// 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/>.

//! Collective system: Members of a set of account IDs can make their collective feelings known
//! through dispatched calls from one of two specialized origins.
//!
//! The membership can be provided in one of two ways: either directly, using the Root-dispatchable
//! function `set_members`, or indirectly, through implementing the `ChangeMembers`.
//!
//! A "prime" member may be set allowing their vote to act as the default vote in case of any
//! abstentions after the voting period.
//!
//! Voting happens through motions comprising a proposal (i.e. a curried dispatchable) plus a
//! number of approvals required for it to pass and be called. Motions are open for members to
//! vote on for a minimum period given by `MotionDuration`. As soon as the needed number of
//! approvals is given, the motion is closed and executed. If the number of approvals is not reached
//! during the voting period, then `close` may be called by any account in order to force the end
//! the motion explicitly. If a prime member is defined then their vote is used in place of any
//! abstentions and the proposal is executed if there are enough approvals counting the new votes.
//!
//! If there are not, or if no prime is set, then the motion is dropped without being executed.

#![cfg_attr(not(feature = "std"), no_std)]
#![recursion_limit="128"]

use sp_std::{prelude::*, result};
use sp_core::u32_trait::Value as U32;
use sp_runtime::RuntimeDebug;
use sp_runtime::traits::Hash;
use frame_support::weights::SimpleDispatchInfo;
use frame_support::{
	dispatch::{Dispatchable, Parameter}, codec::{Encode, Decode},
	traits::{Get, ChangeMembers, InitializeMembers, EnsureOrigin}, decl_module, decl_event,
	decl_storage, decl_error, ensure,
};
use frame_system::{self as system, ensure_signed, ensure_root};

#[cfg(feature = "runtime-benchmarks")]
mod benchmarking;

/// Simple index type for proposal counting.
pub type ProposalIndex = u32;

/// A number of members.
///
/// This also serves as a number of voting members, and since for motions, each member may
/// vote exactly once, therefore also the number of votes for any given motion.
pub type MemberCount = u32;

pub trait Trait<I: Instance=DefaultInstance>: frame_system::Trait {
	/// The outer origin type.
	type Origin: From<RawOrigin<Self::AccountId, I>>;

	/// The outer call dispatch type.
	type Proposal: Parameter + Dispatchable<Origin=<Self as Trait<I>>::Origin> + From<Call<Self, I>>;

	/// The outer event type.
	type Event: From<Event<Self, I>> + Into<<Self as frame_system::Trait>::Event>;

	/// The time-out for council motions.
	type MotionDuration: Get<Self::BlockNumber>;
}

/// Origin for the collective module.
#[derive(PartialEq, Eq, Clone, RuntimeDebug)]
pub enum RawOrigin<AccountId, I> {
	/// It has been condoned by a given number of members of the collective from a given total.
	Members(MemberCount, MemberCount),
	/// It has been condoned by a single member of the collective.
	Member(AccountId),
	/// Dummy to manage the fact we have instancing.
	_Phantom(sp_std::marker::PhantomData<I>),
}

/// Origin for the collective module.
pub type Origin<T, I=DefaultInstance> = RawOrigin<<T as frame_system::Trait>::AccountId, I>;

#[derive(PartialEq, Eq, Clone, Encode, Decode, RuntimeDebug)]
/// Info for keeping track of a motion being voted on.
pub struct Votes<AccountId, BlockNumber> {
	/// The proposal's unique index.
	index: ProposalIndex,
	/// The number of approval votes that are needed to pass the motion.
	threshold: MemberCount,
	/// The current set of voters that approved it.
	ayes: Vec<AccountId>,
	/// The current set of voters that rejected it.
	nays: Vec<AccountId>,
	/// The hard end time of this vote.
	end: BlockNumber,
}

decl_storage! {
	trait Store for Module<T: Trait<I>, I: Instance=DefaultInstance> as Collective {
		/// The hashes of the active proposals.
		pub Proposals get(fn proposals): Vec<T::Hash>;
		/// Actual proposal for a given hash, if it's current.
		pub ProposalOf get(fn proposal_of):
			map hasher(identity) T::Hash => Option<<T as Trait<I>>::Proposal>;
		/// Votes on a given proposal, if it is ongoing.
		pub Voting get(fn voting):
			map hasher(identity) T::Hash => Option<Votes<T::AccountId, T::BlockNumber>>;
		/// Proposals so far.
		pub ProposalCount get(fn proposal_count): u32;
		/// The current members of the collective. This is stored sorted (just by value).
		pub Members get(fn members): Vec<T::AccountId>;
		/// The member who provides the default vote for any other members that do not vote before
		/// the timeout. If None, then no member has that privilege.
		pub Prime get(fn prime): Option<T::AccountId>;
	}
	add_extra_genesis {
		config(phantom): sp_std::marker::PhantomData<I>;
		config(members): Vec<T::AccountId>;
		build(|config| Module::<T, I>::initialize_members(&config.members))
	}
}

