntime>()
		.unwrap();
	let mut ext = sp_io::TestExternalities::new(t);
	ext.execute_with(test)
}