// This file is part of Substrate.

// Copyright (C) 2019-2020 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.

//! Mock helpers for Session.

use super::*;
use std::cell::RefCell;
use frame_support::{impl_outer_origin, parameter_types, weights::Weight};
use sp_core::{crypto::key_types::DUMMY, H256};
use sp_runtime::{
	Perbill, impl_opaque_keys,
	traits::{BlakeTwo256, IdentityLookup, ConvertInto},
	testing::{Header, UintAuthorityId},
};
use sp_staking::SessionIndex;

impl_opaque_keys! {
	pub struct MockSessionKeys {
		pub dummy: UintAuthorityId,
	}
}

impl From<UintAuthorityId> for MockSessionKeys {
	fn from(dummy: UintAuthorityId) -> Self {
		Self { dummy }
	}
}

impl_outer_origin! {
	pub enum Origin for Test  where system = frame_system {}
}

thread_local! {
	pub static VALIDATORS: RefCell<Vec<u64>> = RefCell::new(vec![1, 2, 3]);
	pub static NEXT_VALIDATORS: RefCell<Vec<u64>> = RefCell::new(vec![1, 2, 3]);
	pub static AUTHORITIES: RefCell<Vec<UintAuthorityId>> =
		RefCell::new(vec![UintAuthorityId(1), UintAuthorityId(2), UintAuthorityId(3)]);
	pub static FORCE_SESSION_END: RefCell<bool> = RefCell::new(false);
	pub static SESSION_LENGTH: RefCell<u64> = RefCell::new(2);
	pub static SESSION_CHANGED: RefCell<bool> = RefCell::new(false);
	pub static TEST_SESSION_CHANGED: RefCell<bool> = RefCell::new(false);
	pub static DISABLED: RefCell<bool> = RefCell::new(false);
	// Stores if `on_before_session_end` was called
	pub static BEFORE_SESSION_END_CALLED: RefCell<bool> = RefCell::new(false);
}

pub struct TestShouldEndSession;
impl ShouldEndSession<u64> for TestShouldEndSession {
	fn should_end_session(now: u64) -> bool {
		let l = SESSION_LENGTH.with(|l| *l.borrow());
		now % l == 0 || FORCE_SESSION_END.with(|l| { let r = *l.borrow(); *l.borrow_mut() = false; r })
	}
}

pub struct TestSessionHandler;
impl SessionHandler<u64> for TestSessionHandler {
	const KEY_TYPE_IDS: &'static [sp_runtime::KeyTypeId] = &[UintAuthorityId::ID];
	fn on_genesis_session<T: OpaqueKeys>(_validators: &[(u64, T)]) {}
	fn on_new_session<T: OpaqueKeys>(
		changed: bool,
		validators: &[(u64, T)],
		_queued_validators: &[(u64, T)],
	) {
		SESSION_CHANGED.with(|l| *l.borrow_mut() = changed);
		AUTHORITIES.with(|l|
			*l.borrow_mut() = validators.iter()
				.map(|(_, id)| id.get::<UintAuthorityId>(DUMMY).unwrap_or_default())
				.collect()
		);
	}
	fn on_disabled(_validator_index: usize) {
		DISABLED.with(|l| *l.borrow_mut() = true)
	}
	fn on_before_session_ending() {
		BEFORE_SESSION_END_CALLED.with(|b| *b.borrow_mut() = true);
	}
}

pub struct TestSessionManager;
impl SessionManager<u64> for TestSessionManager {
	fn end_session(_: SessionIndex) {}
	fn start_session(_: SessionIndex) {}
	fn new_session(_: SessionIndex) -> Option<Vec<u64>> {
		if !TEST_SESSION_CHANGED.with(|l| *l.borrow()) {
			VALIDATORS.with(|v| {
				let mut v = v.borrow_mut();
				*v = NEXT_VALIDATORS.with(|l| l.borrow().clone());
				Some(v.clone())
			})
		} else if DISABLED.with(|l| std::mem::replace(&mut *l.borrow_mut(), false)) {
			// If there was a disabled validator, underlying conditions have changed
			// so we return `Some`.
			Some(VALIDATORS.with(|v| v.borrow().clone()))
		} else {
			None
		}
	}
}

