// This file is part of Frontier.

// Copyright (c) Moonsong Labs.
// 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.

#![cfg(test)]

// #[precompile_utils::precompile] need this
extern crate alloc;

use std::{cell::RefCell, rc::Rc};

// Substrate
use frame_support::{
	construct_runtime, derive_impl, parameter_types, traits::Everything, weights::Weight,
};
use sp_core::{H160, H256, U256};
use sp_runtime::{
	traits::{BlakeTwo256, IdentityLookup},
	BuildStorage, Perbill,
};
// Frontier
use fp_evm::{ExitReason, ExitRevert, PrecompileFailure, PrecompileHandle};
use pallet_evm::{CodeMetadata, EnsureAddressNever, EnsureAddressRoot};
use precompile_utils::{
	precompile_set::*,
	solidity::{codec::Writer, revert::revert},
	testing::*,
	EvmResult,
};

pub type AccountId = MockAccount;
pub type Balance = u128;

construct_runtime!(
	pub enum Runtime {
		System: frame_system::{Pallet, Call, Config<T>, Storage, Event<T>},
		Balances: pallet_balances::{Pallet, Call, Storage, Event<T>},
		Evm: pallet_evm::{Pallet, Call, Storage, Event<T>},
		Timestamp: pallet_timestamp::{Pallet, Call, Storage, Inherent},
	}
);

parameter_types! {
	pub const BlockHashCount: u32 = 250;
	pub const MaximumBlockWeight: Weight = Weight::from_parts(1024, 1);
	pub const MaximumBlockLength: u32 = 2 * 1024;
	pub const AvailableBlockRatio: Perbill = Perbill::one();
	pub const SS58Prefix: u8 = 42;
}

#[derive_impl(frame_system::config_preludes::TestDefaultConfig as frame_system::DefaultConfig)]
impl frame_system::Config for Runtime {
	type RuntimeEvent = RuntimeEvent;
	type BaseCallFilter = Everything;
	type BlockWeights = ();
	type BlockLength = ();
	type RuntimeOrigin = RuntimeOrigin;
	type RuntimeCall = RuntimeCall;
	type RuntimeTask = RuntimeTask;
	type Nonce = u64;
	type Hash = H256;
	type Hashing = BlakeTwo256;
	type AccountId = AccountId;
	type Lookup = IdentityLookup<Self::AccountId>;
	type Block = frame_system::mocking::MockBlock<Self>;
	type BlockHashCount = BlockHashCount;
	type DbWeight = ();
	type Version = ();
	type PalletInfo = PalletInfo;
	type AccountData = pallet_balances::AccountData<Balance>;
	type OnNewAccount = ();
	type OnKilledAccount = ();
	type SystemWeightInfo = ();
	type SS58Prefix = SS58Prefix;
	type OnSetCode = ();
	type MaxConsumers = frame_support::traits::ConstU32<16>;
}

parameter_types! {
	pub const ExistentialDeposit: u128 = 0;
}
impl pallet_balances::Config for Runtime {
	type RuntimeEvent = RuntimeEvent;
	type RuntimeHoldReason = RuntimeHoldReason;
	type RuntimeFreezeReason = RuntimeFreezeReason;
	type WeightInfo = ();
	type Balance = Balance;
	type DustRemoval = ();
	type ExistentialDeposit = ExistentialDeposit;
	type AccountStore = System;
	type ReserveIdentifier = [u8; 8];
	type FreezeIdentifier = RuntimeFreezeReason;
	type MaxLocks = ();
	type MaxReserves = ();
	type MaxFreezes = ();
	type DoneSlashHandler = ();
}

#[derive(Debug, Clone)]
pub struct MockPrecompile;

#[precompile_utils::precompile]
impl MockPrecompile {
	// a3cab0dd
	#[precompile::public("subcall()")]
	fn subcall(handle: &mut impl PrecompileHandle) -> EvmResult {
		match handle.call(
			handle.code_address(),
			None,
			// calls subcallLayer2()
			Writer::new_with_selector(0x0b93381bu32).build(),
			None,
			false,
			&evm::Context {
				caller: handle.code_address(),
				address: handle.code_address(),
				apparent_value: 0.into(),
			},
		) {
			(ExitReason::Succeed(_), _) => Ok(()),
			(ExitReason::Revert(_), v) => Err(PrecompileFailure::Revert {
				exit_status: ExitRevert::Reverted,
				output: v,
			}),
			_ => Err(revert("unexpected error")),
		}
	}

	// 0b93381b
	#[precompile::public("success()")]
	fn success(_: &mut impl PrecompileHandle) -> EvmResult {
		Ok(())
	}
}

