// This file is part of Substrate.

// 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.

//! Benchmarks for the Session Pallet.
// This is separated into its own crate due to cyclic dependency issues.

#![cfg(feature = "runtime-benchmarks")]
#![cfg_attr(not(feature = "std"), no_std)]

mod mock;

use sp_runtime::traits::{One, StaticLookup, TrailingZeroInput};
use sp_std::{prelude::*, vec};

use codec::Decode;
use frame_benchmarking::v1::benchmarks;
use frame_support::traits::{Get, KeyOwnerProofSystem, OnInitialize};
use frame_system::{pallet_prelude::BlockNumberFor, RawOrigin};
use pallet_session::{historical::Pallet as Historical, Pallet as Session, *};
use pallet_staking::{
	benchmarking::create_validator_with_nominators, testing_utils::create_validators,
	MaxNominationsOf, RewardDestination,
};

const MAX_VALIDATORS: u32 = 1000;

pub struct Pallet<T: Config>(pallet_session::Pallet<T>);
pub trait Config:
	pallet_session::Config + pallet_session::historical::Config + pallet_staking::Config
{
}

impl<T: Config> OnInitialize<BlockNumberFor<T>> for Pallet<T> {
	fn on_initialize(n: BlockNumberFor<T>) -> frame_support::weights::Weight {
		pallet_session::Pallet::<T>::on_initialize(n)
	}
}

benchmarks! {
	set_keys {
		let n = MaxNominationsOf::<T>::get();
		let (v_stash, _) = create_validator_with_nominators::<T>(
			n,
			MaxNominationsOf::<T>::get(),
			false,
			true,
			RewardDestination::Staked,
		)?;
		let v_controller = pallet_staking::Pallet::<T>::bonded(&v_stash).ok_or("not stash")?;

		let keys = T::Keys::decode(&mut TrailingZeroInput::zeroes()).unwrap();
		let proof: Vec<u8> = vec![0,1,2,3];
		// Whitelist controller account from further DB operations.
		let v_controller_key = frame_system::Account::<T>::hashed_key_for(&v_controller);
		frame_benchmarking::benchmarking::add_to_whitelist(v_controller_key.into());
	}: _(RawOrigin::Signed(v_controller), keys, proof)

	purge_keys {
		let n = MaxNominationsOf::<T>::get();
		let (v_stash, _) = create_validator_with_nominators::<T>(
			n,
			MaxNominationsOf::<T>::get(),
			false,
			true,
			RewardDestination::Staked,
		)?;
		let v_controller = pallet_staking::Pallet::<T>::bonded(&v_stash).ok_or("not stash")?;
		let keys = T::Keys::decode(&mut TrailingZeroInput::zeroes()).unwrap();
		let proof: Vec<u8> = vec![0,1,2,3];
		Session::<T>::set_keys(RawOrigin::Signed(v_controller.clone()).into(), keys, proof)?;
		// Whitelist controller account from further DB operations.
		let v_controller_key = frame_system::Account::<T>::hashed_key_for(&v_controller);
		frame_benchmarking::benchmarking::add_to_whitelist(v_controller_key.into());
	}: _(RawOrigin::Signed(v_controller))

	#[extra]
	check_membership_proof_current_session {
		let n in 2 .. MAX_VALIDATORS as u32;

		let (key, key_owner_proof1) = check_membership_proof_setup::<T>(n);
		let key_owner_proof2 = key_owner_proof1.clone();
	}: {
		Historical::<T>::check_proof(key, key_owner_proof1);
	}
	verify {
		assert!(Historical::<T>::check_proof(key, key_owner_proof2).is_some());
	}

	#[extra]
	check_membership_proof_historical_session {
		let n in 2 .. MAX_VALIDATORS as u32;

		let (key, key_owner_proof1) = check_membership_proof_setup::<T>(n);

		// skip to the next session so that the session is historical
		// and the membership merkle proof must be checked.
		Session::<T>::rotate_session();

		let key_owner_proof2 = key_owner_proof1.clone();
	}: {
		Historical::<T>::check_proof(key, key_owner_proof1);
	}
	verify {
		assert!(Historical::<T>::check_proof(key, key_owner_proof2).is_some());
	}

	impl_benchmark_test_suite!(Pallet, crate::mock::new_test_ext(), crate::mock::Test, extra = false);
}

/// Sets up the benchmark for checking a membership proof. It creates the given
/// number of validators, sets random session keys and then creates a membership
/// proof for the first authority and returns its key and the proof.
fn check_membership_proof_setup<T: Config>(
	n: u32,
) -> ((sp_runtime::KeyTypeId, &'static [u8; 32]), sp_session::MembershipProof) {
	pallet_staking::ValidatorCount::<T>::put(n);

	// create validators and set random session keys
	for (n, who) in create_validators::<T>(n, 1000).unwrap().into_iter().enumerate() {
		use rand::{RngCore, SeedableRng};

		let validator = T::Lookup::lookup(who).unwrap();
		let controller = pallet_staking::Pallet::<T>::bonded(&validator).unwrap();

		let keys = {
			let mut keys = [0u8; 128];

			// we keep the keys for the first validator as 0x00000...
			if n > 0 {
				let mut rng = rand::rngs::StdRng::seed_from_u64(n as u64);
				rng.fill_bytes(&mut keys);
			}

			keys
		};

		let keys: T::Keys = Decode::decode(&mut &keys[..]).unwrap();
		let proof: Vec<u8> = vec![];

		Session::<T>::set_keys(RawOrigin::Signed(controller).into(), keys, proof).unwrap();
	}

	Pallet::<T>::on_initialize(frame_system::pallet_prelude::BlockNumberFor::<T>::one());

	// skip sessions until the new validator set is enacted
	while Session::<T>::validators().len() < n as usize {
		Session::<T>::rotate_session();
	}

	let key = (sp_runtime::KeyTypeId(*b"babe"), &[0u8; 32]);

	(key, Historical::<T>::prove(key).unwrap())
}
