referrerpolicy=no-referrer-when-downgrade
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
// Copyright (C) Parity Technologies (UK) Ltd.
// This file is part of Polkadot.

// Polkadot 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.

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

//! Pallet to process purchase of DOTs.

use alloc::vec::Vec;
use codec::{Decode, Encode};
use frame_support::{
	pallet_prelude::*,
	traits::{Currency, EnsureOrigin, ExistenceRequirement, Get, VestingSchedule},
};
use frame_system::pallet_prelude::*;
pub use pallet::*;
use scale_info::TypeInfo;
use sp_core::sr25519;
use sp_runtime::{
	traits::{CheckedAdd, Saturating, Verify, Zero},
	AnySignature, DispatchError, DispatchResult, Permill, RuntimeDebug,
};

type BalanceOf<T> =
	<<T as Config>::Currency as Currency<<T as frame_system::Config>::AccountId>>::Balance;

/// The kind of statement an account needs to make for a claim to be valid.
#[derive(Encode, Decode, Clone, Copy, Eq, PartialEq, RuntimeDebug, TypeInfo)]
pub enum AccountValidity {
	/// Account is not valid.
	Invalid,
	/// Account has initiated the account creation process.
	Initiated,
	/// Account is pending validation.
	Pending,
	/// Account is valid with a low contribution amount.
	ValidLow,
	/// Account is valid with a high contribution amount.
	ValidHigh,
	/// Account has completed the purchase process.
	Completed,
}

impl Default for AccountValidity {
	fn default() -> Self {
		AccountValidity::Invalid
	}
}

impl AccountValidity {
	fn is_valid(&self) -> bool {
		match self {
			Self::Invalid => false,
			Self::Initiated => false,
			Self::Pending => false,
			Self::ValidLow => true,
			Self::ValidHigh => true,
			Self::Completed => false,
		}
	}
}

/// All information about an account regarding the purchase of DOTs.
#[derive(Encode, Decode, Default, Clone, Eq, PartialEq, RuntimeDebug, TypeInfo)]
pub struct AccountStatus<Balance> {
	/// The current validity status of the user. Will denote if the user has passed KYC,
	/// how much they are able to purchase, and when their purchase process has completed.
	validity: AccountValidity,
	/// The amount of free DOTs they have purchased.
	free_balance: Balance,
	/// The amount of locked DOTs they have purchased.
	locked_balance: Balance,
	/// Their sr25519/ed25519 signature verifying they have signed our required statement.
	signature: Vec<u8>,
	/// The percentage of VAT the purchaser is responsible for. This is already factored into
	/// account balance.
	vat: Permill,
}

#[frame_support::pallet]
pub mod pallet {
	use super::*;

	#[pallet::pallet]
	#[pallet::without_storage_info]
	pub struct Pallet<T>(_);

	#[pallet::config]
	pub trait Config: frame_system::Config {
		/// The overarching event type.
		type RuntimeEvent: From<Event<Self>> + IsType<<Self as frame_system::Config>::RuntimeEvent>;

		/// Balances Pallet
		type Currency: Currency<Self::AccountId>;

		/// Vesting Pallet
		type VestingSchedule: VestingSchedule<
			Self::AccountId,
			Moment = BlockNumberFor<Self>,
			Currency = Self::Currency,
		>;

		/// The origin allowed to set account status.
		type ValidityOrigin: EnsureOrigin<Self::RuntimeOrigin>;

		/// The origin allowed to make configurations to the pallet.
		type ConfigurationOrigin: EnsureOrigin<Self::RuntimeOrigin>;

		/// The maximum statement length for the statement users to sign when creating an account.
		#[pallet::constant]
		type MaxStatementLength: Get<u32>;

		/// The amount of purchased locked DOTs that we will unlock for basic actions on the chain.
		#[pallet::constant]
		type UnlockedProportion: Get<Permill>;

		/// The maximum amount of locked DOTs that we will unlock.
		#[pallet::constant]
		type MaxUnlocked: Get<BalanceOf<Self>>;
	}

	#[pallet::event]
	#[pallet::generate_deposit(pub(super) fn deposit_event)]
	pub enum Event<T: Config> {
		/// A new account was created.
		AccountCreated { who: T::AccountId },
		/// Someone's account validity was updated.
		ValidityUpdated { who: T::AccountId, validity: AccountValidity },
		/// Someone's purchase balance was updated.
		BalanceUpdated { who: T::AccountId, free: BalanceOf<T>, locked: BalanceOf<T> },
		/// A payout was made to a purchaser.
		PaymentComplete { who: T::AccountId, free: BalanceOf<T>, locked: BalanceOf<T> },
		/// A new payment account was set.
		PaymentAccountSet { who: T::AccountId },
		/// A new statement was set.
		StatementUpdated,
		/// A new statement was set. `[block_number]`
		UnlockBlockUpdated { block_number: BlockNumberFor<T> },
	}