decl_event! {
	pub enum Event<T, I=DefaultInstance> where
		<T as frame_system::Trait>::Hash,
		<T as frame_system::Trait>::AccountId,
	{
		/// A motion (given hash) has been proposed (by given account) with a threshold (given
		/// `MemberCount`).
		Proposed(AccountId, ProposalIndex, Hash, MemberCount),
		/// A motion (given hash) has been voted on by given account, leaving
		/// a tally (yes votes and no votes given respectively as `MemberCount`).
		Voted(AccountId, Hash, bool, MemberCount, MemberCount),
		/// A motion was approved by the required threshold.
		Approved(Hash),
		/// A motion was not approved by the required threshold.
		Disapproved(Hash),
		/// A motion was executed; `bool` is true if returned without error.
		Executed(Hash, bool),
		/// A single member did some action; `bool` is true if returned without error.
		MemberExecuted(Hash, bool),
		/// A proposal was closed after its duration was up.
		Closed(Hash, MemberCount, MemberCount),
	}
}

decl_error! {
	pub enum Error for Module<T: Trait<I>, I: Instance> {
		/// Account is not a member
		NotMember,
		/// Duplicate proposals not allowed
		DuplicateProposal,
		/// Proposal must exist
		ProposalMissing,
		/// Mismatched index
		WrongIndex,
		/// Duplicate vote ignored
		DuplicateVote,
		/// Members are already initialized!
		AlreadyInitialized,
		/// The close call is made too early, before the end of the voting.
		TooEarly,
	}
}

// Note: this module is not benchmarked. The weights are obtained based on the similarity of the
// executed logic with other democracy function. Note that councillor operations are assigned to the
// operational class.
decl_module! {
	pub struct Module<T: Trait<I>, I: Instance=DefaultInstance> for enum Call where origin: <T as frame_system::Trait>::Origin {
		type Error = Error<T, I>;

		fn deposit_event() = default;

		/// Set the collective's membership.
		///
		/// - `new_members`: The new member list. Be nice to the chain and
		//	provide it sorted.
		/// - `prime`: The prime member whose vote sets the default.
		///
		/// Requires root origin.
		#[weight = SimpleDispatchInfo::FixedOperational(100_000)]
		fn set_members(origin, new_members: Vec<T::AccountId>, prime: Option<T::AccountId>) {
			ensure_root(origin)?;
			let mut new_members = new_members;
			new_members.sort();
			let old = Members::<T, I>::get();
			<Self as ChangeMembers<T::AccountId>>::set_members_sorted(&new_members[..], &old);
			Prime::<T, I>::set(prime);
		}

		/// Dispatch a proposal from a member using the `Member` origin.
		///
		/// Origin must be a member of the collective.
		#[weight = SimpleDispatchInfo::FixedOperational(100_000)]
		fn execute(origin, proposal: Box<<T as Trait<I>>::Proposal>) {
			let who = ensure_signed(origin)?;
			ensure!(Self::is_member(&who), Error::<T, I>::NotMember);

			let proposal_hash = T::Hashing::hash_of(&proposal);
			let ok = proposal.dispatch(RawOrigin::Member(who).into()).is_ok();
			Self::deposit_event(RawEvent::MemberExecuted(proposal_hash, ok));
		}

		/// # <weight>
		/// - Bounded storage reads and writes.
		/// - Argument `threshold` has bearing on weight.
		/// # </weight>
		#[weight = SimpleDispatchInfo::FixedOperational(5_000_000)]
		fn propose(origin, #[compact] threshold: MemberCount, proposal: Box<<T as Trait<I>>::Proposal>) {
			let who = ensure_signed(origin)?;
			ensure!(Self::is_member(&who), Error::<T, I>::NotMember);

			let proposal_hash = T::Hashing::hash_of(&proposal);

			ensure!(!<ProposalOf<T, I>>::contains_key(proposal_hash), Error::<T, I>::DuplicateProposal);

			if threshold < 2 {
				let seats = Self::members().len() as MemberCount;
				let ok = proposal.dispatch(RawOrigin::Members(1, seats).into()).is_ok();
				Self::deposit_event(RawEvent::Executed(proposal_hash, ok));
			} else {
				let index = Self::proposal_count();
				<ProposalCount<I>>::mutate(|i| *i += 1);
				<Proposals<T, I>>::mutate(|proposals| proposals.push(proposal_hash));
				<ProposalOf<T, I>>::insert(proposal_hash, *proposal);
				let end = system::Module::<T>::block_number() + T::MotionDuration::get();
				let votes = Votes { index, threshold, ayes: vec![who.clone()], nays: vec![], end };
				<Voting<T, I>>::insert(proposal_hash, votes);

