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
// This file is part of Substrate.

// Copyright (C) 2019-2022 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.

//! # Nicks Pallet
//!
//! - [`Config`]
//! - [`Call`]
//!
//! ## Overview
//!
//! Nicks is an example pallet for keeping track of account names on-chain. It makes no effort to
//! create a name hierarchy, be a DNS replacement or provide reverse lookups. Furthermore, the
//! weights attached to this pallet's dispatchable functions are for demonstration purposes only and
//! have not been designed to be economically secure. Do not use this pallet as-is in production.
//!
//! ## Interface
//!
//! ### Dispatchable Functions
//!
//! * `set_name` - Set the associated name of an account; a small deposit is reserved if not already
//!   taken.
//! * `clear_name` - Remove an account's associated name; the deposit is returned.
//! * `kill_name` - Forcibly remove the associated name; the deposit is lost.

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

use frame_support::traits::{Currency, OnUnbalanced, ReservableCurrency};
pub use pallet::*;
use sp_runtime::traits::{StaticLookup, Zero};
use sp_std::prelude::*;

type AccountIdOf<T> = <T as frame_system::Config>::AccountId;
type BalanceOf<T> = <<T as Config>::Currency as Currency<AccountIdOf<T>>>::Balance;
type NegativeImbalanceOf<T> =
	<<T as Config>::Currency as Currency<AccountIdOf<T>>>::NegativeImbalance;
type AccountIdLookupOf<T> = <<T as frame_system::Config>::Lookup as StaticLookup>::Source;

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

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

		/// The currency trait.
		type Currency: ReservableCurrency<Self::AccountId>;

		/// Reservation fee.
		#[pallet::constant]
		type ReservationFee: Get<BalanceOf<Self>>;

		/// What to do with slashed funds.
		type Slashed: OnUnbalanced<NegativeImbalanceOf<Self>>;

		/// The origin which may forcibly set or remove a name. Root can always do this.
		type ForceOrigin: EnsureOrigin<Self::RuntimeOrigin>;

		/// The minimum length a name may be.
		#[pallet::constant]
		type MinLength: Get<u32>;

		/// The maximum length a name may be.
		#[pallet::constant]
		type MaxLength: Get<u32>;
	}

	#[pallet::event]
	#[pallet::generate_deposit(pub(super) fn deposit_event)]
	pub enum Event<T: Config> {
		/// A name was set.
		NameSet { who: T::AccountId },
		/// A name was forcibly set.
		NameForced { target: T::AccountId },
		/// A name was changed.
		NameChanged { who: T::AccountId },
		/// A name was cleared, and the given balance returned.
		NameCleared { who: T::AccountId, deposit: BalanceOf<T> },
		/// A name was removed and the given balance slashed.
		NameKilled { target: T::AccountId, deposit: BalanceOf<T> },
	}

	/// Error for the nicks pallet.
	#[pallet::error]
	pub enum Error<T> {
		/// A name is too short.
		TooShort,
		/// A name is too long.
		TooLong,
		/// An account isn't named.
		Unnamed,
	}

	/// The lookup table for names.
	#[pallet::storage]
	pub(super) type NameOf<T: Config> =
		StorageMap<_, Twox64Concat, T::AccountId, (BoundedVec<u8, T::MaxLength>, BalanceOf<T>)>;

	#[pallet::pallet]
	#[pallet::generate_store(pub(super) trait Store)]
	pub struct Pallet<T>(_);

	#[pallet::call]
	impl<T: Config> Pallet<T> {
		/// Set an account's name. The name should be a UTF-8-encoded string by convention, though
		/// we don't check it.
		///
		/// The name may not be more than `T::MaxLength` bytes, nor less than `T::MinLength` bytes.
		///
		/// If the account doesn't already have a name, then a fee of `ReservationFee` is reserved
		/// in the account.
		///
		/// The dispatch origin for this call must be _Signed_.
		///
		/// # <weight>
		/// - O(1).
		/// - At most one balance operation.
		/// - One storage read/write.
		/// - One event.
		/// # </weight>
		#[pallet::weight(50_000_000)]
		pub fn set_name(origin: OriginFor<T>, name: Vec<u8>) -> DispatchResult {
			let sender = ensure_signed(origin)?;

			let bounded_name: BoundedVec<_, _> =
				name.try_into().map_err(|_| Error::<T>::TooLong)?;
			ensure!(bounded_name.len() >= T::MinLength::get() as usize, Error::<T>::TooShort);

			let deposit = if let Some((_, deposit)) = <NameOf<T>>::get(&sender) {
				Self::deposit_event(Event::<T>::NameChanged { who: sender.clone() });
				deposit
			} else {
				let deposit = T::ReservationFee::get();
				T::Currency::reserve(&sender, deposit)?;
				Self::deposit_event(Event::<T>::NameSet { who: sender.clone() });
				deposit
			};