#[derive(Default)]
struct MockPrecompileHandle {
	contracts_being_constructed: Vec<H160>,
}
impl MockPrecompileHandle {
	fn with_contracts_being_constructed(mut self, contracts_being_constructed: Vec<H160>) -> Self {
		self.contracts_being_constructed = contracts_being_constructed;
		self
	}
}
impl PrecompileHandle for MockPrecompileHandle {
	fn call(
		&mut self,
		_: H160,
		_: Option<evm::Transfer>,
		_: Vec<u8>,
		_: Option<u64>,
		_: bool,
		_: &evm::Context,
	) -> (ExitReason, Vec<u8>) {
		unimplemented!()
	}

	fn record_cost(&mut self, _: u64) -> Result<(), evm::ExitError> {
		Ok(())
	}

	fn record_external_cost(
		&mut self,
		_ref_time: Option<u64>,
		_proof_size: Option<u64>,
		_storage_growth: Option<u64>,
	) -> Result<(), fp_evm::ExitError> {
		Ok(())
	}

	fn refund_external_cost(&mut self, _ref_time: Option<u64>, _proof_size: Option<u64>) {}

	fn remaining_gas(&self) -> u64 {
		0
	}

	fn log(&mut self, _: H160, _: Vec<H256>, _: Vec<u8>) -> Result<(), evm::ExitError> {
		unimplemented!()
	}

	fn code_address(&self) -> H160 {
		unimplemented!()
	}

	fn input(&self) -> &[u8] {
		unimplemented!()
	}

	fn context(&self) -> &evm::Context {
		unimplemented!()
	}

	fn origin(&self) -> H160 {
		Alice.into()
	}

	fn is_static(&self) -> bool {
		true
	}

	fn gas_limit(&self) -> Option<u64> {
		unimplemented!()
	}

	fn is_contract_being_constructed(&self, address: H160) -> bool {
		self.contracts_being_constructed.contains(&address)
	}
}

pub type Precompiles<R> = PrecompileSetBuilder<
	R,
	(
		PrecompileAt<AddressU64<1>, MockPrecompile>,
		PrecompileAt<AddressU64<2>, MockPrecompile, CallableByContract>,
		PrecompileAt<AddressU64<3>, MockPrecompile, CallableByPrecompile>,
		PrecompileAt<AddressU64<4>, MockPrecompile, SubcallWithMaxNesting<1>>,
	),
>;

pub type PCall = MockPrecompileCall;

const MAX_POV_SIZE: u64 = 5 * 1024 * 1024;

parameter_types! {
	pub BlockGasLimit: U256 = U256::from(u64::MAX);
	pub PrecompilesValue: Precompiles<Runtime> = Precompiles::new();
	pub const WeightPerGas: Weight = Weight::from_parts(1, 0);
	pub GasLimitPovSizeRatio: u64 = {
		let block_gas_limit = BlockGasLimit::get().min(u64::MAX.into()).low_u64();
		block_gas_limit.saturating_div(MAX_POV_SIZE)
	};
}

impl pallet_evm::Config for Runtime {
	type AccountProvider = pallet_evm::FrameSystemAccountProvider<Self>;
	type FeeCalculator = ();
	type GasWeightMapping = pallet_evm::FixedGasWeightMapping<Self>;
	type WeightPerGas = WeightPerGas;
	type BlockHashMapping = pallet_evm::SubstrateBlockHashMapping<Self>;
	type CallOrigin = EnsureAddressRoot<AccountId>;
	type WithdrawOrigin = EnsureAddressNever<AccountId>;
	type AddressMapping = AccountId;
	type Currency = Balances;
	type RuntimeEvent = RuntimeEvent;
	type PrecompilesType = Precompiles<Runtime>;
	type PrecompilesValue = PrecompilesValue;
	type ChainId = ();
	type BlockGasLimit = BlockGasLimit;
	type Runner = pallet_evm::runner::stack::Runner<Self>;
	type OnChargeTransaction = ();
	type OnCreate = ();
	type FindAuthor = ();
	type GasLimitPovSizeRatio = GasLimitPovSizeRatio;
	type GasLimitStorageGrowthRatio = ();
	type Timestamp = Timestamp;
	type CreateInnerOriginFilter = ();
	type CreateOriginFilter = ();
	type WeightInfo = pallet_evm::weights::SubstrateWeight<Runtime>;
}

parameter_types! {
	pub const MinimumPeriod: u64 = 5;
}
impl pallet_timestamp::Config for Runtime {
	type Moment = u64;
	type OnTimestampSet = ();
	type MinimumPeriod = MinimumPeriod;
	type WeightInfo = ();
}

#[derive(Default)]
struct ExtBuilder {}

impl ExtBuilder {
	fn build(self) -> sp_io::TestExternalities {
		let t = frame_system::GenesisConfig::<Runtime>::default()
			.build_storage()
			.expect("Frame system builds valid default genesis config");

		let mut ext = sp_io::TestExternalities::new(t);
		ext.execute_with(|| {
			System::set_block_number(1);
		});
		ext
	}
}

fn precompiles() -> Precompiles<Runtime> {
	PrecompilesValue::get()
}

#[test]
fn default_checks_succeed_when_called_by_eoa() {
	ExtBuilder::default().build().execute_with(|| {
		precompiles()
			.prepare_test(Alice, H160::from_low_u64_be(1), PCall::success {})
			.with_subcall_handle(|Subcall { .. }| panic!("there should be no subcall"))
			.execute_returns(())
	})
}