	#[pallet::error]
	pub enum Error<T> {
		/// Account is not currently valid to use.
		InvalidAccount,
		/// Account used in the purchase already exists.
		ExistingAccount,
		/// Provided signature is invalid
		InvalidSignature,
		/// Account has already completed the purchase process.
		AlreadyCompleted,
		/// An overflow occurred when doing calculations.
		Overflow,
		/// The statement is too long to be stored on chain.
		InvalidStatement,
		/// The unlock block is in the past!
		InvalidUnlockBlock,
		/// Vesting schedule already exists for this account.
		VestingScheduleExists,
	}

	// A map of all participants in the DOT purchase process.
	#[pallet::storage]
	pub(super) type Accounts<T: Config> =
		StorageMap<_, Blake2_128Concat, T::AccountId, AccountStatus<BalanceOf<T>>, ValueQuery>;

	// The account that will be used to payout participants of the DOT purchase process.
	#[pallet::storage]
	pub(super) type PaymentAccount<T: Config> = StorageValue<_, T::AccountId, OptionQuery>;

	// The statement purchasers will need to sign to participate.
	#[pallet::storage]
	pub(super) type Statement<T> = StorageValue<_, Vec<u8>, ValueQuery>;

	// The block where all locked dots will unlock.
	#[pallet::storage]
	pub(super) type UnlockBlock<T: Config> = StorageValue<_, BlockNumberFor<T>, ValueQuery>;

	#[pallet::hooks]
	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {}

	#[pallet::call]
	impl<T: Config> Pallet<T> {
		/// Create a new account. Proof of existence through a valid signed message.
		///
		/// We check that the account does not exist at this stage.
		///
		/// Origin must match the `ValidityOrigin`.
		#[pallet::call_index(0)]
		#[pallet::weight(Weight::from_parts(200_000_000, 0) + T::DbWeight::get().reads_writes(4, 1))]
		pub fn create_account(
			origin: OriginFor<T>,
			who: T::AccountId,
			signature: Vec<u8>,
		) -> DispatchResult {
			T::ValidityOrigin::ensure_origin(origin)?;
			// Account is already being tracked by the pallet.
			ensure!(!Accounts::<T>::contains_key(&who), Error::<T>::ExistingAccount);
			// Account should not have a vesting schedule.
			ensure!(
				T::VestingSchedule::vesting_balance(&who).is_none(),
				Error::<T>::VestingScheduleExists
			);

			// Verify the signature provided is valid for the statement.
			Self::verify_signature(&who, &signature)?;

			// Create a new pending account.
			let status = AccountStatus {
				validity: AccountValidity::Initiated,
				signature,
				free_balance: Zero::zero(),
				locked_balance: Zero::zero(),
				vat: Permill::zero(),
			};
			Accounts::<T>::insert(&who, status);
			Self::deposit_event(Event::<T>::AccountCreated { who });
			Ok(())
		}

		/// Update the validity status of an existing account. If set to completed, the account
		/// will no longer be able to continue through the crowdfund process.
		///
		/// We check that the account exists at this stage, but has not completed the process.
		///
		/// Origin must match the `ValidityOrigin`.
		#[pallet::call_index(1)]
		#[pallet::weight(T::DbWeight::get().reads_writes(1, 1))]
		pub fn update_validity_status(
			origin: OriginFor<T>,
			who: T::AccountId,
			validity: AccountValidity,
		) -> DispatchResult {
			T::ValidityOrigin::ensure_origin(origin)?;
			ensure!(Accounts::<T>::contains_key(&who), Error::<T>::InvalidAccount);
			Accounts::<T>::try_mutate(
				&who,
				|status: &mut AccountStatus<BalanceOf<T>>| -> DispatchResult {
					ensure!(
						status.validity != AccountValidity::Completed,
						Error::<T>::AlreadyCompleted
					);
					status.validity = validity;
					Ok(())
				},
			)?;
			Self::deposit_event(Event::<T>::ValidityUpdated { who, validity });
			Ok(())
		}

		/// Update the balance of a valid account.
		///
		/// We check that the account is valid for a balance transfer at this point.
		///
		/// Origin must match the `ValidityOrigin`.
		#[pallet::call_index(2)]
		#[pallet::weight(T::DbWeight::get().reads_writes(2, 1))]
		pub fn update_balance(
			origin: OriginFor<T>,
			who: T::AccountId,
			free_balance: BalanceOf<T>,
			locked_balance: BalanceOf<T>,
			vat: Permill,
		) -> DispatchResult {
			T::ValidityOrigin::ensure_origin(origin)?;

			Accounts::<T>::try_mutate(
				&who,
				|status: &mut AccountStatus<BalanceOf<T>>| -> DispatchResult {
					// Account has a valid status (not Invalid, Pending, or Completed)...
					ensure!(status.validity.is_valid(), Error::<T>::InvalidAccount);

					free_balance.checked_add(&locked_balance).ok_or(Error::<T>::Overflow)?;
					status.free_balance = free_balance;
					status.locked_balance = locked_balance;
					status.vat = vat;
					Ok(())
				},
			)?;
			Self::deposit_event(Event::<T>::BalanceUpdated {
				who,
				free: free_balance,
				locked: locked_balance,
			});
			Ok(())
		}

