// This file is part of Bizinikiwi.

// 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.

use crate::{
	address::AddressMapper,
	precompiles::{BuiltinAddressMatcher, BuiltinPrecompile, Error, Ext},
	vm::RuntimeCosts,
	Config, H160,
};
use alloc::vec::Vec;
use alloy_core::sol_types::SolValue;
use codec::Encode;
use core::{marker::PhantomData, num::NonZero};
use pezpallet_revive_uapi::precompiles::system::ISystem;
use pezsp_core::hexdisplay::AsBytesRef;

pub struct System<T>(PhantomData<T>);

impl<T: Config> BuiltinPrecompile for System<T> {
	type T = T;
	type Interface = ISystem::ISystemCalls;
	const MATCHER: BuiltinAddressMatcher =
		BuiltinAddressMatcher::Fixed(NonZero::new(0x900).unwrap());
	const HAS_CONTRACT_INFO: bool = false;

	fn call(
		_address: &[u8; 20],
		input: &Self::Interface,
		env: &mut impl Ext<T = Self::T>,
	) -> Result<Vec<u8>, Error> {
		use ISystem::ISystemCalls;
		match input {
			ISystemCalls::terminate(_) if env.is_read_only() =>
				Err(crate::Error::<T>::StateChangeDenied.into()),
			ISystemCalls::hashBlake256(ISystem::hashBlake256Call { input }) => {
				env.gas_meter_mut().charge(RuntimeCosts::HashBlake256(input.len() as u32))?;
				let output = pezsp_io::hashing::blake2_256(input.as_bytes_ref());
				Ok(output.abi_encode())
			},
			ISystemCalls::hashBlake128(ISystem::hashBlake128Call { input }) => {
				env.gas_meter_mut().charge(RuntimeCosts::HashBlake128(input.len() as u32))?;
				let output = pezsp_io::hashing::blake2_128(input.as_bytes_ref());
				Ok(output.abi_encode())
			},
			ISystemCalls::toAccountId(ISystem::toAccountIdCall { input }) => {
				env.gas_meter_mut().charge(RuntimeCosts::ToAccountId)?;
				let account_id = env.to_account_id(&H160::from_slice(input.as_slice()));
				Ok(account_id.encode().abi_encode())
			},
			ISystemCalls::callerIsOrigin(ISystem::callerIsOriginCall {}) => {
				env.gas_meter_mut().charge(RuntimeCosts::CallerIsOrigin)?;
				let is_origin = env.caller_is_origin(true);
				Ok(is_origin.abi_encode())
			},
			ISystemCalls::callerIsRoot(ISystem::callerIsRootCall {}) => {
				env.gas_meter_mut().charge(RuntimeCosts::CallerIsRoot)?;
				let is_root = env.caller_is_root(true);
				Ok(is_root.abi_encode())
			},
			ISystemCalls::ownCodeHash(ISystem::ownCodeHashCall {}) => {
				env.gas_meter_mut().charge(RuntimeCosts::OwnCodeHash)?;
				let caller = env.caller();
				let addr = T::AddressMapper::to_address(caller.account_id()?);
				let output = env.code_hash(&addr.into()).0.abi_encode();
				Ok(output)
			},
			ISystemCalls::minimumBalance(ISystem::minimumBalanceCall {}) => {
				env.gas_meter_mut().charge(RuntimeCosts::MinimumBalance)?;
				let minimum_balance = env.minimum_balance();
				Ok(minimum_balance.to_big_endian().abi_encode())
			},
			ISystemCalls::weightLeft(ISystem::weightLeftCall {}) => {
				env.gas_meter_mut().charge(RuntimeCosts::WeightLeft)?;
				let ref_time = env.gas_meter().gas_left().ref_time();
				let proof_size = env.gas_meter().gas_left().proof_size();
				let res = (ref_time, proof_size);
				Ok(res.abi_encode())
			},
			ISystemCalls::terminate(ISystem::terminateCall { beneficiary }) => {
				// no need to adjust gas because this always deletes code
				env.gas_meter_mut().charge(RuntimeCosts::Terminate { code_removed: true })?;
				let h160 = H160::from_slice(beneficiary.as_slice());
				env.terminate_caller(&h160).map_err(Error::try_to_revert::<T>)?;
				Ok(Vec::new())
			},
		}
	}
}

#[cfg(test)]
mod tests {
	use super::*;
	use crate::{
		address::AddressMapper,
		call_builder::{caller_funding, CallSetup},
		pezpallet,
		precompiles::{
			alloy::sol_types::{sol_data::Bytes, SolType},
			tests::run_test_vectors,
			BuiltinPrecompile,
		},
		tests::{ExtBuilder, Test},
	};
	use codec::Decode;
	use pezframe_support::traits::fungible::Mutate;

	#[test]
	fn test_system_precompile() {
		run_test_vectors::<System<Test>>(include_str!("testdata/900-blake2_256.json"));
		run_test_vectors::<System<Test>>(include_str!("testdata/900-blake2_128.json"));
		run_test_vectors::<System<Test>>(include_str!("testdata/900-to_account_id.json"));
	}

	#[test]
	fn test_system_precompile_unmapped_account() {
		ExtBuilder::default().build().execute_with(|| {
			// given
			let mut call_setup = CallSetup::<Test>::default();
			let (mut ext, _) = call_setup.ext();
			let unmapped_address = H160::zero();

			// when
			let input = ISystem::ISystemCalls::toAccountId(ISystem::toAccountIdCall {
				input: unmapped_address.0.into(),
			});
			let raw_data =
				<System<Test>>::call(&<System<Test>>::MATCHER.base_address(), &input, &mut ext)
					.unwrap();

			// then
			let expected_fallback_account_id =
				Bytes::abi_decode(&raw_data).expect("decoding failed");
			assert_eq!(
				expected_fallback_account_id.0.as_ref()[20..32],
				[0xEE; 12],
				"no fallback suffix found where one should be"
			);
		})
	}

	#[test]
	fn test_system_precompile_mapped_account() {
		use crate::test_utils::EVE;
		ExtBuilder::default().build().execute_with(|| {
			// given
			let mapped_address = {
				<Test as pezpallet::Config>::Currency::set_balance(&EVE, caller_funding::<Test>());
				let _ = <Test as pezpallet::Config>::AddressMapper::map(&EVE);
				<Test as pezpallet::Config>::AddressMapper::to_address(&EVE)
			};

			let mut call_setup = CallSetup::<Test>::default();
			let (mut ext, _) = call_setup.ext();

			// when
			let input = ISystem::ISystemCalls::toAccountId(ISystem::toAccountIdCall {
				input: mapped_address.0.into(),
			});
			let raw_data =
				<System<Test>>::call(&<System<Test>>::MATCHER.base_address(), &input, &mut ext)
					.unwrap();

			// then
			let data = Bytes::abi_decode(&raw_data).expect("decoding failed");
			assert_ne!(
				data.0.as_ref()[20..32],
				[0xEE; 12],
				"fallback suffix found where none should be"
			);
			assert_eq!(
				<Test as pezframe_system::Config>::AccountId::decode(&mut data.as_ref()),
				Ok(EVE),
			);
		})
	}
}