			<NameOf<T>>::insert(&sender, (bounded_name, deposit));
			Ok(())
		}

		/// Clear an account's name and return the deposit. Fails if the account was not named.
		///
		/// The dispatch origin for this call must be _Signed_.
		///
		/// # <weight>
		/// - O(1).
		/// - One balance operation.
		/// - One storage read/write.
		/// - One event.
		/// # </weight>
		#[pallet::weight(70_000_000)]
		pub fn clear_name(origin: OriginFor<T>) -> DispatchResult {
			let sender = ensure_signed(origin)?;

			let deposit = <NameOf<T>>::take(&sender).ok_or(Error::<T>::Unnamed)?.1;

			let err_amount = T::Currency::unreserve(&sender, deposit);
			debug_assert!(err_amount.is_zero());

			Self::deposit_event(Event::<T>::NameCleared { who: sender, deposit });
			Ok(())
		}

		/// Remove an account's name and take charge of the deposit.
		///
		/// Fails if `target` has not been named. The deposit is dealt with through `T::Slashed`
		/// imbalance handler.
		///
		/// The dispatch origin for this call must match `T::ForceOrigin`.
		///
		/// # <weight>
		/// - O(1).
		/// - One unbalanced handler (probably a balance transfer)
		/// - One storage read/write.
		/// - One event.
		/// # </weight>
		#[pallet::weight(70_000_000)]
		pub fn kill_name(origin: OriginFor<T>, target: AccountIdLookupOf<T>) -> DispatchResult {
			T::ForceOrigin::ensure_origin(origin)?;

			// Figure out who we're meant to be clearing.
			let target = T::Lookup::lookup(target)?;
			// Grab their deposit (and check that they have one).
			let deposit = <NameOf<T>>::take(&target).ok_or(Error::<T>::Unnamed)?.1;
			// Slash their deposit from them.
			T::Slashed::on_unbalanced(T::Currency::slash_reserved(&target, deposit).0);

			Self::deposit_event(Event::<T>::NameKilled { target, deposit });
			Ok(())
		}

		/// Set a third-party account's name with no deposit.
		///
		/// No length checking is done on the name.
		///
		/// The dispatch origin for this call must match `T::ForceOrigin`.
		///
		/// # <weight>
		/// - O(1).
		/// - At most one balance operation.
		/// - One storage read/write.
		/// - One event.
		/// # </weight>
		#[pallet::weight(70_000_000)]
		pub fn force_name(
			origin: OriginFor<T>,
			target: AccountIdLookupOf<T>,
			name: Vec<u8>,
		) -> DispatchResult {
			T::ForceOrigin::ensure_origin(origin)?;

			let bounded_name: BoundedVec<_, _> =
				name.try_into().map_err(|_| Error::<T>::TooLong)?;
			let target = T::Lookup::lookup(target)?;
			let deposit = <NameOf<T>>::get(&target).map(|x| x.1).unwrap_or_else(Zero::zero);
			<NameOf<T>>::insert(&target, (bounded_name, deposit));

			Self::deposit_event(Event::<T>::NameForced { target });
			Ok(())
		}
	}
}

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

	use frame_support::{
		assert_noop, assert_ok, ord_parameter_types, parameter_types,
		traits::{ConstU32, ConstU64},
	};
	use frame_system::EnsureSignedBy;
	use sp_core::H256;
	use sp_runtime::{
		testing::Header,
		traits::{BadOrigin, BlakeTwo256, IdentityLookup},
	};

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

	frame_support::construct_runtime!(
		pub enum Test where
			Block = Block,
			NodeBlock = Block,
			UncheckedExtrinsic = UncheckedExtrinsic,
		{
			System: frame_system,
			Balances: pallet_balances,
			Nicks: pallet_nicks,
		}
	);

	parameter_types! {
		pub BlockWeights: frame_system::limits::BlockWeights =
			frame_system::limits::BlockWeights::simple_max(frame_support::weights::Weight::from_ref_time(1024));
	}
	impl frame_system::Config for Test {
		type BaseCallFilter = frame_support::traits::Everything;
		type BlockWeights = ();
		type BlockLength = ();
		type DbWeight = ();
		type RuntimeOrigin = RuntimeOrigin;
		type Index = u64;
		type BlockNumber = u64;
		type Hash = H256;
		type RuntimeCall = RuntimeCall;
		type Hashing = BlakeTwo256;
		type AccountId = u64;
		type Lookup = IdentityLookup<Self::AccountId>;
		type Header = Header;
		type RuntimeEvent = RuntimeEvent;
		type BlockHashCount = ConstU64<250>;
		type Version = ();
		type PalletInfo = PalletInfo;
		type AccountData = pallet_balances::AccountData<u64>;
		type OnNewAccount = ();
		type OnKilledAccount = ();
		type SystemWeightInfo = ();
		type SS58Prefix = ();
		type OnSetCode = ();
		type MaxConsumers = ConstU32<16>;
	}