		/// Pay the user and complete the purchase process.
		///
		/// We reverify all assumptions about the state of an account, and complete the process.
		///
		/// Origin must match the configured `PaymentAccount` (if it is not configured then this
		/// will always fail with `BadOrigin`).
		#[pallet::call_index(3)]
		#[pallet::weight(T::DbWeight::get().reads_writes(4, 2))]
		pub fn payout(origin: OriginFor<T>, who: T::AccountId) -> DispatchResult {
			// Payments must be made directly by the `PaymentAccount`.
			let payment_account = ensure_signed(origin)?;
			let test_against = PaymentAccount::<T>::get().ok_or(DispatchError::BadOrigin)?;
			ensure!(payment_account == test_against, DispatchError::BadOrigin);

			// Account should not have a vesting schedule.
			ensure!(
				T::VestingSchedule::vesting_balance(&who).is_none(),
				Error::<T>::VestingScheduleExists
			);

			Accounts::<T>::try_mutate(
				&who,
				|status: &mut AccountStatus<BalanceOf<T>>| -> DispatchResult {
					// Account has a valid status (not Invalid, Pending, or Completed)...
					ensure!(status.validity.is_valid(), Error::<T>::InvalidAccount);

					// Transfer funds from the payment account into the purchasing user.
					let total_balance = status
						.free_balance
						.checked_add(&status.locked_balance)
						.ok_or(Error::<T>::Overflow)?;
					T::Currency::transfer(
						&payment_account,
						&who,
						total_balance,
						ExistenceRequirement::AllowDeath,
					)?;

					if !status.locked_balance.is_zero() {
						let unlock_block = UnlockBlock::<T>::get();
						// We allow some configurable portion of the purchased locked DOTs to be
						// unlocked for basic usage.
						let unlocked = (T::UnlockedProportion::get() * status.locked_balance)
							.min(T::MaxUnlocked::get());
						let locked = status.locked_balance.saturating_sub(unlocked);
						// We checked that this account has no existing vesting schedule. So this
						// function should never fail, however if it does, not much we can do about
						// it at this point.
						let _ = T::VestingSchedule::add_vesting_schedule(
							// Apply vesting schedule to this user
							&who,
							// For this much amount
							locked,
							// Unlocking the full amount after one block
							locked,
							// When everything unlocks
							unlock_block,
						);
					}

					// Setting the user account to `Completed` ends the purchase process for this
					// user.
					status.validity = AccountValidity::Completed;
					Self::deposit_event(Event::<T>::PaymentComplete {
						who: who.clone(),
						free: status.free_balance,
						locked: status.locked_balance,
					});
					Ok(())
				},
			)?;
			Ok(())
		}

		/* Configuration Operations */

		/// Set the account that will be used to payout users in the DOT purchase process.
		///
		/// Origin must match the `ConfigurationOrigin`
		#[pallet::call_index(4)]
		#[pallet::weight(T::DbWeight::get().writes(1))]
		pub fn set_payment_account(origin: OriginFor<T>, who: T::AccountId) -> DispatchResult {
			T::ConfigurationOrigin::ensure_origin(origin)?;
			// Possibly this is worse than having the caller account be the payment account?
			PaymentAccount::<T>::put(who.clone());
			Self::deposit_event(Event::<T>::PaymentAccountSet { who });
			Ok(())
		}

		/// Set the statement that must be signed for a user to participate on the DOT sale.
		///
		/// Origin must match the `ConfigurationOrigin`
		#[pallet::call_index(5)]
		#[pallet::weight(T::DbWeight::get().writes(1))]
		pub fn set_statement(origin: OriginFor<T>, statement: Vec<u8>) -> DispatchResult {
			T::ConfigurationOrigin::ensure_origin(origin)?;
			ensure!(
				(statement.len() as u32) < T::MaxStatementLength::get(),
				Error::<T>::InvalidStatement
			);
			// Possibly this is worse than having the caller account be the payment account?
			Statement::<T>::set(statement);
			Self::deposit_event(Event::<T>::StatementUpdated);
			Ok(())
		}

		/// Set the block where locked DOTs will become unlocked.
		///
		/// Origin must match the `ConfigurationOrigin`
		#[pallet::call_index(6)]
		#[pallet::weight(T::DbWeight::get().writes(1))]
		pub fn set_unlock_block(
			origin: OriginFor<T>,
			unlock_block: BlockNumberFor<T>,
		) -> DispatchResult {
			T::ConfigurationOrigin::ensure_origin(origin)?;
			ensure!(
				unlock_block > frame_system::Pallet::<T>::block_number(),
				Error::<T>::InvalidUnlockBlock
			);
			// Possibly this is worse than having the caller account be the payment account?
			UnlockBlock::<T>::set(unlock_block);
			Self::deposit_event(Event::<T>::UnlockBlockUpdated { block_number: unlock_block });
			Ok(())
		}
	}
}

impl<T: Config> Pallet<T> {
	fn verify_signature(who: &T::AccountId, signature: &[u8]) -> Result<(), DispatchError> {
		// sr25519 always expects a 64 byte signature.
		let signature: AnySignature = sr25519::Signature::try_from(signature)
			.map_err(|_| Error::<T>::InvalidSignature)?
			.into();

