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
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
// This file is part of Substrate.

// Copyright (C) 2017-2021 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.

//! # Democracy Pallet
//!
//! - [`Config`]
//! - [`Call`]
//!
//! ## Overview
//!
//! The Democracy pallet handles the administration of general stakeholder voting.
//!
//! There are two different queues that a proposal can be added to before it
//! becomes a referendum, 1) the proposal queue consisting of all public proposals
//! and 2) the external queue consisting of a single proposal that originates
//! from one of the _external_ origins (such as a collective group).
//!
//! Every launch period - a length defined in the runtime - the Democracy pallet
//! launches a referendum from a proposal that it takes from either the proposal
//! queue or the external queue in turn. Any token holder in the system can vote
//! on referenda. The voting system
//! uses time-lock voting by allowing the token holder to set their _conviction_
//! behind a vote. The conviction will dictate the length of time the tokens
//! will be locked, as well as the multiplier that scales the vote power.
//!
//! ### Terminology
//!
//! - **Enactment Period:** The minimum period of locking and the period between a proposal being
//! approved and enacted.
//! - **Lock Period:** A period of time after proposal enactment that the tokens of _winning_ voters
//! will be locked.
//! - **Conviction:** An indication of a voter's strength of belief in their vote. An increase
//! of one in conviction indicates that a token holder is willing to lock their tokens for twice
//! as many lock periods after enactment.
//! - **Vote:** A value that can either be in approval ("Aye") or rejection ("Nay") of a particular
//!   referendum.
//! - **Proposal:** A submission to the chain that represents an action that a proposer (either an
//! account or an external origin) suggests that the system adopt.
//! - **Referendum:** A proposal that is in the process of being voted on for either acceptance or
//!   rejection as a change to the system.
//! - **Delegation:** The act of granting your voting power to the decisions of another account for
//!   up to a certain conviction.
//!
//! ### Adaptive Quorum Biasing
//!
//! A _referendum_ can be either simple majority-carries in which 50%+1 of the
//! votes decide the outcome or _adaptive quorum biased_. Adaptive quorum biasing
//! makes the threshold for passing or rejecting a referendum higher or lower
//! depending on how the referendum was originally proposed. There are two types of
//! adaptive quorum biasing: 1) _positive turnout bias_ makes a referendum
//! require a super-majority to pass that decreases as turnout increases and
//! 2) _negative turnout bias_ makes a referendum require a super-majority to
//! reject that decreases as turnout increases. Another way to think about the
//! quorum biasing is that _positive bias_ referendums will be rejected by
//! default and _negative bias_ referendums get passed by default.
//!
//! ## Interface
//!
//! ### Dispatchable Functions
//!
//! #### Public
//!
//! These calls can be made from any externally held account capable of creating
//! a signed extrinsic.
//!
//! Basic actions:
//! - `propose` - Submits a sensitive action, represented as a hash. Requires a deposit.
//! - `second` - Signals agreement with a proposal, moves it higher on the proposal queue, and
//!   requires a matching deposit to the original.
//! - `vote` - Votes in a referendum, either the vote is "Aye" to enact the proposal or "Nay" to
//!   keep the status quo.
//! - `unvote` - Cancel a previous vote, this must be done by the voter before the vote ends.
//! - `delegate` - Delegates the voting power (tokens * conviction) to another account.
//! - `undelegate` - Stops the delegation of voting power to another account.
//!
//! Administration actions that can be done to any account:
//! - `reap_vote` - Remove some account's expired votes.
//! - `unlock` - Redetermine the account's balance lock, potentially making tokens available.
//!
//! Preimage actions:
//! - `note_preimage` - Registers the preimage for an upcoming proposal, requires a deposit that is
//!   returned once the proposal is enacted.
//! - `note_preimage_operational` - same but provided by `T::OperationalPreimageOrigin`.
//! - `note_imminent_preimage` - Registers the preimage for an upcoming proposal. Does not require a
//!   deposit, but the proposal must be in the dispatch queue.
//! - `note_imminent_preimage_operational` - same but provided by `T::OperationalPreimageOrigin`.
//! - `reap_preimage` - Removes the preimage for an expired proposal. Will only work under the
//!   condition that it's the same account that noted it and after the voting period, OR it's a
//!   different account after the enactment period.
//!
//! #### Cancellation Origin
//!
//! This call can only be made by the `CancellationOrigin`.
//!
//! - `emergency_cancel` - Schedules an emergency cancellation of a referendum. Can only happen once
//!   to a specific referendum.
//!
//! #### ExternalOrigin
//!
//! This call can only be made by the `ExternalOrigin`.
//!
//! - `external_propose` - Schedules a proposal to become a referendum once it is is legal for an
//!   externally proposed referendum.
//!
//! #### External Majority Origin
//!
//! This call can only be made by the `ExternalMajorityOrigin`.
//!
//! - `external_propose_majority` - Schedules a proposal to become a majority-carries referendum
//!   once it is legal for an externally proposed referendum.
//!
//! #### External Default Origin
//!
//! This call can only be made by the `ExternalDefaultOrigin`.
//!
//! - `external_propose_default` - Schedules a proposal to become a negative-turnout-bias referendum
//!   once it is legal for an externally proposed referendum.
//!
//! #### Fast Track Origin
//!
//! This call can only be made by the `FastTrackOrigin`.
//!
//! - `fast_track` - Schedules the current externally proposed proposal that is "majority-carries"
//!   to become a referendum immediately.
//!
//! #### Veto Origin
//!
//! This call can only be made by the `VetoOrigin`.
//!
//! - `veto_external` - Vetoes and blacklists the external proposal hash.
//!
//! #### Root
//!
//! - `cancel_referendum` - Removes a referendum.
//! - `cancel_queued` - Cancels a proposal that is queued for enactment.
//! - `clear_public_proposal` - Removes all public proposals.

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

use codec::{Decode, Encode, Input};
use frame_support::{
	ensure,
	traits::{
		schedule::{DispatchTime, Named as ScheduleNamed},
		BalanceStatus, Currency, Get, LockIdentifier, LockableCurrency, OnUnbalanced,
		ReservableCurrency, WithdrawReasons,
	},
	weights::Weight,
};
use sp_runtime::{
	traits::{Bounded, Dispatchable, Hash, Saturating, Zero},
	ArithmeticError, DispatchError, DispatchResult, RuntimeDebug,
};
use sp_std::prelude::*;

mod conviction;
mod types;
mod vote;
mod vote_threshold;
pub mod weights;
pub use conviction::Conviction;
pub use pallet::*;
pub use types::{Delegations, ReferendumInfo, ReferendumStatus, Tally, UnvoteScope};
pub use vote::{AccountVote, Vote, Voting};
pub use vote_threshold::{Approved, VoteThreshold};
pub use weights::WeightInfo;

#[cfg(test)]
mod tests;

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

const DEMOCRACY_ID: LockIdentifier = *b"democrac";

/// The maximum number of vetoers on a single proposal used to compute Weight.
///
/// NOTE: This is not enforced by any logic.
pub const MAX_VETOERS: u32 = 100;

/// A proposal index.
pub type PropIndex = u32;

/// A referendum index.
pub type ReferendumIndex = u32;

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

#[derive(Clone, Encode, Decode, RuntimeDebug)]
pub enum PreimageStatus<AccountId, Balance, BlockNumber> {
	/// The preimage is imminently needed at the argument.
	Missing(BlockNumber),
	/// The preimage is available.
	Available {
		data: Vec<u8>,
		provider: AccountId,
		deposit: Balance,
		since: BlockNumber,
		/// None if it's not imminent.
		expiry: Option<BlockNumber>,
	},
}

impl<AccountId, Balance, BlockNumber> PreimageStatus<AccountId, Balance, BlockNumber> {
	fn to_missing_expiry(self) -> Option<BlockNumber> {
		match self {
			PreimageStatus::Missing(expiry) => Some(expiry),
			_ => None,
		}
	}
}

// A value placed in storage that represents the current version of the Democracy storage.
// This value is used by the `on_runtime_upgrade` logic to determine whether we run
// storage migration logic.
#[derive(Encode, Decode, Clone, Copy, PartialEq, Eq, RuntimeDebug)]
enum Releases {
	V1,
}

#[frame_support::pallet]
pub mod pallet {
	use super::*;
	use frame_support::{
		dispatch::DispatchResultWithPostInfo,
		pallet_prelude::*,
		traits::EnsureOrigin,
		weights::{DispatchClass, Pays},
		Parameter,
	};
	use frame_system::{ensure_root, ensure_signed, pallet_prelude::*};
	use sp_runtime::DispatchResult;

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

	#[pallet::config]
	pub trait Config: frame_system::Config + Sized {
		type Proposal: Parameter + Dispatchable<Origin = Self::Origin> + From<Call<Self>>;
		type Event: From<Event<Self>> + IsType<<Self as frame_system::Config>::Event>;

		/// Currency type for this pallet.
		type Currency: ReservableCurrency<Self::AccountId>
			+ LockableCurrency<Self::AccountId, Moment = Self::BlockNumber>;

		/// The minimum period of locking and the period between a proposal being approved and
		/// enacted.
		///
		/// It should generally be a little more than the unstake period to ensure that
		/// voting stakers have an opportunity to remove themselves from the system in the case
		/// where they are on the losing side of a vote.
		#[pallet::constant]
		type EnactmentPeriod: Get<Self::BlockNumber>;

		/// How often (in blocks) new public referenda are launched.
		#[pallet::constant]
		type LaunchPeriod: Get<Self::BlockNumber>;

