// This file is part of Substrate.

// Copyright (C) 2019-2021 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.

//! Tests for the pallet.

use super::*;
use mock::*;

use frame_support::{assert_noop, assert_ok, traits::OnInitialize};
use sp_runtime::traits::BadOrigin;

type ScoredPool = Pallet<Test>;
type System = frame_system::Pallet<Test>;
type Balances = pallet_balances::Pallet<Test>;

#[test]
fn query_membership_works() {
	new_test_ext().execute_with(|| {
		assert_eq!(ScoredPool::members(), vec![20, 40]);
		assert_eq!(Balances::reserved_balance(31), CandidateDeposit::get());
		assert_eq!(Balances::reserved_balance(40), CandidateDeposit::get());
		assert_eq!(MEMBERS.with(|m| m.borrow().clone()), vec![20, 40]);
	});
}

#[test]
fn submit_candidacy_must_not_work() {
	new_test_ext().execute_with(|| {
		assert_noop!(
			ScoredPool::submit_candidacy(Origin::signed(99)),
			pallet_balances::Error::<Test, _>::InsufficientBalance,
		);
		assert_noop!(
			ScoredPool::submit_candidacy(Origin::signed(40)),
			Error::<Test, _>::AlreadyInPool
		);
	});
}

#[test]
fn submit_candidacy_works() {
	new_test_ext().execute_with(|| {
		// given
		let who = 15;

		// when
		assert_ok!(ScoredPool::submit_candidacy(Origin::signed(who)));
		assert_eq!(fetch_from_pool(15), Some((who, None)));

		// then
		assert_eq!(Balances::reserved_balance(who), CandidateDeposit::get());
	});
}

#[test]
fn scoring_works() {
	new_test_ext().execute_with(|| {
		// given
		let who = 15;
		let score = 99;
		assert_ok!(ScoredPool::submit_candidacy(Origin::signed(who)));

		// when
		let index = find_in_pool(who).expect("entity must be in pool") as u32;
		assert_ok!(ScoredPool::score(Origin::signed(ScoreOrigin::get()), who, index, score));

		// then
		assert_eq!(fetch_from_pool(who), Some((who, Some(score))));
		assert_eq!(find_in_pool(who), Some(0)); // must be first element, since highest scored
	});
}

#[test]
fn scoring_same_element_with_same_score_works() {
	new_test_ext().execute_with(|| {
		// given
		let who = 31;
		let index = find_in_pool(who).expect("entity must be in pool") as u32;
		let score = 2;

		// when
		assert_ok!(ScoredPool::score(Origin::signed(ScoreOrigin::get()), who, index, score));

		// then
		assert_eq!(fetch_from_pool(who), Some((who, Some(score))));

		// must have been inserted right before the `20` element which is
		// of the same score as `31`. so sort order is maintained.
		assert_eq!(find_in_pool(who), Some(1));
	});
}

#[test]
fn kicking_works_only_for_authorized() {
	new_test_ext().execute_with(|| {
		let who = 40;
		let index = find_in_pool(who).expect("entity must be in pool") as u32;
		assert_noop!(ScoredPool::kick(Origin::signed(99), who, index), BadOrigin);
	});
}

#[test]
fn kicking_works() {
	new_test_ext().execute_with(|| {
		// given
		let who = 40;
		assert_eq!(Balances::reserved_balance(who), CandidateDeposit::get());
		assert_eq!(find_in_pool(who), Some(0));

		// when
		let index = find_in_pool(who).expect("entity must be in pool") as u32;
		assert_ok!(ScoredPool::kick(Origin::signed(KickOrigin::get()), who, index));

		// then
		assert_eq!(find_in_pool(who), None);
		assert_eq!(ScoredPool::members(), vec![20, 31]);
		assert_eq!(MEMBERS.with(|m| m.borrow().clone()), ScoredPool::members());
		assert_eq!(Balances::reserved_balance(who), 0); // deposit must have been returned
	});
}

#[test]
fn unscored_entities_must_not_be_used_for_filling_members() {
	new_test_ext().execute_with(|| {
		// given
		// we submit a candidacy, score will be `None`
		assert_ok!(ScoredPool::submit_candidacy(Origin::signed(15)));

		// when
		// we remove every scored member
		ScoredPool::pool().into_iter().for_each(|(who, score)| {
			if let Some(_) = score {
				let index = find_in_pool(who).expect("entity must be in pool") as u32;
				assert_ok!(ScoredPool::kick(Origin::signed(KickOrigin::get()), who, index));
			}
		});

		// then
		// the `None` candidates should not have been filled in
		assert!(ScoredPool::members().is_empty());
		assert_eq!(MEMBERS.with(|m| m.borrow().clone()), ScoredPool::members());
	});
}