				Self::deposit_event(RawEvent::Proposed(who, index, proposal_hash, threshold));
			}
		}

		/// # <weight>
		/// - Bounded storage read and writes.
		/// - Will be slightly heavier if the proposal is approved / disapproved after the vote.
		/// # </weight>
		#[weight = SimpleDispatchInfo::FixedOperational(200_000)]
		fn vote(origin, proposal: T::Hash, #[compact] index: ProposalIndex, approve: bool) {
			let who = ensure_signed(origin)?;
			ensure!(Self::is_member(&who), Error::<T, I>::NotMember);

			let mut voting = Self::voting(&proposal).ok_or(Error::<T, I>::ProposalMissing)?;
			ensure!(voting.index == index, Error::<T, I>::WrongIndex);

			let position_yes = voting.ayes.iter().position(|a| a == &who);
			let position_no = voting.nays.iter().position(|a| a == &who);

			if approve {
				if position_yes.is_none() {
					voting.ayes.push(who.clone());
				} else {
					Err(Error::<T, I>::DuplicateVote)?
				}
				if let Some(pos) = position_no {
					voting.nays.swap_remove(pos);
				}
			} else {
				if position_no.is_none() {
					voting.nays.push(who.clone());
				} else {
					Err(Error::<T, I>::DuplicateVote)?
				}
				if let Some(pos) = position_yes {
					voting.ayes.swap_remove(pos);
				}
			}

			let yes_votes = voting.ayes.len() as MemberCount;
			let no_votes = voting.nays.len() as MemberCount;
			Self::deposit_event(RawEvent::Voted(who, proposal, approve, yes_votes, no_votes));

			let seats = Self::members().len() as MemberCount;

			let approved = yes_votes >= voting.threshold;
			let disapproved = seats.saturating_sub(no_votes) < voting.threshold;
			if approved || disapproved {
				Self::finalize_proposal(approved, seats, voting, proposal);
			} else {
				Voting::<T, I>::insert(&proposal, voting);
			}
		}

		/// May be called by any signed account after the voting duration has ended in order to
		/// finish voting and close the proposal.
		///
		/// Abstentions are counted as rejections unless there is a prime member set and the prime
		/// member cast an approval.
		///
		/// - the weight of `proposal` preimage.
		/// - up to three events deposited.
		/// - one read, two removals, one mutation. (plus three static reads.)
		/// - computation and i/o `O(P + L + M)` where:
		///   - `M` is number of members,
		///   - `P` is number of active proposals,
		///   - `L` is the encoded length of `proposal` preimage.
		#[weight = SimpleDispatchInfo::FixedOperational(200_000)]
		fn close(origin, proposal: T::Hash, #[compact] index: ProposalIndex) {
			let _ = ensure_signed(origin)?;

			let voting = Self::voting(&proposal).ok_or(Error::<T, I>::ProposalMissing)?;
			ensure!(voting.index == index, Error::<T, I>::WrongIndex);
			ensure!(system::Module::<T>::block_number() >= voting.end, Error::<T, I>::TooEarly);

			// default to true only if there's a prime and they voted in favour.
			let default = Self::prime().map_or(
				false,
				|who| voting.ayes.iter().any(|a| a == &who),
			);

			let mut no_votes = voting.nays.len() as MemberCount;
			let mut yes_votes = voting.ayes.len() as MemberCount;
			let seats = Self::members().len() as MemberCount;
			let abstentions = seats - (yes_votes + no_votes);
			match default {
				true => yes_votes += abstentions,
				false => no_votes += abstentions,
			}

			Self::deposit_event(RawEvent::Closed(proposal, yes_votes, no_votes));
			Self::finalize_proposal(yes_votes >= voting.threshold, seats, voting, proposal);
		}
	}
}

impl<T: Trait<I>, I: Instance> Module<T, I> {
	pub fn is_member(who: &T::AccountId) -> bool {
		Self::members().contains(who)
	}

	/// Weight:
	/// If `approved`:
	/// - the weight of `proposal` preimage.
	/// - two events deposited.
	/// - two removals, one mutation.
	/// - computation and i/o `O(P + L)` where:
	///   - `P` is number of active proposals,
	///   - `L` is the encoded length of `proposal` preimage.
	///
	/// If not `approved`:
	/// - one event deposited.
	/// Two removals, one mutation.
	/// Computation and i/o `O(P)` where:
	/// - `P` is number of active proposals
	fn finalize_proposal(
		approved: bool,
		seats: MemberCount,
		voting: Votes<T::AccountId, T::BlockNumber>,
		proposal: T::Hash,
	) {
		if approved {
			Self::deposit_event(RawEvent::Approved(proposal));