		/// How often (in blocks) to check for new votes.
		#[pallet::constant]
		type VotingPeriod: Get<Self::BlockNumber>;

		/// The minimum amount to be used as a deposit for a public referendum proposal.
		#[pallet::constant]
		type MinimumDeposit: Get<BalanceOf<Self>>;

		/// Origin from which the next tabled referendum may be forced. This is a normal
		/// "super-majority-required" referendum.
		type ExternalOrigin: EnsureOrigin<Self::Origin>;

		/// Origin from which the next tabled referendum may be forced; this allows for the tabling
		/// of a majority-carries referendum.
		type ExternalMajorityOrigin: EnsureOrigin<Self::Origin>;

		/// Origin from which the next tabled referendum may be forced; this allows for the tabling
		/// of a negative-turnout-bias (default-carries) referendum.
		type ExternalDefaultOrigin: EnsureOrigin<Self::Origin>;

		/// Origin from which the next majority-carries (or more permissive) referendum may be
		/// tabled to vote according to the `FastTrackVotingPeriod` asynchronously in a similar
		/// manner to the emergency origin. It retains its threshold method.
		type FastTrackOrigin: EnsureOrigin<Self::Origin>;

		/// Origin from which the next majority-carries (or more permissive) referendum may be
		/// tabled to vote immediately and asynchronously in a similar manner to the emergency
		/// origin. It retains its threshold method.
		type InstantOrigin: EnsureOrigin<Self::Origin>;

		/// Indicator for whether an emergency origin is even allowed to happen. Some chains may
		/// want to set this permanently to `false`, others may want to condition it on things such
		/// as an upgrade having happened recently.
		#[pallet::constant]
		type InstantAllowed: Get<bool>;

		/// Minimum voting period allowed for a fast-track referendum.
		#[pallet::constant]
		type FastTrackVotingPeriod: Get<Self::BlockNumber>;

		/// Origin from which any referendum may be cancelled in an emergency.
		type CancellationOrigin: EnsureOrigin<Self::Origin>;

		/// Origin from which proposals may be blacklisted.
		type BlacklistOrigin: EnsureOrigin<Self::Origin>;

		/// Origin from which a proposal may be cancelled and its backers slashed.
		type CancelProposalOrigin: EnsureOrigin<Self::Origin>;

		/// Origin for anyone able to veto proposals.
		///
		/// # Warning
		///
		/// The number of Vetoers for a proposal must be small, extrinsics are weighted according to
		/// [MAX_VETOERS](./const.MAX_VETOERS.html)
		type VetoOrigin: EnsureOrigin<Self::Origin, Success = Self::AccountId>;

		/// Period in blocks where an external proposal may not be re-submitted after being vetoed.
		#[pallet::constant]
		type CooloffPeriod: Get<Self::BlockNumber>;

		/// The amount of balance that must be deposited per byte of preimage stored.
		#[pallet::constant]
		type PreimageByteDeposit: Get<BalanceOf<Self>>;

		/// An origin that can provide a preimage using operational extrinsics.
		type OperationalPreimageOrigin: EnsureOrigin<Self::Origin, Success = Self::AccountId>;

		/// Handler for the unbalanced reduction when slashing a preimage deposit.
		type Slash: OnUnbalanced<NegativeImbalanceOf<Self>>;

		/// The Scheduler.
		type Scheduler: ScheduleNamed<Self::BlockNumber, Self::Proposal, Self::PalletsOrigin>;

		/// Overarching type of all pallets origins.
		type PalletsOrigin: From<frame_system::RawOrigin<Self::AccountId>>;

		/// The maximum number of votes for an account.
		///
		/// Also used to compute weight, an overly big value can
		/// lead to extrinsic with very big weight: see `delegate` for instance.
		#[pallet::constant]
		type MaxVotes: Get<u32>;

		/// Weight information for extrinsics in this pallet.
		type WeightInfo: WeightInfo;

		/// The maximum number of public proposals that can exist at any time.
		#[pallet::constant]
		type MaxProposals: Get<u32>;
	}

	// TODO: Refactor public proposal queue into its own pallet.
	// https://github.com/paritytech/substrate/issues/5322
	/// The number of (public) proposals that have been made so far.
	#[pallet::storage]
	#[pallet::getter(fn public_prop_count)]
	pub type PublicPropCount<T> = StorageValue<_, PropIndex, ValueQuery>;

	/// The public proposals. Unsorted. The second item is the proposal's hash.
	#[pallet::storage]
	#[pallet::getter(fn public_props)]
	pub type PublicProps<T: Config> =
		StorageValue<_, Vec<(PropIndex, T::Hash, T::AccountId)>, ValueQuery>;

	/// Those who have locked a deposit.
	///
	/// TWOX-NOTE: Safe, as increasing integer keys are safe.
	#[pallet::storage]
	#[pallet::getter(fn deposit_of)]
	pub type DepositOf<T: Config> =
		StorageMap<_, Twox64Concat, PropIndex, (Vec<T::AccountId>, BalanceOf<T>)>;

	/// Map of hashes to the proposal preimage, along with who registered it and their deposit.
	/// The block number is the block at which it was deposited.
	// TODO: Refactor Preimages into its own pallet.
	// https://github.com/paritytech/substrate/issues/5322
	#[pallet::storage]
	pub type Preimages<T: Config> = StorageMap<
		_,
		Identity,
		T::Hash,
		PreimageStatus<T::AccountId, BalanceOf<T>, T::BlockNumber>,
	>;

	/// The next free referendum index, aka the number of referenda started so far.
	#[pallet::storage]
	#[pallet::getter(fn referendum_count)]
	pub type ReferendumCount<T> = StorageValue<_, ReferendumIndex, ValueQuery>;

	/// The lowest referendum index representing an unbaked referendum. Equal to
	/// `ReferendumCount` if there isn't a unbaked referendum.
	#[pallet::storage]
	#[pallet::getter(fn lowest_unbaked)]
	pub type LowestUnbaked<T> = StorageValue<_, ReferendumIndex, ValueQuery>;

	/// Information concerning any given referendum.
	///
	/// TWOX-NOTE: SAFE as indexes are not under an attacker’s control.
	#[pallet::storage]
	#[pallet::getter(fn referendum_info)]
	pub type ReferendumInfoOf<T: Config> = StorageMap<
		_,
		Twox64Concat,
		ReferendumIndex,
		ReferendumInfo<T::BlockNumber, T::Hash, BalanceOf<T>>,
	>;

	/// All votes for a particular voter. We store the balance for the number of votes that we
	/// have recorded. The second item is the total amount of delegations, that will be added.
	///
	/// TWOX-NOTE: SAFE as `AccountId`s are crypto hashes anyway.
	#[pallet::storage]
	pub type VotingOf<T: Config> = StorageMap<
		_,
		Twox64Concat,
		T::AccountId,
		Voting<BalanceOf<T>, T::AccountId, T::BlockNumber>,
		ValueQuery,
	>;

	/// Accounts for which there are locks in action which may be removed at some point in the
	/// future. The value is the block number at which the lock expires and may be removed.
	///
	/// TWOX-NOTE: OK ― `AccountId` is a secure hash.
	#[pallet::storage]
	#[pallet::getter(fn locks)]
	pub type Locks<T: Config> = StorageMap<_, Twox64Concat, T::AccountId, T::BlockNumber>;

	/// True if the last referendum tabled was submitted externally. False if it was a public
	/// proposal.
	// TODO: There should be any number of tabling origins, not just public and "external"
	// (council). https://github.com/paritytech/substrate/issues/5322
	#[pallet::storage]
	pub type LastTabledWasExternal<T> = StorageValue<_, bool, ValueQuery>;

	/// The referendum to be tabled whenever it would be valid to table an external proposal.
	/// This happens when a referendum needs to be tabled and one of two conditions are met:
	/// - `LastTabledWasExternal` is `false`; or
	/// - `PublicProps` is empty.
	#[pallet::storage]
	pub type NextExternal<T: Config> = StorageValue<_, (T::Hash, VoteThreshold)>;

	/// A record of who vetoed what. Maps proposal hash to a possible existent block number
	/// (until when it may not be resubmitted) and who vetoed it.
	#[pallet::storage]
	pub type Blacklist<T: Config> =
		StorageMap<_, Identity, T::Hash, (T::BlockNumber, Vec<T::AccountId>)>;

	/// Record of all proposals that have been subject to emergency cancellation.
	#[pallet::storage]
	pub type Cancellations<T: Config> = StorageMap<_, Identity, T::Hash, bool, ValueQuery>;

	/// Storage version of the pallet.
	///
	/// New networks start with last version.
	#[pallet::storage]
	pub(crate) type StorageVersion<T> = StorageValue<_, Releases>;

	#[pallet::genesis_config]
	pub struct GenesisConfig<T: Config> {
		_phantom: sp_std::marker::PhantomData<T>,
	}

	#[cfg(feature = "std")]
	impl<T: Config> Default for GenesisConfig<T> {
		fn default() -> Self {
			GenesisConfig { _phantom: Default::default() }
		}
	}

	#[pallet::genesis_build]
	impl<T: Config> GenesisBuild<T> for GenesisConfig<T> {
		fn build(&self) {
			PublicPropCount::<T>::put(0 as PropIndex);
			ReferendumCount::<T>::put(0 as ReferendumIndex);
			LowestUnbaked::<T>::put(0 as ReferendumIndex);
			StorageVersion::<T>::put(Releases::V1);
		}
	}