		// In Polkadot, the AccountId is always the same as the 32 byte public key.
		let account_bytes: [u8; 32] = account_to_bytes(who)?;
		let public_key = sr25519::Public::from_raw(account_bytes);

		let message = Statement::<T>::get();

		// Check if everything is good or not.
		match signature.verify(message.as_slice(), &public_key) {
			true => Ok(()),
			false => Err(Error::<T>::InvalidSignature)?,
		}
	}
}

// This function converts a 32 byte AccountId to its byte-array equivalent form.
fn account_to_bytes<AccountId>(account: &AccountId) -> Result<[u8; 32], DispatchError>
where
	AccountId: Encode,
{
	let account_vec = account.encode();
	ensure!(account_vec.len() == 32, "AccountId must be 32 bytes.");
	let mut bytes = [0u8; 32];
	bytes.copy_from_slice(&account_vec);
	Ok(bytes)
}

/// WARNING: Executing this function will clear all storage used by this pallet.
/// Be sure this is what you want...
pub fn remove_pallet<T>() -> frame_support::weights::Weight
where
	T: frame_system::Config,
{
	#[allow(deprecated)]
	use frame_support::migration::remove_storage_prefix;
	#[allow(deprecated)]
	remove_storage_prefix(b"Purchase", b"Accounts", b"");
	#[allow(deprecated)]
	remove_storage_prefix(b"Purchase", b"PaymentAccount", b"");
	#[allow(deprecated)]
	remove_storage_prefix(b"Purchase", b"Statement", b"");
	#[allow(deprecated)]
	remove_storage_prefix(b"Purchase", b"UnlockBlock", b"");

	<T as frame_system::Config>::BlockWeights::get().max_block
}

#[cfg(test)]
mod tests {
	use super::*;

	use sp_core::{crypto::AccountId32, H256};
	use sp_keyring::{Ed25519Keyring, Sr25519Keyring};
	// The testing primitives are very useful for avoiding having to work with signatures
	// or public keys. `u64` is used as the `AccountId` and no `Signature`s are required.
	use crate::purchase;
	use frame_support::{
		assert_noop, assert_ok, derive_impl, ord_parameter_types, parameter_types,
		traits::{Currency, WithdrawReasons},
	};
	use sp_runtime::{
		traits::{BlakeTwo256, Dispatchable, Identity, IdentityLookup},
		ArithmeticError, BuildStorage,
		DispatchError::BadOrigin,
	};

	type Block = frame_system::mocking::MockBlock<Test>;

	frame_support::construct_runtime!(
		pub enum Test
		{
			System: frame_system,
			Balances: pallet_balances,
			Vesting: pallet_vesting,
			Purchase: purchase,
		}
	);

	type AccountId = AccountId32;

	#[derive_impl(frame_system::config_preludes::TestDefaultConfig)]
	impl frame_system::Config for Test {
		type BaseCallFilter = frame_support::traits::Everything;
		type BlockWeights = ();
		type BlockLength = ();
		type DbWeight = ();
		type RuntimeOrigin = RuntimeOrigin;
		type RuntimeCall = RuntimeCall;
		type Nonce = u64;
		type Hash = H256;
		type Hashing = BlakeTwo256;
		type AccountId = AccountId;
		type Lookup = IdentityLookup<AccountId>;
		type Block = Block;
		type RuntimeEvent = RuntimeEvent;
		type Version = ();
		type PalletInfo = PalletInfo;
		type AccountData = pallet_balances::AccountData<u64>;
		type OnNewAccount = ();
		type OnKilledAccount = ();
		type SystemWeightInfo = ();
		type SS58Prefix = ();
		type OnSetCode = ();
		type MaxConsumers = frame_support::traits::ConstU32<16>;
	}

	#[derive_impl(pallet_balances::config_preludes::TestDefaultConfig)]
	impl pallet_balances::Config for Test {
		type AccountStore = System;
	}

	parameter_types! {
		pub const MinVestedTransfer: u64 = 1;
		pub UnvestedFundsAllowedWithdrawReasons: WithdrawReasons =
			WithdrawReasons::except(WithdrawReasons::TRANSFER | WithdrawReasons::RESERVE);
	}

	impl pallet_vesting::Config for Test {
		type RuntimeEvent = RuntimeEvent;
		type Currency = Balances;
		type BlockNumberToBalance = Identity;
		type MinVestedTransfer = MinVestedTransfer;
		type WeightInfo = ();
		type UnvestedFundsAllowedWithdrawReasons = UnvestedFundsAllowedWithdrawReasons;
		type BlockNumberProvider = System;
		const MAX_VESTING_SCHEDULES: u32 = 28;
	}

	parameter_types! {
		pub const MaxStatementLength: u32 =  1_000;
		pub const UnlockedProportion: Permill = Permill::from_percent(10);
		pub const MaxUnlocked: u64 = 10;
	}

	ord_parameter_types! {
		pub const ValidityOrigin: AccountId = AccountId32::from([0u8; 32]);
		pub const PaymentOrigin: AccountId = AccountId32::from([1u8; 32]);
		pub const ConfigurationOrigin: AccountId = AccountId32::from([2u8; 32]);
	}

	impl Config for Test {
		type RuntimeEvent = RuntimeEvent;
		type Currency = Balances;
		type VestingSchedule = Vesting;
		type ValidityOrigin = frame_system::EnsureSignedBy<ValidityOrigin, AccountId>;
		type ConfigurationOrigin = frame_system::EnsureSignedBy<ConfigurationOrigin, AccountId>;
		type MaxStatementLength = MaxStatementLength;
		type UnlockedProportion = UnlockedProportion;
		type MaxUnlocked = MaxUnlocked;
	}

