track AJNA token balances

schema.graphql

@@ -223,6 +223,8 @@ type Account @entity {
   proposalsCreated: [Proposal!]!
   # ecosystem coordination proposals passed and funded 
   proposalsExecuted: [Proposal!]!
+  # balance of AJNA tokens this account holds
+  tokens: BigDecimal!
   # account to which this account is delegating votes
   delegatedTo: Account
   # accounts from which votes are delegated

src/mappings/ajna-token.ts

@@ -2,6 +2,7 @@ import { Bytes } from "@graphprotocol/graph-ts"
 import {
   DelegateChanged as DelegateChangedEvent,
   DelegateVotesChanged as DelegateVotesChangedEvent,
+  AjnaTokenTransfer as AjnaTokenTransferEvent,
 } from "../../generated/AjnaToken/AjnaToken"
 import {
   Account,
@@ -11,6 +12,7 @@ import {
 import { loadOrCreateAccount } from "../utils/account"
 import { addressToBytes, wadToDecimal } from "../utils/convert"
 import { addDelegator, removeDelegator } from "../utils/grants/voter"
+import { getTokenBalance } from "../utils/token-erc20"
 
 export function handleDelegateChanged(event: DelegateChangedEvent): void {
   let entity = new DelegateChanged(
@@ -69,3 +71,17 @@ export function handleDelegateVotesChanged(
   delegate.save()
   entity.save()
 }
+
+export function handleAjnaTokenTransfer(
+  event: AjnaTokenTransferEvent
+): void {
+  const ajnaToken = event.transaction.from
+
+  const fromAccount  = loadOrCreateAccount(addressToBytes(event.params.from))
+  fromAccount.tokens = wadToDecimal(getTokenBalance(ajnaToken, event.params.from))
+  fromAccount.save()
+
+  const toAccount  = loadOrCreateAccount(addressToBytes(event.params.to))
+  toAccount.tokens = wadToDecimal(getTokenBalance(ajnaToken, event.params.to))
+  toAccount.save()
+}

src/utils/account.ts

@@ -24,6 +24,7 @@ export function loadOrCreateAccount(accountId: Bytes): Account {
       account.delegatedFrom           = []
       account.rewardsClaimed          = ZERO_BD
       account.distributionPeriodVotes = []
+      account.tokens                  = ZERO_BD
       account.tokensDelegated         = ZERO_BD
 
       account.txCount = ZERO_BI

subgraph.yaml

@@ -161,6 +161,8 @@ dataSources:
           handler: handleDelegateChanged
         - event: DelegateVotesChanged(indexed address,uint256,uint256)
           handler: handleDelegateVotesChanged
+        - event: AjnaTokenTransfer(indexed address,indexed address,uint256)
+          handler: handleAjnaTokenTransfer
       file: ./src/mappings/ajna-token.ts
   - kind: ethereum
     name: BurnWrappedAjna