	#[pallet::event]
	#[pallet::generate_deposit(pub(super) fn deposit_event)]
	#[pallet::metadata(
		T::AccountId = "AccountId",
		Vec<T::AccountId> = "Vec<AccountId>",
		BalanceOf<T> = "Balance",
		T::BlockNumber = "BlockNumber",
		T::Hash = "Hash",
	)]
	pub enum Event<T: Config> {
		/// A motion has been proposed by a public account. \[proposal_index, deposit\]
		Proposed(PropIndex, BalanceOf<T>),
		/// A public proposal has been tabled for referendum vote. \[proposal_index, deposit,
		/// depositors\]
		Tabled(PropIndex, BalanceOf<T>, Vec<T::AccountId>),
		/// An external proposal has been tabled.
		ExternalTabled,
		/// A referendum has begun. \[ref_index, threshold\]
		Started(ReferendumIndex, VoteThreshold),
		/// A proposal has been approved by referendum. \[ref_index\]
		Passed(ReferendumIndex),
		/// A proposal has been rejected by referendum. \[ref_index\]
		NotPassed(ReferendumIndex),
		/// A referendum has been cancelled. \[ref_index\]
		Cancelled(ReferendumIndex),
		/// A proposal has been enacted. \[ref_index, result\]
		Executed(ReferendumIndex, DispatchResult),
		/// An account has delegated their vote to another account. \[who, target\]
		Delegated(T::AccountId, T::AccountId),
		/// An \[account\] has cancelled a previous delegation operation.
		Undelegated(T::AccountId),
		/// An external proposal has been vetoed. \[who, proposal_hash, until\]
		Vetoed(T::AccountId, T::Hash, T::BlockNumber),
		/// A proposal's preimage was noted, and the deposit taken. \[proposal_hash, who, deposit\]
		PreimageNoted(T::Hash, T::AccountId, BalanceOf<T>),
		/// A proposal preimage was removed and used (the deposit was returned).
		/// \[proposal_hash, provider, deposit\]
		PreimageUsed(T::Hash, T::AccountId, BalanceOf<T>),
		/// A proposal could not be executed because its preimage was invalid.
		/// \[proposal_hash, ref_index\]
		PreimageInvalid(T::Hash, ReferendumIndex),
		/// A proposal could not be executed because its preimage was missing.
		/// \[proposal_hash, ref_index\]
		PreimageMissing(T::Hash, ReferendumIndex),
		/// A registered preimage was removed and the deposit collected by the reaper.
		/// \[proposal_hash, provider, deposit, reaper\]
		PreimageReaped(T::Hash, T::AccountId, BalanceOf<T>, T::AccountId),
		/// A proposal \[hash\] has been blacklisted permanently.
		Blacklisted(T::Hash),
	}

	#[pallet::error]
	pub enum Error<T> {
		/// Value too low
		ValueLow,
		/// Proposal does not exist
		ProposalMissing,
		/// Cannot cancel the same proposal twice
		AlreadyCanceled,
		/// Proposal already made
		DuplicateProposal,
		/// Proposal still blacklisted
		ProposalBlacklisted,
		/// Next external proposal not simple majority
		NotSimpleMajority,
		/// Invalid hash
		InvalidHash,
		/// No external proposal
		NoProposal,
		/// Identity may not veto a proposal twice
		AlreadyVetoed,
		/// Preimage already noted
		DuplicatePreimage,
		/// Not imminent
		NotImminent,
		/// Too early
		TooEarly,
		/// Imminent
		Imminent,
		/// Preimage not found
		PreimageMissing,
		/// Vote given for invalid referendum
		ReferendumInvalid,
		/// Invalid preimage
		PreimageInvalid,
		/// No proposals waiting
		NoneWaiting,
		/// The given account did not vote on the referendum.
		NotVoter,
		/// The actor has no permission to conduct the action.
		NoPermission,
		/// The account is already delegating.
		AlreadyDelegating,
		/// Too high a balance was provided that the account cannot afford.
		InsufficientFunds,
		/// The account is not currently delegating.
		NotDelegating,
		/// The account currently has votes attached to it and the operation cannot succeed until
		/// these are removed, either through `unvote` or `reap_vote`.
		VotesExist,
		/// The instant referendum origin is currently disallowed.
		InstantNotAllowed,
		/// Delegation to oneself makes no sense.
		Nonsense,
		/// Invalid upper bound.
		WrongUpperBound,
		/// Maximum number of votes reached.
		MaxVotesReached,
		/// Maximum number of proposals reached.
		TooManyProposals,
	}

	#[pallet::hooks]
	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {
		/// Weight: see `begin_block`
		fn on_initialize(n: T::BlockNumber) -> Weight {
			Self::begin_block(n).unwrap_or_else(|e| {
				sp_runtime::print(e);
				0
			})
		}
	}

	#[pallet::call]
	impl<T: Config> Pallet<T> {
		/// Propose a sensitive action to be taken.
		///
		/// The dispatch origin of this call must be _Signed_ and the sender must
		/// have funds to cover the deposit.
		///
		/// - `proposal_hash`: The hash of the proposal preimage.
		/// - `value`: The amount of deposit (must be at least `MinimumDeposit`).
		///
		/// Emits `Proposed`.
		///
		/// Weight: `O(p)`
		#[pallet::weight(T::WeightInfo::propose())]
		pub fn propose(
			origin: OriginFor<T>,
			proposal_hash: T::Hash,
			#[pallet::compact] value: BalanceOf<T>,
		) -> DispatchResult {
			let who = ensure_signed(origin)?;
			ensure!(value >= T::MinimumDeposit::get(), Error::<T>::ValueLow);

			let index = Self::public_prop_count();
			let real_prop_count = PublicProps::<T>::decode_len().unwrap_or(0) as u32;
			let max_proposals = T::MaxProposals::get();
			ensure!(real_prop_count < max_proposals, Error::<T>::TooManyProposals);

			if let Some((until, _)) = <Blacklist<T>>::get(proposal_hash) {
				ensure!(
					<frame_system::Pallet<T>>::block_number() >= until,
					Error::<T>::ProposalBlacklisted,
				);
			}

			T::Currency::reserve(&who, value)?;
			PublicPropCount::<T>::put(index + 1);
			<DepositOf<T>>::insert(index, (&[&who][..], value));

			<PublicProps<T>>::append((index, proposal_hash, who));

			Self::deposit_event(Event::<T>::Proposed(index, value));
			Ok(())
		}

		/// Signals agreement with a particular proposal.
		///
		/// The dispatch origin of this call must be _Signed_ and the sender
		/// must have funds to cover the deposit, equal to the original deposit.
		///
		/// - `proposal`: The index of the proposal to second.
		/// - `seconds_upper_bound`: an upper bound on the current number of seconds on this
		///   proposal. Extrinsic is weighted according to this value with no refund.
		///
		/// Weight: `O(S)` where S is the number of seconds a proposal already has.
		#[pallet::weight(T::WeightInfo::second(*seconds_upper_bound))]
		pub fn second(
			origin: OriginFor<T>,
			#[pallet::compact] proposal: PropIndex,
			#[pallet::compact] seconds_upper_bound: u32,
		) -> DispatchResult {
			let who = ensure_signed(origin)?;

			let seconds =
				Self::len_of_deposit_of(proposal).ok_or_else(|| Error::<T>::ProposalMissing)?;
			ensure!(seconds <= seconds_upper_bound, Error::<T>::WrongUpperBound);
			let mut deposit = Self::deposit_of(proposal).ok_or(Error::<T>::ProposalMissing)?;
			T::Currency::reserve(&who, deposit.1)?;
			deposit.0.push(who);
			<DepositOf<T>>::insert(proposal, deposit);
			Ok(())
		}

		/// Vote in a referendum. If `vote.is_aye()`, the vote is to enact the proposal;
		/// otherwise it is a vote to keep the status quo.
		///
		/// The dispatch origin of this call must be _Signed_.
		///
		/// - `ref_index`: The index of the referendum to vote for.
		/// - `vote`: The vote configuration.
		///
		/// Weight: `O(R)` where R is the number of referendums the voter has voted on.
		#[pallet::weight(
			T::WeightInfo::vote_new(T::MaxVotes::get())
				.max(T::WeightInfo::vote_existing(T::MaxVotes::get()))
		)]
		pub fn vote(
			origin: OriginFor<T>,
			#[pallet::compact] ref_index: ReferendumIndex,
			vote: AccountVote<BalanceOf<T>>,
		) -> DispatchResult {
			let who = ensure_signed(origin)?;
			Self::try_vote(&who, ref_index, vote)
		}

		/// Schedule an emergency cancellation of a referendum. Cannot happen twice to the same
		/// referendum.
		///
		/// The dispatch origin of this call must be `CancellationOrigin`.
		///
		/// -`ref_index`: The index of the referendum to cancel.
		///
		/// Weight: `O(1)`.
		#[pallet::weight((T::WeightInfo::emergency_cancel(), DispatchClass::Operational))]
		pub fn emergency_cancel(
			origin: OriginFor<T>,
			ref_index: ReferendumIndex,
		) -> DispatchResult {
			T::CancellationOrigin::ensure_origin(origin)?;

			let status = Self::referendum_status(ref_index)?;
			let h = status.proposal_hash;
			ensure!(!<Cancellations<T>>::contains_key(h), Error::<T>::AlreadyCanceled);

			<Cancellations<T>>::insert(h, true);
			Self::internal_cancel_referendum(ref_index);
			Ok(())
		}