#[test]
fn refreshing_works() {
	new_test_ext().execute_with(|| {
		// given
		let who = 15;
		assert_ok!(ScoredPool::submit_candidacy(Origin::signed(who)));
		let index = find_in_pool(who).expect("entity must be in pool") as u32;
		assert_ok!(ScoredPool::score(Origin::signed(ScoreOrigin::get()), who, index, 99));

		// when
		ScoredPool::refresh_members(ScoredPool::pool(), ChangeReceiver::MembershipChanged);

		// then
		assert_eq!(ScoredPool::members(), vec![15, 40]);
		assert_eq!(MEMBERS.with(|m| m.borrow().clone()), ScoredPool::members());
	});
}

#[test]
fn refreshing_happens_every_period() {
	new_test_ext().execute_with(|| {
		// given
		System::set_block_number(1);
		assert_ok!(ScoredPool::submit_candidacy(Origin::signed(15)));
		let index = find_in_pool(15).expect("entity must be in pool") as u32;
		assert_ok!(ScoredPool::score(Origin::signed(ScoreOrigin::get()), 15, index, 99));
		assert_eq!(ScoredPool::members(), vec![20, 40]);

		// when
		System::set_block_number(4);
		ScoredPool::on_initialize(4);

		// then
		assert_eq!(ScoredPool::members(), vec![15, 40]);
		assert_eq!(MEMBERS.with(|m| m.borrow().clone()), ScoredPool::members());
	});
}

#[test]
fn withdraw_candidacy_must_only_work_for_members() {
	new_test_ext().execute_with(|| {
		let who = 77;
		let index = 0;
		assert_noop!(
			ScoredPool::withdraw_candidacy(Origin::signed(who), index),
			Error::<Test, _>::WrongAccountIndex
		);
	});
}

#[test]
fn oob_index_should_abort() {
	new_test_ext().execute_with(|| {
		let who = 40;
		let oob_index = ScoredPool::pool().len() as u32;
		assert_noop!(
			ScoredPool::withdraw_candidacy(Origin::signed(who), oob_index),
			Error::<Test, _>::InvalidIndex
		);
		assert_noop!(
			ScoredPool::score(Origin::signed(ScoreOrigin::get()), who, oob_index, 99),
			Error::<Test, _>::InvalidIndex
		);
		assert_noop!(
			ScoredPool::kick(Origin::signed(KickOrigin::get()), who, oob_index),
			Error::<Test, _>::InvalidIndex
		);
	});
}

#[test]
fn index_mismatches_should_abort() {
	new_test_ext().execute_with(|| {
		let who = 40;
		let index = 3;
		assert_noop!(
			ScoredPool::withdraw_candidacy(Origin::signed(who), index),
			Error::<Test, _>::WrongAccountIndex
		);
		assert_noop!(
			ScoredPool::score(Origin::signed(ScoreOrigin::get()), who, index, 99),
			Error::<Test, _>::WrongAccountIndex
		);
		assert_noop!(
			ScoredPool::kick(Origin::signed(KickOrigin::get()), who, index),
			Error::<Test, _>::WrongAccountIndex
		);
	});
}

#[test]
fn withdraw_unscored_candidacy_must_work() {
	new_test_ext().execute_with(|| {
		// given
		let who = 5;

		// when
		let index = find_in_pool(who).expect("entity must be in pool") as u32;
		assert_ok!(ScoredPool::withdraw_candidacy(Origin::signed(who), index));

		// then
		assert_eq!(fetch_from_pool(5), None);
	});
}

#[test]
fn withdraw_scored_candidacy_must_work() {
	new_test_ext().execute_with(|| {
		// given
		let who = 40;
		assert_eq!(Balances::reserved_balance(who), CandidateDeposit::get());

		// when
		let index = find_in_pool(who).expect("entity must be in pool") as u32;
		assert_ok!(ScoredPool::withdraw_candidacy(Origin::signed(who), index));

		// then
		assert_eq!(fetch_from_pool(who), None);
		assert_eq!(ScoredPool::members(), vec![20, 31]);
		assert_eq!(Balances::reserved_balance(who), 0);
	});
}

#[test]
fn candidacy_resubmitting_works() {
	new_test_ext().execute_with(|| {
		// given
		let who = 15;

		// when
		assert_ok!(ScoredPool::submit_candidacy(Origin::signed(who)));
		assert_eq!(ScoredPool::candidate_exists(who), true);
		let index = find_in_pool(who).expect("entity must be in pool") as u32;
		assert_ok!(ScoredPool::withdraw_candidacy(Origin::signed(who), index));
		assert_eq!(ScoredPool::candidate_exists(who), false);
		assert_ok!(ScoredPool::submit_candidacy(Origin::signed(who)));

		// then
		assert_eq!(ScoredPool::candidate_exists(who), true);
	});
}