			// execute motion, assuming it exists.
			if let Some(p) = ProposalOf::<T, I>::take(&proposal) {
				let origin = RawOrigin::Members(voting.threshold, seats).into();
				let ok = p.dispatch(origin).is_ok();
				Self::deposit_event(RawEvent::Executed(proposal, ok));
			}
		} else {
			// disapproved
			ProposalOf::<T, I>::remove(&proposal);
			Self::deposit_event(RawEvent::Disapproved(proposal));
		}

		// remove vote
		Voting::<T, I>::remove(&proposal);
		Proposals::<T, I>::mutate(|proposals| proposals.retain(|h| h != &proposal));
	}
}

impl<T: Trait<I>, I: Instance> ChangeMembers<T::AccountId> for Module<T, I> {
	fn change_members_sorted(
		_incoming: &[T::AccountId],
		outgoing: &[T::AccountId],
		new: &[T::AccountId],
	) {
		// remove accounts from all current voting in motions.
		let mut outgoing = outgoing.to_vec();
		outgoing.sort_unstable();
		for h in Self::proposals().into_iter() {
			<Voting<T, I>>::mutate(h, |v|
				if let Some(mut votes) = v.take() {
					votes.ayes = votes.ayes.into_iter()
						.filter(|i| outgoing.binary_search(i).is_err())
						.collect();
					votes.nays = votes.nays.into_iter()
						.filter(|i| outgoing.binary_search(i).is_err())
						.collect();
					*v = Some(votes);
				}
			);
		}
		Members::<T, I>::put(new);
		Prime::<T, I>::kill();
	}

	fn set_prime(prime: Option<T::AccountId>) {
		Prime::<T, I>::set(prime);
	}
}

impl<T: Trait<I>, I: Instance> InitializeMembers<T::AccountId> for Module<T, I> {
	fn initialize_members(members: &[T::AccountId]) {
		if !members.is_empty() {
			assert!(<Members<T, I>>::get().is_empty(), "Members are already initialized!");
			<Members<T, I>>::put(members);
		}
	}
}

/// Ensure that the origin `o` represents at least `n` members. Returns `Ok` or an `Err`
/// otherwise.
pub fn ensure_members<OuterOrigin, AccountId, I>(o: OuterOrigin, n: MemberCount)
	-> result::Result<MemberCount, &'static str>
where
	OuterOrigin: Into<result::Result<RawOrigin<AccountId, I>, OuterOrigin>>
{
	match o.into() {
		Ok(RawOrigin::Members(x, _)) if x >= n => Ok(n),
		_ => Err("bad origin: expected to be a threshold number of members"),
	}
}

pub struct EnsureMember<AccountId, I=DefaultInstance>(sp_std::marker::PhantomData<(AccountId, I)>);
impl<
	O: Into<Result<RawOrigin<AccountId, I>, O>> + From<RawOrigin<AccountId, I>>,
	AccountId: Default,
	I,
> EnsureOrigin<O> for EnsureMember<AccountId, I> {
	type Success = AccountId;
	fn try_origin(o: O) -> Result<Self::Success, O> {
		o.into().and_then(|o| match o {
			RawOrigin::Member(id) => Ok(id),
			r => Err(O::from(r)),
		})
	}

	#[cfg(feature = "runtime-benchmarks")]
	fn successful_origin() -> O {
		O::from(RawOrigin::Member(Default::default()))
	}
}

pub struct EnsureMembers<N: U32, AccountId, I=DefaultInstance>(sp_std::marker::PhantomData<(N, AccountId, I)>);
impl<
	O: Into<Result<RawOrigin<AccountId, I>, O>> + From<RawOrigin<AccountId, I>>,
	N: U32,
	AccountId,
	I,
> EnsureOrigin<O> for EnsureMembers<N, AccountId, I> {
	type Success = (MemberCount, MemberCount);
	fn try_origin(o: O) -> Result<Self::Success, O> {
		o.into().and_then(|o| match o {
			RawOrigin::Members(n, m) if n >= N::VALUE => Ok((n, m)),
			r => Err(O::from(r)),
		})
	}

	#[cfg(feature = "runtime-benchmarks")]
	fn successful_origin() -> O {
		O::from(RawOrigin::Members(N::VALUE, N::VALUE))
	}
}

pub struct EnsureProportionMoreThan<N: U32, D: U32, AccountId, I=DefaultInstance>(
	sp_std::marker::PhantomData<(N, D, AccountId, I)>
);
impl<
	O: Into<Result<RawOrigin<AccountId, I>, O>> + From<RawOrigin<AccountId, I>>,
	N: U32,
	D: U32,
	AccountId,
	I,
> EnsureOrigin<O> for EnsureProportionMoreThan<N, D, AccountId, I> {
	type Success = ();
	fn try_origin(o: O) -> Result<Self::Success, O> {
		o.into().and_then(|o| match o {
			RawOrigin::Members(n, m) if n * D::VALUE > N::VALUE * m => Ok(()),
			r => Err(O::from(r)),
		})
	}