#[test]
fn default_checks_revert_when_called_by_precompile() {
	ExtBuilder::default().build().execute_with(|| {
		precompiles()
			.prepare_test(
				H160::from_low_u64_be(1),
				H160::from_low_u64_be(1),
				PCall::success {},
			)
			.with_subcall_handle(|Subcall { .. }| panic!("there should be no subcall"))
			.execute_reverts(|r| r == b"Function not callable by precompiles")
	})
}

#[test]
fn default_checks_revert_when_called_by_contract() {
	ExtBuilder::default().build().execute_with(|| {
		let _ = pallet_evm::Pallet::<Runtime>::create_account(
			Alice.into(),
			hex_literal::hex!("1460006000fd").to_vec(),
			None,
		);

		precompiles()
			.prepare_test(Alice, H160::from_low_u64_be(1), PCall::success {})
			.with_subcall_handle(|Subcall { .. }| panic!("there should be no subcall"))
			.execute_reverts(|r| r == b"Function not callable by smart contracts")
	})
}

#[test]
fn default_checks_revert_when_doing_subcall() {
	ExtBuilder::default().build().execute_with(|| {
		precompiles()
			.prepare_test(Alice, H160::from_low_u64_be(1), PCall::subcall {})
			.with_subcall_handle(|Subcall { .. }| panic!("there should be no subcall"))
			.execute_reverts(|r| r == b"subcalls disabled for this precompile")
	})
}

#[test]
fn callable_by_contract_works() {
	ExtBuilder::default().build().execute_with(|| {
		let _ = pallet_evm::Pallet::<Runtime>::create_account(
			Alice.into(),
			hex_literal::hex!("1460006000fd").to_vec(),
			None,
		);

		precompiles()
			.prepare_test(Alice, H160::from_low_u64_be(2), PCall::success {})
			.with_subcall_handle(|Subcall { .. }| panic!("there should be no subcall"))
			.execute_returns(())
	})
}

#[test]
fn callable_by_precompile_works() {
	ExtBuilder::default().build().execute_with(|| {
		precompiles()
			.prepare_test(
				H160::from_low_u64_be(3),
				H160::from_low_u64_be(3),
				PCall::success {},
			)
			.with_subcall_handle(|Subcall { .. }| panic!("there should be no subcall"))
			.execute_returns(())
	})
}

#[test]
fn subcalls_works_when_allowed() {
	ExtBuilder::default().build().execute_with(|| {
		let subcall_occured = Rc::new(RefCell::new(false));
		{
			let subcall_occured = Rc::clone(&subcall_occured);
			precompiles()
				.prepare_test(Alice, H160::from_low_u64_be(4), PCall::subcall {})
				.with_subcall_handle(move |Subcall { .. }| {
					*subcall_occured.borrow_mut() = true;
					SubcallOutput::succeed()
				})
				.execute_returns(());
		}
		assert!(*subcall_occured.borrow());
	})
}

#[test]
fn get_address_type_works_for_eoa() {
	ExtBuilder::default().build().execute_with(|| {
		let externally_owned_account: H160 = Alice.into();
		let mut handle = MockPrecompileHandle::default();

		assert_eq!(
			AddressType::EOA,
			get_address_type::<Runtime>(&mut handle, externally_owned_account).expect("OOG")
		);
	})
}

#[test]
fn get_address_type_works_for_precompile() {
	ExtBuilder::default().build().execute_with(|| {
		let precompiles: Vec<H160> = Precompiles::<Runtime>::used_addresses_h160().collect();
		// We expect 4 precompiles
		assert_eq!(precompiles.len(), 4);

		let mut handle = MockPrecompileHandle::default();
		precompiles.iter().cloned().for_each(|precompile| {
			assert_eq!(
				AddressType::Precompile,
				get_address_type::<Runtime>(&mut handle, precompile).expect("OOG")
			);
		});
	})
}

#[test]
fn get_address_type_works_for_smart_contract() {
	ExtBuilder::default().build().execute_with(|| {
		let address = H160::repeat_byte(0x1d);
		pallet_evm::AccountCodesMetadata::<Runtime>::insert(
			address,
			CodeMetadata {
				hash: Default::default(),
				size: 1,
			},
		);

		let mut handle = MockPrecompileHandle::default();
		assert_eq!(
			AddressType::Contract,
			get_address_type::<Runtime>(&mut handle, address).expect("OOG")
		);
	})
}

#[test]
fn get_address_type_works_for_smart_contract_being_constructed() {
	ExtBuilder::default().build().execute_with(|| {
		let contract_being_constucted = H160::repeat_byte(0x1d);
		let mut handle = MockPrecompileHandle::default()
			.with_contracts_being_constructed(vec![contract_being_constucted]);

		assert_eq!(
			AddressType::Contract,
			get_address_type::<Runtime>(&mut handle, contract_being_constucted).expect("OOG")
		);
	})
}