	// This function basically just builds a genesis storage key/value store according to
	// our desired mockup. It also executes our `setup` function which sets up this pallet for use.
	pub fn new_test_ext() -> sp_io::TestExternalities {
		let t = frame_system::GenesisConfig::<Test>::default().build_storage().unwrap();
		let mut ext = sp_io::TestExternalities::new(t);
		ext.execute_with(|| setup());
		ext
	}

	fn setup() {
		let statement = b"Hello, World".to_vec();
		let unlock_block = 100;
		Purchase::set_statement(RuntimeOrigin::signed(configuration_origin()), statement).unwrap();
		Purchase::set_unlock_block(RuntimeOrigin::signed(configuration_origin()), unlock_block)
			.unwrap();
		Purchase::set_payment_account(
			RuntimeOrigin::signed(configuration_origin()),
			payment_account(),
		)
		.unwrap();
		Balances::make_free_balance_be(&payment_account(), 100_000);
	}

	fn alice() -> AccountId {
		Sr25519Keyring::Alice.to_account_id()
	}

	fn alice_ed25519() -> AccountId {
		Ed25519Keyring::Alice.to_account_id()
	}

	fn bob() -> AccountId {
		Sr25519Keyring::Bob.to_account_id()
	}

	fn alice_signature() -> [u8; 64] {
		// echo -n "Hello, World" | subkey -s sign "bottom drive obey lake curtain smoke basket hold
		// race lonely fit walk//Alice"
		hex_literal::hex!("20e0faffdf4dfe939f2faa560f73b1d01cde8472e2b690b7b40606a374244c3a2e9eb9c8107c10b605138374003af8819bd4387d7c24a66ee9253c2e688ab881")
	}

	fn bob_signature() -> [u8; 64] {
		// echo -n "Hello, World" | subkey -s sign "bottom drive obey lake curtain smoke basket hold
		// race lonely fit walk//Bob"
		hex_literal::hex!("d6d460187ecf530f3ec2d6e3ac91b9d083c8fbd8f1112d92a82e4d84df552d18d338e6da8944eba6e84afaacf8a9850f54e7b53a84530d649be2e0119c7ce889")
	}

	fn alice_signature_ed25519() -> [u8; 64] {
		// echo -n "Hello, World" | subkey -e sign "bottom drive obey lake curtain smoke basket hold
		// race lonely fit walk//Alice"
		hex_literal::hex!("ee3f5a6cbfc12a8f00c18b811dc921b550ddf272354cda4b9a57b1d06213fcd8509f5af18425d39a279d13622f14806c3e978e2163981f2ec1c06e9628460b0e")
	}

	fn validity_origin() -> AccountId {
		ValidityOrigin::get()
	}

	fn configuration_origin() -> AccountId {
		ConfigurationOrigin::get()
	}

	fn payment_account() -> AccountId {
		[42u8; 32].into()
	}

	#[test]
	fn set_statement_works_and_handles_basic_errors() {
		new_test_ext().execute_with(|| {
			let statement = b"Test Set Statement".to_vec();
			// Invalid origin
			assert_noop!(
				Purchase::set_statement(RuntimeOrigin::signed(alice()), statement.clone()),
				BadOrigin,
			);
			// Too Long
			let long_statement = [0u8; 10_000].to_vec();
			assert_noop!(
				Purchase::set_statement(
					RuntimeOrigin::signed(configuration_origin()),
					long_statement
				),
				Error::<Test>::InvalidStatement,
			);
			// Just right...
			assert_ok!(Purchase::set_statement(
				RuntimeOrigin::signed(configuration_origin()),
				statement.clone()
			));
			assert_eq!(Statement::<Test>::get(), statement);
		});
	}

	#[test]
	fn set_unlock_block_works_and_handles_basic_errors() {
		new_test_ext().execute_with(|| {
			let unlock_block = 69;
			// Invalid origin
			assert_noop!(
				Purchase::set_unlock_block(RuntimeOrigin::signed(alice()), unlock_block),
				BadOrigin,
			);
			// Block Number in Past
			let bad_unlock_block = 50;
			System::set_block_number(bad_unlock_block);
			assert_noop!(
				Purchase::set_unlock_block(
					RuntimeOrigin::signed(configuration_origin()),
					bad_unlock_block
				),
				Error::<Test>::InvalidUnlockBlock,
			);
			// Just right...
			assert_ok!(Purchase::set_unlock_block(
				RuntimeOrigin::signed(configuration_origin()),
				unlock_block
			));
			assert_eq!(UnlockBlock::<Test>::get(), unlock_block);
		});
	}