#[cfg(feature = "historical")]
impl crate::historical::SessionManager<u64, u64> for TestSessionManager {
	fn end_session(_: SessionIndex) {}
	fn start_session(_: SessionIndex) {}
	fn new_session(new_index: SessionIndex)
		-> Option<Vec<(u64, u64)>>
	{
		<Self as SessionManager<_>>::new_session(new_index)
			.map(|vals| vals.into_iter().map(|val| (val, val)).collect())
	}
}

pub fn authorities() -> Vec<UintAuthorityId> {
	AUTHORITIES.with(|l| l.borrow().to_vec())
}

pub fn force_new_session() {
	FORCE_SESSION_END.with(|l| *l.borrow_mut() = true )
}

pub fn set_session_length(x: u64) {
	SESSION_LENGTH.with(|l| *l.borrow_mut() = x )
}

pub fn session_changed() -> bool {
	SESSION_CHANGED.with(|l| *l.borrow())
}

pub fn set_next_validators(next: Vec<u64>) {
	NEXT_VALIDATORS.with(|v| *v.borrow_mut() = next);
}

pub fn before_session_end_called() -> bool {
	BEFORE_SESSION_END_CALLED.with(|b| *b.borrow())
}

pub fn reset_before_session_end_called() {
	BEFORE_SESSION_END_CALLED.with(|b| *b.borrow_mut() = false);
}

pub fn new_test_ext() -> sp_io::TestExternalities {
	let mut t = frame_system::GenesisConfig::default().build_storage::<Test>().unwrap();
	GenesisConfig::<Test> {
		keys: NEXT_VALIDATORS.with(|l|
			l.borrow().iter().cloned().map(|i| (i, i, UintAuthorityId(i).into())).collect()
		),
	}.assimilate_storage(&mut t).unwrap();
	sp_io::TestExternalities::new(t)
}

#[derive(Clone, Eq, PartialEq)]
pub struct Test;

parameter_types! {
	pub const BlockHashCount: u64 = 250;
	pub const MaximumBlockWeight: Weight = 1024;
	pub const MaximumBlockLength: u32 = 2 * 1024;
	pub const MinimumPeriod: u64 = 5;
	pub const AvailableBlockRatio: Perbill = Perbill::one();
}

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 = ();
	type BlockHashCount = BlockHashCount;
	type MaximumBlockWeight = MaximumBlockWeight;
	type DbWeight = ();
	type BlockExecutionWeight = ();
	type ExtrinsicBaseWeight = ();
	type MaximumExtrinsicWeight = MaximumBlockWeight;
	type AvailableBlockRatio = AvailableBlockRatio;
	type MaximumBlockLength = MaximumBlockLength;
	type Version = ();
	type ModuleToIndex = ();
	type AccountData = ();
	type OnNewAccount = ();
	type OnKilledAccount = ();
}

impl pallet_timestamp::Trait for Test {
	type Moment = u64;
	type OnTimestampSet = ();
	type MinimumPeriod = MinimumPeriod;
}

parameter_types! {
	pub const DisabledValidatorsThreshold: Perbill = Perbill::from_percent(33);
}

impl Trait for Test {
	type ShouldEndSession = TestShouldEndSession;
	#[cfg(feature = "historical")]
	type SessionManager = crate::historical::NoteHistoricalRoot<Test, TestSessionManager>;
	#[cfg(not(feature = "historical"))]
	type SessionManager = TestSessionManager;
	type SessionHandler = TestSessionHandler;
	type ValidatorId = u64;
	type ValidatorIdOf = ConvertInto;
	type Keys = MockSessionKeys;
	type Event = ();
	type DisabledValidatorsThreshold = DisabledValidatorsThreshold;
	type NextSessionRotation = ();
}

#[cfg(feature = "historical")]
impl crate::historical::Trait for Test {
	type FullIdentification = u64;
	type FullIdentificationOf = sp_runtime::traits::ConvertInto;
}

pub type System = frame_system::Module<Test>;
pub type Session = Module<Test>;