		/// Schedule a referendum to be tabled once it is legal to schedule an external
		/// referendum.
		///
		/// The dispatch origin of this call must be `ExternalOrigin`.
		///
		/// - `proposal_hash`: The preimage hash of the proposal.
		///
		/// Weight: `O(V)` with V number of vetoers in the blacklist of proposal.
		///   Decoding vec of length V. Charged as maximum
		#[pallet::weight(T::WeightInfo::external_propose(MAX_VETOERS))]
		pub fn external_propose(origin: OriginFor<T>, proposal_hash: T::Hash) -> DispatchResult {
			T::ExternalOrigin::ensure_origin(origin)?;
			ensure!(!<NextExternal<T>>::exists(), Error::<T>::DuplicateProposal);
			if let Some((until, _)) = <Blacklist<T>>::get(proposal_hash) {
				ensure!(
					<frame_system::Pallet<T>>::block_number() >= until,
					Error::<T>::ProposalBlacklisted,
				);
			}
			<NextExternal<T>>::put((proposal_hash, VoteThreshold::SuperMajorityApprove));
			Ok(())
		}

		/// Schedule a majority-carries referendum to be tabled next once it is legal to schedule
		/// an external referendum.
		///
		/// The dispatch of this call must be `ExternalMajorityOrigin`.
		///
		/// - `proposal_hash`: The preimage hash of the proposal.
		///
		/// Unlike `external_propose`, blacklisting has no effect on this and it may replace a
		/// pre-scheduled `external_propose` call.
		///
		/// Weight: `O(1)`
		#[pallet::weight(T::WeightInfo::external_propose_majority())]
		pub fn external_propose_majority(
			origin: OriginFor<T>,
			proposal_hash: T::Hash,
		) -> DispatchResult {
			T::ExternalMajorityOrigin::ensure_origin(origin)?;
			<NextExternal<T>>::put((proposal_hash, VoteThreshold::SimpleMajority));
			Ok(())
		}

		/// Schedule a negative-turnout-bias referendum to be tabled next once it is legal to
		/// schedule an external referendum.
		///
		/// The dispatch of this call must be `ExternalDefaultOrigin`.
		///
		/// - `proposal_hash`: The preimage hash of the proposal.
		///
		/// Unlike `external_propose`, blacklisting has no effect on this and it may replace a
		/// pre-scheduled `external_propose` call.
		///
		/// Weight: `O(1)`
		#[pallet::weight(T::WeightInfo::external_propose_default())]
		pub fn external_propose_default(
			origin: OriginFor<T>,
			proposal_hash: T::Hash,
		) -> DispatchResult {
			T::ExternalDefaultOrigin::ensure_origin(origin)?;
			<NextExternal<T>>::put((proposal_hash, VoteThreshold::SuperMajorityAgainst));
			Ok(())
		}

		/// Schedule the currently externally-proposed majority-carries referendum to be tabled
		/// immediately. If there is no externally-proposed referendum currently, or if there is one
		/// but it is not a majority-carries referendum then it fails.
		///
		/// The dispatch of this call must be `FastTrackOrigin`.
		///
		/// - `proposal_hash`: The hash of the current external proposal.
		/// - `voting_period`: The period that is allowed for voting on this proposal. Increased to
		///   `FastTrackVotingPeriod` if too low.
		/// - `delay`: The number of block after voting has ended in approval and this should be
		///   enacted. This doesn't have a minimum amount.
		///
		/// Emits `Started`.
		///
		/// Weight: `O(1)`
		#[pallet::weight(T::WeightInfo::fast_track())]
		pub fn fast_track(
			origin: OriginFor<T>,
			proposal_hash: T::Hash,
			voting_period: T::BlockNumber,
			delay: T::BlockNumber,
		) -> DispatchResult {
			// Rather complicated bit of code to ensure that either:
			// - `voting_period` is at least `FastTrackVotingPeriod` and `origin` is
			//   `FastTrackOrigin`; or
			// - `InstantAllowed` is `true` and `origin` is `InstantOrigin`.
			let maybe_ensure_instant = if voting_period < T::FastTrackVotingPeriod::get() {
				Some(origin)
			} else {
				if let Err(origin) = T::FastTrackOrigin::try_origin(origin) {
					Some(origin)
				} else {
					None
				}
			};
			if let Some(ensure_instant) = maybe_ensure_instant {
				T::InstantOrigin::ensure_origin(ensure_instant)?;
				ensure!(T::InstantAllowed::get(), Error::<T>::InstantNotAllowed);
			}

			let (e_proposal_hash, threshold) =
				<NextExternal<T>>::get().ok_or(Error::<T>::ProposalMissing)?;
			ensure!(
				threshold != VoteThreshold::SuperMajorityApprove,
				Error::<T>::NotSimpleMajority,
			);
			ensure!(proposal_hash == e_proposal_hash, Error::<T>::InvalidHash);

			<NextExternal<T>>::kill();
			let now = <frame_system::Pallet<T>>::block_number();
			Self::inject_referendum(now + voting_period, proposal_hash, threshold, delay);
			Ok(())
		}

		/// Veto and blacklist the external proposal hash.
		///
		/// The dispatch origin of this call must be `VetoOrigin`.
		///
		/// - `proposal_hash`: The preimage hash of the proposal to veto and blacklist.
		///
		/// Emits `Vetoed`.
		///
		/// Weight: `O(V + log(V))` where V is number of `existing vetoers`
		#[pallet::weight(T::WeightInfo::veto_external(MAX_VETOERS))]
		pub fn veto_external(origin: OriginFor<T>, proposal_hash: T::Hash) -> DispatchResult {
			let who = T::VetoOrigin::ensure_origin(origin)?;

			if let Some((e_proposal_hash, _)) = <NextExternal<T>>::get() {
				ensure!(proposal_hash == e_proposal_hash, Error::<T>::ProposalMissing);
			} else {
				Err(Error::<T>::NoProposal)?;
			}

			let mut existing_vetoers =
				<Blacklist<T>>::get(&proposal_hash).map(|pair| pair.1).unwrap_or_else(Vec::new);
			let insert_position =
				existing_vetoers.binary_search(&who).err().ok_or(Error::<T>::AlreadyVetoed)?;

			existing_vetoers.insert(insert_position, who.clone());
			let until = <frame_system::Pallet<T>>::block_number() + T::CooloffPeriod::get();
			<Blacklist<T>>::insert(&proposal_hash, (until, existing_vetoers));

			Self::deposit_event(Event::<T>::Vetoed(who, proposal_hash, until));
			<NextExternal<T>>::kill();
			Ok(())
		}

		/// Remove a referendum.
		///
		/// The dispatch origin of this call must be _Root_.
		///
		/// - `ref_index`: The index of the referendum to cancel.
		///
		/// # Weight: `O(1)`.
		#[pallet::weight(T::WeightInfo::cancel_referendum())]
		pub fn cancel_referendum(
			origin: OriginFor<T>,
			#[pallet::compact] ref_index: ReferendumIndex,
		) -> DispatchResult {
			ensure_root(origin)?;
			Self::internal_cancel_referendum(ref_index);
			Ok(())
		}

		/// Cancel a proposal queued for enactment.
		///
		/// The dispatch origin of this call must be _Root_.
		///
		/// - `which`: The index of the referendum to cancel.
		///
		/// Weight: `O(D)` where `D` is the items in the dispatch queue. Weighted as `D = 10`.
		#[pallet::weight((T::WeightInfo::cancel_queued(10), DispatchClass::Operational))]
		pub fn cancel_queued(origin: OriginFor<T>, which: ReferendumIndex) -> DispatchResult {
			ensure_root(origin)?;
			T::Scheduler::cancel_named((DEMOCRACY_ID, which).encode())
				.map_err(|_| Error::<T>::ProposalMissing)?;
			Ok(())
		}

		/// Delegate the voting power (with some given conviction) of the sending account.
		///
		/// The balance delegated is locked for as long as it's delegated, and thereafter for the
		/// time appropriate for the conviction's lock period.
		///
		/// The dispatch origin of this call must be _Signed_, and the signing account must either:
		///   - be delegating already; or
		///   - have no voting activity (if there is, then it will need to be removed/consolidated
		///     through `reap_vote` or `unvote`).
		///
		/// - `to`: The account whose voting the `target` account's voting power will follow.
		/// - `conviction`: The conviction that will be attached to the delegated votes. When the
		///   account is undelegated, the funds will be locked for the corresponding period.
		/// - `balance`: The amount of the account's balance to be used in delegating. This must not
		///   be more than the account's current balance.
		///
		/// Emits `Delegated`.
		///
		/// Weight: `O(R)` where R is the number of referendums the voter delegating to has
		///   voted on. Weight is charged as if maximum votes.
		// NOTE: weight must cover an incorrect voting of origin with max votes, this is ensure
		// because a valid delegation cover decoding a direct voting with max votes.
		#[pallet::weight(T::WeightInfo::delegate(T::MaxVotes::get()))]
		pub fn delegate(
			origin: OriginFor<T>,
			to: T::AccountId,
			conviction: Conviction,
			balance: BalanceOf<T>,
		) -> DispatchResultWithPostInfo {
			let who = ensure_signed(origin)?;
			let votes = Self::try_delegate(who, to, conviction, balance)?;