	#[test]
	fn set_payment_account_works_and_handles_basic_errors() {
		new_test_ext().execute_with(|| {
			let payment_account: AccountId = [69u8; 32].into();
			// Invalid Origin
			assert_noop!(
				Purchase::set_payment_account(
					RuntimeOrigin::signed(alice()),
					payment_account.clone()
				),
				BadOrigin,
			);
			// Just right...
			assert_ok!(Purchase::set_payment_account(
				RuntimeOrigin::signed(configuration_origin()),
				payment_account.clone()
			));
			assert_eq!(PaymentAccount::<Test>::get(), Some(payment_account));
		});
	}

	#[test]
	fn signature_verification_works() {
		new_test_ext().execute_with(|| {
			assert_ok!(Purchase::verify_signature(&alice(), &alice_signature()));
			assert_ok!(Purchase::verify_signature(&alice_ed25519(), &alice_signature_ed25519()));
			assert_ok!(Purchase::verify_signature(&bob(), &bob_signature()));

			// Mixing and matching fails
			assert_noop!(
				Purchase::verify_signature(&alice(), &bob_signature()),
				Error::<Test>::InvalidSignature
			);
			assert_noop!(
				Purchase::verify_signature(&bob(), &alice_signature()),
				Error::<Test>::InvalidSignature
			);
		});
	}

	#[test]
	fn account_creation_works() {
		new_test_ext().execute_with(|| {
			assert!(!Accounts::<Test>::contains_key(alice()));
			assert_ok!(Purchase::create_account(
				RuntimeOrigin::signed(validity_origin()),
				alice(),
				alice_signature().to_vec(),
			));
			assert_eq!(
				Accounts::<Test>::get(alice()),
				AccountStatus {
					validity: AccountValidity::Initiated,
					free_balance: Zero::zero(),
					locked_balance: Zero::zero(),
					signature: alice_signature().to_vec(),
					vat: Permill::zero(),
				}
			);
		});
	}

	#[test]
	fn account_creation_handles_basic_errors() {
		new_test_ext().execute_with(|| {
			// Wrong Origin
			assert_noop!(
				Purchase::create_account(
					RuntimeOrigin::signed(alice()),
					alice(),
					alice_signature().to_vec()
				),
				BadOrigin,
			);

			// Wrong Account/Signature
			assert_noop!(
				Purchase::create_account(
					RuntimeOrigin::signed(validity_origin()),
					alice(),
					bob_signature().to_vec()
				),
				Error::<Test>::InvalidSignature,
			);

			// Account with vesting
			Balances::make_free_balance_be(&alice(), 100);
			assert_ok!(<Test as Config>::VestingSchedule::add_vesting_schedule(
				&alice(),
				100,
				1,
				50
			));
			assert_noop!(
				Purchase::create_account(
					RuntimeOrigin::signed(validity_origin()),
					alice(),
					alice_signature().to_vec()
				),
				Error::<Test>::VestingScheduleExists,
			);

			// Duplicate Purchasing Account
			assert_ok!(Purchase::create_account(
				RuntimeOrigin::signed(validity_origin()),
				bob(),
				bob_signature().to_vec()
			));
			assert_noop!(
				Purchase::create_account(
					RuntimeOrigin::signed(validity_origin()),
					bob(),
					bob_signature().to_vec()
				),
				Error::<Test>::ExistingAccount,
			);
		});
	}

	#[test]
	fn update_validity_status_works() {
		new_test_ext().execute_with(|| {
			// Alice account is created.
			assert_ok!(Purchase::create_account(
				RuntimeOrigin::signed(validity_origin()),
				alice(),
				alice_signature().to_vec(),
			));
			// She submits KYC, and we update the status to `Pending`.
			assert_ok!(Purchase::update_validity_status(
				RuntimeOrigin::signed(validity_origin()),
				alice(),
				AccountValidity::Pending,
			));
			// KYC comes back negative, so we mark the account invalid.
			assert_ok!(Purchase::update_validity_status(
				RuntimeOrigin::signed(validity_origin()),
				alice(),
				AccountValidity::Invalid,
			));
			assert_eq!(
				Accounts::<Test>::get(alice()),
				AccountStatus {
					validity: AccountValidity::Invalid,
					free_balance: Zero::zero(),
					locked_balance: Zero::zero(),
					signature: alice_signature().to_vec(),
					vat: Permill::zero(),
				}
			);
			// She fixes it, we mark her account valid.
			assert_ok!(Purchase::update_validity_status(
				RuntimeOrigin::signed(validity_origin()),
				alice(),
				AccountValidity::ValidLow,
			));
			assert_eq!(
				Accounts::<Test>::get(alice()),
				AccountStatus {
					validity: AccountValidity::ValidLow,
					free_balance: Zero::zero(),
					locked_balance: Zero::zero(),
					signature: alice_signature().to_vec(),
					vat: Permill::zero(),
				}
			);
		});
	}