	impl pallet_balances::Config for Test {
		type MaxLocks = ();
		type MaxReserves = ();
		type ReserveIdentifier = [u8; 8];
		type Balance = u64;
		type RuntimeEvent = RuntimeEvent;
		type DustRemoval = ();
		type ExistentialDeposit = ConstU64<1>;
		type AccountStore = System;
		type WeightInfo = ();
	}

	ord_parameter_types! {
		pub const One: u64 = 1;
	}
	impl Config for Test {
		type RuntimeEvent = RuntimeEvent;
		type Currency = Balances;
		type ReservationFee = ConstU64<2>;
		type Slashed = ();
		type ForceOrigin = EnsureSignedBy<One, u64>;
		type MinLength = ConstU32<3>;
		type MaxLength = ConstU32<16>;
	}

	fn new_test_ext() -> sp_io::TestExternalities {
		let mut t = frame_system::GenesisConfig::default().build_storage::<Test>().unwrap();
		pallet_balances::GenesisConfig::<Test> { balances: vec![(1, 10), (2, 10)] }
			.assimilate_storage(&mut t)
			.unwrap();
		t.into()
	}

	#[test]
	fn kill_name_should_work() {
		new_test_ext().execute_with(|| {
			assert_ok!(Nicks::set_name(RuntimeOrigin::signed(2), b"Dave".to_vec()));
			assert_eq!(Balances::total_balance(&2), 10);
			assert_ok!(Nicks::kill_name(RuntimeOrigin::signed(1), 2));
			assert_eq!(Balances::total_balance(&2), 8);
			assert_eq!(<NameOf<Test>>::get(2), None);
		});
	}

	#[test]
	fn force_name_should_work() {
		new_test_ext().execute_with(|| {
			assert_noop!(
				Nicks::set_name(RuntimeOrigin::signed(2), b"Dr. David Brubeck, III".to_vec()),
				Error::<Test>::TooLong,
			);

			assert_ok!(Nicks::set_name(RuntimeOrigin::signed(2), b"Dave".to_vec()));
			assert_eq!(Balances::reserved_balance(2), 2);
			assert_noop!(
				Nicks::force_name(RuntimeOrigin::signed(1), 2, b"Dr. David Brubeck, III".to_vec()),
				Error::<Test>::TooLong,
			);
			assert_ok!(Nicks::force_name(
				RuntimeOrigin::signed(1),
				2,
				b"Dr. Brubeck, III".to_vec()
			));
			assert_eq!(Balances::reserved_balance(2), 2);
			let (name, amount) = <NameOf<Test>>::get(2).unwrap();
			assert_eq!(name, b"Dr. Brubeck, III".to_vec());
			assert_eq!(amount, 2);
		});
	}

	#[test]
	fn normal_operation_should_work() {
		new_test_ext().execute_with(|| {
			assert_ok!(Nicks::set_name(RuntimeOrigin::signed(1), b"Gav".to_vec()));
			assert_eq!(Balances::reserved_balance(1), 2);
			assert_eq!(Balances::free_balance(1), 8);
			assert_eq!(<NameOf<Test>>::get(1).unwrap().0, b"Gav".to_vec());

			assert_ok!(Nicks::set_name(RuntimeOrigin::signed(1), b"Gavin".to_vec()));
			assert_eq!(Balances::reserved_balance(1), 2);
			assert_eq!(Balances::free_balance(1), 8);
			assert_eq!(<NameOf<Test>>::get(1).unwrap().0, b"Gavin".to_vec());

			assert_ok!(Nicks::clear_name(RuntimeOrigin::signed(1)));
			assert_eq!(Balances::reserved_balance(1), 0);
			assert_eq!(Balances::free_balance(1), 10);
		});
	}

	#[test]
	fn error_catching_should_work() {
		new_test_ext().execute_with(|| {
			assert_noop!(Nicks::clear_name(RuntimeOrigin::signed(1)), Error::<Test>::Unnamed);

			assert_noop!(
				Nicks::set_name(RuntimeOrigin::signed(3), b"Dave".to_vec()),
				pallet_balances::Error::<Test, _>::InsufficientBalance
			);

			assert_noop!(
				Nicks::set_name(RuntimeOrigin::signed(1), b"Ga".to_vec()),
				Error::<Test>::TooShort
			);
			assert_noop!(
				Nicks::set_name(RuntimeOrigin::signed(1), b"Gavin James Wood, Esquire".to_vec()),
				Error::<Test>::TooLong
			);
			assert_ok!(Nicks::set_name(RuntimeOrigin::signed(1), b"Dave".to_vec()));
			assert_noop!(Nicks::kill_name(RuntimeOrigin::signed(2), 1), BadOrigin);
			assert_noop!(
				Nicks::force_name(RuntimeOrigin::signed(2), 1, b"Whatever".to_vec()),
				BadOrigin
			);
		});
	}
}