// Copyright 2017-2020 Parity Technologies (UK) Ltd.
// This file is part of Substrate.

// Substrate 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.

// Substrate 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 Substrate.  If not, see <http://www.gnu.org/licenses/>.

//! Tests for the module.

#![cfg(test)]

use sp_runtime::{testing::Digest, traits::{Header, OnFinalize}};
use crate::mock::*;
use frame_system::{EventRecord, Phase};
use codec::{Decode, Encode};
use fg_primitives::ScheduledChange;
use super::*;

#[test]
fn authorities_change_logged() {
	new_test_ext(vec![(1, 1), (2, 1), (3, 1)]).execute_with(|| {
		System::initialize(&1, &Default::default(), &Default::default(), &Default::default());
		Grandpa::schedule_change(to_authorities(vec![(4, 1), (5, 1), (6, 1)]), 0, None).unwrap();

		System::note_finished_extrinsics();
		Grandpa::on_finalize(1);

		let header = System::finalize();
		assert_eq!(header.digest, Digest {
			logs: vec![
				grandpa_log(ConsensusLog::ScheduledChange(
					ScheduledChange { delay: 0, next_authorities: to_authorities(vec![(4, 1), (5, 1), (6, 1)]) }
				)),
			],
		});

		assert_eq!(System::events(), vec![
			EventRecord {
				phase: Phase::Finalization,
				event: Event::NewAuthorities(to_authorities(vec![(4, 1), (5, 1), (6, 1)])).into(),
				topics: vec![],
			},
		]);
	});
}

#[test]
fn authorities_change_logged_after_delay() {
	new_test_ext(vec![(1, 1), (2, 1), (3, 1)]).execute_with(|| {
		System::initialize(&1, &Default::default(), &Default::default(), &Default::default());
		Grandpa::schedule_change(to_authorities(vec![(4, 1), (5, 1), (6, 1)]), 1, None).unwrap();
		Grandpa::on_finalize(1);
		let header = System::finalize();
		assert_eq!(header.digest, Digest {
			logs: vec![
				grandpa_log(ConsensusLog::ScheduledChange(
					ScheduledChange { delay: 1, next_authorities: to_authorities(vec![(4, 1), (5, 1), (6, 1)]) }
				)),
			],
		});

		// no change at this height.
		assert_eq!(System::events(), vec![]);

		System::initialize(&2, &header.hash(), &Default::default(), &Default::default());
		System::note_finished_extrinsics();
		Grandpa::on_finalize(2);

		let _header = System::finalize();
		assert_eq!(System::events(), vec![
			EventRecord {
				phase: Phase::Finalization,
				event: Event::NewAuthorities(to_authorities(vec![(4, 1), (5, 1), (6, 1)])).into(),
				topics: vec![],
			},
		]);
	});
}

#[test]
fn cannot_schedule_change_when_one_pending() {
	new_test_ext(vec![(1, 1), (2, 1), (3, 1)]).execute_with(|| {
		System::initialize(&1, &Default::default(), &Default::default(), &Default::default());
		Grandpa::schedule_change(to_authorities(vec![(4, 1), (5, 1), (6, 1)]), 1, None).unwrap();
		assert!(<PendingChange<Test>>::exists());
		assert!(Grandpa::schedule_change(to_authorities(vec![(5, 1)]), 1, None).is_err());

		Grandpa::on_finalize(1);
		let header = System::finalize();

		System::initialize(&2, &header.hash(), &Default::default(), &Default::default());
		assert!(<PendingChange<Test>>::exists());
		assert!(Grandpa::schedule_change(to_authorities(vec![(5, 1)]), 1, None).is_err());

		Grandpa::on_finalize(2);
		let header = System::finalize();

		System::initialize(&3, &header.hash(), &Default::default(), &Default::default());
		assert!(!<PendingChange<Test>>::exists());
		assert!(Grandpa::schedule_change(to_authorities(vec![(5, 1)]), 1, None).is_ok());

		Grandpa::on_finalize(3);
		let _header = System::finalize();
	});
}

#[test]
fn new_decodes_from_old() {
	let old = OldStoredPendingChange {
		scheduled_at: 5u32,
		delay: 100u32,
		next_authorities: to_authorities(vec![(1, 5), (2, 10), (3, 2)]),
	};

	let encoded = old.encode();
	let new = StoredPendingChange::<u32>::decode(&mut &encoded[..]).unwrap();
	assert!(new.forced.is_none());
	assert_eq!(new.scheduled_at, old.scheduled_at);
	assert_eq!(new.delay, old.delay);
	assert_eq!(new.next_authorities, old.next_authorities);
}

#[test]
fn dispatch_forced_change() {
	new_test_ext(vec![(1, 1), (2, 1), (3, 1)]).execute_with(|| {
		System::initialize(&1, &Default::default(), &Default::default(), &Default::default());
		Grandpa::schedule_change(
			to_authorities(vec![(4, 1), (5, 1), (6, 1)]),
			5,
			Some(0),
		).unwrap();

		assert!(<PendingChange<Test>>::exists());
		assert!(Grandpa::schedule_change(to_authorities(vec![(5, 1)]), 1, Some(0)).is_err());

		Grandpa::on_finalize(1);
		let mut header = System::finalize();

		for i in 2..7 {
			System::initialize(&i, &header.hash(), &Default::default(), &Default::default());
			assert!(<PendingChange<Test>>::get().unwrap().forced.is_some());
			assert_eq!(Grandpa::next_forced(), Some(11));
			assert!(Grandpa::schedule_change(to_authorities(vec![(5, 1)]), 1, None).is_err());
			assert!(Grandpa::schedule_change(to_authorities(vec![(5, 1)]), 1, Some(0)).is_err());

