Derive for democracy locks (#2264)

* Derive for democracy locks

* Cater for old referendums

* Split lock parsing

CHANGELOG.md

@@ -1,6 +1,7 @@
 # 1.14.0-beta.x
 
-- Align imOnline `Heartbeats` with Substrate (Thanks to https://github.com/arjanz)
+- Align imOnline `Heartbeat` with Substrate (Thanks to https://github.com/arjanz)
+- Add `derive.democracy.locks` to return extended lock info based on votes
 - Ensure metadata is only requested once upon startup (bypass on upgrade subscriptions)
 - Expand testing around `ExtrinsicEra` construction
 

packages/api-derive/src/democracy/index.ts

@@ -3,6 +3,7 @@
 // of the Apache-2.0 license. See the LICENSE file for details.
 
 export * from './dispatchQueue';
+export * from './locks';
 export * from './nextExternal';
 export * from './preimage';
 export * from './preimages';

packages/api-derive/src/democracy/locks.ts

@@ -0,0 +1,66 @@
+// Copyright 2017-2020 @polkadot/api-derive authors & contributors
+// This software may be modified and distributed under the terms
+// of the Apache-2.0 license. See the LICENSE file for details.
+
+import { AccountId, ReferendumInfo, ReferendumInfoTo239, VotingDirect, VotingDirectVote } from '@polkadot/types/interfaces';
+import { ApiInterfaceRx } from '@polkadot/api/types';
+import { DeriveDemocracyLock } from '../types';
+
+import BN from 'bn.js';
+import { Observable, of } from 'rxjs';
+import { map, switchMap } from 'rxjs/operators';
+import { Option } from '@polkadot/types';
+import { isUndefined } from '@polkadot/util';
+
+import { memo } from '../util';
+
+const LOCKUPS = [0, 1, 2, 4, 8, 16, 32];
+const ZERO = new BN(0);
+
+function parseLock (api: ApiInterfaceRx, [referendumId, accountVote]: VotingDirectVote, referendum: ReferendumInfo): DeriveDemocracyLock {
+  const { balance, vote } = accountVote.asStandard;
+  let unlockAt = ZERO;
+
+  if (referendum.isFinished) {
+    const { approved, end } = referendum.asFinished;
+
+    if ((approved.isTrue && vote.isAye) || (approved.isFalse && vote.isNay)) {
+      unlockAt = end.add(api.consts.democracy.enactmentPeriod.muln(LOCKUPS[vote.conviction.index]));
+    }
+  }
+
+  return { balance, isFinished: referendum.isFinished, referendumId, unlockAt, vote };
+}
+
+function directLocks (api: ApiInterfaceRx, { votes }: VotingDirect): Observable<DeriveDemocracyLock[]> {
+  if (!votes.length) {
+    return of([]);
+  }
+
+  return api.query.democracy.referendumInfoOf.multi<Option<ReferendumInfo | ReferendumInfoTo239>>(votes.map(([referendumId]) => referendumId)).pipe(
+    map((referendums) =>
+      votes
+        .map((vote, index): [VotingDirectVote, ReferendumInfo | ReferendumInfoTo239 | null] =>
+          [vote, referendums[index].unwrapOr(null)]
+        )
+        .filter((item): item is [VotingDirectVote, ReferendumInfo] =>
+          !!item[1] && isUndefined((item[1] as ReferendumInfoTo239).end) && item[0][1].isStandard
+        )
+        .map(([directVote, referendum]) =>
+          parseLock(api, directVote, referendum)
+        )
+    )
+  );
+}
+
+export function locks (api: ApiInterfaceRx): (accountId: string | AccountId) => Observable<DeriveDemocracyLock[]> {
+  return memo((accountId: string | AccountId): Observable<DeriveDemocracyLock[]> =>
+    api.query.democracy.votingOf(accountId).pipe(
+      switchMap((voting): Observable<DeriveDemocracyLock[]> =>
+        voting.isDirect
+          ? directLocks(api, voting.asDirect)
+          : of([])
+      )
+    )
+  );
+}

packages/api-derive/src/democracy/types.ts

@@ -7,6 +7,14 @@ import { AccountId, Balance, BlockNumber, Hash, Proposal, PropIndex, ReferendumI
 
 import { Vec } from '@polkadot/types';
 
+export interface DeriveDemocracyLock {
+  balance: Balance;
+  isFinished: boolean;
+  referendumId: ReferendumIndex;
+  unlockAt: BN;
+  vote: Vote;
+}
+
 export interface DeriveDispatch {
   at: BlockNumber;
   index: ReferendumIndex;