	#[test]
	fn update_validity_status_handles_basic_errors() {
		new_test_ext().execute_with(|| {
			// Wrong Origin
			assert_noop!(
				Purchase::update_validity_status(
					RuntimeOrigin::signed(alice()),
					alice(),
					AccountValidity::Pending,
				),
				BadOrigin
			);
			// Inactive Account
			assert_noop!(
				Purchase::update_validity_status(
					RuntimeOrigin::signed(validity_origin()),
					alice(),
					AccountValidity::Pending,
				),
				Error::<Test>::InvalidAccount
			);
			// Already Completed
			assert_ok!(Purchase::create_account(
				RuntimeOrigin::signed(validity_origin()),
				alice(),
				alice_signature().to_vec(),
			));
			assert_ok!(Purchase::update_validity_status(
				RuntimeOrigin::signed(validity_origin()),
				alice(),
				AccountValidity::Completed,
			));
			assert_noop!(
				Purchase::update_validity_status(
					RuntimeOrigin::signed(validity_origin()),
					alice(),
					AccountValidity::Pending,
				),
				Error::<Test>::AlreadyCompleted
			);
		});
	}

	#[test]
	fn update_balance_works() {
		new_test_ext().execute_with(|| {
			// Alice account is created
			assert_ok!(Purchase::create_account(
				RuntimeOrigin::signed(validity_origin()),
				alice(),
				alice_signature().to_vec()
			));
			// And approved for basic contribution
			assert_ok!(Purchase::update_validity_status(
				RuntimeOrigin::signed(validity_origin()),
				alice(),
				AccountValidity::ValidLow,
			));
			// We set a balance on the user based on the payment they made. 50 locked, 50 free.
			assert_ok!(Purchase::update_balance(
				RuntimeOrigin::signed(validity_origin()),
				alice(),
				50,
				50,
				Permill::from_rational(77u32, 1000u32),
			));
			assert_eq!(
				Accounts::<Test>::get(alice()),
				AccountStatus {
					validity: AccountValidity::ValidLow,
					free_balance: 50,
					locked_balance: 50,
					signature: alice_signature().to_vec(),
					vat: Permill::from_parts(77000),
				}
			);
			// We can update the balance based on new information.
			assert_ok!(Purchase::update_balance(
				RuntimeOrigin::signed(validity_origin()),
				alice(),
				25,
				50,
				Permill::zero(),
			));
			assert_eq!(
				Accounts::<Test>::get(alice()),
				AccountStatus {
					validity: AccountValidity::ValidLow,
					free_balance: 25,
					locked_balance: 50,
					signature: alice_signature().to_vec(),
					vat: Permill::zero(),
				}
			);
		});
	}

	#[test]
	fn update_balance_handles_basic_errors() {
		new_test_ext().execute_with(|| {
			// Wrong Origin
			assert_noop!(
				Purchase::update_balance(
					RuntimeOrigin::signed(alice()),
					alice(),
					50,
					50,
					Permill::zero(),
				),
				BadOrigin
			);
			// Inactive Account
			assert_noop!(
				Purchase::update_balance(
					RuntimeOrigin::signed(validity_origin()),
					alice(),
					50,
					50,
					Permill::zero(),
				),
				Error::<Test>::InvalidAccount
			);
			// Overflow
			assert_noop!(
				Purchase::update_balance(
					RuntimeOrigin::signed(validity_origin()),
					alice(),
					u64::MAX,
					u64::MAX,
					Permill::zero(),
				),
				Error::<Test>::InvalidAccount
			);
		});
	}