	#[cfg(feature = "runtime-benchmarks")]
	fn successful_origin() -> O {
		O::from(RawOrigin::Members(1u32, 0u32))
	}
}

pub struct EnsureProportionAtLeast<N: U32, D: U32, AccountId, I=DefaultInstance>(
	sp_std::marker::PhantomData<(N, D, AccountId, I)>
);
impl<
	O: Into<Result<RawOrigin<AccountId, I>, O>> + From<RawOrigin<AccountId, I>>,
	N: U32,
	D: U32,
	AccountId,
	I,
> EnsureOrigin<O> for EnsureProportionAtLeast<N, D, AccountId, I> {
	type Success = ();
	fn try_origin(o: O) -> Result<Self::Success, O> {
		o.into().and_then(|o| match o {
			RawOrigin::Members(n, m) if n * D::VALUE >= N::VALUE * m => Ok(()),
			r => Err(O::from(r)),
		})
	}

	#[cfg(feature = "runtime-benchmarks")]
	fn successful_origin() -> O {
		O::from(RawOrigin::Members(0u32, 0u32))
	}
}

#[cfg(test)]
mod tests {
	use super::*;
	use frame_support::{Hashable, assert_ok, assert_noop, parameter_types, weights::Weight};
	use frame_system::{self as system, EventRecord, Phase};
	use hex_literal::hex;
	use sp_core::H256;
	use sp_runtime::{
		Perbill, traits::{BlakeTwo256, IdentityLookup, Block as BlockT}, testing::Header,
		BuildStorage,
	};
	use crate as collective;

	parameter_types! {
		pub const BlockHashCount: u64 = 250;
		pub const MaximumBlockWeight: Weight = 1024;
		pub const MaximumBlockLength: u32 = 2 * 1024;
		pub const AvailableBlockRatio: Perbill = Perbill::one();
		pub const MotionDuration: u64 = 3;
	}
	impl frame_system::Trait for Test {
		type Origin = Origin;
		type Index = u64;
		type BlockNumber = u64;
		type Call = ();
		type Hash = H256;
		type Hashing = BlakeTwo256;
		type AccountId = u64;
		type Lookup = IdentityLookup<Self::AccountId>;
		type Header = Header;
		type Event = Event;
		type BlockHashCount = BlockHashCount;
		type MaximumBlockWeight = MaximumBlockWeight;
		type MaximumBlockLength = MaximumBlockLength;
		type AvailableBlockRatio = AvailableBlockRatio;
		type Version = ();
		type ModuleToIndex = ();
		type AccountData = ();
		type OnNewAccount = ();
		type OnKilledAccount = ();
	}
	impl Trait<Instance1> for Test {
		type Origin = Origin;
		type Proposal = Call;
		type Event = Event;
		type MotionDuration = MotionDuration;
	}
	impl Trait for Test {
		type Origin = Origin;
		type Proposal = Call;
		type Event = Event;
		type MotionDuration = MotionDuration;
	}

	pub type Block = sp_runtime::generic::Block<Header, UncheckedExtrinsic>;
	pub type UncheckedExtrinsic = sp_runtime::generic::UncheckedExtrinsic<u32, u64, Call, ()>;

	frame_support::construct_runtime!(
		pub enum Test where
			Block = Block,
			NodeBlock = Block,
			UncheckedExtrinsic = UncheckedExtrinsic
		{
			System: system::{Module, Call, Event<T>},
			Collective: collective::<Instance1>::{Module, Call, Event<T>, Origin<T>, Config<T>},
			DefaultCollective: collective::{Module, Call, Event<T>, Origin<T>, Config<T>},
		}
	);

	pub fn new_test_ext() -> sp_io::TestExternalities {
		let mut ext: sp_io::TestExternalities = GenesisConfig {
			collective_Instance1: Some(collective::GenesisConfig {
				members: vec![1, 2, 3],
				phantom: Default::default(),
			}),
			collective: None,
		}.build_storage().unwrap().into();
		ext.execute_with(|| System::set_block_number(1));
		ext
	}

	#[test]
	fn motions_basic_environment_works() {
		new_test_ext().execute_with(|| {
			assert_eq!(Collective::members(), vec![1, 2, 3]);
			assert_eq!(Collective::proposals(), Vec::<H256>::new());
		});
	}

	fn make_proposal(value: u64) -> Call {
		Call::System(frame_system::Call::remark(value.encode()))
	}

	#[test]
	fn close_works() {
		new_test_ext().execute_with(|| {
			let proposal = make_proposal(42);
			let hash = BlakeTwo256::hash_of(&proposal);

			assert_ok!(Collective::propose(Origin::signed(1), 3, Box::new(proposal.clone())));
			assert_ok!(Collective::vote(Origin::signed(2), hash.clone(), 0, true));