			Ok(Some(T::WeightInfo::delegate(votes)).into())
		}

		/// Undelegate the voting power of the sending account.
		///
		/// Tokens may be unlocked following once an amount of time consistent with the lock period
		/// of the conviction with which the delegation was issued.
		///
		/// The dispatch origin of this call must be _Signed_ and the signing account must be
		/// currently delegating.
		///
		/// Emits `Undelegated`.
		///
		/// Weight: `O(R)` where R is the number of referendums the voter delegating to has
		///   voted on. Weight is charged as if maximum votes.
		// NOTE: weight must cover an incorrect voting of origin with max votes, this is ensure
		// because a valid delegation cover decoding a direct voting with max votes.
		#[pallet::weight(T::WeightInfo::undelegate(T::MaxVotes::get().into()))]
		pub fn undelegate(origin: OriginFor<T>) -> DispatchResultWithPostInfo {
			let who = ensure_signed(origin)?;
			let votes = Self::try_undelegate(who)?;
			Ok(Some(T::WeightInfo::undelegate(votes)).into())
		}

		/// Clears all public proposals.
		///
		/// The dispatch origin of this call must be _Root_.
		///
		/// Weight: `O(1)`.
		#[pallet::weight(T::WeightInfo::clear_public_proposals())]
		pub fn clear_public_proposals(origin: OriginFor<T>) -> DispatchResult {
			ensure_root(origin)?;
			<PublicProps<T>>::kill();
			Ok(())
		}

		/// Register the preimage for an upcoming proposal. This doesn't require the proposal to be
		/// in the dispatch queue but does require a deposit, returned once enacted.
		///
		/// The dispatch origin of this call must be _Signed_.
		///
		/// - `encoded_proposal`: The preimage of a proposal.
		///
		/// Emits `PreimageNoted`.
		///
		/// Weight: `O(E)` with E size of `encoded_proposal` (protected by a required deposit).
		#[pallet::weight(T::WeightInfo::note_preimage(encoded_proposal.len() as u32))]
		pub fn note_preimage(origin: OriginFor<T>, encoded_proposal: Vec<u8>) -> DispatchResult {
			Self::note_preimage_inner(ensure_signed(origin)?, encoded_proposal)?;
			Ok(())
		}

		/// Same as `note_preimage` but origin is `OperationalPreimageOrigin`.
		#[pallet::weight((
			T::WeightInfo::note_preimage(encoded_proposal.len() as u32),
			DispatchClass::Operational,
		))]
		pub fn note_preimage_operational(
			origin: OriginFor<T>,
			encoded_proposal: Vec<u8>,
		) -> DispatchResult {
			let who = T::OperationalPreimageOrigin::ensure_origin(origin)?;
			Self::note_preimage_inner(who, encoded_proposal)?;
			Ok(())
		}

		/// Register the preimage for an upcoming proposal. This requires the proposal to be
		/// in the dispatch queue. No deposit is needed. When this call is successful, i.e.
		/// the preimage has not been uploaded before and matches some imminent proposal,
		/// no fee is paid.
		///
		/// The dispatch origin of this call must be _Signed_.
		///
		/// - `encoded_proposal`: The preimage of a proposal.
		///
		/// Emits `PreimageNoted`.
		///
		/// Weight: `O(E)` with E size of `encoded_proposal` (protected by a required deposit).
		#[pallet::weight(T::WeightInfo::note_imminent_preimage(encoded_proposal.len() as u32))]
		pub fn note_imminent_preimage(
			origin: OriginFor<T>,
			encoded_proposal: Vec<u8>,
		) -> DispatchResultWithPostInfo {
			Self::note_imminent_preimage_inner(ensure_signed(origin)?, encoded_proposal)?;
			// We check that this preimage was not uploaded before in
			// `note_imminent_preimage_inner`, thus this call can only be successful once. If
			// successful, user does not pay a fee.
			Ok(Pays::No.into())
		}

		/// Same as `note_imminent_preimage` but origin is `OperationalPreimageOrigin`.
		#[pallet::weight((
			T::WeightInfo::note_imminent_preimage(encoded_proposal.len() as u32),
			DispatchClass::Operational,
		))]
		pub fn note_imminent_preimage_operational(
			origin: OriginFor<T>,
			encoded_proposal: Vec<u8>,
		) -> DispatchResultWithPostInfo {
			let who = T::OperationalPreimageOrigin::ensure_origin(origin)?;
			Self::note_imminent_preimage_inner(who, encoded_proposal)?;
			// We check that this preimage was not uploaded before in
			// `note_imminent_preimage_inner`, thus this call can only be successful once. If
			// successful, user does not pay a fee.
			Ok(Pays::No.into())
		}

		/// Remove an expired proposal preimage and collect the deposit.
		///
		/// The dispatch origin of this call must be _Signed_.
		///
		/// - `proposal_hash`: The preimage hash of a proposal.
		/// - `proposal_length_upper_bound`: an upper bound on length of the proposal. Extrinsic is
		///   weighted according to this value with no refund.
		///
		/// This will only work after `VotingPeriod` blocks from the time that the preimage was
		/// noted, if it's the same account doing it. If it's a different account, then it'll only
		/// work an additional `EnactmentPeriod` later.
		///
		/// Emits `PreimageReaped`.
		///
		/// Weight: `O(D)` where D is length of proposal.
		#[pallet::weight(T::WeightInfo::reap_preimage(*proposal_len_upper_bound))]
		pub fn reap_preimage(
			origin: OriginFor<T>,
			proposal_hash: T::Hash,
			#[pallet::compact] proposal_len_upper_bound: u32,
		) -> DispatchResult {
			let who = ensure_signed(origin)?;

			ensure!(
				Self::pre_image_data_len(proposal_hash)? <= proposal_len_upper_bound,
				Error::<T>::WrongUpperBound,
			);

			let (provider, deposit, since, expiry) = <Preimages<T>>::get(&proposal_hash)
				.and_then(|m| match m {
					PreimageStatus::Available { provider, deposit, since, expiry, .. } =>
						Some((provider, deposit, since, expiry)),
					_ => None,
				})
				.ok_or(Error::<T>::PreimageMissing)?;

			let now = <frame_system::Pallet<T>>::block_number();
			let (voting, enactment) = (T::VotingPeriod::get(), T::EnactmentPeriod::get());
			let additional = if who == provider { Zero::zero() } else { enactment };
			ensure!(now >= since + voting + additional, Error::<T>::TooEarly);
			ensure!(expiry.map_or(true, |e| now > e), Error::<T>::Imminent);

			let res =
				T::Currency::repatriate_reserved(&provider, &who, deposit, BalanceStatus::Free);
			debug_assert!(res.is_ok());
			<Preimages<T>>::remove(&proposal_hash);
			Self::deposit_event(Event::<T>::PreimageReaped(proposal_hash, provider, deposit, who));
			Ok(())
		}

		/// Unlock tokens that have an expired lock.
		///
		/// The dispatch origin of this call must be _Signed_.
		///
		/// - `target`: The account to remove the lock on.
		///
		/// Weight: `O(R)` with R number of vote of target.
		#[pallet::weight(
			T::WeightInfo::unlock_set(T::MaxVotes::get())
				.max(T::WeightInfo::unlock_remove(T::MaxVotes::get()))
		)]
		pub fn unlock(origin: OriginFor<T>, target: T::AccountId) -> DispatchResult {
			ensure_signed(origin)?;
			Self::update_lock(&target);
			Ok(())
		}

		/// Remove a vote for a referendum.
		///
		/// If:
		/// - the referendum was cancelled, or
		/// - the referendum is ongoing, or
		/// - the referendum has ended such that
		///   - the vote of the account was in opposition to the result; or
		///   - there was no conviction to the account's vote; or
		///   - the account made a split vote
		/// ...then the vote is removed cleanly and a following call to `unlock` may result in more
		/// funds being available.
		///
		/// If, however, the referendum has ended and:
		/// - it finished corresponding to the vote of the account, and
		/// - the account made a standard vote with conviction, and
		/// - the lock period of the conviction is not over
		/// ...then the lock will be aggregated into the overall account's lock, which may involve
		/// *overlocking* (where the two locks are combined into a single lock that is the maximum
		/// of both the amount locked and the time is it locked for).
		///
		/// The dispatch origin of this call must be _Signed_, and the signer must have a vote
		/// registered for referendum `index`.
		///
		/// - `index`: The index of referendum of the vote to be removed.
		///
		/// Weight: `O(R + log R)` where R is the number of referenda that `target` has voted on.
		///   Weight is calculated for the maximum number of vote.
		#[pallet::weight(T::WeightInfo::remove_vote(T::MaxVotes::get()))]
		pub fn remove_vote(origin: OriginFor<T>, index: ReferendumIndex) -> DispatchResult {
			let who = ensure_signed(origin)?;
			Self::try_remove_vote(&who, index, UnvoteScope::Any)
		}

		/// Remove a vote for a referendum.
		///
		/// If the `target` is equal to the signer, then this function is exactly equivalent to
		/// `remove_vote`. If not equal to the signer, then the vote must have expired,
		/// either because the referendum was cancelled, because the voter lost the referendum or
		/// because the conviction period is over.
		///
		/// The dispatch origin of this call must be _Signed_.
		///
		/// - `target`: The account of the vote to be removed; this account must have voted for
		///   referendum `index`.
		/// - `index`: The index of referendum of the vote to be removed.
		///
		/// Weight: `O(R + log R)` where R is the number of referenda that `target` has voted on.
		///   Weight is calculated for the maximum number of vote.
		#[pallet::weight(T::WeightInfo::remove_other_vote(T::MaxVotes::get()))]
		pub fn remove_other_vote(
			origin: OriginFor<T>,
			target: T::AccountId,
			index: ReferendumIndex,
		) -> DispatchResult {
			let who = ensure_signed(origin)?;
			let scope = if target == who { UnvoteScope::Any } else { UnvoteScope::OnlyExpired };
			Self::try_remove_vote(&target, index, scope)?;
			Ok(())
		}