			Grandpa::on_finalize(i);
			header = System::finalize();
		}

		// change has been applied at the end of block 6.
		// add a normal change.
		{
			System::initialize(&7, &header.hash(), &Default::default(), &Default::default());
			assert!(!<PendingChange<Test>>::exists());
			assert_eq!(Grandpa::grandpa_authorities(), to_authorities(vec![(4, 1), (5, 1), (6, 1)]));
			assert!(Grandpa::schedule_change(to_authorities(vec![(5, 1)]), 1, None).is_ok());
			Grandpa::on_finalize(7);
			header = System::finalize();
		}

		// run the normal change.
		{
			System::initialize(&8, &header.hash(), &Default::default(), &Default::default());
			assert!(<PendingChange<Test>>::exists());
			assert_eq!(Grandpa::grandpa_authorities(), to_authorities(vec![(4, 1), (5, 1), (6, 1)]));
			assert!(Grandpa::schedule_change(to_authorities(vec![(5, 1)]), 1, None).is_err());
			Grandpa::on_finalize(8);
			header = System::finalize();
		}

		// normal change applied. but we can't apply a new forced change for some
		// time.
		for i in 9..11 {
			System::initialize(&i, &header.hash(), &Default::default(), &Default::default());
			assert!(!<PendingChange<Test>>::exists());
			assert_eq!(Grandpa::grandpa_authorities(), to_authorities(vec![(5, 1)]));
			assert_eq!(Grandpa::next_forced(), Some(11));
			assert!(Grandpa::schedule_change(to_authorities(vec![(5, 1), (6, 1)]), 5, Some(0)).is_err());
			Grandpa::on_finalize(i);
			header = System::finalize();
		}

		{
			System::initialize(&11, &header.hash(), &Default::default(), &Default::default());
			assert!(!<PendingChange<Test>>::exists());
			assert!(Grandpa::schedule_change(to_authorities(vec![(5, 1), (6, 1), (7, 1)]), 5, Some(0)).is_ok());
			assert_eq!(Grandpa::next_forced(), Some(21));
			Grandpa::on_finalize(11);
			header = System::finalize();
		}
		let _ = header;
	});
}

#[test]
fn schedule_pause_only_when_live() {
	new_test_ext(vec![(1, 1), (2, 1), (3, 1)]).execute_with(|| {
		// we schedule a pause at block 1 with delay of 1
		System::initialize(&1, &Default::default(), &Default::default(), &Default::default());
		Grandpa::schedule_pause(1).unwrap();

		// we've switched to the pending pause state
		assert_eq!(
			Grandpa::state(),
			StoredState::PendingPause {
				scheduled_at: 1u64,
				delay: 1,
			},
		);

		Grandpa::on_finalize(1);
		let _ = System::finalize();

		System::initialize(&2, &Default::default(), &Default::default(), &Default::default());

		// signaling a pause now should fail
		assert!(Grandpa::schedule_pause(1).is_err());

		Grandpa::on_finalize(2);
		let _ = System::finalize();

		// after finalizing block 2 the set should have switched to paused state
		assert_eq!(
			Grandpa::state(),
			StoredState::Paused,
		);
	});
}

#[test]
fn schedule_resume_only_when_paused() {
	new_test_ext(vec![(1, 1), (2, 1), (3, 1)]).execute_with(|| {
		System::initialize(&1, &Default::default(), &Default::default(), &Default::default());

		// the set is currently live, resuming it is an error
		assert!(Grandpa::schedule_resume(1).is_err());

		assert_eq!(
			Grandpa::state(),
			StoredState::Live,
		);

		// we schedule a pause to be applied instantly
		Grandpa::schedule_pause(0).unwrap();
		Grandpa::on_finalize(1);
		let _ = System::finalize();

		assert_eq!(
			Grandpa::state(),
			StoredState::Paused,
		);

		// we schedule the set to go back live in 2 blocks
		System::initialize(&2, &Default::default(), &Default::default(), &Default::default());
		Grandpa::schedule_resume(2).unwrap();
		Grandpa::on_finalize(2);
		let _ = System::finalize();

		System::initialize(&3, &Default::default(), &Default::default(), &Default::default());
		Grandpa::on_finalize(3);
		let _ = System::finalize();

		System::initialize(&4, &Default::default(), &Default::default(), &Default::default());
		Grandpa::on_finalize(4);
		let _ = System::finalize();

		// it should be live at block 4
		assert_eq!(
			Grandpa::state(),
			StoredState::Live,
		);
	});
}

#[test]
fn time_slot_have_sane_ord() {
	// Ensure that `Ord` implementation is sane.
	const FIXTURE: &[GrandpaTimeSlot] = &[
		GrandpaTimeSlot {
			set_id: 0,
			round: 0,
		},
		GrandpaTimeSlot {
			set_id: 0,
			round: 1,
		},
		GrandpaTimeSlot {
			set_id: 1,
			round: 0,
		},
		GrandpaTimeSlot {
			set_id: 1,
			round: 1,
		},
		GrandpaTimeSlot {
			set_id: 1,
			round: 2,
		}
	];
	assert!(FIXTURE.windows(2).all(|f| f[0] < f[1]));
}

#[test]
#[cfg(feature = "migrate-authorities")]
fn authorities_migration() {
	use sp_runtime::traits::OnInitialize;

	with_externalities(&mut new_test_ext(vec![]), || {
		let authorities = to_authorities(vec![(1, 1), (2, 1), (3, 1)]);

		Authorities::put(authorities.clone());
		assert!(Grandpa::grandpa_authorities().is_empty());

		Grandpa::on_initialize(1);

		assert!(!Authorities::exists());
		assert_eq!(Grandpa::grandpa_authorities(), authorities);
	});
}