			System::set_block_number(3);
			assert_noop!(
				Collective::close(Origin::signed(4), hash.clone(), 0),
				Error::<Test, Instance1>::TooEarly
			);

			System::set_block_number(4);
			assert_ok!(Collective::close(Origin::signed(4), hash.clone(), 0));

			let record = |event| EventRecord { phase: Phase::Initialization, event, topics: vec![] };
			assert_eq!(System::events(), vec![
				record(Event::collective_Instance1(RawEvent::Proposed(1, 0, hash.clone(), 3))),
				record(Event::collective_Instance1(RawEvent::Voted(2, hash.clone(), true, 2, 0))),
				record(Event::collective_Instance1(RawEvent::Closed(hash.clone(), 2, 1))),
				record(Event::collective_Instance1(RawEvent::Disapproved(hash.clone())))
			]);
		});
	}

	#[test]
	fn close_with_prime_works() {
		new_test_ext().execute_with(|| {
			let proposal = make_proposal(42);
			let hash = BlakeTwo256::hash_of(&proposal);
			assert_ok!(Collective::set_members(Origin::ROOT, vec![1, 2, 3], Some(3)));

			assert_ok!(Collective::propose(Origin::signed(1), 3, Box::new(proposal.clone())));
			assert_ok!(Collective::vote(Origin::signed(2), hash.clone(), 0, true));

			System::set_block_number(4);
			assert_ok!(Collective::close(Origin::signed(4), hash.clone(), 0));

			let record = |event| EventRecord { phase: Phase::Initialization, event, topics: vec![] };
			assert_eq!(System::events(), vec![
				record(Event::collective_Instance1(RawEvent::Proposed(1, 0, hash.clone(), 3))),
				record(Event::collective_Instance1(RawEvent::Voted(2, hash.clone(), true, 2, 0))),
				record(Event::collective_Instance1(RawEvent::Closed(hash.clone(), 2, 1))),
				record(Event::collective_Instance1(RawEvent::Disapproved(hash.clone())))
			]);
		});
	}

	#[test]
	fn close_with_voting_prime_works() {
		new_test_ext().execute_with(|| {
			let proposal = make_proposal(42);
			let hash = BlakeTwo256::hash_of(&proposal);
			assert_ok!(Collective::set_members(Origin::ROOT, vec![1, 2, 3], Some(1)));

			assert_ok!(Collective::propose(Origin::signed(1), 3, Box::new(proposal.clone())));
			assert_ok!(Collective::vote(Origin::signed(2), hash.clone(), 0, true));

			System::set_block_number(4);
			assert_ok!(Collective::close(Origin::signed(4), hash.clone(), 0));

			let record = |event| EventRecord { phase: Phase::Initialization, event, topics: vec![] };
			assert_eq!(System::events(), vec![
				record(Event::collective_Instance1(RawEvent::Proposed(1, 0, hash.clone(), 3))),
				record(Event::collective_Instance1(RawEvent::Voted(2, hash.clone(), true, 2, 0))),
				record(Event::collective_Instance1(RawEvent::Closed(hash.clone(), 3, 0))),
				record(Event::collective_Instance1(RawEvent::Approved(hash.clone()))),
				record(Event::collective_Instance1(RawEvent::Executed(hash.clone(), false)))
			]);
		});
	}

	#[test]
	fn removal_of_old_voters_votes_works() {
		new_test_ext().execute_with(|| {
			let proposal = make_proposal(42);
			let hash = BlakeTwo256::hash_of(&proposal);
			let end = 4;
			assert_ok!(Collective::propose(Origin::signed(1), 3, Box::new(proposal.clone())));
			assert_ok!(Collective::vote(Origin::signed(2), hash.clone(), 0, true));
			assert_eq!(
				Collective::voting(&hash),
				Some(Votes { index: 0, threshold: 3, ayes: vec![1, 2], nays: vec![], end })
			);
			Collective::change_members_sorted(&[4], &[1], &[2, 3, 4]);
			assert_eq!(
				Collective::voting(&hash),
				Some(Votes { index: 0, threshold: 3, ayes: vec![2], nays: vec![], end })
			);

			let proposal = make_proposal(69);
			let hash = BlakeTwo256::hash_of(&proposal);
			assert_ok!(Collective::propose(Origin::signed(2), 2, Box::new(proposal.clone())));
			assert_ok!(Collective::vote(Origin::signed(3), hash.clone(), 1, false));
			assert_eq!(
				Collective::voting(&hash),
				Some(Votes { index: 1, threshold: 2, ayes: vec![2], nays: vec![3], end })
			);
			Collective::change_members_sorted(&[], &[3], &[2, 4]);
			assert_eq!(
				Collective::voting(&hash),
				Some(Votes { index: 1, threshold: 2, ayes: vec![2], nays: vec![], end })
			);
		});
	}