		/// Enact a proposal from a referendum. For now we just make the weight be the maximum.
		#[pallet::weight(T::BlockWeights::get().max_block)]
		pub fn enact_proposal(
			origin: OriginFor<T>,
			proposal_hash: T::Hash,
			index: ReferendumIndex,
		) -> DispatchResult {
			ensure_root(origin)?;
			Self::do_enact_proposal(proposal_hash, index)
		}

		/// Permanently place a proposal into the blacklist. This prevents it from ever being
		/// proposed again.
		///
		/// If called on a queued public or external proposal, then this will result in it being
		/// removed. If the `ref_index` supplied is an active referendum with the proposal hash,
		/// then it will be cancelled.
		///
		/// The dispatch origin of this call must be `BlacklistOrigin`.
		///
		/// - `proposal_hash`: The proposal hash to blacklist permanently.
		/// - `ref_index`: An ongoing referendum whose hash is `proposal_hash`, which will be
		/// cancelled.
		///
		/// Weight: `O(p)` (though as this is an high-privilege dispatch, we assume it has a
		///   reasonable value).
		#[pallet::weight((T::WeightInfo::blacklist(T::MaxProposals::get()), DispatchClass::Operational))]
		pub fn blacklist(
			origin: OriginFor<T>,
			proposal_hash: T::Hash,
			maybe_ref_index: Option<ReferendumIndex>,
		) -> DispatchResult {
			T::BlacklistOrigin::ensure_origin(origin)?;

			// Insert the proposal into the blacklist.
			let permanent = (T::BlockNumber::max_value(), Vec::<T::AccountId>::new());
			Blacklist::<T>::insert(&proposal_hash, permanent);

			// Remove the queued proposal, if it's there.
			PublicProps::<T>::mutate(|props| {
				if let Some(index) = props.iter().position(|p| p.1 == proposal_hash) {
					let (prop_index, ..) = props.remove(index);
					if let Some((whos, amount)) = DepositOf::<T>::take(prop_index) {
						for who in whos.into_iter() {
							T::Slash::on_unbalanced(T::Currency::slash_reserved(&who, amount).0);
						}
					}
				}
			});

			// Remove the external queued referendum, if it's there.
			if matches!(NextExternal::<T>::get(), Some((h, ..)) if h == proposal_hash) {
				NextExternal::<T>::kill();
			}

			// Remove the referendum, if it's there.
			if let Some(ref_index) = maybe_ref_index {
				if let Ok(status) = Self::referendum_status(ref_index) {
					if status.proposal_hash == proposal_hash {
						Self::internal_cancel_referendum(ref_index);
					}
				}
			}

			Self::deposit_event(Event::<T>::Blacklisted(proposal_hash));
			Ok(())
		}

		/// Remove a proposal.
		///
		/// The dispatch origin of this call must be `CancelProposalOrigin`.
		///
		/// - `prop_index`: The index of the proposal to cancel.
		///
		/// Weight: `O(p)` where `p = PublicProps::<T>::decode_len()`
		#[pallet::weight(T::WeightInfo::cancel_proposal(T::MaxProposals::get()))]
		pub fn cancel_proposal(
			origin: OriginFor<T>,
			#[pallet::compact] prop_index: PropIndex,
		) -> DispatchResult {
			T::CancelProposalOrigin::ensure_origin(origin)?;

			PublicProps::<T>::mutate(|props| props.retain(|p| p.0 != prop_index));
			if let Some((whos, amount)) = DepositOf::<T>::take(prop_index) {
				for who in whos.into_iter() {
					T::Slash::on_unbalanced(T::Currency::slash_reserved(&who, amount).0);
				}
			}

			Ok(())
		}
	}
}

impl<T: Config> Pallet<T> {
	// exposed immutables.

	/// Get the amount locked in support of `proposal`; `None` if proposal isn't a valid proposal
	/// index.
	pub fn backing_for(proposal: PropIndex) -> Option<BalanceOf<T>> {
		Self::deposit_of(proposal).map(|(l, d)| d * (l.len() as u32).into())
	}

	/// Get all referenda ready for tally at block `n`.
	pub fn maturing_referenda_at(
		n: T::BlockNumber,
	) -> Vec<(ReferendumIndex, ReferendumStatus<T::BlockNumber, T::Hash, BalanceOf<T>>)> {
		let next = Self::lowest_unbaked();
		let last = Self::referendum_count();
		Self::maturing_referenda_at_inner(n, next..last)
	}

	fn maturing_referenda_at_inner(
		n: T::BlockNumber,
		range: core::ops::Range<PropIndex>,
	) -> Vec<(ReferendumIndex, ReferendumStatus<T::BlockNumber, T::Hash, BalanceOf<T>>)> {
		range
			.into_iter()
			.map(|i| (i, Self::referendum_info(i)))
			.filter_map(|(i, maybe_info)| match maybe_info {
				Some(ReferendumInfo::Ongoing(status)) => Some((i, status)),
				_ => None,
			})
			.filter(|(_, status)| status.end == n)
			.collect()
	}

	// Exposed mutables.

	/// Start a referendum.
	pub fn internal_start_referendum(
		proposal_hash: T::Hash,
		threshold: VoteThreshold,
		delay: T::BlockNumber,
	) -> ReferendumIndex {
		<Pallet<T>>::inject_referendum(
			<frame_system::Pallet<T>>::block_number() + T::VotingPeriod::get(),
			proposal_hash,
			threshold,
			delay,
		)
	}

	/// Remove a referendum.
	pub fn internal_cancel_referendum(ref_index: ReferendumIndex) {
		Self::deposit_event(Event::<T>::Cancelled(ref_index));
		ReferendumInfoOf::<T>::remove(ref_index);
	}

	// private.

	/// Ok if the given referendum is active, Err otherwise
	fn ensure_ongoing(
		r: ReferendumInfo<T::BlockNumber, T::Hash, BalanceOf<T>>,
	) -> Result<ReferendumStatus<T::BlockNumber, T::Hash, BalanceOf<T>>, DispatchError> {
		match r {
			ReferendumInfo::Ongoing(s) => Ok(s),
			_ => Err(Error::<T>::ReferendumInvalid.into()),
		}
	}

	fn referendum_status(
		ref_index: ReferendumIndex,
	) -> Result<ReferendumStatus<T::BlockNumber, T::Hash, BalanceOf<T>>, DispatchError> {
		let info = ReferendumInfoOf::<T>::get(ref_index).ok_or(Error::<T>::ReferendumInvalid)?;
		Self::ensure_ongoing(info)
	}

	/// Actually enact a vote, if legit.
	fn try_vote(
		who: &T::AccountId,
		ref_index: ReferendumIndex,
		vote: AccountVote<BalanceOf<T>>,
	) -> DispatchResult {
		let mut status = Self::referendum_status(ref_index)?;
		ensure!(vote.balance() <= T::Currency::free_balance(who), Error::<T>::InsufficientFunds);
		VotingOf::<T>::try_mutate(who, |voting| -> DispatchResult {
			if let Voting::Direct { ref mut votes, delegations, .. } = voting {
				match votes.binary_search_by_key(&ref_index, |i| i.0) {
					Ok(i) => {
						// Shouldn't be possible to fail, but we handle it gracefully.
						status.tally.remove(votes[i].1).ok_or(ArithmeticError::Underflow)?;
						if let Some(approve) = votes[i].1.as_standard() {
							status.tally.reduce(approve, *delegations);
						}
						votes[i].1 = vote;
					},
					Err(i) => {
						ensure!(
							votes.len() as u32 <= T::MaxVotes::get(),
							Error::<T>::MaxVotesReached
						);
						votes.insert(i, (ref_index, vote));
					},
				}
				// Shouldn't be possible to fail, but we handle it gracefully.
				status.tally.add(vote).ok_or(ArithmeticError::Overflow)?;
				if let Some(approve) = vote.as_standard() {
					status.tally.increase(approve, *delegations);
				}
				Ok(())
			} else {
				Err(Error::<T>::AlreadyDelegating.into())
			}
		})?;
		// Extend the lock to `balance` (rather than setting it) since we don't know what other
		// votes are in place.
		T::Currency::extend_lock(DEMOCRACY_ID, who, vote.balance(), WithdrawReasons::TRANSFER);
		ReferendumInfoOf::<T>::insert(ref_index, ReferendumInfo::Ongoing(status));
		Ok(())
	}