	#[test]
	fn payout_works() {
		new_test_ext().execute_with(|| {
			// Alice and Bob accounts are created
			assert_ok!(Purchase::create_account(
				RuntimeOrigin::signed(validity_origin()),
				alice(),
				alice_signature().to_vec()
			));
			assert_ok!(Purchase::create_account(
				RuntimeOrigin::signed(validity_origin()),
				bob(),
				bob_signature().to_vec()
			));
			// Alice is approved for basic contribution
			assert_ok!(Purchase::update_validity_status(
				RuntimeOrigin::signed(validity_origin()),
				alice(),
				AccountValidity::ValidLow,
			));
			// Bob is approved for high contribution
			assert_ok!(Purchase::update_validity_status(
				RuntimeOrigin::signed(validity_origin()),
				bob(),
				AccountValidity::ValidHigh,
			));
			// We set a balance on the users based on the payment they made. 50 locked, 50 free.
			assert_ok!(Purchase::update_balance(
				RuntimeOrigin::signed(validity_origin()),
				alice(),
				50,
				50,
				Permill::zero(),
			));
			assert_ok!(Purchase::update_balance(
				RuntimeOrigin::signed(validity_origin()),
				bob(),
				100,
				150,
				Permill::zero(),
			));
			// Now we call payout for Alice and Bob.
			assert_ok!(Purchase::payout(RuntimeOrigin::signed(payment_account()), alice(),));
			assert_ok!(Purchase::payout(RuntimeOrigin::signed(payment_account()), bob(),));
			// Payment is made.
			assert_eq!(<Test as Config>::Currency::free_balance(&payment_account()), 99_650);
			assert_eq!(<Test as Config>::Currency::free_balance(&alice()), 100);
			// 10% of the 50 units is unlocked automatically for Alice
			assert_eq!(<Test as Config>::VestingSchedule::vesting_balance(&alice()), Some(45));
			assert_eq!(<Test as Config>::Currency::free_balance(&bob()), 250);
			// A max of 10 units is unlocked automatically for Bob
			assert_eq!(<Test as Config>::VestingSchedule::vesting_balance(&bob()), Some(140));
			// Status is completed.
			assert_eq!(
				Accounts::<Test>::get(alice()),
				AccountStatus {
					validity: AccountValidity::Completed,
					free_balance: 50,
					locked_balance: 50,
					signature: alice_signature().to_vec(),
					vat: Permill::zero(),
				}
			);
			assert_eq!(
				Accounts::<Test>::get(bob()),
				AccountStatus {
					validity: AccountValidity::Completed,
					free_balance: 100,
					locked_balance: 150,
					signature: bob_signature().to_vec(),
					vat: Permill::zero(),
				}
			);
			// Vesting lock is removed in whole on block 101 (100 blocks after block 1)
			System::set_block_number(100);
			let vest_call = RuntimeCall::Vesting(pallet_vesting::Call::<Test>::vest {});
			assert_ok!(vest_call.clone().dispatch(RuntimeOrigin::signed(alice())));
			assert_ok!(vest_call.clone().dispatch(RuntimeOrigin::signed(bob())));
			assert_eq!(<Test as Config>::VestingSchedule::vesting_balance(&alice()), Some(45));
			assert_eq!(<Test as Config>::VestingSchedule::vesting_balance(&bob()), Some(140));
			System::set_block_number(101);
			assert_ok!(vest_call.clone().dispatch(RuntimeOrigin::signed(alice())));
			assert_ok!(vest_call.clone().dispatch(RuntimeOrigin::signed(bob())));
			assert_eq!(<Test as Config>::VestingSchedule::vesting_balance(&alice()), None);
			assert_eq!(<Test as Config>::VestingSchedule::vesting_balance(&bob()), None);
		});
	}

	#[test]
	fn payout_handles_basic_errors() {
		new_test_ext().execute_with(|| {
			// Wrong Origin
			assert_noop!(Purchase::payout(RuntimeOrigin::signed(alice()), alice(),), BadOrigin);
			// Account with Existing Vesting Schedule
			Balances::make_free_balance_be(&bob(), 100);
			assert_ok!(
				<Test as Config>::VestingSchedule::add_vesting_schedule(&bob(), 100, 1, 50,)
			);
			assert_noop!(
				Purchase::payout(RuntimeOrigin::signed(payment_account()), bob(),),
				Error::<Test>::VestingScheduleExists
			);
			// Invalid Account (never created)
			assert_noop!(
				Purchase::payout(RuntimeOrigin::signed(payment_account()), alice(),),
				Error::<Test>::InvalidAccount
			);
			// Invalid Account (created, but not valid)
			assert_ok!(Purchase::create_account(
				RuntimeOrigin::signed(validity_origin()),
				alice(),
				alice_signature().to_vec()
			));
			assert_noop!(
				Purchase::payout(RuntimeOrigin::signed(payment_account()), alice(),),
				Error::<Test>::InvalidAccount
			);
			// Not enough funds in payment account
			assert_ok!(Purchase::update_validity_status(
				RuntimeOrigin::signed(validity_origin()),
				alice(),
				AccountValidity::ValidHigh,
			));
			assert_ok!(Purchase::update_balance(
				RuntimeOrigin::signed(validity_origin()),
				alice(),
				100_000,
				100_000,
				Permill::zero(),
			));
			assert_noop!(
				Purchase::payout(RuntimeOrigin::signed(payment_account()), alice()),
				ArithmeticError::Underflow
			);
		});
	}

	#[test]
	fn remove_pallet_works() {
		new_test_ext().execute_with(|| {
			let account_status = AccountStatus {
				validity: AccountValidity::Completed,
				free_balance: 1234,
				locked_balance: 4321,
				signature: b"my signature".to_vec(),
				vat: Permill::from_percent(50),
			};

			// Add some storage.
			Accounts::<Test>::insert(alice(), account_status.clone());
			Accounts::<Test>::insert(bob(), account_status);
			PaymentAccount::<Test>::put(alice());
			Statement::<Test>::put(b"hello, world!".to_vec());
			UnlockBlock::<Test>::put(4);

			// Verify storage exists.
			assert_eq!(Accounts::<Test>::iter().count(), 2);
			assert!(PaymentAccount::<Test>::exists());
			assert!(Statement::<Test>::exists());
			assert!(UnlockBlock::<Test>::exists());

			// Remove storage.
			remove_pallet::<Test>();

			// Verify storage is gone.
			assert_eq!(Accounts::<Test>::iter().count(), 0);
			assert!(!PaymentAccount::<Test>::exists());
			assert!(!Statement::<Test>::exists());
			assert!(!UnlockBlock::<Test>::exists());
		});
	}
}