	#[test]
	fn removal_of_old_voters_votes_works_with_set_members() {
		new_test_ext().execute_with(|| {
			let proposal = make_proposal(42);
			let hash = BlakeTwo256::hash_of(&proposal);
			let end = 4;
			assert_ok!(Collective::propose(Origin::signed(1), 3, Box::new(proposal.clone())));
			assert_ok!(Collective::vote(Origin::signed(2), hash.clone(), 0, true));
			assert_eq!(
				Collective::voting(&hash),
				Some(Votes { index: 0, threshold: 3, ayes: vec![1, 2], nays: vec![], end })
			);
			assert_ok!(Collective::set_members(Origin::ROOT, vec![2, 3, 4], None));
			assert_eq!(
				Collective::voting(&hash),
				Some(Votes { index: 0, threshold: 3, ayes: vec![2], nays: vec![], end })
			);

			let proposal = make_proposal(69);
			let hash = BlakeTwo256::hash_of(&proposal);
			assert_ok!(Collective::propose(Origin::signed(2), 2, Box::new(proposal.clone())));
			assert_ok!(Collective::vote(Origin::signed(3), hash.clone(), 1, false));
			assert_eq!(
				Collective::voting(&hash),
				Some(Votes { index: 1, threshold: 2, ayes: vec![2], nays: vec![3], end })
			);
			assert_ok!(Collective::set_members(Origin::ROOT, vec![2, 4], None));
			assert_eq!(
				Collective::voting(&hash),
				Some(Votes { index: 1, threshold: 2, ayes: vec![2], nays: vec![], end })
			);
		});
	}

	#[test]
	fn propose_works() {
		new_test_ext().execute_with(|| {
			let proposal = make_proposal(42);
			let hash = proposal.blake2_256().into();
			let end = 4;
			assert_ok!(Collective::propose(Origin::signed(1), 3, Box::new(proposal.clone())));
			assert_eq!(Collective::proposals(), vec![hash]);
			assert_eq!(Collective::proposal_of(&hash), Some(proposal));
			assert_eq!(
				Collective::voting(&hash),
				Some(Votes { index: 0, threshold: 3, ayes: vec![1], nays: vec![], end })
			);

			assert_eq!(System::events(), vec![
				EventRecord {
					phase: Phase::Initialization,
					event: Event::collective_Instance1(RawEvent::Proposed(
						1,
						0,
						hex!["68eea8f20b542ec656c6ac2d10435ae3bd1729efc34d1354ab85af840aad2d35"].into(),
						3,
					)),
					topics: vec![],
				}
			]);
		});
	}

	#[test]
	fn motions_ignoring_non_collective_proposals_works() {
		new_test_ext().execute_with(|| {
			let proposal = make_proposal(42);
			assert_noop!(
				Collective::propose(Origin::signed(42), 3, Box::new(proposal.clone())),
				Error::<Test, Instance1>::NotMember
			);
		});
	}

	#[test]
	fn motions_ignoring_non_collective_votes_works() {
		new_test_ext().execute_with(|| {
			let proposal = make_proposal(42);
			let hash: H256 = proposal.blake2_256().into();
			assert_ok!(Collective::propose(Origin::signed(1), 3, Box::new(proposal.clone())));
			assert_noop!(
				Collective::vote(Origin::signed(42), hash.clone(), 0, true),
				Error::<Test, Instance1>::NotMember,
			);
		});
	}

	#[test]
	fn motions_ignoring_bad_index_collective_vote_works() {
		new_test_ext().execute_with(|| {
			System::set_block_number(3);
			let proposal = make_proposal(42);
			let hash: H256 = proposal.blake2_256().into();
			assert_ok!(Collective::propose(Origin::signed(1), 3, Box::new(proposal.clone())));
			assert_noop!(
				Collective::vote(Origin::signed(2), hash.clone(), 1, true),
				Error::<Test, Instance1>::WrongIndex,
			);
		});
	}

	#[test]
	fn motions_revoting_works() {
		new_test_ext().execute_with(|| {
			let proposal = make_proposal(42);
			let hash: H256 = proposal.blake2_256().into();
			let end = 4;
			assert_ok!(Collective::propose(Origin::signed(1), 2, Box::new(proposal.clone())));
			assert_eq!(
				Collective::voting(&hash),
				Some(Votes { index: 0, threshold: 2, ayes: vec![1], nays: vec![], end })
			);
			assert_noop!(
				Collective::vote(Origin::signed(1), hash.clone(), 0, true),
				Error::<Test, Instance1>::DuplicateVote,
			);
			assert_ok!(Collective::vote(Origin::signed(1), hash.clone(), 0, false));
			assert_eq!(
				Collective::voting(&hash),
				Some(Votes { index: 0, threshold: 2, ayes: vec![], nays: vec![1], end })
			);
			assert_noop!(
				Collective::vote(Origin::signed(1), hash.clone(), 0, false),
				Error::<Test, Instance1>::DuplicateVote,
			);