	/// Remove the account's vote for the given referendum if possible. This is possible when:
	/// - The referendum has not finished.
	/// - The referendum has finished and the voter lost their direction.
	/// - The referendum has finished and the voter's lock period is up.
	///
	/// This will generally be combined with a call to `unlock`.
	fn try_remove_vote(
		who: &T::AccountId,
		ref_index: ReferendumIndex,
		scope: UnvoteScope,
	) -> DispatchResult {
		let info = ReferendumInfoOf::<T>::get(ref_index);
		VotingOf::<T>::try_mutate(who, |voting| -> DispatchResult {
			if let Voting::Direct { ref mut votes, delegations, ref mut prior } = voting {
				let i = votes
					.binary_search_by_key(&ref_index, |i| i.0)
					.map_err(|_| Error::<T>::NotVoter)?;
				match info {
					Some(ReferendumInfo::Ongoing(mut status)) => {
						ensure!(matches!(scope, UnvoteScope::Any), Error::<T>::NoPermission);
						// Shouldn't be possible to fail, but we handle it gracefully.
						status.tally.remove(votes[i].1).ok_or(ArithmeticError::Underflow)?;
						if let Some(approve) = votes[i].1.as_standard() {
							status.tally.reduce(approve, *delegations);
						}
						ReferendumInfoOf::<T>::insert(ref_index, ReferendumInfo::Ongoing(status));
					},
					Some(ReferendumInfo::Finished { end, approved }) =>
						if let Some((lock_periods, balance)) = votes[i].1.locked_if(approved) {
							let unlock_at = end + T::EnactmentPeriod::get() * lock_periods.into();
							let now = frame_system::Pallet::<T>::block_number();
							if now < unlock_at {
								ensure!(
									matches!(scope, UnvoteScope::Any),
									Error::<T>::NoPermission
								);
								prior.accumulate(unlock_at, balance)
							}
						},
					None => {}, // Referendum was cancelled.
				}
				votes.remove(i);
			}
			Ok(())
		})?;
		Ok(())
	}

	/// Return the number of votes for `who`
	fn increase_upstream_delegation(who: &T::AccountId, amount: Delegations<BalanceOf<T>>) -> u32 {
		VotingOf::<T>::mutate(who, |voting| match voting {
			Voting::Delegating { delegations, .. } => {
				// We don't support second level delegating, so we don't need to do anything more.
				*delegations = delegations.saturating_add(amount);
				1
			},
			Voting::Direct { votes, delegations, .. } => {
				*delegations = delegations.saturating_add(amount);
				for &(ref_index, account_vote) in votes.iter() {
					if let AccountVote::Standard { vote, .. } = account_vote {
						ReferendumInfoOf::<T>::mutate(ref_index, |maybe_info| {
							if let Some(ReferendumInfo::Ongoing(ref mut status)) = maybe_info {
								status.tally.increase(vote.aye, amount);
							}
						});
					}
				}
				votes.len() as u32
			},
		})
	}

	/// Return the number of votes for `who`
	fn reduce_upstream_delegation(who: &T::AccountId, amount: Delegations<BalanceOf<T>>) -> u32 {
		VotingOf::<T>::mutate(who, |voting| match voting {
			Voting::Delegating { delegations, .. } => {
				// We don't support second level delegating, so we don't need to do anything more.
				*delegations = delegations.saturating_sub(amount);
				1
			},
			Voting::Direct { votes, delegations, .. } => {
				*delegations = delegations.saturating_sub(amount);
				for &(ref_index, account_vote) in votes.iter() {
					if let AccountVote::Standard { vote, .. } = account_vote {
						ReferendumInfoOf::<T>::mutate(ref_index, |maybe_info| {
							if let Some(ReferendumInfo::Ongoing(ref mut status)) = maybe_info {
								status.tally.reduce(vote.aye, amount);
							}
						});
					}
				}
				votes.len() as u32
			},
		})
	}

	/// Attempt to delegate `balance` times `conviction` of voting power from `who` to `target`.
	///
	/// Return the upstream number of votes.
	fn try_delegate(
		who: T::AccountId,
		target: T::AccountId,
		conviction: Conviction,
		balance: BalanceOf<T>,
	) -> Result<u32, DispatchError> {
		ensure!(who != target, Error::<T>::Nonsense);
		ensure!(balance <= T::Currency::free_balance(&who), Error::<T>::InsufficientFunds);
		let votes = VotingOf::<T>::try_mutate(&who, |voting| -> Result<u32, DispatchError> {
			let mut old = Voting::Delegating {
				balance,
				target: target.clone(),
				conviction,
				delegations: Default::default(),
				prior: Default::default(),
			};
			sp_std::mem::swap(&mut old, voting);
			match old {
				Voting::Delegating { balance, target, conviction, delegations, prior, .. } => {
					// remove any delegation votes to our current target.
					Self::reduce_upstream_delegation(&target, conviction.votes(balance));
					voting.set_common(delegations, prior);
				},
				Voting::Direct { votes, delegations, prior } => {
					// here we just ensure that we're currently idling with no votes recorded.
					ensure!(votes.is_empty(), Error::<T>::VotesExist);
					voting.set_common(delegations, prior);
				},
			}
			let votes = Self::increase_upstream_delegation(&target, conviction.votes(balance));
			// Extend the lock to `balance` (rather than setting it) since we don't know what other
			// votes are in place.
			T::Currency::extend_lock(DEMOCRACY_ID, &who, balance, WithdrawReasons::TRANSFER);
			Ok(votes)
		})?;
		Self::deposit_event(Event::<T>::Delegated(who, target));
		Ok(votes)
	}

	/// Attempt to end the current delegation.
	///
	/// Return the number of votes of upstream.
	fn try_undelegate(who: T::AccountId) -> Result<u32, DispatchError> {
		let votes = VotingOf::<T>::try_mutate(&who, |voting| -> Result<u32, DispatchError> {
			let mut old = Voting::default();
			sp_std::mem::swap(&mut old, voting);
			match old {
				Voting::Delegating { balance, target, conviction, delegations, mut prior } => {
					// remove any delegation votes to our current target.
					let votes =
						Self::reduce_upstream_delegation(&target, conviction.votes(balance));
					let now = frame_system::Pallet::<T>::block_number();
					let lock_periods = conviction.lock_periods().into();
					prior.accumulate(now + T::EnactmentPeriod::get() * lock_periods, balance);
					voting.set_common(delegations, prior);

					Ok(votes)
				},
				Voting::Direct { .. } => Err(Error::<T>::NotDelegating.into()),
			}
		})?;
		Self::deposit_event(Event::<T>::Undelegated(who));
		Ok(votes)
	}

	/// Rejig the lock on an account. It will never get more stringent (since that would indicate
	/// a security hole) but may be reduced from what they are currently.
	fn update_lock(who: &T::AccountId) {
		let lock_needed = VotingOf::<T>::mutate(who, |voting| {
			voting.rejig(frame_system::Pallet::<T>::block_number());
			voting.locked_balance()
		});
		if lock_needed.is_zero() {
			T::Currency::remove_lock(DEMOCRACY_ID, who);
		} else {
			T::Currency::set_lock(DEMOCRACY_ID, who, lock_needed, WithdrawReasons::TRANSFER);
		}
	}

	/// Start a referendum
	fn inject_referendum(
		end: T::BlockNumber,
		proposal_hash: T::Hash,
		threshold: VoteThreshold,
		delay: T::BlockNumber,
	) -> ReferendumIndex {
		let ref_index = Self::referendum_count();
		ReferendumCount::<T>::put(ref_index + 1);
		let status =
			ReferendumStatus { end, proposal_hash, threshold, delay, tally: Default::default() };
		let item = ReferendumInfo::Ongoing(status);
		<ReferendumInfoOf<T>>::insert(ref_index, item);
		Self::deposit_event(Event::<T>::Started(ref_index, threshold));
		ref_index
	}

	/// Table the next waiting proposal for a vote.
	fn launch_next(now: T::BlockNumber) -> DispatchResult {
		if LastTabledWasExternal::<T>::take() {
			Self::launch_public(now).or_else(|_| Self::launch_external(now))
		} else {
			Self::launch_external(now).or_else(|_| Self::launch_public(now))
		}
		.map_err(|_| Error::<T>::NoneWaiting.into())
	}

	/// Table the waiting external proposal for a vote, if there is one.
	fn launch_external(now: T::BlockNumber) -> DispatchResult {
		if let Some((proposal, threshold)) = <NextExternal<T>>::take() {
			LastTabledWasExternal::<T>::put(true);
			Self::deposit_event(Event::<T>::ExternalTabled);
			Self::inject_referendum(
				now + T::VotingPeriod::get(),
				proposal,
				threshold,
				T::EnactmentPeriod::get(),
			);
			Ok(())
		} else {
			Err(Error::<T>::NoneWaiting)?
		}
	}

	/// Table the waiting public proposal with the highest backing for a vote.
	fn launch_public(now: T::BlockNumber) -> DispatchResult {
		let mut public_props = Self::public_props();
		if let Some((winner_index, _)) = public_props.iter().enumerate().max_by_key(
			// defensive only: All current public proposals have an amount locked
			|x| Self::backing_for((x.1).0).unwrap_or_else(Zero::zero),
		) {
			let (prop_index, proposal, _) = public_props.swap_remove(winner_index);
			<PublicProps<T>>::put(public_props);

			if let Some((depositors, deposit)) = <DepositOf<T>>::take(prop_index) {
				// refund depositors
				for d in &depositors {
					T::Currency::unreserve(d, deposit);
				}
				Self::deposit_event(Event::<T>::Tabled(prop_index, deposit, depositors));
				Self::inject_referendum(
					now + T::VotingPeriod::get(),
					proposal,
					VoteThreshold::SuperMajorityApprove,
					T::EnactmentPeriod::get(),
				);
			}
			Ok(())
		} else {
			Err(Error::<T>::NoneWaiting)?
		}
	}

	fn do_enact_proposal(proposal_hash: T::Hash, index: ReferendumIndex) -> DispatchResult {
		let preimage = <Preimages<T>>::take(&proposal_hash);
		if let Some(PreimageStatus::Available { data, provider, deposit, .. }) = preimage {
			if let Ok(proposal) = T::Proposal::decode(&mut &data[..]) {
				let err_amount = T::Currency::unreserve(&provider, deposit);
				debug_assert!(err_amount.is_zero());
				Self::deposit_event(Event::<T>::PreimageUsed(proposal_hash, provider, deposit));

				let res = proposal
					.dispatch(frame_system::RawOrigin::Root.into())
					.map(|_| ())
					.map_err(|e| e.error);
				Self::deposit_event(Event::<T>::Executed(index, res));