			assert_eq!(System::events(), vec![
				EventRecord {
					phase: Phase::Initialization,
					event: Event::collective_Instance1(RawEvent::Proposed(
						1,
						0,
						hex!["68eea8f20b542ec656c6ac2d10435ae3bd1729efc34d1354ab85af840aad2d35"].into(),
						2,
					)),
					topics: vec![],
				},
				EventRecord {
					phase: Phase::Initialization,
					event: Event::collective_Instance1(RawEvent::Voted(
						1,
						hex!["68eea8f20b542ec656c6ac2d10435ae3bd1729efc34d1354ab85af840aad2d35"].into(),
						false,
						0,
						1,
					)),
					topics: vec![],
				}
			]);
		});
	}

	#[test]
	fn motions_reproposing_disapproved_works() {
		new_test_ext().execute_with(|| {
			let proposal = make_proposal(42);
			let hash: H256 = proposal.blake2_256().into();
			assert_ok!(Collective::propose(Origin::signed(1), 3, Box::new(proposal.clone())));
			assert_ok!(Collective::vote(Origin::signed(2), hash.clone(), 0, false));
			assert_eq!(Collective::proposals(), vec![]);
			assert_ok!(Collective::propose(Origin::signed(1), 2, Box::new(proposal.clone())));
			assert_eq!(Collective::proposals(), vec![hash]);
		});
	}

	#[test]
	fn motions_disapproval_works() {
		new_test_ext().execute_with(|| {
			let proposal = make_proposal(42);
			let hash: H256 = proposal.blake2_256().into();
			assert_ok!(Collective::propose(Origin::signed(1), 3, Box::new(proposal.clone())));
			assert_ok!(Collective::vote(Origin::signed(2), hash.clone(), 0, false));

			assert_eq!(System::events(), vec![
				EventRecord {
					phase: Phase::Initialization,
					event: Event::collective_Instance1(
						RawEvent::Proposed(
							1,
							0,
							hex!["68eea8f20b542ec656c6ac2d10435ae3bd1729efc34d1354ab85af840aad2d35"].into(),
							3,
						)),
					topics: vec![],
				},
				EventRecord {
					phase: Phase::Initialization,
					event: Event::collective_Instance1(RawEvent::Voted(
						2,
						hex!["68eea8f20b542ec656c6ac2d10435ae3bd1729efc34d1354ab85af840aad2d35"].into(),
						false,
						1,
						1,
					)),
					topics: vec![],
				},
				EventRecord {
					phase: Phase::Initialization,
					event: Event::collective_Instance1(RawEvent::Disapproved(
						hex!["68eea8f20b542ec656c6ac2d10435ae3bd1729efc34d1354ab85af840aad2d35"].into(),
					)),
					topics: vec![],
				}
			]);
		});
	}

	#[test]
	fn motions_approval_works() {
		new_test_ext().execute_with(|| {
			let proposal = make_proposal(42);
			let hash: H256 = proposal.blake2_256().into();
			assert_ok!(Collective::propose(Origin::signed(1), 2, Box::new(proposal.clone())));
			assert_ok!(Collective::vote(Origin::signed(2), hash.clone(), 0, true));

			assert_eq!(System::events(), vec![
				EventRecord {
					phase: Phase::Initialization,
					event: Event::collective_Instance1(RawEvent::Proposed(
						1,
						0,
						hex!["68eea8f20b542ec656c6ac2d10435ae3bd1729efc34d1354ab85af840aad2d35"].into(),
						2,
					)),
					topics: vec![],
				},
				EventRecord {
					phase: Phase::Initialization,
					event: Event::collective_Instance1(RawEvent::Voted(
						2,
						hex!["68eea8f20b542ec656c6ac2d10435ae3bd1729efc34d1354ab85af840aad2d35"].into(),
						true,
						2,
						0,
					)),
					topics: vec![],
				},
				EventRecord {
					phase: Phase::Initialization,
					event: Event::collective_Instance1(RawEvent::Approved(
						hex!["68eea8f20b542ec656c6ac2d10435ae3bd1729efc34d1354ab85af840aad2d35"].into(),
					)),
					topics: vec![],
				},
				EventRecord {
					phase: Phase::Initialization,
					event: Event::collective_Instance1(RawEvent::Executed(
						hex!["68eea8f20b542ec656c6ac2d10435ae3bd1729efc34d1354ab85af840aad2d35"].into(),
						false,
					)),
					topics: vec![],
				}
			]);
		});
	}
}