				Ok(())
			} else {
				T::Slash::on_unbalanced(T::Currency::slash_reserved(&provider, deposit).0);
				Self::deposit_event(Event::<T>::PreimageInvalid(proposal_hash, index));
				Err(Error::<T>::PreimageInvalid.into())
			}
		} else {
			Self::deposit_event(Event::<T>::PreimageMissing(proposal_hash, index));
			Err(Error::<T>::PreimageMissing.into())
		}
	}

	fn bake_referendum(
		now: T::BlockNumber,
		index: ReferendumIndex,
		status: ReferendumStatus<T::BlockNumber, T::Hash, BalanceOf<T>>,
	) -> Result<bool, DispatchError> {
		let total_issuance = T::Currency::total_issuance();
		let approved = status.threshold.approved(status.tally, total_issuance);

		if approved {
			Self::deposit_event(Event::<T>::Passed(index));
			if status.delay.is_zero() {
				let _ = Self::do_enact_proposal(status.proposal_hash, index);
			} else {
				let when = now + status.delay;
				// Note that we need the preimage now.
				Preimages::<T>::mutate_exists(
					&status.proposal_hash,
					|maybe_pre| match *maybe_pre {
						Some(PreimageStatus::Available { ref mut expiry, .. }) =>
							*expiry = Some(when),
						ref mut a => *a = Some(PreimageStatus::Missing(when)),
					},
				);

				if T::Scheduler::schedule_named(
					(DEMOCRACY_ID, index).encode(),
					DispatchTime::At(when),
					None,
					63,
					frame_system::RawOrigin::Root.into(),
					Call::enact_proposal(status.proposal_hash, index).into(),
				)
				.is_err()
				{
					frame_support::print("LOGIC ERROR: bake_referendum/schedule_named failed");
				}
			}
		} else {
			Self::deposit_event(Event::<T>::NotPassed(index));
		}

		Ok(approved)
	}

	/// Current era is ending; we should finish up any proposals.
	///
	///
	/// # <weight>
	/// If a referendum is launched or maturing, this will take full block weight. Otherwise:
	/// - Complexity: `O(R)` where `R` is the number of unbaked referenda.
	/// - Db reads: `LastTabledWasExternal`, `NextExternal`, `PublicProps`, `account`,
	///   `ReferendumCount`, `LowestUnbaked`
	/// - Db writes: `PublicProps`, `account`, `ReferendumCount`, `DepositOf`, `ReferendumInfoOf`
	/// - Db reads per R: `DepositOf`, `ReferendumInfoOf`
	/// # </weight>
	fn begin_block(now: T::BlockNumber) -> Result<Weight, DispatchError> {
		let max_block_weight = T::BlockWeights::get().max_block;
		let mut weight = 0;

		// pick out another public referendum if it's time.
		if (now % T::LaunchPeriod::get()).is_zero() {
			// Errors come from the queue being empty. we don't really care about that, and even if
			// we did, there is nothing we can do here.
			let _ = Self::launch_next(now);
			weight = max_block_weight;
		}

		let next = Self::lowest_unbaked();
		let last = Self::referendum_count();
		let r = last.saturating_sub(next);
		weight = weight.saturating_add(T::WeightInfo::on_initialize_base(r));
		// tally up votes for any expiring referenda.
		for (index, info) in Self::maturing_referenda_at_inner(now, next..last).into_iter() {
			let approved = Self::bake_referendum(now, index, info)?;
			ReferendumInfoOf::<T>::insert(index, ReferendumInfo::Finished { end: now, approved });
			weight = max_block_weight;
		}

		Ok(weight)
	}

	/// Reads the length of account in DepositOf without getting the complete value in the runtime.
	///
	/// Return 0 if no deposit for this proposal.
	fn len_of_deposit_of(proposal: PropIndex) -> Option<u32> {
		// DepositOf first tuple element is a vec, decoding its len is equivalent to decode a
		// `Compact<u32>`.
		decode_compact_u32_at(&<DepositOf<T>>::hashed_key_for(proposal))
	}

	/// Check that pre image exists and its value is variant `PreimageStatus::Missing`.
	///
	/// This check is done without getting the complete value in the runtime to avoid copying a big
	/// value in the runtime.
	fn check_pre_image_is_missing(proposal_hash: T::Hash) -> DispatchResult {
		// To decode the enum variant we only need the first byte.
		let mut buf = [0u8; 1];
		let key = <Preimages<T>>::hashed_key_for(proposal_hash);
		let bytes =
			sp_io::storage::read(&key, &mut buf, 0).ok_or_else(|| Error::<T>::NotImminent)?;
		// The value may be smaller that 1 byte.
		let mut input = &buf[0..buf.len().min(bytes as usize)];

		match input.read_byte() {
			Ok(0) => Ok(()), // PreimageStatus::Missing is variant 0
			Ok(1) => Err(Error::<T>::DuplicatePreimage.into()),
			_ => {
				sp_runtime::print("Failed to decode `PreimageStatus` variant");
				Err(Error::<T>::NotImminent.into())
			},
		}
	}

	/// Check that pre image exists, its value is variant `PreimageStatus::Available` and decode
	/// the length of `data: Vec<u8>` fields.
	///
	/// This check is done without getting the complete value in the runtime to avoid copying a big
	/// value in the runtime.
	///
	/// If the pre image is missing variant or doesn't exist then the error `PreimageMissing` is
	/// returned.
	fn pre_image_data_len(proposal_hash: T::Hash) -> Result<u32, DispatchError> {
		// To decode the `data` field of Available variant we need:
		// * one byte for the variant
		// * at most 5 bytes to decode a `Compact<u32>`
		let mut buf = [0u8; 6];
		let key = <Preimages<T>>::hashed_key_for(proposal_hash);
		let bytes =
			sp_io::storage::read(&key, &mut buf, 0).ok_or_else(|| Error::<T>::PreimageMissing)?;
		// The value may be smaller that 6 bytes.
		let mut input = &buf[0..buf.len().min(bytes as usize)];

		match input.read_byte() {
			Ok(1) => (), // Check that input exists and is second variant.
			Ok(0) => return Err(Error::<T>::PreimageMissing.into()),
			_ => {
				sp_runtime::print("Failed to decode `PreimageStatus` variant");
				return Err(Error::<T>::PreimageMissing.into())
			},
		}

		// Decode the length of the vector.
		let len = codec::Compact::<u32>::decode(&mut input)
			.map_err(|_| {
				sp_runtime::print("Failed to decode `PreimageStatus` variant");
				DispatchError::from(Error::<T>::PreimageMissing)
			})?
			.0;

		Ok(len)
	}

	// See `note_preimage`
	fn note_preimage_inner(who: T::AccountId, encoded_proposal: Vec<u8>) -> DispatchResult {
		let proposal_hash = T::Hashing::hash(&encoded_proposal[..]);
		ensure!(!<Preimages<T>>::contains_key(&proposal_hash), Error::<T>::DuplicatePreimage);

		let deposit = <BalanceOf<T>>::from(encoded_proposal.len() as u32)
			.saturating_mul(T::PreimageByteDeposit::get());
		T::Currency::reserve(&who, deposit)?;

		let now = <frame_system::Pallet<T>>::block_number();
		let a = PreimageStatus::Available {
			data: encoded_proposal,
			provider: who.clone(),
			deposit,
			since: now,
			expiry: None,
		};
		<Preimages<T>>::insert(proposal_hash, a);

		Self::deposit_event(Event::<T>::PreimageNoted(proposal_hash, who, deposit));

		Ok(())
	}

	// See `note_imminent_preimage`
	fn note_imminent_preimage_inner(
		who: T::AccountId,
		encoded_proposal: Vec<u8>,
	) -> DispatchResult {
		let proposal_hash = T::Hashing::hash(&encoded_proposal[..]);
		Self::check_pre_image_is_missing(proposal_hash)?;
		let status = Preimages::<T>::get(&proposal_hash).ok_or(Error::<T>::NotImminent)?;
		let expiry = status.to_missing_expiry().ok_or(Error::<T>::DuplicatePreimage)?;

		let now = <frame_system::Pallet<T>>::block_number();
		let free = <BalanceOf<T>>::zero();
		let a = PreimageStatus::Available {
			data: encoded_proposal,
			provider: who.clone(),
			deposit: Zero::zero(),
			since: now,
			expiry: Some(expiry),
		};
		<Preimages<T>>::insert(proposal_hash, a);

		Self::deposit_event(Event::<T>::PreimageNoted(proposal_hash, who, free));

		Ok(())
	}
}

/// Decode `Compact<u32>` from the trie at given key.
fn decode_compact_u32_at(key: &[u8]) -> Option<u32> {
	// `Compact<u32>` takes at most 5 bytes.
	let mut buf = [0u8; 5];
	let bytes = sp_io::storage::read(&key, &mut buf, 0)?;
	// The value may be smaller than 5 bytes.
	let mut input = &buf[0..buf.len().min(bytes as usize)];
	match codec::Compact::<u32>::decode(&mut input) {
		Ok(c) => Some(c.0),
		Err(_) => {
			sp_runtime::print("Failed to decode compact u32 at:");
			sp_runtime::print(key);
			None
		},
	}
}